Question to build mold for vac-forming..

[derfieseKlaus]

..hey guys, i want to build a costum. my idea is:
1. the rough shape with Pepakura
2. resin, clay and bondo for details
3. so I get forms for the vacuum table, I wanted the pieces pep with expanding foam (to seal the window) spray out and share! Has anyone ever done or someone has another idea, I like the pep pieces for thermoformed get? what you think?

and thanks for the great ideas here, the forum is really great!

best regards
raphael

 

[derfieseKlaus]

one picture more :cool

 

[cavx]

I also have a question on making molds (masters, forms or what ever the proper name is). I have watched several videos and the part to be vac formed seems to be made out of wood, MDF etc.

So my question is:

Could the part being vac formed be made from plaster if it is solid?

 

[micdavis]

Yes it can be solid plaster. But Hydrostone or Hydrocal are better and not that much more than plaster, if at all.

Plaster will chip and crack easier, maybe even on the first pull. With the other two you can usually count on 20 or 30 before things start to go.

 

[cavx]

Awesome, thank you for answering so fast.

Another question if I may?

Whilst watching lots of You Tube videos tonight, I saw a few times when multiple bucks were placed on the table that "webs" would appear between the shapes being pulled.

So my question is: Is this plastic type dependent or because the bucks were too closely spaced?

 

[cavx]

Well after watching a heap more video, I found the answer. Apparently there is a height to spacing ratio. I did my first vacuum form today and whilst I need to fix an air leak, it is fun and easy to do. I used HIP for my parts.

 

[3d-builder]

here are some parts made for forming made out of Ultracal 30 a tooling gypsum cement .......same stuff micdavis was speakig about.....it's very good very strong. It will hold a nice edge unlike plaster it won't wick moisture for days and has a much higher PSI strength than plaster.

Here it is being formed...

Hope that helps......:lol

 

[cavx]

Awesome, thank you for that. If you had not mentioned what it is, I would have assumed MDF.

This site is soooo cool the way other enthusiasts share info so freely.

I spoke to a guy in a shop about vac forming my part and it was suggested that I might need to re-sculpt the for the purpose of this. I am thinking MDF and just making the base solid.

The parts for my full sized table should be ready on Friday. There is so much I want to make, I just need to do a few good pulls to know I can do this, then start a collection of bucks.

I am making my table 600mm x 600mm.