Thank you everyone who responded to my deep-draw question! Your
collective wisdom is ‘deeply’ appreciated.
I had a very exasperating problem with my last batch of castings,
and I am at a loss as to what’s going on.
I have a table-top vacuum machine, the kind that uses a solid flask.
Lately, I have not been able to get a seal on my flasks. Thanks to
the Ganoksin tips, my spruing has improved to the point where
bubbling is minimal even without a seal, but it is still a problem in
some cases. Since I’m under a deadline to get out a bunch of pieces,
I can’t afford to have a significant failure rate.
Changing pads hasn’t helped. The machine is pulling a vacuum (I’ve
tested it every time), but I just can’t get the flasks to seal. I’m
thinking of gluing the pad down in case air is seeping underneath.
Pushing down with the tongs has no effect. The investments don’t
appear to have any cracks, and there aren’t any blow-outs through the
I would be grateful for any tips or suggestions.