Making a Foam Buck for Mold Making

Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.

PlanetAlexander

Active Member
G'day Makers, I had the opportunity to try something new for a project (I can't reveal the project yet). But for it, I chose to make a cast of the final version. I didn't have any clay (such as Monster Clay), all I had was EVA foam and foam clay. So I took a risk and made a buck from foam/foam clay and made a mold and casted it... and since it worked, I'd like to share with you all the process I went through.

I can't show (yet) the main thing I was making but I did make a test horn to make sure this process would work before I tried it on the real deal. This horn was made from foam clay and when dry, I used a dremel to make the groove texture. I also made a second horn (not textured) and you'll see why soon.

After that I covered both horns in Flexbond, a common sealer for EVA foam. I applied two layers and made sure to brush it in the direction of the grooves. This can also be watered down to minimise brush strokes.

Next I primed only the textured horn with Rust-oleum flat white primer. Throughout this entire build process I was worried about the silicone not curing and I was hoping that it would cure with the primer on. I only primed one to see if silicone would cure on Flexbond.
DSC06140.JPG

Foam clay buck, sealed and primed

I used Smooth-on Rebound 25 to make the silicone molds. The first layer was applied to the foam horns and... they both cured! I honestly didn't expect the un-primed horn to cure, but it did. This is also my first time making molds/working with silicone and resin. I made sure to wear latex-free gloves and use a new, clean brush.
DSC06141.JPG

Left is the horn that wasn't primed with spray paint, on the right is the final mold of the textured horn

I finished the textured horn mold with another layer, then two more with Thi-vex added in. Next I made the jacket mold from pottery plaster (although in the future something like Plasti-paste would work better I imagine). I casted the horn from Smooth-cast 300 and added a bit of the paint I had for the main project, because why not?
DSC06142.JPG


So, there you have it - It is possible to make bucks for molds from EVA foam! Although, it probably is easier to just 3D print the parts and/or make them from proper clay, to reduce the steps taken (plus foam clay isn't as manipulative as other clay is).
 

Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.

userd1402

Sr Member
RPF PREMIUM MEMBER
Looks great. I’m planning a project myself which will require a mold and I’m interested to know what ‘foam clay’ is? Do you have a brand name for this stuff so I could look it up online? Cheers.
 

PlanetAlexander

Active Member
Looks great. I’m planning a project myself which will require a mold and I’m interested to know what ‘foam clay’ is? Do you have a brand name for this stuff so I could look it up online? Cheers.
Foam clay is a product that handles like a really soft clay, and dries to a foam-like state, which can be sanded, sealed, painted etc. like EVA foam. It's really good for sculpting and making organic details. I got mine from the Hero Studio, but other places like Lumin's Workshop or even SKS Props stocks it.
 

Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.

Top