I wanted to make a simple, low cost vacuum chamber. Using a previous Instructionable, I made one (see the blue RTV?) but I was unhappy with the result - especially the cost. I had about $16 in 2 fittings alone - the most expensive being a brass bulkhead and the container. I thought that I could do one simpler and more economical with more commonly obtained and cheaper items.
I decided to use a large, wide-mouth canning jar as the chamber. It's strong, and you can easily see what's going on inside. Plus they're cheap - we had several in storage from our canning forays (my wife won't miss one, or two..)
I built 2 chambers - one for quickly marinading meat for jerky. Our 13u baseball team eats a lot of jerky. The other one will go to stabilize wood. I make pens, bowls, and other projects on a lathe and always use stabilized woods as wood that is stabilized is inert, not prone to temperature changes, won't pick up oils from hands, and actually becomes harder after my process.
Gather your supplies - 1 simple T fitting at Menards - ~$1.25, 1/4" valve at Menards $4, a couple of wide mouth canning lids, piece of scrap aluminum, teflon tape, 1/2" bolt and nut, old air fitting, and an old gauge I found.
Step 1: Make Your Bulkhead
The bolt I used is about 1 1/2" long. Drill a small hole through the middle (I was a bit off but as long as it's through and through, you are OK). Diameter of the small hole is not important. This will be your bulkhead.
Assemble everything. I drilled a hole that was slightly larger than the bolt through the 2 lids and the scrap aluminum. I made rubber washers from some rubber sheeting laying around - an old bike tire would work also. I made 2 washers - one for each side of the lid. I was going to cap the other end of the T fitting but found a gauge that fit. Make sure you use Teflon tape where there are threads.
I connected the air fitting to an air pump from Harbor Freight and it easily pulls -25lbs of vacuum. When it hits -25, I shut the valve and disconnect the air line.