Group Build - Vacuum Form Table

Area for developing group projects, such as workshop equipment
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swinkdaddy
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Group Build - Vacuum Form Table

Postby swinkdaddy » Tue Aug 23, 2011 8:59 am

Anyone interested in helping put together a 4x4' vacuum forming station? The idea has floated around now for a while, but with the group build dragon coming up. I'd like to see this become a reality so we can form lightweight plastic parts.

My plan is make it a stand alone station that uses a dump valve to evacuate the air into a vacuum drum. (as opposed to using a shop vac).
For that I am on the lookout for an old style piston air compressor to reverse the lines to make it into a vacuum pump.
some heating elements/wire and thermo controls for the preheat hood.

Anyone want in on this project?
Have kilt, will travel...

Judeling
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Re: Group Build - Vacuum Form Table

Postby Judeling » Tue Aug 23, 2011 9:43 am

Swink

Talk to Bil D. first He has a larger table but has not brought it in because of space issues until now.

Before we do this we need to have the space. I have been eying the wall area just east of metal land across from the yellow door as a possible plastics area. I have also been looking (casually) for an electric range for elements. Depending on the design a 4'x4' table can take up much more space then that. So determining living space would be important.

Do we also build the rollers to provide stock?

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smittex
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Re: Group Build - Vacuum Form Table

Postby smittex » Tue Aug 23, 2011 1:38 pm

I'm in!

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Orkraider
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Re: Group Build - Vacuum Form Table

Postby Orkraider » Wed Aug 24, 2011 4:31 pm

I"m in.

I need access to one of these for the stormtrooper costume I want to make, as well as a great many other things.

If I was cruising craigslist for parts for this, what all would they be?

Also, I know someone brought by some Sintra, but if we could find a source for more, that'd be helpful.

Riley
Riley Harrison
facebook.com/rileyharrison

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swinkdaddy
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Re: Group Build - Vacuum Form Table

Postby swinkdaddy » Thu Aug 25, 2011 7:47 am

Orkraider wrote:If I was cruising craigslist for parts for this, what all would they be?


Old piston and motor (the type with a belt) air compressor, about 15-25 gallon one should do it. But the size of tank isn't essential. Even a 55 gallon drum can be converted to the vacuum chamber and the pump set into station. Basically you reroute the lines so the pump evacuates air from the tank making a vacuum chamber.

2-4 inch dump valve. any quick turn, large volume inline valve should work.

as for the heating element, we will prob need to string our own Nichrome wire, to create a 4x4 oven hood. I need to to more research on this.

Heating element controller, again need to do more research first. If we string up X ft of Nichrome with Y diameter, we need Z amp rating. that kind of thing.

Any engineers out there who want to take a stab at calculating a 4' x 4' oven with about 6 inches between lines???
Have kilt, will travel...

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otto_pjm
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Re: Group Build - Vacuum Form Table

Postby otto_pjm » Thu Aug 25, 2011 8:36 am

On the construction of the vacuum system, this site has great info.

http://www.joewoodworker.com/veneering/ ... mpress.htm

This guy does vacuum clamping for veneering, but has jigs and plans for vacuum hold down and other uses as well. He has one design where you pump up the pressure and flip the valve to pull down whatever you are working on, and the pump only operates to compensate for leakage, to me that seems like a great option for thermo-forming, as you can have a strong pulling force all at once.

Axman has had one of the vacuum pumps he uses in some of his plans in the past.

Also, material wise for the pedal powered (whatever it will be). There's a guy (Cliff I believe) who has a lot of alumabond and similar materials he wants to sell. I have a bunch of pieces under my CNC you can check out. It's basically a sandwich of thin AL 1/4" or so HDPE and thin AL. It's used for structural and decrative stuff. It can be bent in a brake, or by hand into any shape, it holds it's form, and it's much lighter than a solid AL panel would be, and cheaper too. (but it's still not cheap). At any rate it would be nice material for the pedal thing as it's light, but can hold it's shape on it's own.

Dibond is another variety the guy has some of.

I wish I had more time, but I'm going to focus on the CNC so it can cut mold's etc for the pedal project.

Pete

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otto_pjm
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Re: Group Build - Vacuum Form Table

Postby otto_pjm » Thu Aug 25, 2011 9:13 am

otto_pjm wrote:On the construction of the vacuum system, this site has great info.

http://www.joewoodworker.com/veneering/ ... mpress.htm

This guy does vacuum clamping for veneering, but has jigs and plans for vacuum hold down and other uses as well. He has one design where you pump up the pressure and flip the valve to pull down whatever you are working on, and the pump only operates to compensate for leakage, to me that seems like a great option for thermo-forming, as you can have a strong pulling force all at once.

Pete


This is a link to the specific system I mentioned above, the author estimates $180 and 3-4 hours to build. It's all common parts, mostly brass fittings, PVC pipe, etc, weighs 11 pounds and needs a medium sized air compressor and can produce vacuum of 28" of Hg. (Mercury). This would be cool as it could be used for thermo-forming, veneering, and vacuum hold down, as the vacuum bits are small and self contained.

http://www.joewoodworker.com/veneering/v2-about.htm

Pete

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smittex
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Re: Group Build - Vacuum Form Table

Postby smittex » Thu Aug 25, 2011 6:37 pm

For 6" crosshatch, 50' of 22 awg nichrome will consume 288W @ 120v, 32 awg would consume 24w. At higher voltages, you can push more current, thus power. Don't know heat txfr equation for air... the nichrome looks too expensive considering efficiency of generating heat. Consider range top spiral heaters or infrared heating elements such as drawer type toasters?

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boltz
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Re: Group Build - Vacuum Form Table

Postby boltz » Thu Aug 25, 2011 8:19 pm

How about heat lamps? Like the 250 watters used to keep french fries warm?

-Jim Hart

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swinkdaddy
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Re: Group Build - Vacuum Form Table

Postby swinkdaddy » Thu Aug 25, 2011 9:11 pm

Looking around the webs, a spool of 32 awg is going for $8.50 for 100ft.
http://www.nichromewire.biz/36_100ft.html
Have kilt, will travel...


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