IPMS-USA Journal: 'Build your own vacuum chamber'

wrote:


The usual workaround is degassing RTV rubber with vacuum to have crisp molds and pressurizing the resin cast to make air bubbles collapse in the resin mass until the resin is cured, resulting in compact and flawless finished parts. That's the most common method, apart from free air casting, I've seen used in Italy, Europe.
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Luca Beato - http://xoomer.virgilio.it/huey /
FAQ del plastimodellismo su http://www.ipmsitaly.com/faq/modelfaq.html
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Rusty White wrote:

I think you mean 30"Hg ,ie: 30 inches of mercury not atmospheres
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Kevin (Bluey)
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Rob,
You don't need to build a vacuum chamber. You can get one at Sears for $100.00. It is a syphon tank spray setup. You just delete one of the openings and put a vacuum gauge in one and a valve in the remaining one and you are ready to go. very safe too.
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Mike West wrote:

Do Sears export?
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You can also build one from a pressure cooker. I had two converted from pressure cookers I bought at Ace Hardware. You still have to add the quick connect, the pressure gauge (that's on my airline coming from the wall), and bleeder valve. They both work very nicely. However, my pressure cookers have a saftey hole in the rim of the cooker which will blow the gasket if it rises above 40lbs per sq inch. I blocked mine off with thin sheet metal made from an Xacto saw. I can now pressure it up as I need. However, 40lbs is enough. The whole setup costs around $120.00 +or-.
Rusty White Flagship Models Inc. flagshipmodels.com
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Rusty, you might want to reconsider that as they are placed there for a reason.
KL
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says...

Apart from the excellent suggestions made in the replies, can anyone tell me what the IPMS-USA magazine article is about? I'm in the Netherlands, so I have little or no chance to lay my hands on it. Is it worth chasing down for that article?
Rob
My models: www.xs4all.nl/~robdebie/models.htm Me 163B site: www.xs4all.nl/~robdebie/me163.htm AQM-34 site: www.xs4all.nl/~robdebie/aqm34.htm
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: : Apart from the excellent suggestions made in the replies, can anyone tell : me what the IPMS-USA magazine article is about? I'm in the Netherlands, so : I have little or no chance to lay my hands on it. Is it worth chasing down : for that article? :     The long time editor of the IPMS Journal, for the IPMS/USA organization, claims to have been forced out of his position.
    That was page 1, and in color. Pages 2 and 3 were a center fold section showing the 100 or so issues that he was the editor of. Also in color.
    The gent involved did not exactly cover himself in honor and glory in his parting shot, I am sorry to say.
    Really, a tempest in a teapot, unless you happen to be in his shoes.
                            Bruce
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"I like bad!" Bruce Burden Austin, TX.
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Rob de Bie wrote:

My vacuum chamber is a clear glass oven proof casserole dish , my wife no longer wanted ,its quite large ,I have it up turned on a raised wooden base which has a rubber mat glued to it ,the gasket that forms the seal is made from clear silicone sealer ,I coated the casserole dish edge with petroleum jelly and pressed it into the silicone which I applied to the rubber mat ,left it cure and gently removed the glass dish. The vacuum is drawn through a hole in the wooden base .Vacuum pump is a refridgeration compressor from an old freezer,I just use the suction side to draw the vacuum on a tank and open a valve to create the vacuum in the chamber.The tank is a modified dry powder fire extinguisher. I'm planning on building a pressure chamber from an old LP gas cylinder.
Most of my tools and equipment are all home made from stuff I get from auctions and second hand shops.
My spray booth is made from packing crate ply wood , and a 900 mm kitchen range hood. It is filtered and has an internal light , and the fan is variable speed,and has a rotating stand to place the model on while painting.
I guess I'm a bit fortunate being an indentured Fitter and Machinist with many years experience in the engineering business.I am also a qualified Manual Metal Arc and Metal Inert Gas welder.I have a fairly well equipped workshop at home and can do most things for myself .My next acquisition will be a 12 X 36 inch metal lathe.
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Kevin (Bluey)
"I'm not young enough to know everything."
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I'm jealous dude. I'm completely mechanicaly inept. I don't have the ingenuity or skills to build my own mechanical stuff. Let us know how that lathe goes. It will be interesting to see what you cobble together. I need to get one for myself, but I'll probably end up buying one and spending more than I need to.
Rusty White Flagship Mdoels Inc. flagshipmodels.com
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Rusty White wrote:

I will be buying the lathe ,I went to an auction a few weeks ago and missed out on a Harrison M300 in first class condition. Went for a good price though ,although a bit high for me at the time. Just depends on the ebb and flow of the finances , trying to justify it to the Minister for Finances and War , I have explained that I can do jobs with it for money , which will help pay for it and my hobby .
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Kevin (Bluey)
"I'm not young enough to know everything."
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You can do wonders with a $5.00 used vacume machine motor........ I built my own 18 in X 18 in table vacume machine for vacume forming various items. All you have to do is have a vacume chamber and the vac motor with a instant release valve. I think that would suffice for an air removal for RTV, etc. When evacuating the air from any mold material all you need is about a 30 second to 1 minute vacume to remove the air and pour......The vacume motor does not have to run until the mold material cures. The air does not return to the medium, however, you can also put vacume on the piece after the pour to insure that all of the air has been evacuated and the mold material has entered every tiny expanse.
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