Making a Concrete Mold Using Fiberglass
HTML-код
- Опубликовано: 8 фев 2025
- Turn on Closed Captions (CC) for detailed step by step info.
We were hired to make "the latest in concrete road obstructions" for a new development here in St. Louis. These bollards will prevent traffic from colliding with pedestrians in a new area made only for people and not cars.
In the video I begin by making an MDF master, a full sized model around which we will make the mold. After surface prep and paint, a metal divider is temporarily installed in order create a flange and establish a parting line on the fiberglass mold. Partall, a mold release is sprayed to create a film barrier between the master and the gelcoat. The white gelcoat then is applied, forming what will be the hard, slick, interior of the mold. Many coats of fiberglass and resin are applied to reinforce the mold.
When the first side is done, the metal divider is removed and more partall is applied and the process repeats for the second side. When all the structural elements like rebar and plywood are installed, it's time to trim the loose fibers and pop the mold from the master.
Pouring 3500 lbs of concrete into a mold was sketchy the first time but the sand-filled bin worked to stabilize the mold as it increased in weight. Vibrating periodically helps to loosen bubbles that may be stuck in the concrete but too much vibrating can weaken concrete by causing separation between the cement and aggregate.
That’s beautiful ❤
You make beautiful products
Class work and video 📹. Looking in from Ireland 🇮🇪
These look very effective for vehicle control. I could also see these as viable points for supporting cover fire from the outside-in since a crouched person could hide behind these.
Super cool! I love seeing the steps come together to make the final product. Now i'm inspired to do something like this (much smaller scale) in my home landscape! Keep up the great work!
beautiful work
Love these shapes. Nice skills My Man!! Would love to see one of your pieces glow....
that is a beautiful mold
Did they get banged up with all that traffic? Great job guys!
Those are amazing!
would be a cool paintball bunker, you guys could open a unique field
This is so bad ass!
Did you apply a release agent to the mould before casting the concrete?
What mix concrete do you guys use for something this big?!?! Great video thank you for posting.
Wow. This just expanded the crap out of my imagination of concrete mold making lol. Great work! What did you use to attach the metal divider to the mold?
Hey man awesome video! Can I ask what mould release you used for this project? I’m having real trouble releasing concrete from a gelcoat finish.
I think it’s just PVA parting film and paste wax. Typically wipe it over the PVA and let it dry. Wipe off excess and repeat a second time. Would you happen to know what the green stuff is at the beginning?
Mauricio Gonzalez I was thinking it might be PVA. But I thought that would be water based and dissolve when the concrete is poured into the mould.
Is there anything you do to the bondo to make it more workable or increase the working time?
I would love to find out what type of Gelcoat was used, was it waxed or Unwaxed gelcoat
skateable!
Hi Dave, good workmanship there. Did you apply a mould release to the gel coat before pouring in the concrete? Kevin
Any idea how to make a mold for a non-truncated cone with a diameter of 21.5"??? I need to do this to cast with concrete, but I'm having a bit of technical difficulty figuring it out.
Should I have the 3D files sent to a metalsmith, or make the form out of Owens Corning and then do a fiberglass mold like this? Any help is very much appreciated!
Thanks for the awesome informative video! I've been researching online for weeks because i'm making a concrete sculpture out of a fiberglass mold and every video is making me think I need a latex/ rubber barrier between the fiberglass and concrete. Is this true or can I just use a release agent with the concrete cast straight in the fiberglass? Thanks.
I saw your question and I’m trying to find out what kind of material is applied first and then the fiberglass and resin it’s that white color material that you brush on please let me know when you get a chance thanks
@@edgarsolis9158 it’d be either gel coat or top coat, they’re both same but top coat has wax added to it
Info about your company? Website?
Next you try to make GFRC silica sand fiberglass chopped to make a light planter
SO good ! whats the green stuff that you spray on and peel off?
Pva release agent
What’s the green stuff that was there before the pva? When they were add bindi and sanding.
What is the white material that you brushed on before applying the fiber-mat and resin? Epoxy? Resin and talc mixture?
The white layer is the gel coat. It’s the first layer of the actual mold, the inner most layer that the concrete contacts when poured. We are building the mold from the inside out. Thanks for the question.
@@dave_makes_magport Thanks very much for your reply. I understand your process but what is that actual material/product you used for the "gel coat"?
Ok gotcha. I can’t find the exact specs of the white gel coat we are using in this video. But it’s Polynt brand. We are now using a tougher gel coat, known as tooling gel coat for this purpose. That is also Polynt brand and is 945YA058-LP L/F orange tooling. We switched to this because it lasts through many more pours than the white stuff.
@@dave_makes_magport Awesome. Thank you so much for the info. This project looks beautiful and your video was great reference for some large scale cast concrete sculptures I'll be making. THANK YOU!
Awesome project now they are ready for graffitti....lol
What material is that green film you are peeling off the mould? thanks
It's called Partall Film #10. It's a polyvinyl alcohol based parting film that can be cleaned with soap and water.
Dave Moore hey man, what’s the green stuff that you apply to the panels? Not the PVA but what’s on there before the bondo?
consider making bricks like frank lloyd wright
Hi Dave.
What a huge project I love it and it gaves me lot of ideas.
I'm looking to make a dodecahedron pot planter like this one: www.basilic.com.co/pictures/MOLD_EXAMPLE.jpg
I have a question that maybe you could help me resolve. When I cut the wood on the edges I have to cut then 45 degrees ??
Thanks in advise for your help.
Hi, Dave. I thnik I solve my question the cut has to be done at 116,57 degrees
to much concrete easy to spray cement and silica sand and fiberglass to make light cement planter