I was able to push the vacuum straight on to the end of the 90 from the back, and it created a good seal (I couldn’t feel any leakage from around the intake)
I did it about 4 times. Just needs a wiggle and a push and it seats well against the pipe, from the back with the top shelf installed.
Here’s a side view of the whole thing. There’s going to be a sealed door where the bucket is. The vacuum door will have a intake for cool air near the bottom, and the shelf above the vacuum is angled to allow the hot air to travel out by convection.
Just pushing a piece of wood and carpet against the back side the vaccuum was under 50dB, down from about 65dB outside it. That’s certainly managable.
Added a couple images to the first post. It’s getting close. I need to sort out the doors next I think.
I just noticed that your cyclone is mounted to the shelf. Is there anything sealing the cyclone to the bucket underneath it? The bucket needs to be 100% sealed to the cyclone or else the shop vac is going to just suck air through the bottom of the cyclone instead of through the hose.
It’s the biggest problem I had with the Thien baffle I tried to make. Air kept getting pulled through gaps between the baffle and the bucket.
The bucket enclosure and door will be sealed. It’s based on a design I linked earlier I believe. Apparently I didn’t link it but here’s the design: https://www.instructables.com/id/Portable-Dust-Collection-System-With-Noise-Reducti/
I put my thein baffle inside a barrel I bought. Then I sealed all the new openings I made with a tube of silicone. The barrel was like $5 from a local place. I guess they are used all the time in cafeterias. Mine said it contained lactose or dry milk or something.
Weather sealed and caulked.
Mmmm… The old 5 gal Bucket o’ Lactose… My guts are gurgling just thinking about it. 
No. I think it was closer to 40-50 gallons.
Photo album:
It say in one of the pictures “lactose hydrous 316”. Not even gonna google that.
Early test seems like a seal success. I put my hand over the incoming pipe on the side and the vacuum bogged right down. The only downside is I don’t have an easy way to tell if the bucket is full but I’ll just have to remember to check it periodically.
Guess you’ll have to cut a window into the door so you can spy on the bucket.
And then cut a window in the bucket. Or find a clear plastic tupperware that’ll fit in the same space.
Perhaps a window in the door, the a light behind the bucket that you can turn on to backlight the bucket and show you how full it is?
I honestly won’t be running this that often. Checking it after every 5 cuts or so will be plenty.
I’m thinking just a piece of plexi over a 3" hole in the shelf above the bucket should be easier. I’ll bring a saw home tomorrow, if I remember.
Put a bathroom scale under the whole thing.
Not really, just saying there’s more than one way to determine if its getting full. Be creative!
I bought a distance meter that I plan on mounting to the lid, then have a Esp32 light up an led when the bucket is full.
