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LMI Vacuum Bridge Clamp
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Author:  bcombs510 [ Mon Sep 12, 2016 6:53 pm ]
Post subject:  LMI Vacuum Bridge Clamp
Hello,

This is more of a uke question but I'm posting here to get more views, so apologies for that. I keep doing this so hopefully the OLF board doesn't vote me off the island.

I have the LMI vacuum bridge clamp on the way along with their valve that lets it work with my compressor. I bought this because of TAS, mostly, but also because I can see using it a bunch to simplify the process. I ordered it out of frustration trying to get clamps and cauls set up properly in this Tenor Uke I'm working on without destroying it. :mrgreen:

Question - The clamping area is 8.25" x 3.5" which is super close to the surface area of the uke but I won't be sure until it gets here. If it is too big, I'm wondering if I could take a piece of thin board that is oversized (say 12" x 6") and rout a hole that is closer to the bridge footprint (say 7" x 3") and put gasket on the bottom of the board to protect the uke and put the bridge clamp on the 12" x 6" board and still have enough clamping pressure to attach the bridge? I guess the question is - If you own one of these, is there enough clamping pressure that rigging it like this would still achieve the desired result?

Hopefully that makes sense. If not I can draw up a picture in mspaint that will confuse the situation further.

Thanks!
Brad
Author:  bobgramann [ Mon Sep 12, 2016 8:29 pm ]
Post subject:  Re: LMI Vacuum Bridge Clamp
Sounds like it's worth the experiment. I have one of those clamps. I use it with a diaphragm vacuum pump. It works wonderfully. I ordered some extra membrane material from LMI, and using their clamp as a model, I've made clamps of other sizes for other gluing operations. I used closed-cell foam weatherstripping for gasket material. I don't know if your venturi vacuum source will be sufficient--I've never tried it.
Author:  kencierp [ Mon Sep 12, 2016 9:14 pm ]
Post subject:  Re: LMI Vacuum Bridge Clamp
Here's my DIY vacuum bridge clamps -- guitar and uke


http://acousticguitarconstructionforum. ... ?f=7&t=817
Author:  bcombs510 [ Mon Sep 12, 2016 9:41 pm ]
Post subject:  Re: LMI Vacuum Bridge Clamp
Thanks, Ken. I ordered some extra membrane from LMI when I ordered their clamp. I may end up making a custom clamp for ukes. Your post there will surely help!


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Author:  mayor [ Mon Sep 12, 2016 10:43 pm ]
Post subject:  Re: LMI Vacuum Bridge Clamp
I have a 6 gal Porter Cable compressor that I used with the vacuum clamp. Using about 100psi, I was able to maintain about -27 in on the vacuum gauge. Granted, it was noisy as the compressor was on for about 75% of the time. I did need to buy a fitting to connect into the compressor quick-connect. The vacuum clamp is really great.
I think with your setup, the extra board and membrane will need to be pretty thin, because the rubber membrane of the clamp will not stretch too far, especially if it has to travel an extra 1/4" or more to reach the surface of the uke.
Author:  johnparchem [ Tue Sep 13, 2016 12:36 am ]
Post subject:  Re: LMI Vacuum Bridge Clamp
I made a custom clamp as the LMI clamp is too big for a tenor guitar. I like your idea though but I agree with mayor's comments about height.
Author:  bcombs510 [ Sat Sep 17, 2016 12:38 pm ]
Post subject:  Re: LMI Vacuum Bridge Clamp
So I started with the idea of trying to use the LMI clamp with a small board between the clamp and the soundboard so that it would fit the Uke. This seems to be working. I have the recommended clamping pressure and the vinyl sheet is clamped down pretty well all around the perimeter of the bridge. I'll clean out the glue squeeze out after 10 minutes and then leave it clamped for an hour.

Image

Image


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Author:  Hesh [ Sat Sep 17, 2016 10:24 pm ]
Post subject:  Re: LMI Vacuum Bridge Clamp
Great looking uke Brad.

That may work. Some of our Collins Saddle Mill users do something similar for angled saddles.
Author:  bcombs510 [ Sun Sep 18, 2016 1:04 pm ]
Post subject:  Re: LMI Vacuum Bridge Clamp
Thanks, Hesh! It seems to have worked great! Hopefully the recipient can make it sing. :) I can make it play three chords.


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