As I've mentioned a few times here, I rigged this up after my turned pieces started exceeding the size of my 5 gallon DNA bucket. Prior to making this, I would soak oversized pieces in a heavy garbage bag sitting on a box or large dishpan. It was always a hassle emptying the DNA from the bag when done, so I wanted something a bit more permanent.
I bought a large plastic tub from Target, but it needed a lid that would seal.
To make the lid, I used a pre-cut 3/4" plywood disk that's sold at the borg as a cheap table top. It started out at 30" in diameter, but I mounted it on a faceplate and trimmed it to size on the lathe. (The dropped extension bed and 38" swing on the PM was very handy for this step.) Sorry, no pics of that step. The final diameter was sized to fit just above the first "ledge" in the side of the tub. (You'll see the ledge I'm talking about in one of the later pics.)
Next, I put a few coats of water-based poly on the disk to seal it. No pics of that, either.
Then I mounted it back on the lathe, and attached self-adhesive weatherstripping to the edge. The lathe was used only as a handy place to hold the disk on edge while I stuck the weatherstripping on.
Here's a close-up shot of the weatherstripping. It has dual seals on it:
I added a couple of handles, and it was ready to put on the tub. I soon discovered, though, that it was hard to push the lid down evenly, since it trapped air in the tub, and tended to want to rock to one side or the other. Time for Plan B.
I added a galvanized pipe flange (or whatever that part is called), drilled a hole in the lid, and sealed the joint between the wood and the flange well. Then I added a small length of 1/2" pipe, a ball valve, and a quick-connect air fitting. You can see the ledge in the side of the tub right above the white label. The lid sits on top of that ledge:
The pipe acts as a vent. It lets air out when I'm putting the lid on, and it allows air in when I'm pulling the lid off. I put the quick-connect fitting on it to allow me to attach my vacuum pump, although in use, I've found that to be unnecessary. I can just push the lid on slowly with the valve open, then when it hits the ledge in the tub, I close the valve. the suction fit at that point is very strong...I could probably lift the whole tub (including a few gallons of DNA) just by lifting the handles on the lid. With the valve open though, the lid lifts off without a whole lot of tugging.
Here's a better view of the plumbing:
And one last shot, showing how it normally looks in my shop, complete with heavy rubber gloves for reaching into the DNA.
One trick I used to minimize the amount of DNA I need is to place chunks of concrete in the tub, either on the sides of the piece, or in the case of a bowl, inside the piece. This helps raise the liquid level in the tub, much like putting a brick in your toilet tank to conserve water. The concrete also comes in handy for weighting down pieces that want to float in the DNA.
So...that's how I do it. Hopefully, this will give others some usable ideas.