Wow, thank you very much. We try to show some of the best tricks in the mold making process so our customers have the highest chance of success making great parts.
I am brand new to resin-ing. I'm miles away from pouring my own molds, but I have so many awesome ideas that require I learn how! When this video popped up I knew I had to watch it. (Actually I had to watch it a few times bc I didn't understand some of the silicone/molding jargon the first times, that's how new I am to all this lol) But wow!! Did I ever learn a lot! With the simple, easy-to-follow instructions and your skilled guidance and explanations, this looks totally doable for me when the time comes. Thank you so much for sharing this with the public. Very appreciated.
Hi Dustin, thanks for the compliment. This video is representative of our company's knowledge and experience in this industry. If you have a project or application that requires mold making and casting, consider us as you source! info@bjbenterprises.com
Brilliant, Brilliant, Brilliant! Thank you so much, I am a South African so there is very little chance that I will be able to do business with BJB and yet they make this content available to all of us for free. High quality, in depth detail regarding the holistic process. You guys are as generous as you are skillful!!
+Grim Falcon Wow, thanks for the compliments! Although we've pretty much shipped all over the world, getting product to South Africa is indeed expensive from the US.
I'm with the crowd on this one! I've watched dozens and dozens of instructional videos while I've been learning the silicone mold making process, and this one is like an epiphany. Thank you for the clarity and for sharing your skills.
I found this tutorial exeptional in explanation and found the detailed reasons why a certain procedure is executed very helpful. The teacher was very clear and professional in speaking and was easy to understand. The lack of any background music was also very much appreciated as it was not present to drown out the presenter and also because I suffer from misophonia, a hearing condition. Thank you very much for your very well presented presentation about your products and the processes in which to use them effectively.
I rarely comment on any RUclips videos but I have to now because I think you guys deserve it. One of the best tutorials ever and exactly what I need!! I'm jumping onto your website now. Please keep up the good work!
Yes, there are several methods you can use to hold down the pattern. White Elmer's glue is another method some people use, as well as hot glue, oil based clay, and a variety of others. Be sure the silicone is compatible with that material and make sure it doesn't damage the pattern when removing.
@@bjbenterprises Thank you SO MUCH for the information. You have been super helpful and I really appreciate it. Keep up the amazing work & God Bless! 🙏🏻
@@bjbenterprises I worked it out.. jealousy :) keep up the good work. i've only recently started to master 3d printing but you can't beat PU systems by the looks of it, for repeatability and speed.. i just know your vids are going to help me no end in my new job role. A million thanks for disambiguating it an making it look easy.. 10/10 from me :)
EASILY the best video I've seen on the topic, by far. ..Very professional and informative but still kept it as simple as possible.. Keep up the great work.
Excellent video that gives me the confidence to reproduce some (unavailable) plastic parts missing from my Jaguar XK8 project car that were missing when I purchased it - Many Thanks
Hi, I agree that you have the very best videos on RUclips for making silicone molds, and casting the parts. I am making 1/25 scale model car parts like valve covers, various engine parts, wheels and tires, and probably other things including possibly a whole body and a whole frame. What I am trying to do is to cast several parts in one mold, to save both time and mold making. Injection molded styrene plastic parts are connected with sprues that run from part to part. Is such an operation possible by using resin flowing, only by gravity, to make more than one part in a mold at a time?
Good question. Multiple cavity molds are possible if the parts are fairly simple, and you have appropriate vents set up for the parts to allow for trapped air to escape. However, it's not done as often with urethane casting compared to injection molding. If the parts are small, then there is not a lot of silicone material saved by combining multiple parts in one mold vs separate. If one of the mold cavities has an issue or wears out, then you end up with wasted casting material and bad parts from one cavity whenever you cast. It's a process worth exploring if you have a need to reproduce several simple parts at once. Keep in mind that thin sprues will not feed the other cavities very well so it's best to feed each mold cavity from a larger, central reservoir and go from there.
You can make almost anything like traffic light parts, car wheel covers and even spare parts for old toys. This tutorial just made me think of establishing something called 'The Robot Hospital'.
that was a nice instructional video. I would like to try out making molds. One area i wish you had done more with on this video is the step of selecting the material used to cast and preparing it for pouring and perhaps showed a variety of those products that could have been used for this silicone mold.
Thanks for the comment. Choosing a material is an entire conversation on its own due to the variety of materials available and also the physical properties needed by the part and application. One of the first things we look at is choosing what Durometer we need for a material, and go from there. This is one of the most important things to learn when you are first getting into mold making and casting. We do have a video on that topic. ruclips.net/video/Q6jn223_1Mw/видео.html
A very good video. Comprehensive coverage on everything. Very well presented and with ALL the details that are so lacking in so many others. Great. Thankyou
Thank you for that. We're happy this info is getting to those who appreciate it. Also keep in mind that we have all of those handy items that are used in the videos like vents, fill ports, funnels, registration keys... plus the mold making and casting materials. www.bjbenterprises.com
I’m in the process of making my list of products right now. If I contact you all via email, are you guys pretty responsive? I’m not sure exactly which silicone to pick for my particular application.
@@petebutler5139 yes we typically respond within 15-30 minutes, or you can use our chat feature. Send any material questions to: info@bjbenterprises.com
Fantastic video, very calming to watch and listen to. Just discovered the possibility of a silicone mold. I am very eager to try this myself one day. Thanks!
I noticed that, at 17:14 in the video, you use what looks like some sort of PVC pipe injection device. What is that, exactly? Is there another video in which we can learn how to make one of those for larger molded parts? Thank you!
Hi Matt, what you are seeing there is a static mix tube from our meter-mix dispense equipment. So it's not as simple as a PVC pipe injection rig. Having said that, there are some people who use tall PVC pipes to act as their pour funnel and occasionally they will rig-up a piston inside of it to manually force material into the mold. Here is a sample video of the equipment I mentioned: ruclips.net/video/62G4NlXKurI/видео.html
Thank you! What would you recommend for a casting made in a silicone mold that's about 5" x 2" x 1" (about 10 cubic inches). I'd be interested to know what sort of resin or material you'd use to actually MAKE the casting, and the method by which you'd do it. Thank you!
We have so many options, it depends on what you want the finished part to feel like (ABS? PC? Polypropylene? Rubber?). Our part 2 video addresses casting parts, but if you need more help choosing it's best to chat with our Tech Staff to narrow down material selection: info@bjbenterprises.com ruclips.net/video/tnY86LIHf_I/видео.html
Excellent presentation. You could tell me how you could make a flexible syringe in silicone, to recover its deformation, to send air by squeezing it with your hand towards a hose of an instrument. The original is built in rubber.
This is a little too complicated to answer in a RUclips comment. Please contact our technical department and they can help you find the right method and materials to help create a mold and flexible part. info@bjbenterprises.com
There are occasions where a vent needs to be added after the mold is made. You may find there is a problem area in the mold that needs a vent, the acrylic vent post came loose while pouring silicone and had to be removed before cure, or you simply forgot a vent somewhere. A couple of options: you could simply drill a small hole through the silicone (however it leaves a rough hole that will break down quicker over time), or you can bore out a vent using a small brass tube that has been sharpened at the end (this produces the cleanest result).
AH! Plenty of thanks! I am learning to make molds and casting, but was not aware of the feed and vent tubes, and how to position them. I seen some examples when peple pour resin into the first half, and then place the top mold part on top- but that will surely guarantee the pry line, and maybe some stubborn bubbles.
Thanks for a fantastic tutorial. I need to replicate a small plastic part and this video has shown me everything I need to know. Could I just ask: Wouldn't it be useful to leave the box around the mold while casting to prevent any distortion of the mold? Or does the thickness of your mold prevent this?
On a small mold like this with a thick perimeter of silicone around the mold, we can get away with strapping it to a flat board as shown in the Part 2 casting video. In some cases we will make a custom sized top and bottom board to hold things together and without distortion. In many production shops, wood or plastic mold boxes are used with the silicone molds to ensure mold geometry is accurate. The one issue that we see with full mold boxes is that over time the silicone may experience some shrinkage and the mold box sides prevent a good, solid seal between the silicone halves, and cast material leaks out around the parting flange. If you use the top and bottom boards, taped tight and secure, then you don't have to worry about this issue.
The simple answer is no (with household tools or equipment). There are several ways people deal with bubbles. Vacuum pumps and chambers is the most common but many home DIY casters use small pressure pots as well and find that convenient and effective.
How would you go about making a mould for a spherical object with no flat edges like a marble? Thank you in advance as your time and help is much appreciated.
There are a couple ways. You could rotationally cast it and make it hollow with a given wall thickness which would produce the cleanest part out of the mold (only a mold split line). Or, if you want a solid cast part, you would need to make a mold with a small fill port and deal with the reality there will be a small mark that would require some post demold clean up. Setting up the pattern to make a mold is pretty straight forward using a bed of clay to sink the part halfway into, creating a clean parting line. Or, you can use a solid board and bore a shallow hole into the surface using the appropriate diameter drill bit and fine tune/clean up the edges with a small amount of modeling clay to make a water-tight seal around the parting line. The alignment keys and fill ports/vents can be added as seen in this and many of our other moldmaking tutorials. Roto-casting: ruclips.net/video/kdN6Quj14P4/видео.html and setting up a round object for molding: ruclips.net/video/DIFWTiVWHts/видео.html
@@bjbenterprises OK thank you, I appreciate the time you have taken to reply in such detail and the fact that you have provided links to more information.
Yes, you can cast Silicone into Silicone with an appropriate mold release if the geometry allows easy application. Note that a Platinum based silicone would not cure well in a Tin based silicone mold (cure inhibition).
This is the best mould making video on RUclips! So clear and informative, straightforward with 100% of the video on topic! Thank you so much, I was almost going to give up making my own moulds but now I shall definitely be doing them. I shall see if your products are available in my country and if they are I shall definitely be buying from you!
I recently found an old vintage part in plastic that would require at least a 3 piece mold. I have scoured the web and have seen some references to them along with some pictures but thats about it. It would be nice to see a video on that to better help get my head wrapped around it. Splitting something in half is pretty straight forward. splitting it into 3 or more parts well that would be a something :D
Thanks for the idea. Yes it can be a little trickier to set up parting line for a 3-piece mold. You need to imagine what direction the mold pieces need to be removed away from the part based on geometry and details. In other words, the mold pieces need to pull off without getting trapped by the part geometry. It's still much easier with silicone molds vs traditional rigid tooling, but we understand the details of "how" to approach it are a challenge. If you need help, feel free to reach our to our tech team and they may be able to assist your mold design. A short description and a few pics work best: info@bjbenterprises.com
I want to make a mold for casting an arm to be make into a jewelry charm. I wanted to perhaps use resin to make the piece or something that would be a finish like glass or stone. Any suggestions? .
Send your project requirements to our technical staff with any pictures and a full description of the parts you want to make. The more detail the better: info@bjbenterprises.com
Hi, you can find a huge variety of elastomer polyurethanes on our website here. bjbenterprises.com/index.php/polyurethanes/castable/flexible/ If you aren't sure about what product would work for you, please don't hesitate to contact us: info@bjbenterprises.com
BJBEnterprises I was looking at your water clear polyurethane casting and read the MSDS sheet. I have a a few questions: 1. These are tint-able so I was thinking about using them for custom tail lights and signals in a car, do the colors fade and is there a way to prevent it? 2. How UV resistant are these and will they "craze" or crack over time?
Hello Eric. The Water Clear Polyurethanes we offer are the preferred material for reproduction tail lights and signals. Certain formulas like the WC-783 and WC-792 feature additional UV absorbers in them to provide years of outdoor use and color stability. They have been extensively in after-market automotive parts and popular theme park attractions because of this UV stability. If you would like more assistance on these products and recommended mold materials, feel free to contact us at our Tech Dept: info@bjbenterprises.com or call 714-734-8450 Regards!
We have a couple systems that are low in viscosity and pour well without vacuum. For a Platinum silicone, the TC-5041 bjbenterprises.com/index.php/tc-5041-a-b/and for a Tin silicone TC-5024 bjbenterprises.com/index.php/tc-5024-a-b/ You can also add a small amount of the silicone thinner SC-5001 bjbenterprises.com/index.php/sc-5002-silicone-thinner/ to help cut some of the surface tension and lower viscosity.
Vibration is a common method in certain industries (like concrete and ceramics) but it is a very inefficient method for casting materials like silicone, polyurethane, and epoxy. Vibration works well on concrete, liquid metals, and ceramics because of the high level of filler content and difference in density of the liquid carrier vs fillers. The viscosity and surface tension of the liquid carrier also plays a huge roll in the process (water, for example, has extremely low surface tension). For our material process, vacuum is more useful and much more efficient than vibration. Vacuum also has the added benefit of stripping moisture from the casting system. That is especially useful in polyurethanes and epoxies where moisture can negatively affect the cure profile.
Chris Bulen Yes, there are several sources out there that sell plastic vacuum chambers. If you Google "Plastic Vacuum Chamber" you'll see the variety of vessels sold for this purpose. -BJB
We don't have a video specifically on just that topic, but we discuss in detail here in this video: ruclips.net/video/iRj6xzNx7P4/видео.htmlm20s as well as our other mold tutorial: ruclips.net/video/b_KMWhJyYLE/видео.htmlm24s
Great question. Yes, you can also use dowel pins for alignment if that is what you prefer. For pins, you don't want to use the silicone as a pin. Always use a rigid piece of material like metal or plastic.
Hi, I am interested in making silicone cooking tools. I am a complete newbie, and I wonder if there is food-grade silicone that can be poured into a mold. You seem like you might know how to go about this. Could you please provide me with any information you can?
The short answer is yes, there are food-grade silicones to do this process. BJB does not sell a food-grade silicone for this process. The casting and mold process is similar. Good luck in your endeavor!
Great video . Is there any other video like this explaining the procedure of making metal casts , lets say like rings , with silicone mold ? And if yes , how many replicas this silicon mold can produce metal rings , before the mold is no longer usable ?
Silicone molds can be used for "low-melt metals" but typical jewelry metals used to make rings would likely be too high temp. You may only get 1 or 2 castings before the silicone mold is ruined. We have had customers use the method in unique situations, but it is not a great solution for multiple parts or production. Customers do use silicone molds for casting wax masters and then performing typical lost wax metal casting.
You don't necessarily need a mold release if the surface is fairly smooth, but if you have a lot of texture or undercuts a mold release might make it easier to demold once the silicone has cured. The issue becomes more of a mechanical lock and not a "bonding" issue. For mold release, our ZIP ME-301 would work well. You should also be cautious of different clays with Platinum Silicone and run a small test before you cast a mold over the clay.
I want to make a cast of my old computer case from the 1980s and cast it in a silicone that won't sag in the middle because the case is fairly big. It is I two pieces (top and bottom section.). I want to change the white plastic to a transparent resin with fluorescent green dye mixed in it and I'll mount black light leds inside to make the whole final case glow. I may fill in all screw holes in with modeling clay and just tap them new in the final resin case. I plan on filling the case with modeling clay and doing a two part mold. Odd those the best approachfor something this large? I saw you mention an objet like the cover of an air conditioner. That is about the same size and the plastic is about the same thickness. Thank you for any help you can give me with this project.
It is certainly possible to do what you are asking, however it is typically advised to learn how to do silicone mold making and casting on a small part first to learn how the process is done. Making a mold that large involves a lot of materials and proper set up for best results and this only comes with some experience. Our best advice would be to watch several tutorials on RUclips of molding various large electronic parts before attempting. If you have a clear path you wish to proceed with, you may contact our tech department to answer any further questions about materials and some set up help. info@bjbenterprises.com
VERY NICE VIDEO: question as you showed the poring and riser tubes, would the tips where they are super glued to the Patten not show on the surface after casting or would you buff them out?
Good question. Yes, there will usually be a small mark where the point had been glues to the pattern. The mark is typically easy to sand off so it is less noticeable. We'll usually try and place the vents in an area that will eventually be hidden so it's not too obvious, just like injection molded parts.
1) can you supply small qty of metal powders and resin(1kg...)? 2) can you supply by express (dhl,fedex...) door delivery? 3) can you tell me approx cost of different metal powder (1kg)& mould making material?
Edwin Duran Molded Polyurethanes are used quite often as after-market automotive parts. We have many customers who make anything from tail-light lenses, grills, to interior parts. The question of whether your desired part will be suited to making silicone molds and casting comes down to geometry and size. A large silicone mold might be very expensive but there are ways to build molds with a combination of materials to incorporate the ease of using silicone and supporting it with wood, fiberglass, or another rigid & inexpensive material.
Edwin Duran It's possible that if the part is large, you may need to look into dispense equipment. For initial prototyping, you might be able to get away with a polyurethane system with a long(er) work time and wait for the cure. When things look good, you can step up to faster work times and quicker demolds. The trick is getting the mold filled; that's where equipment may be inevitable. But surprisingly, we have many low-volume production customers who still hand pour and may simply use ovens or heat boxes to speed up the demold/cure.
Hi Great video! I'm wondering whether silicone will stick to things while it's curing? I want to mould a seal and attach it to carbon fiber. If I abrade the CF and then pour the uncured silicone on it to cure in place will it bond to the CF?
Jools Taylor mold making silicone will not stick to carbon fiber. It must be mechanically locked or it will peel off. Flexible polyurethane will bond very well to prepared carbon fiber surfaces but if you need certain chemical or heat resistance it’s good to check with us for suitability. Info@bjbenterprises.com
Thank you very much. I have watched this before but didn't remember some important details and my first cast didn't turn out well. After watching it again I noticed every detail you included to make the cast part look perfect. Thanks again.
I used double-faced Scotch brand tape to adhere my flat backed bead to a flat surface, but the liquid silicone molding material, Alumilite Quick-Set, remained liquid and pitted where it was in contact with the tape. Is there a better double-faced tape or sheet of double-faced adhesive to use that won't cause this reaction?
That's interesting that you had what we call "chemical inhibition" issues with a Tin-Based Silicone. Tin Silicones tend to be much more tolerant and user friendly against a variety of surfaces. In a situation like this, I would run a small experiment to test several different tape adhesives. Put the different tapes in a small container and pour a small amount of silicone over the top of them and check the results. It's hard to say exactly what will work since we don't know what Scotch Brand uses for their adhesive on tape. We often use Nitto Tape Brand for our double sided tape and have great results. www.amazon.com/Nitto-Permacel-P-02-Double-Coated/dp/B003ZFAN4U/ref=sr_1_3?ie=UTF8&qid=1522946471&sr=8-3&keywords=nitto+tape+double+sided
Thanks for producing such a clear and concise training video. The best that I have seen. In the video, you did not mention if the mold and the resin should be put in a pressure pot while the casting is being cured to avoid bubbles. Please advise.
Fook Y Loh pressure casting is a great way to improve the quality of your parts, but setting up a mold properly from the beginning is the best method for overall consistency. Pressure casting should be an “insurance policy” and not depended on to minimize trapped air bubbles. It’s easy to use pressure casting on small molds but what if you are casting a large mold and your mold doesn’t fit in your pressure vessel? If you learn and practice the proper way to arrange vents and the fill port, you can often produce excellent results without pressure as shown in the video. Great question and thank you for the comment! -BJB
This video (and part 2) is absolutely fantastic - it gets into the maths and science behind mold making, and makes it very clear and engaging. I'm planning to cast a model of an excavator bucket and being similar (in principle) to the helmet, I will be able to follow most of this to the letter. However, the bucket has relatively sharp teeth pointing away from its concave body so if I mount it as you have mounted the helmet, the sharpest parts will be inclined upward rather than downward. I was thinking of running small vents from each of the five teeth to counter this.
LennyRhys Hi Lenny, yes you would probably want to put the teeth vertical and simply run small vents off of them. You can customize the shape of the vents to make a "Tab" instead of a sharp point which might help better define the edge of the teeth. If you put a definite line at the point the tab touches, it will typically break clean at that spot when removing the vents during the demold process. Think of the tabs that hold parts on the runners of a typical plastic model kit and you've got the idea!
BJBEnterprises Thanks so much for the quick and helpful response! One last question that I don't think was answered in the video: does the mating surface of the two silicone mold "halves" have to be horizontal, or is that more for simplicity rather than necessity? The reason I ask is that I want to run the seam along the opening of the bucket, but the sidewalls of the bucket are not straight; instead they look like... pacman with a very wide open mouth, about 160 degrees. If the mold halves matched this angle, might there be complications?
LennyRhys Correct, the split line was done flat for simplicity. There is no problem to do what you need to do for the bucket. If your parting line (mold flange) is curved or changes levels you simply need to build up something underneath the part to meet that level. Most people likely use modeling clay because it is easy to mold and shape, but you can also custom cut wood pieces (or use a plastic like the styrene shown in this video) to create that line if the geometry is fairly simple . We address that in our other video: ruclips.net/video/b_KMWhJyYLE/видео.htmlm The next thing to do is make sure you have good alignment keys for proper registration. If you cast the silicone mold into a square/rectangular block, you can place it on a board and angle the fill port and vents accordingly.
You have a marvelous video. I was casting plastic marker lights for my car trailer. My clear plastic casting resin flowed like thick honey (low viscosity). I tinted the plastic red. Do you sell a casting plastic resin that has a high viscosity rate? How long did your plastic resin take to fully cure? My resin cured in 2 days. I had issues with air bubbles. Going to use a paint pot to degas the resin in the future.
Hi Richard, thanks. It sounds like your clear casting resin is thicker or "Higher Viscosity" than our Water Clear systems. If you have the Data Sheet, look at what the mixed viscosity is listed as in Centipoise (cps) and compare with ours on the website; a higher number means thicker and a lower number means thinner. I would consider anything under 1000 cps to be fairly easy to pour but certainly anything under 300-500 cps is very thin. Honey would be around 2000-3000 cps. Pulling vacuum to degas the material first is essential on clear systems. Pressure casting after the filling the mold will ensure you fill all of the detail and don't trap any bubbles as the liquid flows through the mold. We have a new video (part 2 to this video) set to be released very soon and will answer many of your questions so subscribe and stay tuned!
Thanks for the information. Tried using a heat gun with minimal results. Going to use a paint pot to remove the air bubbles. Yes, I went by the correct mixing ratios. Finally cast a trailer marker light lense that looked satisfactory. When I immersed the light in hot water, the resin light got very flexible. Do you have a product that I can mix to make the resin more resistant to heat. My concern is when I install my trailer light in the hot summer weather, the light may collapse.
I would not bother with using a heat gun to heat liquids or cure parts. It is too hot and does not heat the product evenly. The liquid (in small volumes) really needs to soak in a warm environment for 10 minutes or more. A heat gun may scorch it. As far as heat resistance goes, there is no magic additive to make something more heat resistant. It starts with the base resin system you are using and it sounds like the stuff you have is more hobby-grade and not designed for making lenses. We have several clear products that are used extensively for after-market tail light lenses and have good heat resistance. Note that to achieve the best heat resistance out of a product, you will want to observe the post-cure schedule stated on our material Data Sheet and cure the part at elevated temperature. This is standard procedure in polyurethane casting (and epoxies) if you are trying to achieve the maximum properties of a casting material.
Hi, how did you mount the inner plug onto the surface? I have a kind of a cup to make a mold from and I don't want to stay the plug inside the cup while demolding. Hope you get what I mean. Thanks Phil
Philip Braches The plug used here was made from silicone so it did not stick to the helmet or base surface. The silicone plug is easily removed after the first half of the mold is finished and you are ready to pour the second half. I hope that answers your question.
Great Job, How many times can you reproduce the Fireman's Helmet, before the mold is no longer usable?Respectfully, Jim P. Reason I am asking is i need to pour make some old replica Cox Magnesium Speed Plans for Vintage Speed Airplanes U-Control gas operated, model engines in the .049 ci. engines,meaning the piston is a ""hair under 1/2"" I will have probably a 3/16" thickness, and I need a stiff rigid plastic with a little flex but not to the point you drop it you break it. I will need to cut threads at a certain point or counter sink small 3 m nut, Hot Fuel Proof, and potentially 250-300 degrees. I was thinking of using a Delrin plastic as that is what was used 20-30-40 Years ago and holds up well. May I get your opinion, I like your simple straight forward stile, clean crisp molds, it is all great works, Respectfully, Jim P. I would like to send you a Pic of what a Cox Speed Pan for 1/2A Engines, Any way of doing that, so you could see if i am wasting my time??
Hi James, thanks for your comment. I am very aware of .049 engines and U-control. I would imagine we might have a material that would fit your needs. We have many rigid, high performance castable polyurethanes that can withstand over 200F heat. The trick will be to see how it behaves with Nitro fuel and Castor Oil. A couple products to look at would be the TC-895 and TC-896 on our site: www.bjbenterprises.com How many parts will you get out of a silicone mold? There are several variables but 25-50 is a possible quantity. Also, feel free to email us to see what the parts are you are looking at re-creating and we can go from there. Regards -BJB
Yes, but how hot is hot? 100, 200, 1000? Most platinum silicones do well up to around 450F/230C. We have a couple of silicones that have been used for low melt metals up to 800F/430C in short uses.
Dear, what would be the best method to build a mold silicone to copy the body of a mockup of a bus with about 40cm in length where the part would be hollow inside to reduce weight.
Leonardo, if you want to build a hollow structure from a solid model, typically you build the outer mold first and then put in the mold a product like sheet wax in the desired thickness of your walls, to simulate the part thickness. Then you cast the second, inner mold. Remove the sheet wax and now you have the correct wall thickness to cast a part.
THIS IS PROBABLY THE BEST MOLD MAKING VIDEO ON THE INTERNET
Little correction, not only on internet but on earth. The best explanation and demo.
Might be the nicest silicone mold I've seen done
Wow, thank you very much. We try to show some of the best tricks in the mold making process so our customers have the highest chance of success making great parts.
I am brand new to resin-ing. I'm miles away from pouring my own molds, but I have so many awesome ideas that require I learn how!
When this video popped up I knew I had to watch it. (Actually I had to watch it a few times bc I didn't understand some of the silicone/molding jargon the first times, that's how new I am to all this lol)
But wow!! Did I ever learn a lot! With the simple, easy-to-follow instructions and your skilled guidance and explanations, this looks totally doable for me when the time comes.
Thank you so much for sharing this with the public. Very appreciated.
Excellent tutorial. You know you have a rational, technically minded instructor when they've opted for a tungsten ring over a gold one.
Haha, good eye!
I'm super impressed with the care taken to very clearly detail the mold making process. I can't imagine a better mold making tutorial.
Hi Dustin, thanks for the compliment. This video is representative of our company's knowledge and experience in this industry. If you have a project or application that requires mold making and casting, consider us as you source! info@bjbenterprises.com
It's definitely the best "how to make 2-part-silicone mold" video on youtube !
Everything is clear and informative. Thank you for your amazing job !
Wow, thank you! We do our best.
This video is one of the best training video's I have ever seen. Fantastic job.
Brilliant, Brilliant, Brilliant!
Thank you so much, I am a South African so there is very little chance that I will be able to do business with BJB and yet they make this content available to all of us for free. High quality, in depth detail regarding the holistic process. You guys are as generous as you are skillful!!
+Grim Falcon Wow, thanks for the compliments! Although we've pretty much shipped all over the world, getting product to South Africa is indeed expensive from the US.
Just found this. Extraordinary in every way; content, delivery, and production.
Thank you!
I'm with the crowd on this one! I've watched dozens and dozens of instructional videos while I've been learning the silicone mold making process, and this one is like an epiphany. Thank you for the clarity and for sharing your skills.
Wow, what a compliment. Thank you! Be sure to subscribe and share!
One of the best tutorials I have seen on RUclips. Good job sirs.
I found this tutorial exeptional in explanation and found the detailed reasons why a certain procedure is executed very helpful. The teacher was very clear and professional in speaking and was easy to understand. The lack of any background music was also very much appreciated as it was not present to drown out the presenter and also because I suffer from misophonia, a hearing condition. Thank you very much for your very well presented presentation about your products and the processes in which to use them effectively.
ytfp $#€×*&?€&7'^_' aew
I rarely comment on any RUclips videos but I have to now because I think you guys deserve it. One of the best tutorials ever and exactly what I need!! I'm jumping onto your website now. Please keep up the good work!
Wow that is awesome! Thank you for the kind words and we will continue putting out great content!
Excellent tutorial! Quick, simple, no interjection of personality, nor loud music.
Yes, cause god forfrikkinbid that someone in thei corporate takeover world dare to exhibit a personality which might cause you to have a feeling
I have to say this is by far the clearest, most helpful and informative video about casting I've seen so far. Really helpful, thank you.
Great video/tutorial! Could I use Clear Adhesive Vinyl Laminate instead of double sided tape? Thanks!
Yes, there are several methods you can use to hold down the pattern. White Elmer's glue is another method some people use, as well as hot glue, oil based clay, and a variety of others. Be sure the silicone is compatible with that material and make sure it doesn't damage the pattern when removing.
@@bjbenterprises Thank you SO MUCH for the information. You have been super helpful and I really appreciate it. Keep up the amazing work & God Bless! 🙏🏻
wow..! what a good and beautiful teacher..! BIG THANKS
Not sure how 133 people can thumbs down your efforts, I think your vids are brilliant - cheers :)
Thank you Lee, we're not sure either.
@@bjbenterprises I worked it out.. jealousy :) keep up the good work. i've only recently started to master 3d printing but you can't beat PU systems by the looks of it, for repeatability and speed.. i just know your vids are going to help me no end in my new job role. A million thanks for disambiguating it an making it look easy.. 10/10 from me :)
Thankss for sharing BJBEnterprises
I hope you can make another video for casting. Thumbs up.
gfhr b39 check out our channel and subscribe, we have lots more casting videos and more on the way.
Perfect tutorial... amazing example which build's up hope and makes us to think in a new... method
EASILY the best video I've seen on the topic, by far. ..Very professional and informative but still kept it as simple as possible.. Keep up the great work.
Wow! What a clean mold. Well done!
Thanks!
Excellent video that gives me the confidence to reproduce some (unavailable) plastic parts missing from my Jaguar XK8 project car that were missing when I purchased it - Many Thanks
By far the most clear informative video I’ve seen. Great job !!!
Realy realy great video. Nice info, good sound and lighting, and it realy shows me, that you know what it is all about. Thanks.
+hfranke07 Thank you on all points! The new light stands in our studio are working, then.
Hi, I agree that you have the very best videos on RUclips for making silicone molds, and casting the parts. I am making 1/25 scale model car parts like valve covers, various engine parts, wheels and tires, and probably other things including possibly a whole body and a whole frame.
What I am trying to do is to cast several parts in one mold, to save both time and mold making. Injection molded styrene plastic parts are connected with sprues that run from part to part. Is such an operation possible by using resin flowing, only by gravity, to make more than one part in a mold at a time?
Good question. Multiple cavity molds are possible if the parts are fairly simple, and you have appropriate vents set up for the parts to allow for trapped air to escape. However, it's not done as often with urethane casting compared to injection molding. If the parts are small, then there is not a lot of silicone material saved by combining multiple parts in one mold vs separate. If one of the mold cavities has an issue or wears out, then you end up with wasted casting material and bad parts from one cavity whenever you cast. It's a process worth exploring if you have a need to reproduce several simple parts at once. Keep in mind that thin sprues will not feed the other cavities very well so it's best to feed each mold cavity from a larger, central reservoir and go from there.
You can make almost anything like traffic light parts, car wheel covers and even spare parts for old toys.
This tutorial just made me think of establishing something called 'The Robot Hospital'.
First vid that’s told my why I shouldn’t take the pattern out of the mould at the mid point.
Wow! Plastic heat injection mold will have the run for their money.
Excellent explanation. Learnt a lot. Thank you
Very nice instructions
👏🏽👏🏽👏🏽
Congratulations from Brazil 🇧🇷🇧🇷🇧🇷
Parana state
Araucaria city
Wow this is like "next level" mold making. It looks so precise, clean and professional!
that was a nice instructional video. I would like to try out making molds. One area i wish you had done more with on this video is the step of selecting the material used to cast and preparing it for pouring and perhaps showed a variety of those products that could have been used for this silicone mold.
Thanks for the comment. Choosing a material is an entire conversation on its own due to the variety of materials available and also the physical properties needed by the part and application. One of the first things we look at is choosing what Durometer we need for a material, and go from there. This is one of the most important things to learn when you are first getting into mold making and casting. We do have a video on that topic. ruclips.net/video/Q6jn223_1Mw/видео.html
A very good video. Comprehensive coverage on everything. Very well presented and with ALL the details that are so lacking in so many others. Great. Thankyou
What a great instructional video! You covered everything I have been trying to figure out myself thanks!
Excellent EXCELLENT training video. I have shared it quite a bit with my fellow hobbyists.
Thank you for that. We're happy this info is getting to those who appreciate it. Also keep in mind that we have all of those handy items that are used in the videos like vents, fill ports, funnels, registration keys... plus the mold making and casting materials. www.bjbenterprises.com
I’m in the process of making my list of products right now. If I contact you all via email, are you guys pretty responsive? I’m not sure exactly which silicone to pick for my particular application.
@@petebutler5139 yes we typically respond within 15-30 minutes, or you can use our chat feature. Send any material questions to: info@bjbenterprises.com
Very nice... me gustaría asesoría y contactos para adquirir sus productos para mis proyectos.
Fantastic video, very calming to watch and listen to. Just discovered the possibility of a silicone mold. I am very eager to try this myself one day. Thanks!
Thank you for the feedback! It's a great skill to learn and hopefully we have given you the confidence to go try it.
Check out silicon putty, that is super easy
Diane Dragon soso
Definitely one of the best tutorial I've ever seen!
I noticed that, at 17:14 in the video, you use what looks like some sort of PVC pipe injection device. What is that, exactly? Is there another video in which we can learn how to make one of those for larger molded parts?
Thank you!
Hi Matt, what you are seeing there is a static mix tube from our meter-mix dispense equipment. So it's not as simple as a PVC pipe injection rig. Having said that, there are some people who use tall PVC pipes to act as their pour funnel and occasionally they will rig-up a piston inside of it to manually force material into the mold. Here is a sample video of the equipment I mentioned: ruclips.net/video/62G4NlXKurI/видео.html
Thank you! What would you recommend for a casting made in a silicone mold that's about 5" x 2" x 1" (about 10 cubic inches).
I'd be interested to know what sort of resin or material you'd use to actually MAKE the casting, and the method by which you'd do it.
Thank you!
We have so many options, it depends on what you want the finished part to feel like (ABS? PC? Polypropylene? Rubber?). Our part 2 video addresses casting parts, but if you need more help choosing it's best to chat with our Tech Staff to narrow down material selection: info@bjbenterprises.com ruclips.net/video/tnY86LIHf_I/видео.html
Excellent presentation. You could tell me how you could make a flexible syringe in silicone, to recover its deformation, to send air by squeezing it with your hand towards a hose of an instrument. The original is built in rubber.
This is a little too complicated to answer in a RUclips comment. Please contact our technical department and they can help you find the right method and materials to help create a mold and flexible part. info@bjbenterprises.com
This video is extremely informative. Thank you.
LOVE the details. Very Informing.
Thanks for a great video. A question is if you forgot to add air vents, is there a way to add them afterward? thanks
There are occasions where a vent needs to be added after the mold is made. You may find there is a problem area in the mold that needs a vent, the acrylic vent post came loose while pouring silicone and had to be removed before cure, or you simply forgot a vent somewhere. A couple of options: you could simply drill a small hole through the silicone (however it leaves a rough hole that will break down quicker over time), or you can bore out a vent using a small brass tube that has been sharpened at the end (this produces the cleanest result).
@@bjbenterprises Thanks great advice.
Have you guys still got the mold for that clear car tail light shown in the video? Would you be interested in producing a small batch in red?
I have to agree the best training video I’ve ever watched bravo job well done and extremely explanatory thank you
thank you for the great hints I have ben making molds for candles for years just never for making plastic.
.... How can you make a mold of something challenging like a squid.. can a squid or octopus be done with one mold.
Can u use a pressure pot on the sillicone?
Wow... Good... But what kind of separator u use....
SUNIL G. SHARMA 14:23
AH! Plenty of thanks! I am learning to make molds and casting, but was not aware of the feed and vent tubes, and how to position them.
I seen some examples when peple pour resin into the first half, and then place the top mold part on top- but that will surely guarantee the pry line, and maybe some stubborn bubbles.
Thanks for a fantastic tutorial. I need to replicate a small plastic part and this video has shown me everything I need to know. Could I just ask: Wouldn't it be useful to leave the box around the mold while casting to prevent any distortion of the mold? Or does the thickness of your mold prevent this?
On a small mold like this with a thick perimeter of silicone around the mold, we can get away with strapping it to a flat board as shown in the Part 2 casting video. In some cases we will make a custom sized top and bottom board to hold things together and without distortion. In many production shops, wood or plastic mold boxes are used with the silicone molds to ensure mold geometry is accurate. The one issue that we see with full mold boxes is that over time the silicone may experience some shrinkage and the mold box sides prevent a good, solid seal between the silicone halves, and cast material leaks out around the parting flange. If you use the top and bottom boards, taped tight and secure, then you don't have to worry about this issue.
@@bjbenterprises Great explanation. Thanks for the tips.
Which siliciones should I use to make chocolate molds?
What tape is that you are using to stick it down?
Can you get rid of the air bubbles without a vacuum pump, at home?
The simple answer is no (with household tools or equipment). There are several ways people deal with bubbles. Vacuum pumps and chambers is the most common but many home DIY casters use small pressure pots as well and find that convenient and effective.
How would you go about making a mould for a spherical object with no flat edges like a marble? Thank you in advance as your time and help is much appreciated.
There are a couple ways. You could rotationally cast it and make it hollow with a given wall thickness which would produce the cleanest part out of the mold (only a mold split line). Or, if you want a solid cast part, you would need to make a mold with a small fill port and deal with the reality there will be a small mark that would require some post demold clean up. Setting up the pattern to make a mold is pretty straight forward using a bed of clay to sink the part halfway into, creating a clean parting line. Or, you can use a solid board and bore a shallow hole into the surface using the appropriate diameter drill bit and fine tune/clean up the edges with a small amount of modeling clay to make a water-tight seal around the parting line. The alignment keys and fill ports/vents can be added as seen in this and many of our other moldmaking tutorials. Roto-casting: ruclips.net/video/kdN6Quj14P4/видео.html and setting up a round object for molding: ruclips.net/video/DIFWTiVWHts/видео.html
@@bjbenterprises OK thank you, I appreciate the time you have taken to reply in such detail and the fact that you have provided links to more information.
Very very interesting, excellent video tutorial
Hi, Can you make a mold of silicone and also cast with silicone if you use a silicone mold release?
Yes, you can cast Silicone into Silicone with an appropriate mold release if the geometry allows easy application. Note that a Platinum based silicone would not cure well in a Tin based silicone mold (cure inhibition).
Great video and level of detail! Thanks
This is the best mould making video on RUclips! So clear and informative, straightforward with 100% of the video on topic! Thank you so much, I was almost going to give up making my own moulds but now I shall definitely be doing them. I shall see if your products are available in my country and if they are I shall definitely be buying from you!
I am practicing with molds. One part molds are simple ad easy, it's the more complicated sculpts and small hands that are challenging.
I recently found an old vintage part in plastic that would require at least a 3 piece mold. I have scoured the web and have seen some references to them along with some pictures but thats about it. It would be nice to see a video on that to better help get my head wrapped around it. Splitting something in half is pretty straight forward. splitting it into 3 or more parts well that would be a something :D
Thanks for the idea. Yes it can be a little trickier to set up parting line for a 3-piece mold. You need to imagine what direction the mold pieces need to be removed away from the part based on geometry and details. In other words, the mold pieces need to pull off without getting trapped by the part geometry. It's still much easier with silicone molds vs traditional rigid tooling, but we understand the details of "how" to approach it are a challenge. If you need help, feel free to reach our to our tech team and they may be able to assist your mold design. A short description and a few pics work best: info@bjbenterprises.com
I want to make a mold for casting an arm to be make into a jewelry charm. I wanted to perhaps use resin to make the piece or something that would be a finish like glass or stone. Any suggestions? .
Send your project requirements to our technical staff with any pictures and a full description of the parts you want to make. The more detail the better: info@bjbenterprises.com
Hi I'm interested in the flexible elastomer that you briefly mention in this video what is that product? Thanks
Hi, you can find a huge variety of elastomer polyurethanes on our website here. bjbenterprises.com/index.php/polyurethanes/castable/flexible/ If you aren't sure about what product would work for you, please don't hesitate to contact us: info@bjbenterprises.com
You might also find our video on Durometer helpful in choosing the right product: ruclips.net/video/Q6jn223_1Mw/видео.html
Although, this video is too old, but it have a big value
BJBEnterprises I was looking at your water clear polyurethane casting and read the MSDS sheet. I have a a few questions:
1. These are tint-able so I was thinking about using them for custom tail lights and signals in a car, do the colors fade and is there a way to prevent it?
2. How UV resistant are these and will they "craze" or crack over time?
Hello Eric. The Water Clear Polyurethanes we offer are the preferred material for reproduction tail lights and signals. Certain formulas like the WC-783 and WC-792 feature additional UV absorbers in them to provide years of outdoor use and color stability. They have been extensively in after-market automotive parts and popular theme park attractions because of this UV stability. If you would like more assistance on these products and recommended mold materials, feel free to contact us at our Tech Dept: info@bjbenterprises.com or call 714-734-8450
Regards!
What's a good silicon to use if you don't have a vacuum pump?
We have a couple systems that are low in viscosity and pour well without vacuum. For a Platinum silicone, the TC-5041 bjbenterprises.com/index.php/tc-5041-a-b/and for a Tin silicone TC-5024 bjbenterprises.com/index.php/tc-5024-a-b/ You can also add a small amount of the silicone thinner SC-5001 bjbenterprises.com/index.php/sc-5002-silicone-thinner/ to help cut some of the surface tension and lower viscosity.
how about vibrating the liquid to get rid of bubbles. a fairly common method
Vibration is a common method in certain industries (like concrete and ceramics) but it is a very inefficient method for casting materials like silicone, polyurethane, and epoxy. Vibration works well on concrete, liquid metals, and ceramics because of the high level of filler content and difference in density of the liquid carrier vs fillers. The viscosity and surface tension of the liquid carrier also plays a huge roll in the process (water, for example, has extremely low surface tension). For our material process, vacuum is more useful and much more efficient than vibration. Vacuum also has the added benefit of stripping moisture from the casting system. That is especially useful in polyurethanes and epoxies where moisture can negatively affect the cure profile.
BJBEnterprises Where can I get a large clear vacuum jar, preferably something more durable than glass? Anyone make a plastic jar with a window in it?
Chris Bulen Yes, there are several sources out there that sell plastic vacuum chambers. If you Google "Plastic Vacuum Chamber" you'll see the variety of vessels sold for this purpose. -BJB
Thank you for sharing an excellent tutorial.
great video
Hi, may i use these process to produce strong plastic gear?
Yes, we have many customers that make different types of gears using this process.
are there any videos that help explain where a pour spout should be placed for a 2 part mold?
We don't have a video specifically on just that topic, but we discuss in detail here in this video: ruclips.net/video/iRj6xzNx7P4/видео.htmlm20s as well as our other mold tutorial: ruclips.net/video/b_KMWhJyYLE/видео.htmlm24s
Hi. This is really great video. Please, can you tell, how thin detail can resin recognise/pick up/replicate.
hi i need a rubber like maltreat that is ok with oil and petal/gas, can take 110c and can have metal cast into it.
thanks
can pegs be used in place of alignments?
Great question. Yes, you can also use dowel pins for alignment if that is what you prefer. For pins, you don't want to use the silicone as a pin. Always use a rigid piece of material like metal or plastic.
Hi, I am interested in making silicone cooking tools. I am a complete newbie, and I wonder if there is food-grade silicone that can be poured into a mold. You seem like you might know how to go about this. Could you please provide me with any information you can?
The short answer is yes, there are food-grade silicones to do this process. BJB does not sell a food-grade silicone for this process. The casting and mold process is similar. Good luck in your endeavor!
Thanks! I'll look into it.
Great video . Is there any other video like this explaining the procedure of making metal casts , lets say like rings , with silicone mold ? And if yes , how many replicas this silicon mold can produce metal rings , before the mold is no longer usable ?
Silicone molds can be used for "low-melt metals" but typical jewelry metals used to make rings would likely be too high temp. You may only get 1 or 2 castings before the silicone mold is ruined. We have had customers use the method in unique situations, but it is not a great solution for multiple parts or production. Customers do use silicone molds for casting wax masters and then performing typical lost wax metal casting.
If your original sculpt is polymer clay, do you need a release over that? What would that be.
You don't necessarily need a mold release if the surface is fairly smooth, but if you have a lot of texture or undercuts a mold release might make it easier to demold once the silicone has cured. The issue becomes more of a mechanical lock and not a "bonding" issue. For mold release, our ZIP ME-301 would work well. You should also be cautious of different clays with Platinum Silicone and run a small test before you cast a mold over the clay.
💙💙💙All of your tutorials are extremely helpful. Thank you!💙💙💙
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Great video! :) Would a 3CFM do fine? What problems can I run into with such pump?
Very nice!
I want to make a cast of my old computer case from the 1980s and cast it in a silicone that won't sag in the middle because the case is fairly big. It is I two pieces (top and bottom section.). I want to change the white plastic to a transparent resin with fluorescent green dye mixed in it and I'll mount black light leds inside to make the whole final case glow. I may fill in all screw holes in with modeling clay and just tap them new in the final resin case. I plan on filling the case with modeling clay and doing a two part mold. Odd those the best approachfor something this large? I saw you mention an objet like the cover of an air conditioner. That is about the same size and the plastic is about the same thickness. Thank you for any help you can give me with this project.
It is certainly possible to do what you are asking, however it is typically advised to learn how to do silicone mold making and casting on a small part first to learn how the process is done. Making a mold that large involves a lot of materials and proper set up for best results and this only comes with some experience. Our best advice would be to watch several tutorials on RUclips of molding various large electronic parts before attempting. If you have a clear path you wish to proceed with, you may contact our tech department to answer any further questions about materials and some set up help. info@bjbenterprises.com
That was a very very helpful professional mold making tutorial. Thank you so much.
VERY NICE VIDEO: question as you showed the poring and riser tubes, would the tips where they are super glued to the Patten not show on the surface after casting or would you buff them out?
Good question. Yes, there will usually be a small mark where the point had been glues to the pattern. The mark is typically easy to sand off so it is less noticeable. We'll usually try and place the vents in an area that will eventually be hidden so it's not too obvious, just like injection molded parts.
1) can you supply small qty of metal powders and resin(1kg...)?
2) can you supply by express (dhl,fedex...) door delivery?
3) can you tell me approx cost of different metal powder (1kg)& mould making material?
Can this process be used to replicate car parts like bumper lips?
Body parts such as body kits. Sorry about the confusion if there was any.
Edwin Duran
Molded Polyurethanes are used quite often as after-market automotive parts. We have many customers who make anything from tail-light lenses, grills, to interior parts. The question of whether your desired part will be suited to making silicone molds and casting comes down to geometry and size. A large silicone mold might be very expensive but there are ways to build molds with a combination of materials to incorporate the ease of using silicone and supporting it with wood, fiberglass, or another rigid & inexpensive material.
Thanks so much for the advice. I will definitely look into how I can make the molds, although the piece itself is quiet large.
Edwin Duran
It's possible that if the part is large, you may need to look into dispense equipment. For initial prototyping, you might be able to get away with a polyurethane system with a long(er) work time and wait for the cure. When things look good, you can step up to faster work times and quicker demolds. The trick is getting the mold filled; that's where equipment may be inevitable. But surprisingly, we have many low-volume production customers who still hand pour and may simply use ovens or heat boxes to speed up the demold/cure.
Hi
Great video!
I'm wondering whether silicone will stick to things while it's curing? I want to mould a seal and attach it to carbon fiber. If I abrade the CF and then pour the uncured silicone on it to cure in place will it bond to the CF?
Jools Taylor mold making silicone will not stick to carbon fiber. It must be mechanically locked or it will peel off. Flexible polyurethane will bond very well to prepared carbon fiber surfaces but if you need certain chemical or heat resistance it’s good to check with us for suitability. Info@bjbenterprises.com
An easy to follow tutorial, I'm gonna try this with a 3d printed trinket to make more for cosplay/props.
Thank you very much. I have watched this before but didn't remember some important details and my first cast didn't turn out well. After watching it again I noticed every detail you included to make the cast part look perfect. Thanks again.
I used double-faced Scotch brand tape to adhere my flat backed bead to a flat surface, but the liquid silicone molding material, Alumilite Quick-Set, remained liquid and pitted where it was in contact with the tape. Is there a better double-faced tape or sheet of double-faced adhesive to use that won't cause this reaction?
That's interesting that you had what we call "chemical inhibition" issues with a Tin-Based Silicone. Tin Silicones tend to be much more tolerant and user friendly against a variety of surfaces. In a situation like this, I would run a small experiment to test several different tape adhesives. Put the different tapes in a small container and pour a small amount of silicone over the top of them and check the results. It's hard to say exactly what will work since we don't know what Scotch Brand uses for their adhesive on tape. We often use Nitto Tape Brand for our double sided tape and have great results. www.amazon.com/Nitto-Permacel-P-02-Double-Coated/dp/B003ZFAN4U/ref=sr_1_3?ie=UTF8&qid=1522946471&sr=8-3&keywords=nitto+tape+double+sided
Thanks for producing such a clear and concise training video. The best that I have seen. In the video, you did not mention if the mold and the resin should be put in a pressure pot while the casting is being cured to avoid bubbles. Please advise.
Fook Y Loh pressure casting is a great way to improve the quality of your parts, but setting up a mold properly from the beginning is the best method for overall consistency. Pressure casting should be an “insurance policy” and not depended on to minimize trapped air bubbles. It’s easy to use pressure casting on small molds but what if you are casting a large mold and your mold doesn’t fit in your pressure vessel? If you learn and practice the proper way to arrange vents and the fill port, you can often produce excellent results without pressure as shown in the video. Great question and thank you for the comment! -BJB
This video (and part 2) is absolutely fantastic - it gets into the maths and science behind mold making, and makes it very clear and engaging. I'm planning to cast a model of an excavator bucket and being similar (in principle) to the helmet, I will be able to follow most of this to the letter. However, the bucket has relatively sharp teeth pointing away from its concave body so if I mount it as you have mounted the helmet, the sharpest parts will be inclined upward rather than downward. I was thinking of running small vents from each of the five teeth to counter this.
LennyRhys Hi Lenny, yes you would probably want to put the teeth vertical and simply run small vents off of them. You can customize the shape of the vents to make a "Tab" instead of a sharp point which might help better define the edge of the teeth. If you put a definite line at the point the tab touches, it will typically break clean at that spot when removing the vents during the demold process. Think of the tabs that hold parts on the runners of a typical plastic model kit and you've got the idea!
BJBEnterprises Thanks so much for the quick and helpful response! One last question that I don't think was answered in the video: does the mating surface of the two silicone mold "halves" have to be horizontal, or is that more for simplicity rather than necessity? The reason I ask is that I want to run the seam along the opening of the bucket, but the sidewalls of the bucket are not straight; instead they look like... pacman with a very wide open mouth, about 160 degrees. If the mold halves matched this angle, might there be complications?
LennyRhys Correct, the split line was done flat for simplicity. There is no problem to do what you need to do for the bucket. If your parting line (mold flange) is curved or changes levels you simply need to build up something underneath the part to meet that level. Most people likely use modeling clay because it is easy to mold and shape, but you can also custom cut wood pieces (or use a plastic like the styrene shown in this video) to create that line if the geometry is fairly simple . We address that in our other video: ruclips.net/video/b_KMWhJyYLE/видео.htmlm The next thing to do is make sure you have good alignment keys for proper registration. If you cast the silicone mold into a square/rectangular block, you can place it on a board and angle the fill port and vents accordingly.
BJBEnterprises Excellent! I will make sure to share my progress and results! Thanks again!
You have a marvelous video. I was casting plastic marker lights for my car trailer. My clear plastic casting resin flowed like thick honey (low viscosity). I tinted the plastic red. Do you sell a casting plastic resin that has a high viscosity rate? How long did your plastic resin take to fully cure? My resin cured in 2 days. I had issues with air bubbles. Going to use a paint pot to degas the resin in the future.
Hi Richard, thanks. It sounds like your clear casting resin is thicker or "Higher Viscosity" than our Water Clear systems. If you have the Data Sheet, look at what the mixed viscosity is listed as in Centipoise (cps) and compare with ours on the website; a higher number means thicker and a lower number means thinner. I would consider anything under 1000 cps to be fairly easy to pour but certainly anything under 300-500 cps is very thin. Honey would be around 2000-3000 cps. Pulling vacuum to degas the material first is essential on clear systems. Pressure casting after the filling the mold will ensure you fill all of the detail and don't trap any bubbles as the liquid flows through the mold. We have a new video (part 2 to this video) set to be released very soon and will answer many of your questions so subscribe and stay tuned!
Thanks for the information. Tried using a heat gun with minimal results. Going to use a paint pot to remove the air bubbles. Yes, I went by the correct mixing ratios. Finally cast a trailer marker light lense that looked satisfactory. When I immersed the light in hot water, the resin light got very flexible. Do you have a product that I can mix to make the resin more resistant to heat. My concern is when I install my trailer light in the hot summer weather, the light may collapse.
I would not bother with using a heat gun to heat liquids or cure parts. It is too hot and does not heat the product evenly. The liquid (in small volumes) really needs to soak in a warm environment for 10 minutes or more. A heat gun may scorch it.
As far as heat resistance goes, there is no magic additive to make something more heat resistant. It starts with the base resin system you are using and it sounds like the stuff you have is more hobby-grade and not designed for making lenses. We have several clear products that are used extensively for after-market tail light lenses and have good heat resistance. Note that to achieve the best heat resistance out of a product, you will want to observe the post-cure schedule stated on our material Data Sheet and cure the part at elevated temperature. This is standard procedure in polyurethane casting (and epoxies) if you are trying to achieve the maximum properties of a casting material.
Hi, how did you mount the inner plug onto the surface? I have a kind of a cup to make a mold from and I don't want to stay the plug inside the cup while demolding. Hope you get what I mean.
Thanks
Phil
Philip Braches The plug used here was made from silicone so it did not stick to the helmet or base surface. The silicone plug is easily removed after the first half of the mold is finished and you are ready to pour the second half. I hope that answers your question.
Thank you very much! You have great videos.
Phil
Great Job, How many times can you reproduce the Fireman's Helmet, before the mold is no longer usable?Respectfully, Jim P.
Reason I am asking is i need to pour make some old replica Cox Magnesium Speed Plans for Vintage Speed Airplanes U-Control gas operated, model engines in the .049 ci. engines,meaning the piston is a ""hair under 1/2"" I will have probably a 3/16" thickness, and I need a stiff rigid plastic with a little flex but not to the point you drop it you break it. I will need to cut threads at a certain point or counter sink small 3 m nut, Hot Fuel Proof, and potentially 250-300 degrees. I was thinking of using a Delrin plastic as that is what was used 20-30-40 Years ago and holds up well. May I get your opinion, I like your simple straight forward stile, clean crisp molds, it is all great works, Respectfully, Jim P. I would like to send you a Pic of what a Cox Speed Pan for 1/2A Engines, Any way of doing that, so you could see if i am wasting my time??
Hi James, thanks for your comment. I am very aware of .049 engines and U-control. I would imagine we might have a material that would fit your needs. We have many rigid, high performance castable polyurethanes that can withstand over 200F heat. The trick will be to see how it behaves with Nitro fuel and Castor Oil. A couple products to look at would be the TC-895 and TC-896 on our site: www.bjbenterprises.com How many parts will you get out of a silicone mold? There are several variables but 25-50 is a possible quantity. Also, feel free to email us to see what the parts are you are looking at re-creating and we can go from there. Regards -BJB
can we use silicone with hot things ?
Yes, but how hot is hot? 100, 200, 1000? Most platinum silicones do well up to around 450F/230C. We have a couple of silicones that have been used for low melt metals up to 800F/430C in short uses.
Dear, what would be the best method to build a mold silicone to copy the body of a mockup of a bus with about 40cm in length where the part would be hollow inside to reduce weight.
Leonardo, if you want to build a hollow structure from a solid model, typically you build the outer mold first and then put in the mold a product like sheet wax in the desired thickness of your walls, to simulate the part thickness. Then you cast the second, inner mold. Remove the sheet wax and now you have the correct wall thickness to cast a part.
Excellent video!
How did the silicone get inside of the hat during the first pour? I thought it was sealed!?
4:15 we show the silicone plug is pre-made.