Re: Investment casting of steel
- View SourceCall some custom gun smiths? You might find one that can make these small parts and have the casting equipment already on hand as this sounds just like some investment cast gun parts.
And as others have pointed out - neither alloy is "mild steel".
--- In firstname.lastname@example.org, "r_e_dorsey" <r_e_dorsey@...> wrote:
> I want to cast 4140 and 6150 steel. Both mild steels. The problem is I only need a dozen parts cast at a time and they are quite small. A foundry doesn't want to bother with it. Is this something a jeweler could do since the parts are small (0.5oz)?
- View SourceIn a message dated 11/29/2009 8:17:11 AM Mountain Standard Time,
the pump is a gast manufacturing diafram pump
the specs say 60 psi 29"hg but the guages have not been calibrated
i might be able to get this done at work this week
do you think it should be ok
Diaphragm pumps are not know for high vacuum, and they are typically rated
optimistically. Then, as they age, their diaphragms start leaking, and their
performance suffers. Also, as your elevation increases, the vacuum you can
pull goes down, and the gauges read higher.
I am at 5300 feet, and on a good day, I may pull 24 inches Hg, with a
The gauge could also be a cheap one, and its accuracy suspect.
You best bet is to suck from a tank, which is plumbed to the chamber,
through a valve which is closed while you pump down the tank. When you cast, open
the valve, and you can get a higher vacuum for a longer period of time,
until the tank and pump equalize. A 30 lb refrigeration tank is a starting
size. A 50 lb tank would be better, but they are harder to find. A 20 lb propane
tank has plumbing that easier to deal with, but they should be cleaned
thoroughly of all oils and residues, which is a chore.
I drill a hole in the top of a tank, and braze a 1/4 in pipe coupling over
the hole, and plumb from there with a tee, and hoses to the chamber and
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