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Plywood to PVC adhesive for blast gate

Lou Jacobs

Lou Jacobs

Joined
Jul 18, 2018
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Baltimore, MD
Website
loujacobswoodturning.com
I’m making my own blast gates for my new dust collection system. I’m debating an adhesive to join the plywood gate to the pvc pipe stubs that will be the connectors to the vacuum pipes. I’m debating between something like Liquid Nails vs. silicone caulk. These gates are made so they’ll be the support brackets for the pipes (on the wall as well as ceiling) as well as cut-offs. I wonder if you’ve done something similar and have recommendations. I got the basic design off of YouTube.
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I have had very poor results trying to bond wood to plastic with epoxy and I've tried several. In fact most epoxies state they won't bond polyethylene or poly propylene. You might have better luck with PVC, but I suggest you work out a mechanical fastener.
 
I'd look for a way to get a screw or bolt through it for mechanical holding and silicone caulk to seal. If you use epoxy then roughen the PVC surface aggressively to provide some mechanical grab.
 
Yes, I got a few of the same ones from Grizzly, but they are pretty flimsy, and I enjoy the process of making something more substantial and suitable to my needs. I’ve read comments on line about those cheap plastic gates eventually clogging with dust and not closing completely. The design I’m using is self-clearing and should not clog. 05F92744-3A57-4840-A154-2B79AC052458.jpeg
 
Liquid nails sucks. Haven't found much use for it on anything. I would try E6000 and scratch the PVC with really course sandpaper to give it some tooth to bite. Epoxy will work if you do that.
 
The problem with the cheapo gates is they leak when closed. In designing your own, how do you plan to allow the seals to be flexible enough to open and close and yet maintain a seal when closed?
 
The plywood is a friction fit. I’ll apply paste wax to it to ease it a bit, but it seems to make a good, tight seal. The neat thing about this design, is that they can be mounted on the ceiling, or behind a tool, and actuated by pulling a cord or rod attached to either corner of the swinging gate piece.
 
Curious why you made that pivot so far from the back. That's going to hang quite a distance off the wall. Silicone is the thing to use there, but I would also make the wood thicker for attaching the pipe. The picture makes that look like 1/2" plywood. I'd feel better about adding another 1/2" thick donut on there to make a flange.
 
Try a polyurethane construction adhesive (like Gorilla glue, just thicker). That stuff will stick to just about anything. It takes days for it to wear off my fingers.
 
Richard, if I understand your question, if I’d made the apex of the gate lower, the swiveling part would have had to be quite a bit wider to swing fully open and closed. I’m not cramped for space, and as I said, several of these will be hanging from the ceiling. Bob, I’ll look into polyurethane construction adhesive. Sounds like what I’m looking for. Thanks all!
 
Lou Jacobs said:
Rob, do you use aluminum gates? I’ve seen comments that those also suffer from loose slides and significant loss of vacuum due to leakage. But yes, the make-it-myself factor is a significant part of the appeal of going this direction. Also the fact that it can be mounted out of reach and operated with cords.
Click to expand...

I do use the aluminum gates - all are 6". There is a set screw to lock the slide in position. I do not notice/hear any vacuum leaks from them.

I bought mine at a company called Blastgate in Warren, MI (which is local to me so no shipping!). Great folks there, the best customer service I have ever experienced! I bought my piping from them too.

I mounted all gates within reach - keeps it simple.
 
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I made about a dozen blast gates out of mdf and plywood 10 years ago. Used Gorilla glue to join them to the pvc. It worked well and I have had no problems.

I've had plastic gates and they were junk. The aluminum gates worked ok, but the ones I had were made a lot of noise. The slide rattled and sometimes whistled. I replaced all but one with my homemade gates.
 
I made my gates from 3/4 ply and 1/4 Masonite gate. The ply has two screws into the PVC pipe and all is sealed with silicone caulk. The caulk holds well and is still a pain when you move a line. The point of this is that the screws hold the pipe not the caulk, but the caulk does do a lot.Photo Resizer 2020_11_03_10_28_08.jpg
 
Robert, 5200 occurred to me. Good idea! I have read about it quite a bit on my boatbuilding forums, though I’ve never used it. It is apparently indestructible and almost impossible to take apart joints that are bonded with it. I discounted the idea just based on expense, as it’s quite a bit more expensive than most of the other options. I’m waiting for a construction adhesive to be delivered today and will move on with this fun challenge. As someone posted on another thread here, part of the appeal of turning for me is solving these kinds of challenges.
 
Eclectic E-6000 adhesive sticks to everything, stays pliable, does not turn brittle, very strong adhesion, available in most stores.
 
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