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The LMI vac clamp is great. In between uses though, you have to protect the surface that comes into contact with the top. DAMHIKT

Steve

I have the LMI clamp because I was too lazy to make my own. It's great. You can get the rubber from LMI as well. I have made a couple of vacuum clamps of different sizes with the rubber I bought from them. You could get the rubber from them and make your own bridge clamp.

I guess I'm assuming it's a silicone rubber membrane and an aluminum frame.
These guys should have you need if your interested in going that route.
http://www.torrtech.com/
I use a vacuum bridge clamp I made, works fine. I'll try to get a picture for you if you want.
Here's a photo of bag I made in situ to reattach a bridge on a 10 string, my clamp wasn't long enough.
As you can see, way too much glue, but good pressure, the guitars doing fine 2 years down the road.
the bags kinda ugly though, but the guitar cleaned up nicely.

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Jim Watts
http://jameswattsguitars.com

What do you use to protect your clamp? I have one as well and just keep it in a zip lock bag?
Blake

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Blake Dixon
Kelowna B.C.

Just made mine last week! I'm getting my gasket tape & vinyl from Joe woodworker http://www.veneersupplies.com/
I bought a cheap chopping board from Walmart and tapped #10 panhead screws every 1".

I've replaced the rubber membrane and the foam weatherstripping material on my LMI clamp. They sell the parts and it's easy to do. Make sure you store it face down on a flat surface or if face up, don't put anything on it. It doesn't take long to deform the foam, even with light pressure. Typically, I take it off after 10-15 minutes and clean off all the squeeze out both from the bridge and from the clamps, then reclamp. Keep it clean or you're asking for trouble. And I'm sure we all know it's only going to fail after the glue is on and time is pressing.

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Mike Lindstrom

I built mine with the rubber from an exercise stretch band. They come in different thicknesses and you can get them in pretty much any department store sporting good section. I used a thinner material because it is what I had. Next time I’ll go thicker.



The frame was made from 1/4” sheets of acrylic that I laminated together with acetone. I stuck the rubber down with RTV gasket sealant then screwed the top half of the frame down. The gasket is the LMI gasket.

Steve Smith has a plan for one in the tutorial section.
http://www.luthiersforum.com/forum/viewtopic.php?f=10117&t=23895

I have making one of these on my list as well. I found this thread with some helpful info:
http://www.luthierforum.com/index.php?/ ... uum-press/
Ebay sources for rubber:
http://stores.ebay.com/Jet-Gasket-and-S ... 7675.l2563
http://stores.ebay.com/RuBBeR-HoUsE-wAs ... 7675.l2563
No rubber but a good source of vacuum stuff, they have some breather release film that looks useful: http://www.avtcomposites.com/cgi-bin/co ... egory=1300

I have done the bond plexi with acetone trick for other vacuum fixtures, works well, so I am planning that route. I wonder if some scrap from an old wet suite would work for the neoprene?

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I see I somehow lost a few sentences in my post above.
I was trying to imply that it's possible to patch silicone rubber using GE RTV 108 adhesive and that Torr Tech has supplies for patching or building vacuum clamps.
The bridge clamp I made looks a lot like the one John Killin posted BTW.

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Jim Watts
http://jameswattsguitars.com

Aww poop! The last time I made that style was six years ago, I made a few with top plates after that but they cost double. I'd put it over a jointer to clean off the top of the acrylic and glue on another piece of rubber if you want to fix it up on the cheap- you can get a 12"x12" piece of neoprene sheet for $6 from McMaster Carr, or ~$10 if you want adhesive backed. I'd send you some for free, but the shipping would cost more than the shipping plus the product from McMaster!

The rubber is neoprene rubber, which is different than neoprene foam (which is what a wetsuit is). If you want other choices, you can look up 'rubber sheet' on Amazon Supply; they have all kinds of weird stuff, and their pricing isn't half bad.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Pool liner might work as well as long as you get the thin stuff. It seams to stretch a lot!

Blake.

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Blake Dixon
Kelowna B.C.

I'm not sure exactly what you mean by transference, like a texture or did it actually adhere? On a fully cured finish, nothing should be able to affect it, but the only finishes which are truly 'fully cured' in a reasonable time in lutherie are polyester and polyurethane. Your best bet to prevent any sort of reaction is silicone rubber, it's the most inert (and expensive) of the common rubbers, though that'll only help if it's a borderline problem.

The other option is to use something like vinyl sheet (shower curtain) for the membrane. It'll work just as well...I've done more than a couple vacuum clamping runs with garbage bags sealed to a hose with rubber bands- so long as it keeps the air out it'll work.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Hi Guys I do not post much as I had to sell all my tools and wood to pay bills and such. I used plastic window material, the stuff they use for windows in canvas covers for boats, it can be found at any fabric store its super cheap and works great.