Can you vac-form over styrofoam?

[dropshipbob]

I have a project that I need several cones for and today I found the exact height and diameter I need, but the item is a styrofoam cone.

Would a vac-forming machine crush this?

And this is the open cell type foam, will this show up on the vac formed pieces?

 

[Fulcrum]

Wouldnt the heat from the plastic melt the cone?

 

[CSMacLaren]

Doing so may even melt the styrofoam. Whatever the project is, you may consider molding it in silicone and creating a plaster buck.

 

[Gordon Gekko]

Would a vac-forming machine crush this?

Yes!

And this is the open cell type foam, will this show up on the vac formed pieces?

Yes!

 

[Boba Binks]

If you want you can always cover the foam with body putty and when it dries sand it smooth. It will work some pulls.

 

[Smiling Demon]

If it is the kind of foam you get at the at the craft store I seriously doubt it would melt it or crush it. All you would need is one. Vac-form a cone then pour plaster into that one and that would reinforce it enough to make as many as you want!!

Sound logical?

 

[tomstrong]

Depending on exactly what kind of foam it is and what kind of plastic you're working with it may or may not get too hot, one thing to probably count on is that it'll get worse with every run.

As a potential alternate, what about vacu-forming a thinner than usual piece of plastic over the foam and not worrying about the plastic sticking to the foam, instead let it stick and consider it to be a permanent part of the mold, then form the subsequent parts over the new plastic layer? It'll change the size a little bit but it should still be close enough to be almost the same size and shape.

 

[t_bone9600]

The body filler idea should work well but test in in an inconspicuous area first. Sometimes "putty" can dissolve foam.

 

[Vadermonkey]

Yeah, doing a layer of Bondo over the form would be the best way to go as was suggested.

You could even thin it with fiberglass resin and brush it on (make sure you add both kinds of catalyst) making it easier to sand smooth but test a spot to make sure it wont melt the foam you are using.

 

[dropshipbob]

To answer a few questions-

Yes, this styrofoam cone was found at a hobby store.

Yes, sounds logical vac-ing over the cone once and letting that remain and vac-ing over that.

I just didn't want the open cell material to leave a texture on subsequent pulls...but sounds like I have more than one option to get rid of that.

Thank you everyone for the info and ideas!

 

[Jumpin Jax]

Yeah, doing a layer of Bondo over the form would be the best way to go as was suggested.

You could even thin it with fiberglass resin and brush it on (make sure you add both kinds of catalyst) making it easier to sand smooth but test a spot to make sure it wont melt the foam you are using.

Bondo is a must.
For maintaining the smooth texture if you have no fiberglass: You can layer the bondo with less cream hardener to prolong the pliability and lower the curing temp, then place wax paper over it to give a glassy smooth surface. Peel off the paper after the bondo cures, and you will have significantly less sanding to do.
JJ

 

[t_bone9600]

Bondo is a must.
For maintaining the smooth texture if you have no fiberglass: You can layer the bondo with less cream hardener to prolong the pliability and lower the curing temp, then place wax paper over it to give a glassy smooth surface.
JJ

Wax paper huh? Hmmmmm. I've never heard of that. Sounds like I have a new technique to try out.

 

[Jaruemalak]

If it is real Styrofoam, I can pretty much guarantee that bondo will attack and eat it. Other foams are more resistant.

If it is a smooth enough cone, spray it down with spray adhesive and then wrap it with a layer of very thin, cheap aluminum foil. The cheaper stuff is usually thinner. Gently burnish the foil with your finger wrapped in thin cloth. This will act as a protective layer to keep the chemicals in the bondo from attacking the foam.

Coating it with a layer of epoxy resin will give the same protection, but the foil method works and is quick.