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Homebuilt tools


#1

I also am interested in any discussion about homemade tools. I
am begining to get into the hobby of silver casting and the idea
of spending a lot of money on tools is a little discouraging. I
have kept an eye out for inexpensive used tools in my area (San
Diego, CA) but they are hard to find.

I would like to build a vacuum casting table using a recycled
vacuum pump I’ve acquired. The pump is a little larger than the
standard vacuum pumps I’ve read about in the specs on casting
machines in the cataloges. The pump I have is a Robinair high
vac 10 cfm pump. Will it be acceptable for use in a homemade
vacuum table for investment prep and casting? The casting
machines seem simple enough to build. Has anyone built one? Any
source for plans?

I read an old book mentioned on this list about building your
own burnout ovens and other tools for home use but it may have
been in the pre vacuum casting era. I don’t know. Any
suggestions from those of you who have been down this path before
would be appreciated.

Thanks,
Ken Hunrichs
@Kenneth_L_Hunrichs


#2

Ken See if you can find a copy of “Rock and Gem” magazine from
June 1991. There is an article in there on “How to make a Vacuum
Caster”. I have built a vacuum unit with a bell jar for
debubbleing but never got around to building the platform for
casting. Already had a working centrifuge. Good Luck making your
unit.

Joe B.


#3

Kenneth Hunrichs wrote:

I would like to build a vacuum casting table using a recycled
vacuum pump I've acquired.  The pump is a little larger than the
standard vacuum pumps I've read about in the specs on casting
machines in the cataloges.  The pump I have is a Robinair high
vac 10 cfm pump.  Will it be acceptable for use in a homemade
vacuum table for investment prep and casting?  The casting
machines seem simple enough to build. Has anyone built one?  Any
source for plans? 

Kenneth,

I built my own vacuum chamber out of a nine inch diameter steel
pipe. I welded a square steel bottom to the pipe and then
machined and welded a round plate to the top. I then cut a
section out of the side of the pipe with a cutting torch and then
fitted a section of 3 inch square tubing to the side of the pipe
over the hole. The three inch square tubing had a piece of plate
machined and welded to the other side. It was machined to accept
1 inch pipe fittings. I used a combination of plastic pipe and
iron fittings. I use ball valves to switch the vacuum between the
bell jar and the casting chamber. I used one inch pipe because I
wanted immediate vacuum. Probably 1/2" pipe would have been
sufficient.

The vacuum pump I use is a used 17cfm unit. I don’t see why a
10cfm wouldn’t work, considering many commercial units use a
3cfm.

I have been extremely satisfied with this casting arrangement. I
mounted a switch for the vacuum pump right next to the casting
chamber. Using a large pump gives immediate results. I use
standard 4"x6" perforated flasks. I wish I had made a larger hole
in the top of the chamber, so that I could use 6" diameter
perforated flasks. I would then need to machine reduction rings
that would reduce the hole size for smaller flasks. Since I
didn’t, I am considering building a second chamber for 6"
diameter flasks.

Next I am planning to build a larger vacuum table for vacuuming
investment.

Kenneth Gastineau
@Kenneth_Gastineau1