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Hello everyone,
I'm trying to make the move to using a vacuum clamping set-up for bridges. I've bought a 1.4 CFM vacuum pump (from Joe Woodworker) and the bridge clamp from LMI. And I've watched any videos that I could find about the topic, but I'm still in the dark somewhat in terms of how to set it up.
I got the filter that Joe recommended, but I guess I still need to source a vacuum gauge (?). I have all the hardware to get all of this set up (except the vacuum gauge), but I'd love to see some pics of folks' set-ups, and hear some tips on how to go about the process. Do you you use a pressure (vacuum) gauge or not, do you have an inline release valve (as I've seen in some pics), etc. Do you just turn on the pump and let it run, or is there some way to monitor and adjust the pressure?
Thanks for the support, as always!
Ken

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Ken Mitchell
Durham, NC

My pump came with a vacuum gauge. It’s not necessary, but after you get used to how things work, it will help know if your setup is leaking. I have a release valve. Without it, you’d have to wait for a leak to remove all of your vacuum before you could reposition the clamp. My pump is a diaphragm pump rated for continuous duty, so I just turn it on and let it run for 2 - 2.5 hours (using 315g hot hide glue). About 5 minutes after I first clamp a bridge, I release the clamp, clean up the squeezeout, and then reclamp. I love the way my setup works. I’ve clamped over 100 bridges with it.

If you’re uneasy about your first bridge, make up a dummy bridge and top and try it out. You will be pleased when you get it figured out. I’m away from home, so you get no pictures.

You can get 1/4” tubing, fittings, and valves pretty cheaply in the plumbing department at Lowes. Hers is where a picture would be nice. I won’t be home for a couple of days. If you haven’t gotten any further by then, bump this discussion so I’ll notice and I will then take some photos.

This is my take on the Joe Woodworker EVS. Forgive the dust. FWIW, I wouldn’t lay it out like this again. I was trying to make it compact, but I can’t access any of the innards now, and it isn’t repairable. Joe also has a very basic continuous run setup—I’d search that out on his site. If you do run with that, you won’t need the release valve. In these setups with vacuum reservoirs, the purpose of the valve is to seal them while the vacuum builds up—not to keep the vacuum from evacuating out of the clamp or bag. The vacuum should slowly release when you turn off the pump.

There was another very recent discussion on vacuum setups, so I’d search it out, too.

One thing to keep in mind is that LMI’s bridge clamp comes with a different setup for attaching the hose than Joe Woodworker uses. Joe’s hose clips on to what almost looks like a Schrader valve without the center pin. Thankfully the local hardware store had whatever it was I needed to make the setup work (wish I had a name for you). It looks like 3/8” into the LMI clamp, 1/4” to the hose.

As far as putting it to use, it’s really simple. Just fix the bridge in place, set the clamp over it, and turn on the pump.

When assembling a vacuum setup I learned a very important lesson. Teflon tape is inadequate to seal up threaded joints. My system had numerous leaks. After talking to an experienced plumber, he recommended pipe dope rated for natural gas plumbing. I took the system completely apart and used the pipe dope which worked perfectly.

I remembered. Here you can see the cheap plastic fittings and valve from Lowes. The fittings are pretty convenient in that they are easy to release to move the vacuum to other tools. I’ve made some vacuum clamps for other operations including holding bodies while I work on them. The release valve makes it easy to reposition the bodies as well while I’m working.

I bought some of the rubber sheet material from LMI for making my own clamps. I’ve actually had my bridge clamp long enough that I had to replace the sheet a couple of years ago.