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I'm preparing to take the plunge into hide glue. I'll be gluing on a bridge soon, and I'd appreciate some advice. I have a vacuum clamp for gluing bridges. After applying the hot hide glue and clamping it with the vacuum clamp, when should I remove the clamp to clean up glue squeeze-out (after which I'll put the clamp back on)? I don't want to weaken the joint by unclamping at a critical time in the glue's setting process...

Thanks in advance for your help.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Todd, as with any new procedure - I'd recommend doing a couple of dry runs to make sure you have the timing down and get a feel for the sequence.   Are you using some kind of pin/index system to position the bridge?

I find the vacuum clamp much easier (with hide glue) than any of the other clamp/caul systems I've tried, but you still need to move reasonably quickly.

Once you get the bridge down and clamped firmly, I would wait about 10 minutes before trying to do any cleanup. Wish I had an exact time for you, but that's generally what I use. Less might work just as well. Any other people want to jump in here?

By this point, the squeeze out will probably not be a rubbery bead you can just peel off. It will be a little harder and tougher, but you can remove it with a little spruce "chisel", moistening with a warm, damp rag, if necessary.

I wouldn't struggle too much with it, or spend too much time unclamped. Don't go for perfection at this point - remember you can clean it up later with a little more effort. The "De Glue Goo" stuff works quite nicely on hide glue.

If you buff your bridge before gluing, the dry glue will pop right off the ebony/rosewood. Sand the underside of the bridge lightly just in case you get any wax/compound on it. If you mask (low tack tape) off the area around the bridge, it also makes cleanup a lot easier.

My last bit of advice is to setup a household iron (low heat, bottom up) and warm the bridge throughly. Don't overheat it and burn yourself when you go to pick it up. I actually place the warm bridge on the top briefly to warm the spruce as well.

(While not completely necessary with the vacuum system, it will give you some extra open time and is very helpful if you were using a traditional clamp/caul arrangement. Also my shop is cold in the winter and I feel the parts should be warmed before gluing.)

Overall, it's a nice clamping system. Only problem I ever had was an old membrane breaking a few minutes into clamping (old, old material). Lucky I didn't walk away! I managed to get the bridge off quickly, cleaned everything up, and put it back on with a soundhole clamp.

Steve

Thanks for your reply, Steve. I just checked out your web site. I am absolutely blown away by your guitars. And I'm a tough critic. Truly awesome.   

Now, back to bridge gluing. Your input is very helpful and much appreciated.    

My bridges are pinless. I could drill little holes through the saddle slot, top, and bridge plate for locating pins, but what I've done before and plan to do again is use little pieces of masking tape (a couple layers) carefully placed on the top at the corners of the bridge to keep it from sliding while gluing. Masking around the entire outline of the bridge to aid glue cleanup is an option I'll give more consideration to, but my bridge outline is very curvy (though it does have corners), which poses a challenge.

In the interest of time savings and minimizing the likelihood of damage to the finish on the top, I'd like to develop a method of removing as much of the glue squeeze out as possible (ideally all of it) before the glue hardens, but the highest priority, for sure, is making sure the strength of the joint isn't compromised by unclamping it at the wrong time or leaving it unclamped too long.

I will warm the bridge first and heat my assembly room to at least 72 degrees.

If any of you other masters of hide glue usage out there can offer your advice as to the best timing for unclamping for glue cleanup, I'll wash all your dishes for a week.     

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Todd I do the same as Steve, 10 minutes, then a quick clean up and replace for 45 more minutes. I would be very hesitant to do a brige with out some sort of locating pin to hold it in place. As the rubber sheeting comes down it may cause the bridge to shift, even a little is bad

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Lance@LuthiersForum.com

Todd, great to hear about your progress. We met in Tacoma in 2004, admiring the fantastic collection they had on display. The Stauffer, Panormo, Torres, Lacote, Ramirez, etc, were definitely inspiration for me.

I asked about alignment pins, because I do think it's important. The vacuum membrane tends to come down straight and even (even on tall, thin braces), but there is still no guarantee against a part slipping. Tape on the corners will help, but I'd prefer pins.

I use a pin bridge, and go through the E strings. I drill these 3/16" and then use 3/16" nylon dowel. Leave them a tiny bit high and you can easily pull them after the glue dries. If you drill through the soundboard/bridge patch, back up the holes with a piece of masking/packing tape. I like to go all the way through to get the pin firmly into the bridge plate.

With your pinless bridge, definitely use small (1/16") pins through the saddle slot. In either case, position the bridge carefully, clamp it firmly through the soundhole and drill your holes. It's just one more thing that will help your gluing process.

With hide glue and vacuum, that bridge is probably rock solid after 10 minutes (maybe I should run a few tests). I still like to get the pressure back as soon as I can. Do a modest cleanup now and then come back to it at your leisure. Bad things always happen to me when I rush around, and hide glue is so easily cleaned up isn't worth taking a chance.

Steve, forgive me, I'm terrible with names, but if you're the guy who sent me the photos you took of those amazing old guitars, then I remember you well. If you're someone else I met while admiring those guitars, then I'll remember you when I see you next and put name and face together. I hope to make it to the Newport fest in Aug... you'll be there with some instruments? It would be great to see them in the flesh.

Thanks again for your responses. Again, very helpful. I'll definitely give serious consideration to your recommendation, and Lance's, on using pins. You've made me nervous about the tape technique, although I must say, in my very limited experience, it's worked quite well for me. I use at least two or three layers of tape blocking in all four corners of the bridge and, in my observation, it holds the bridge in place quite securely. It makes for a neat "pocket" to drop the bridge into after applying the glue.    

Other virtuosos of hide glue are invited to chime in with your thoughts on the timing of unclamping for glue clean up.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Todd, you're remembering the right person - I did send you some photos after the show. Nice to meet you then, and glad to be in contact again. I will be showing at Newport and hope to see you there.

Honestly, the layers of tape (as well as the very shallow finish "pocket") *should* do a fine job of locating the bridge, and keeping it there while clamping. I have done this myself, and it worked just fine.

However, having personally experienced just about every problem that can go wrong during guitar construction - I would opt for the pins. Murphy lurks at every operation...

Steve

Yup, I had a bridge shift on me with the tape.

Steve,
I posted the other day looking for advice on constructing a flip top vac system and you responded with some good advice. Just thought I'd share a picture someone sent me of a system used for building and repairs prosthetic devices. He said it was built from an aluminum cake pan. Amazing what a little bit of ingenuity can do.

[QUOTE=rlabbe] Yup, I had a bridge shift on me with the tape. [/QUOTE]

Were you using a vacuum clamp or conventional clamps? Did you build up at least a couple layers of tape? Did the bridge slide up over the tape or push the tape aside?

Thanks.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

And another thing: Will hide glue stick to the membrane of the vacuum clamp? Would it be advisable to put wax paper on top of the bridge before putting the vacuum clamp on?

Thanks.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Todd, getting glue on the membrane hasn't been a problem for me. It won't stick the membrane to the bridge, if that is your concern. The rubber can (rarely for me) get pulled down into some of the sqeezeout, but it doesn't interfere with anything and can be cleaned up later.

Love the cakepan! I am a big fan of doing the minimum possible on jigs, using them, and then improving as necessary. If it works - use it.

Steve

is LMI the only place that sells this vac-clamp? If there is a cheaper one
I'd be interested...If not I'll just make one!

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John Mayes
http://www.mayesluthier.com

I don't know of anyone else who sells a clamp like this. I sprung for the LMI one, partly because I was uncertain of how to make one and wanted to have a good model for making my own vac clamps in the future.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/