Here’s a somewhat related question I’m hoping somebody here can answer:
How strong is the vacuum formed in the traditional ball-jar canning method.
The reason I ask: I discovered I could dye wood veneer with high quality light-fast dyes using a vacuum pump from an old oxygen concentrator. But one day I sucked some of the dye into the pump. So while waiting to figure out how to fix the pump, I got the notion of boiling the dye with veneer in the jar in the microwave and sealing it with the lid. It formed enough vacuum to dye “through and through” in the time it took to cool enough to handle.
Tried to find some rating of the vacuum in terms of inches-Hg but found nothing online. I was thinking I could do a write up for other wood-workers.
I fixed the compressor by the way, and got a little smarter too.
Here’s a tip for what it’s worth: a refrigerator compressor will draw 20” or so Hg, around say 3/4 atmosphere. They’re quiet and free. The only hitch is finding one and rigging a way to return the oil sprayed out as the pump runs.
Anyway, I’d appreciate any suggestions as to how I could find out about the vacuum in a canning jar. I’ve been to the how-to sites and they don’t give any measurements—all practical.
From what I’ve been able to find the Foodsaver usually pulls between 20 and 25 “in. Hg vac”