W.E.T. [CAD_CAM_EDM_DRO] Re: Vacuum Forming --- Was--->Lights and lenses, the poor mans laser?

Hi Chris:
I am not Graham but here is a few pointer from 35 years ago when
I was a Plastic Lab. Assistant and some recent experiences.
1-If you are making a male form it is quick to make it out of
wood and just drill a lot of 1/32 or smaller hole in the base
near were the vertical form comes down to the base plate.
2-If the form is a cavity then make a male form out of wood and
pour a plaster mold over it. You can use soda straws in
the mold for the air passages just use a small coffee stir
taped in the end for a 1/4 inch or so near the part to get a
small hole.
3-It works better if you have a chamber (1 inch deep box) under
the mold to pull the air out even on all the small holes in
the mold.
4-We used Johnsons car wax for mold release on the wood and the
plaster. Coat the mold completely but with a thin even coat.
5-In the past few years when I needed only one or two parts that
was clear for to see air flow I just heated the plastic in my
wifes convection oven. It was tacked on a rectangle wood
with legs to hold it up about six inches off the bottom of
the oven and have room to sag as heated. When the plastic
sagged almost to the bottom I quickly pulled it out and
pushed it down over the form which was setting up on a
support. I found out from the plastic store the type of
plastic that had the lowest melting temp. and was easy to
form. This made a big difference in the working of the
material. On one deep contoured part I had to add a ring to
get the part to sink down on the male form but this was the
same as you do with deep vacuum formed parts.
GOD'S BLESSINGS
Bill


To: CAD_CAM_EDM_DRO@yahoogroups.com
From: "lcdpublishing" <lcdpublishing@...>
Date sent: Tue, 08 Aug 2006 13:15:01 -0000
Subject: [CAD_CAM_EDM_DRO] Re: Vacuum Forming --- Was--->Lights and lenses, the poor mans laser?
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Graham,

I have been wanting to try some vacuum forming for a while now. Can
you give me a quick rundown on the process? I am planning to make a
molded cover for the back of my machine (the one on the home page).

I know I need a vacuum source - I assume a shop vac would be fine. I
know I need a heat source - your idea is very neat.

What types of plastics can you use and where can you purchase them?

Are there any guidlines as to the mold - number/size of holes finish
needed to keep plastic from sticking etc.?

Thanks

Chris

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Graham Stabler" <eexgs@...>
wrote:

>
> You can melt all kinds of things with lamps, I use a 500W halogen

lamp

> for a small vac former. But unfortunately you can't get the focus
> required for cutting and its a matter of source size not the optics.
> You want something very small and very bright or collimated.
>
> Graham
>