Vacuum Form Question

[TheCreatureWork]

I've been using Rigid Urethane Foam to form puppet eyes in the vacuum forming process. Where I purchase the Rigid Foam has been super expensive- then I got to thinking...can I use a substitute? I have 3- 6ft solid pink insulation sheets (Extruded Polystyrene Rigid) used in home insulation, it is a solid, non-pourous foam...and much cheaper! I imagine it can stand up to the heat from the polyethylene sheets I use in vacuum forming and can be carved very smooth.

My question is has anyone used this insulation sheets for eyes in the vacuum form process? Let me know.

 

[Buck-Beaver]

Out of curiosity, is there a reason you're using a rigid urethane foam to vaccuform eyes instead of thermal plastic?

 

[TheCreatureWork]

Out of curiosity, is there a reason you're using a rigid urethane foam to vaccuform eyes instead of thermal plastic?

The rigid urethane foam is the carved base the heated thermal plastic forms too.

Ps- off topic- how was the Puppet Slam? Lol

 

[Buck-Beaver]

Ah, of course.

I don't know if I can help with your question, but when we do vacuforming at Unraku (unless it's a one-off) the original piece is sculpted in clay, then a positive is cast in a plastic or resin. It's a few extra steps, but seems to produce better results.

I would never think to use polystyrene for a positive because it has a melting point around 240°C (and it's not recommended to heat it above 80°C or so) so I'm pretty sure that our vacuform machine would cook it unless we were very, very careful...but we haven't actually tried this. I'd be very interested to know if it works.

(oh and the puppet slam in Toronto was great, thanks for the mention on Puppeteers Unite!)

 

[TheCreatureWork]

I have a handmade vacuum form machine- attached to a shop vac. The poly is heated up by a heatgun. Then I just turn on the vac and slap the poly onto the former and blame! Instant form. I guess I'll have to test it out. I'll let everyone know how it goes.

Good to hear it Puppet Slam went great. I wanted to go but couldn't :-(

 

[propologist]

Hi Guy's,
I have been vacuumforming plastic for over 30 years in the work I do. As buck has stated it is not recemended to pull styrene sheet over styrene foam as they both have the same melting temperature. The foam would most likely go first (melt) as you are forming the part. But that being said if you are pulling a thin piece of plastic say.030 or so and put the mold up on the bed just before you pull the plastic down over it. It may work for 1 or 2 parts. I would recemend that if it works that you pour plaster or even cement in to the vac part to make a permanent vac tool that can be used over and over and keep that first pull as your master to make more vac tools out of it.

Hope this helps.

Mike

 

[spcglider]

You beat me to it, Mike!

-Gordon

 

[TheCreatureWork]

thanks for the words of advice! I'll let you know what I come up with.

 

[Adam Kreutinger]

I have sculpted things out of roma plastilina then vacuum formed over that works well.

~Adam