How to properly measure MEKP for your polyester resin, gelcoat and more
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- Опубликовано: 26 июн 2024
- Have you ever spent what seems like days measuring drops of mekp or catalyst for your polyester resin? We have all done it in a pinch, but there's a quicker way. In this video I show you how to use some basic math to accurately measure the correct amount of MEKP for your polyester products. We all have a phone with a calculator so that makes this process even easier. This works on every single polyester product, not just the amazing products at totalboat. Here is the formula written out, remember products OTHER than resin require almost double the amount of MEKP to catalyze gelcoat, repair putty or fairing compound, for all your boat repairs or boat builds.
Ounces of resin, times the percentage required of mekp times 30 equals the cc's required. example
6oz resin times 2%= .12 times 30 = 3.6 cc of MEKP
8oz resin times 1%= .08 times 30 = 2.4cc of MEKP
6oz gelcoat times 2%= .12 times 30 = 3.6 times 2 = 7.2cc of MEKP
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MEKP dispenser
fiberglasssupplydepot.com/MEK...
Polyester resin
www.totalboat.com/product/pol...
gelcoat
www.totalboat.com/product/gel...
fairing compound
www.totalboat.com/product/pol...
MEKP
shop.hamiltonmarine.com/produ...
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Thank you. This is exactly what I needed.
Awesome video, it’s my first time doing gelcoat with wax additive, and mekp lol. Was trying to figure out the math but you made it very clear. Thank you. Definitely deserved the like and subscription!
I’m glad you got something out of it! Every time I watch this video I confuse myself 😂. Thanks for the kind words!
Awesome lesson!
Thank you sir
Great explanation!
Thanks bud!
Thank you!! That will help alot..
Very clear (😂) and concise..thank you. Using this on my 97 RV van.
Awesome!
Good 👍👍
Thanks
Unless you are doing a large project then maybe this is needed. Personally I think its easier to count 14 drops into a disposable container, mark the line, and reuse that each time until you're done!
Like I said in the video
Nothing wrong with counting drops. I have tried to mark containers before and the mekp generally removes any kind of marker/paint. You; I suppose, could use tape or something but if your going through all that effort might as well use the dispenser.
If you convert ounces to kilo's/ grams it's even easier. One of the many benefits of the metric system.
This is true!! The metric system is easier most of the time. But since I live in America we use volume measurement.
Your math is OK but you have volume and weight confused. Gallons, Fluid ounces, liters, milliliters and CCs are all volumes. CC stands for cubic centimeter. That's volume, not weight. As for weights and volumes of polyester resins being the same, fluid ounces and ounces weight are two different things. 16 fluid ounces of a resin, may happen to weigh close to 16 ounces or 1 pound, but the formulation can potentially make a difference. Fluid ounces are volume. Ounces are weight.
That said, the way most people will measure resins is by volume as in fluid ounces. A typical paper drink cup is about 3 fluid ounces. That's a handy measuring device because you just toss it when you are done with it. Don't have to clean it like a typical measuring cup. Straight resin and gelcoats are different formulas. Gel coats are resin based, but have different properties like UV resistance, sandability, pigments, viscosity etc. One way to look at it is that gelcoat has more than just resin in it. So their hardner requirements can be bit different. If you weigh the two on a scale, you will likely find a difference in weight per volume.
I don't know of anybody doing any kind of work with resins, body fillers, etc., who use a precision scale in their shops. Volume makes the most sense and is convenient. Now if you have to go by weight, you'll want to do something like weighing a cup full or each component. That will give you a weight per volume measure of that particular material. Then use that in the percent calculation.
You did the math right but have volume and weight confused. And for all practical purposes 1 fluid ounce volume is equal to very nearly 30 CCs or 30ml. (CCs and (milliliters are the same thing) . That brings up a useful trick for small volumes like for repairs. You can buy cheap disposable syringes marked in ml or CCs. Makes it easy to get an accurate mix of small volumes. Use one for resin and one for hardner. Use a bigger one for the resin and a smaller one for the hardener. As long as you don't mix the two, you can get multiple uses before you toss them. All you need to remember is that 30:1 ratio of ml or CCs per fluid ounce.
Ok when I get my whole # do I multiple ot by 2 like he does using fluid oz's for instance im going to have a volume of 16 oz's ×0.02 %= 0.32 × 29.57= 9.46 ×2 =18.92 ...im like the other guy why do I multiple my # by 2 at the end ..seems like alot of MEKP . I was given 4 oz's for the whole gallon. That's roughly 30cc per quart .
Finally I don't have to try and drops ...
That’s what I’m here for!!
Hey friend I’m trying to put a new layer of fiberglass cloth over and old boat with cracked gel coat. I almost got it sanded down to a new surface, there was some warped spots that I sanded into holes that now need to be covered. I don’t know what product to use, resin I would think for the fiberglass cloth right? I want to paint the boat after I resurface it, so paint needs to be able to stick to whatever I use… does total boat have a product that’ll work for me? Laminating resin? I finerglassed things before but never a boat. There is a video of the boat on my channel, it’s called a barracuda Hydrocycle. Thanks for your time buddy.
I’ll keep this as brief as possible. Resin is a misnomer. We have many types, polyester, epoxy, vinyl ester just to make a couple. Your choice will depend on many many factors. I’d like to help, but without seeing the boat, and what your trying to do it’s hard to guide you in the right direction. If you’d like to have a private conversation with me, there are options. I have helped many folks here and on other social media platforms. Pretty simple, doesn’t cost a ton. You can email me at wthurlow@gmail.com if you’d like.
there are a lot of comments on your video, i appreciate your effort, for 1 liter of polyester resin, how many ml of catalyst do i need at 2% ratio? thanks.
If it is 2% by weight then, weigh the liter of polyester resin, multiply by .02. Then weigh out the MEKP. Further, 1 Liter = 1000 ml. The density of Resin is reported to be between 1.1 g/ml to 1.43 g/ml. So use the average of 1.25 g/ml. So 1 Liter of resin will weigh about 1250 mg. the amount of MEKP required will weight 1250*.02 or 25 grams. MEKP is reported to have a density of 1.17 g/ml. so divide 25 grams by 1.17 to get 21.4 ml. If you had used 2% by volume. you would get 1000 ml * .02 = 20 ml which would be slightly on the low side. But anyway. If you weigh the resin. Then multiply out by .02 [=2%]. then take that amount and on a scale, measure out by weight the quantity of MEKP calculated. I'm thinking that they recommend using by weight because in the making of the product is that the density varies a lot and in the extremes can cause poor results.
What if we avoid adding the cobalt the blue color one and just add MEKP to the polyester resin .
I don’t understand what your saying? Cobalt blue what?
Thanks for the video and the tips. I am a bit confused ny your math. You mixed the resin at 2% in you calculation. then mixed the gelcoat at 2% (same quantity). What I don't follow, is doubling the result of the gelcoat mix, which actually makes it 4%. Am I missing something?
Hi cam. It’s 2% by volume not weight. So 7-8 drops for resin, 14-16 gekcoat. That’s why if you have 7cc for resin you need 14cc for gelcoat.
@@HoldFastMarine If 1% for resin is 7-8 drops and 2% for Gelcoat is 14-16 and quote " weight and volume are diffrent, but in terms of these Polyester products they are not", surely there is a mistake? Not trying to be an @...., but I can't get my head around it. Thanks!
@@threadfin2012 you always want to catalyze at 2% if your a noob. I can do .5-1-2-4% etc. When I say they are the same but not it’s so you just focus on the math. So take your ounces for resin; multiply that by the percent you want to catalase at, then multiply that number by 29.571 or even 29-30 Dosent matter really. For your gelcoat, repair putty always 2% unless it’s very hot out. Ounces x 2% x 29.574 x 2 and you’ll have the proper amount. If the number of cc’s comes out to 5.261 for instance just use 5, or 6. It Dosent have to be that specific.
Hello . If you are using CC’S you should be using litres . It’s much easier.
America bro. Imperial all the way! Metric is for tea drinkers! 😂
Just to clarify, if I pour 6 oz of resin into a cup, the formula would be for volume, not weight, correct?
Yes. Best bet is to always catalyze resin at 2% and other polyester stuff at 2%x2
Got it. I was playing around with a 2 oz batch and my measuring bottle doesn’t go that low so I had to count drops. But I catalyzed at 1%, not 2. My mistake.
@@josephwhitehead1692 A 2oz batch would be 14 ish drops of resin, but you could just put in 2cc of mekp and you'd be just fine. You can be off a bit and it won't matter. You can catalyze at 1% and I often do this but only when temperatures are high and I need a little extra time.
@@HoldFastMarine Looking back on it, I actually did catalyze at 2% with 16 drops. I found a chart but it only went to 4 ounces so I divided the catalyst in half. I was surprised how far 2 ounces of resin will go.
If you're adding 2% MEKP by volume. For six ounces that's 180cc x 0.02 = 3.6cc of MEKP. Not sure how you're getting 7.2cc? If you go by drops then 20 drops equals 1cc. So 14 drops/20= 0.7cc... then 0.7cc per ounce x 6 ounces is 4.2cc. If you use 7.2cc for 6 ounces then 7.2ccx20= 144 drops. 144 drops/6 oz = 24 drops/oz.
Are you asking about resin or gelcoat? For resin it would be 3.6 cc. We double it for gelcoat. Therefor 7.2 cc
@@HoldFastMarine I'm asking about the gelcoat. Where do you see that it should be doubled. The instructions I thought said it was 2% of volume? So 2% of 180cc is 3.6cc?
Go buy some gelcoat and try it. When the gelcoat dosent cure, report back.
I'm not the brightest bulb on the tree. I read the back of the total boat resin as 7 to 8 drops per ounce they word it oddly that one ounce is one teaspoon. Needless to say I mixed up a batch with way too much catalyst using this formula
Well yes technically the 7-8 drops is roughly a teaspoon. one teaspoon is for one ounce of resin. Most of the directions are confusing, which is why I made this video. Thanks a lot for watching!!!
a fluid ounce = ~30 ml, a teaspoon =~5 ml. There are exactly 6 US teaspoons in a US fluid ounce. There are 30 drops of MEKP to a ml of MEKP. So, 1 fl ounce of resin needs .02 fl ounce of MEKP = 0.6 ml of MEKP = 18 drops of MEKP
@@HoldFastMarine A teaspoon of MEKP = ~ 5 ml = ~150 drops of MEKP. Also, 7 to 8 drops of MEKP is equal to about 1/4 ml of volume.
How many drops equals one CC? The computer says 20. I bought some poly structural putty (from total boat - I qt.) to do some repair work on the wheel pants of my airplane. The can says 1-2% MEPK. 14 drops per ounce for 1%. So if I use 6 oz of resin, putty in this case, that's 14 x 6 oz = 84 drops, or 4.2 CCs !!??? That seems like a lot of MEPK and it's not a very big bottle. If I use just 6 oz of putty, that leaves 28 oz left in the can. Using your formula: 6 oz putty x 1% = .06 x 30 = 1.8 cc. If 1 cc = 20 drops, 1.8 cc x 20 = 36 drops. What is wrong here?
Always follow the directions. Just because it seems like a lot to you doesn’t mean it’s wrong. I often use 20cc’s for a lot of resin. So let’s do the math together using your 6oz.
6 oz times 1%= .06 x 30=1.8x2=3.6, round it to 4. Stop counting drops and use cc’s
So, what happens if you use too much or too little?
Too much and it’ll harden faster, too little and it’ll harden to slow or not at all
Too much hardener will not only cause it to cure more rapidly, that rapid cure will yield more shrinkage.
Thanks for being an expert
Okay, I still find it confusing when the word "ounces" is used and it isn't 100% clear whether they might mean weight or mean fluid ounces (volume).
It’s maddening
So instead of the math lesson why not put your mixing pot on a scale pour your resin multiply by two percent and that's what your mekp is? example 600 grams of resin X 2% = 12 grams of mekp . Add the mek till your scale reads 612 and call it a day. OH I almost forgot don't forget to put a piece of plastic over the wife's kitchen scale
What if your only mixing 6oz of resin? Most scales won’t even register such a small amount of liquid hardener. Sure you could buy a super expensive or accurate scale until, as you mentioned, spill a whole bunch of mixed resin all over it. Permanently bonding it together.
My wife is a registered nurse and simply had me set my scale to milliliters and add 1-2% mekp to my total. For example 100ml of resin will take 1-2ml of mekp depending on the temperature and work desired work time. She also showed me that cc and ml are interchangeable. So if your dropper is in cc but your scale is in ml you have no issues in putting 2cc mekp into 100ml of resin for example. I’ve had zero issues with this in any of my work.
@@Nino13084 great tip and explanation! I’m doing another gelcoat application video (coming out in a week or two) I’m going to mention this method in it! Your wife’s pretty smart!!
@@HoldFastMarine i agree with my wife being smart. Thank you for the compliment. I personally prefer the metric system so i find it easier to measure in cc, ml, mm and cm. But I urge everyone to use what they’re comfortable with. My local fiberglass supplier in Gulfport, Ms, Ken’s Marine, always tries there best to inform their customers as well on any tips of the trade like yourself. Thank you for taking the time to inform others as well. I’m also a huge fan of Totalboat products. Best bang for your buck as far as I’m concerned.
@@Nino13084 local suppliers are key for the DIY person. Chain store employees don’t know anything about the products they sell. Metric is the way to go, but I’m a stubborn guy and refuse to use it 😂. TotalBoat is great stuff. Don’t forget you can use the discount code for my friends and subscribers. TBholdfast is the code! Thanks for the great conversation!!
You said you were going to convert for mixing by weight but you converted to cc’s which is also volume. So you converted imperial volume to metric volume not weight.
What’s your boating RUclips channel?
Don’t have one. Why is that relevant?
Because your telling me how to do the job I’ve been doing for 25 years. I appreciate you watching however I’m the expert, you are the viewer.
Boating has nothing to do with expertise in composites. I have been laying up, vacuum bagging, designing and engineering for injection molded composites since 1985. That’s a few years more than you since you seem to struggle with middle school concepts like the difference between volume and weight. You can build all the boats you want and it won’t make CCs a weight measurement. You made a mistake and are so arrogant you can’t own up to it.
Why the hell do we use the English system of measurement!
Because AMERICA 😂😂
make it simple measure in ml so 900 ml @ 1% = 9
You could do that.
I phones are crap get a Samsung
Why so I can’t get any photos or videos texted to me by a someone who owns an iPhone?