Ray-Vin Lost Wax Casting Primer
I now have a great vacuum pump, but when I started out, I used a simple setup to generate a one-shot vacuum.
Get yourself an empty camp propane tank, some 1/8" automobile vacuum hose or model airplane fuel, line.
You will need some brass hobby tubing that is a snug to tight fit in the rubber hose.
Make sure the tank is empty, then carefully drill a hole in the top that the brass tubing will just fit into.
Then solder a short length of tubing into the hole. Finished!
So, where's the vacuum?, I hear you ask. Put a teaspoon of water into the tank. Attach the rubber hose to the brass tube.
Have a clamp ready (surgical clamps work best). Tilt the tank to get the water in one corner and then heat that spot with your torch to boil the water.
When you see steam coming out of the hose, remove the heat and clamp off the hose.
When the tank and the steam inside cool, you will have a vacuum source sufficent for one flask.
The second fitting on this tank was added when I got my vacuum pump.
I connect the pump there and the tank now acts as a vacuum accumulator.
The accumulator will also intercept any bits of plaster or metal that get sucked in before they get to the pump.
On the left is the spigot and the base plate with the gasket/spacer in place.
On the right is the underside of the arrangement showing the vacuum hose attachment.
The cat food can is just a riser to support the base plate level without pinching the hose.