Official Luthiers Forum!

Our clients seem quite similar to everyone else's clients - they like their new or repaired guitar's bridge to stay put, and they afford us broad latitude in how we accomplish that goal. While it appears that we builders and repair people, or at least those participating in this thread, have significant variations in our prep and glue-up processes (e.g., making up interior cauls, pre-positioning those cauls and clamps, taping up the top, and pre-warming the mating faces of the joint), I would submit that few of us bill out more than 1.5 to 2.0 hours of labor for bridge removal, cleanup, prep, and re-installation. That supposition - based on our yearly review of repair pricing - suggests that there are a number of successful strategies for bridge work available, and that there is no monopoly of virtue to be assigned to a particular adhesive or combination of clamps.

Please note that that in my earlier description of our material and process description, I was not suggesting that lower gram strength hide-glued or fish-glued, highly stressed bridge joints are prone to failure, but instead, that we have seen a sufficient number of failed joints glued with those adhesive choices to have concerns with their sensitivity to clamping time, glue line pressure, imperfect conditions in the joint (on vintage instruments), and variability of technique. Our experience with 315g has been trouble free (thus far...10 years), and the notion of a stronger, faster-drying glue that still retains the ease of removal that hide glue affords is quite attractive.

Not to speak for others that have elected to use other gram strengths of hot hide, but we prefer the reduced clamping time and time-to-load we see with 315g glue, and the insensitive nature of the glue to the less-than perfect surfaces we see on some vintage instrument bridge patches. Six hours seems to be more than enough time from glue-up to loading in a 70 degree F shop and 45% RH, so quicker turn-around for our clients on time-sensitive repair work and less time out of the case in a shop that has only so many work or storage areas seems to be a fair trade for the need to pre-warm the bridge.


On to specifics...

In terms of application, gel temperature for 315g is about 15-20 deg F higher than 192g, so preheating the bridge (as Mr. Breakstone and others here appear to do) is necessary. A bridge warmed to 130-140 deg F (we do it in foil wrap...about the time we put the 315g on to heat, we wrap the bridge in foil and let it slowly warm to temperature) has the thermal mass to provide 8-10 minutes of time above gel temp. My experience has been that I take about three minutes to apply the glue to both bridge patch and bridge, get the bridge in place and aligned on the dam, the caul in place, and the inner and outer clamps set...leaving a bit of a wait for the squeeze-out to gel and for clean-up. The other people here in the shop are quite a bit faster than that on bridge glue-ups, but - other than the build students here - all have many more iterations of the task. Keep in mind that like Messrs. Breakstone and Collin's approach, we spend more time on preparation - cauls held in place with tiny tabs of double-stick carpet tape; clamps already in body and resting on cork-padded top; glue pot handy for both nice, toasty glue and hot water - so that we can spend less time on the glue-up itself.

I would like to extend my personal thanks to all of the participants on the thread for their freely given advice and very useful comments, critiques, and concerns expressed, but especially to Mr. Breakstone, for his willingness to offer up his shop's techniques and procedures for both scrutiny and use. It is the first and best reason to spend time here.

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A constellation only takes shape when one maps the whole.
- Beth Brower

I've used 315 gram HHG for a couple of years, and as previously stated with proper preparation it's a piece of cake to glue a bridge down. I will admit the first three bridges glued I used Behlen HHG which they claim is 167 gram with no issues to date.

Thanks Woodie, very much appreciated and you and your boss have an open invitation to visit us if you ever wish to do so.

Thanks too for the details of your process which is clearly very well thought out and time proven as well. We get calls from folks in your area who want to ship us work and of course we decline in so much as I don't want to be in the shipping and receiving business AND our business model depends heavily on direct and meaningful dialogue with clients. If you want to PM me how to refer clients to you I would be happy to do so when they contact us from your area.

We've had great luck with what we do and what we use with no failures yet beyond the guy who left a Heshtone in a car in an airport long term lot in Nashville for a week in the summer. His car was dark gray.... I've used this example before but never thought it would actually happen. It did.... unfortunately....

Anyway your mention of ETAs I completely agree with too. Our pricing has been evolving over time based on market, goals, our reputation, influence of my former boss Jack Welch...., and what makes sense. There is also some psychology in play here too. David Farmer will appreciate this.

A couple of years ago we went through a pricing study comparing others in the market, industry norms and some things that I learned in my life and used to teach.

What resulted is our pricing is now at times "bundled" where services that need to go together are now in a bundle.

For example we won't make you a nut. We will make you a custom bone nut specifically made for and fitted to the instrument and then completely set-up the instrument to match your playing style and musical goals. It made no sense to us to hand back some barely playable POS... to someone who will only realize the benefit of being back in the saddle again... so to speak, with a barely playable POS..... Instead they get a completely cleaned and serviced instrument with a new bone nut, super low nut slots, excellent intonation, cleaned electronics, frets, board, and completely set up. I tend to insist on new strings as well.

With that said we charge to reglue a bridge for two hours of our time. Our price for making a nut is about the same as regluing a bridge and when we reglue a bridge we do set-up as well.

So very many people have been playing something that may have never been set-up properly that it's been a huge hit for us as demonstrated by our five star rating on FaceBook to bundle services with an eye toward value and we find less constrained in using methods that may not make sense for some instruments.

It's not uncommon for us to not take work in and in fact it tends to happen nearly every day. If an instrument is $200 to replace and satisfaction can't be guaranteed because of some limiting factor that we can't economically address (needs a neck reset, etc.) we provide the information with an eye toward referring the client to a guitar store for a replacement.

I have learned a lot about being sensitive to folks when they discover that they now have a GLO wall hanging.....

Anyway the bundling has served us very well and increased our profitability in terms of administrative overhead is reduced when average billing is increased. Our clients love what we do and the straight shooting advice mincing no words when appreciated and appropriate.

There are folks who will squirt some glue under a lifted bridge and clamp the crap out of it and call it a day. We recently saw work that someone used filler all around the bridge to cover the gap that existed..... This was done by the largest provider of Guitar repair services in the world.......

Clearly there is no shortage of terrible work out there but there is a shortage of superb work, well thought out pricing, reliable and FAST turn around, and honest critique and advice. That's our goal and if this does not meet the market and it doesn't at times we are fine suggesting that someone has choices as do we.

I have a feeling that some will appreciate the approach of not trying to be all things to all folks....

Thanks again Woodie, much appreciated and I would love to hear in detail how others reglue or initially glue on a bridge on new construction.

Thanks

There are so many variables with bridge re-glues, interpreting what is relevant is pretty tricky. Most useful data only comes from a failure and we work so hard insuring that doesn't happen, there's not a lot to go on.
Some folks worry endlessly about the minutia that produce health and longevity, as though it were a complicated formula. But, eat your vegetables, quit smoking, and wear a seat belt, and your instantly in the 99th percentile of your genetic potential. In my experience, Hide glue is pretty forgiving. Don't sever fibers behind the bridge, use fresh glue, make uncontaminated wood to wood contact, and get it together before it gels. After that, it's going to take a serious hurricane to remove the bridge.

That said:

Gluing bridges well is often the central issue in keeping instruments out of the dumpster. I think my base price for a simple re-glue is probably fairly high but it is one of the few prices I'm completely comfortable with. Bridges lift for a reason. It is almost certainly going to be discovered in the process of a re-glue. Often customers and repair people refer to a,"simple re-glue" as though it's just something that happens from time to time and you just clean up the surfaces and crush it back down, removing another layer of precious top wood in he process. When a bridge comes up it is even more important that it doesn't again. If I'm going to guaranty it won't, (and I do), I have to do a better job than the previous a tempt. I don't see many opportunities for short cuts. Maybe that's why I'm poor even by Luthier stndards.

I still don't get the 315g glue thing. Has anyone thought they have seen a glue strength failure? I see premature gelling as the greatest risk I take when gluing. I would hate to narrow the time window even further. When I clamp a bridge, I'm going to pull the clamps off the next morning. At least in my business, I can't envision how shaving clamp time would amount to much or be worth any increase in risk.

Woodie, 3 minutes? With 315g? I use 192g and if I get over 45 seconds until the clamps are tight I get nervous.

Hesh, I don't see my 5 clamps as really any different than the Stew Mac caul set up. I put the center clamp on, tighten the two on the wings and it's done. Three knobs, just like you. The other two I put on because there is room and it can only even out the pressure. Besides, dude, 5 clamps is like turning your amp to 11!

I also wonder about the notion of Hide, "Drawing joints together". The violin crowd always trot this out. The un-clamped, "rubbed joint" seems like a party trick to me. I have no basis for it, but I'm a little skeptical. I see glue, "drawing a joint together" as the result of the large volume shrinkage when the glue dries and the fact that rubbed joints have worked for centuries is just a testament to how tough and forgiving hide glue is. Not a miracle self clamping quality. But I'm open to persuasion.

One thing I have always felt strongly about is the finish rabbet thing. I do it, but I hate to. I only use it on expensive instruments that still have the aerospace perfection look and a customer expectation to match. You usually need a magnifier to see the difference at the corner of the glue line compared to scoring the very perimeter but I feel like I can't take the risk of any possible value hit on some instrument's. It's a dilemma. I can't prove it but I think manufacturers would be better served by gluing the whole dam thing down. Could you come up with a worse place to concede function to aesthetics?

Thanks guys. I am still using 192, maybe I should look into the bigger numbers.

I get all the clamps set while the bridge sits on a heating blanket with a surface thermometer keeping it about 200 degrees. I have clear packing tape over the pin holes and wings and my 1/16" brads in place in the holes drilled in the saddle slot.

When ready I heat the top with a hair drier, grab the bridge and put a copious amount of glue on it, spead it around with a warm brush, stick some on the top footprint and position the bridge with the brads in the previously drilled holes. Clamps on and usually about two minutes have elapsed. I get lots of squeeze out.

Clean up with paper towels with hot water from the glue pot, sharpened spruce sticks, and a soft toothbrush (thanks Hesh)

My experience is mainly new builds as I probably only do 5 or 6 re-glues a year.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

And another excellent post along with Woodie's, many thanks David!!!

You said "Don't sever fibers behind the bridge, use fresh glue, make uncontaminated wood to wood contact, and get it together before it gels. After that, it's going to take a serious hurricane to remove the bridge."

Pedantic me could learn a lot of things from you my friend! That nails it nicely.

Yeah what's with this drawing parts together thing that none of us can really see or at least I've never witnessed it. One thing is becoming more and more clear to me over time and that is that HHG can be many things to many people it remains up to us to apply human innovation and creativity to make it so.

Thanks David another top shelf post!

Edit: No word on Northwoods yet but when I hear something I'll let you know at once.

Thanks Terry and yet one more great post!

I believe that you rabbit the bridges too IIRC?

Like David F. and when Dave Collins is not looking I nix the rabbiting on cheap instruments but I also do it on high-end stuff just like Collings does.

Here's a 1934 Martin I believe, don't quote me on that Dave's doing this one that he reglued the bridge on a few days ago. It's in for what we call the whole nine yards. Neck reset, refret, bridge reglue or replacement, braces, etc. I'll bill it out at around $1,200 or so and this is the third one of these that we've done on the exact same Martin model recently.

So unfair...I have 19 appointments today and no more than 5 minutes between, then a massage appointment right after work...no time to absorb all these words! Goodness!

Thanks so much - I'll look you fellas up if I make it out that way! Last year's big vacation was Northern California, but my friends keep talking about the charms of the UP!

Re: Mr. Farmer's concern...the first time I did a glue-up, the boss insisted I wait until the glue on the bridge patch had gelled, then pull the bridge out of the warmer and glue it on...the bridge initially sat above the tape dam due to the gelled glue on the patch, then dropped right in to place as everything liquefied with the waste heat from the bridge. The point made was that the component can be used as a source of heat energy to warm the surrounding joint, as well as to re-liquefy already applied glue. Heating the entire bridge provides far more available heat energy than warming just the surface with a gun or lamp...we typically see 315g gel 8-10 minutes after the bridge goes on...so no reason to be in a hurry. While we look for 130-140 deg F with a non-contact thermometer, a lower temp (but still above the gel point) will still stretch out the open time before gelling takes hold.

_________________
A constellation only takes shape when one maps the whole.
- Beth Brower

Woodie, I don't know what shop you work out of, but from reading your posts, I agree with Hesh: the guy you work for must be at the top of his game. I bet you feel fortunate to rub shoulders each day! Thanks for sharing so much. I don't post slot but sure do read.

Andy

Interesting demonstration Woodie G. I guess Hide glue might be considered the original radio frequency cured glue.
If I worry too much about gelling, that would certainly be........................in character.
No sympathy for having to rush to your massage appointment though!

Mr. B...you are too kind. As for every day...unfortunately, no...I still have to get 4 days a week in the office, so long weekends and as many vacation days as I can spare. I suspect that none of the gentlemen here would suggest their abilities rise beyond that of Mr. Keillor's description of the children of Lake Wobegon: above average. Come to think of it, they can be quite juvenile and tantrums are not unheard of, so the description seems apt.

Mr. Farmer...an old biking injury...if I did not absolutely need the therapy, I would go without...but it IS a very nice way to close the day!

_________________
A constellation only takes shape when one maps the whole.
- Beth Brower

That was a great teaching moment and a demonstration that had I watched it I would never forget. Cool way to learn too!

I'm finding that some of the most innovative Luthiers have harnessed physics, thermodynamics and a host of disciplines effectively to unleash the power of science to our and our client's benefit. This is a great example of that.

Thanks Woodie and the UP is killer. Dave, who I call Nanook of the North at times... spends parts of his summers up there every year.

I have been using David & Hesh's bridge glue method successfully for some time (thank you both!) with one difference in my method. I use a q-tip to apply a light coating of paste wax around the perimeter of the bridge prior to heating the bridge & glueing. After the glue squeeze-out gels, it is a very simple cleanup by just lifting one edge of the squeeze-out and peeling it off all around the bridge. No need for water cleanup.

Mike Franks
www.mjfranksguitars.com
www.facebook.com/mjfranksguitars

What a great discussion. Thank you.

Steve

Hi ya Mike! Thanks for the great tip with the wax, I'll have to try that.

Hi Hesh,

Sorry if this is a stupid question, but what do you use on the bottom of the clamp to press against the bridge plate? I usually use a block off wood but it's often tricky to get it all set up correctly, and I was wondering if you had a quick technique for that.

Best,

Jonas

Hi Jonas:

Nothing quick about the bridge plate cauls at times as you have already determined. Since we service over 1,100 instruments annually we've got a drawer full of many cauls for many different instruments. We've had to make these in the past and we keep them after that.

A bit of waxed paper over the proper caul and we're good to go.

Lately I've been using the Stew-Mac white caul which is either made from some cutting board material or possibly something with teflon in it. Can't remember but it's marketed as generic an often is for Martins and the like and non-stick and that's been my experience with it too permitting me to nix the wax paper.

Once in a while we still have to make the odd one-off caul though and we tend to "bang them out" out of scrap ply, and other woods.

I'll mention too from discussions with other Luthiers about bridge regluing. You will find folks doing every thing from the using the biggest clamp that they can find to clamp a flat bridge into submission to others spending time fitting the bridge to the top so that only light finger pressure is required to hold the wings down. We favor the second approach and as such although our cauls often cover under the bridge wings with the SM white generic caul we don't always have the wings covered by the cauls. Because we fit the bridge very well and only minimal pressure is required to clamp the wings AND we can get away with only one clamp most of the time and cauls that cover under the wings are not always necessary.

This is the case with the Stew-Mac generic caul so I'm usually using this one these days on a host of instruments that it seems to fit many of them. For the rest I go to the caul drawer and on occasion have to make a new one too. BTW since the SM caul doesn't cover the wings it works for Lefties too;)

If you are looking to reduce caul creation time consider fitting the bridge very well, we scrape and sand to the dome's shape, know your platen on your belt sander and always scrape last for better joint energy. You may find that a generic caul works on more instruments if you fit the bridges to the tops.

We generally like HHG too as mentioned previously in the thread.

Good luck to ya.

Thanks Hesh!

Excellent explanation.

Best,

Jonas

I'm in the 3 clamp camp. One ibex and two cam clamps. I make the cauls full length and shim the ends with bridge plate thick material for a good bite with the cam clamps. This one has been modified to clear a K&K pickup during a re-glue.


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Good judgement comes from experience. Experience comes from poor judgement.

Hesh - what is the Stew Mac white caul that you've been using?
High-density polyethylene?