So I have the V.I.C12 vacuum casting machine from Rio which has a separate investing table and casting machine side by side running off one 5 CFM vacuum pump.
My issue is with the investing table with a side draw bell jar. At about 25 inches Hg vacuum and above the 1/2” rubber pad gets pulled quite significantly upwards into the jar causing whatever I have sitting on the pad (so far just a beaker of water to test the vacuum) to tilt alarmingly. So far the beaker hasn’t fallen over, but I’m worried about a tall flask tipping while vacuuming and hitting the jar and/or spilling investment everywhere.
I’ve cut a 1” x 1” X-shaped slit through the middle of the rubber pad (Rio’s recommendation to keep the pad flat when vacuuming) with no improvement. Then I tried a little bit of talc inside the slits to help keep them open, that didn’t seem to help. Any other suggestions?
I get good vacuum (about 28 inches Hg max) and can boil room temp water in about 1 minute so it’s working properly, it just seems dangerous to have everything tilting around in there under vacuum.
Thanks in advance for your help!