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I've wondered this for a long time, and it was mentioned in another thread. I'll continue to glue bridges to bare wood, with HHG but I'm curious.

Isn't the finish between the bridge and the topwood a potential.....tone sponge? I know a good finish isn't thick, but it's still there, and it should be flexible. I'm sure that the guitars built this way sound great, but would they sound better if the bridge was glued directly to the top?

Please, anyone who builds this way, don't be insulted by my question. I'm not looking for a fight. I'm just looking to understand why it works.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

well for starters .. it only works with finishes that arent affected by the glue - ie melting .. CA doesnt affect polyester, and Larrivee had been doing this for years on a conversion varnish product from Chemcraft called Sadolin. So once the bridge is on, you can clean up any squeeze out with acetone.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

NO!

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Larrivee started routing off the finish under their bridges a few years back. I think they changed sealers and were worried about adhesion problems. My concern is the tone loss caused by the finish between the bridge and the top. I can't see any way this doesn't hurt tone.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Ovation glues the bridge on over the finish. In this case, it's epoxy over lots of epoxy: their 'finish' ends up being about .030" thick. I'll note that the bridges still come up, and often take a chunk of top along.

I can't for the life of me figure out why .005-.010" of hard and brittle nitro would be more of a 'tone sponge' than .002"-.006" of tough and flexible Titebond. Maybe both together would be a problem, but who can say how much of one, since I'm sure the bridge would not stay down anyway. I use HHG myself, but not primarily for it's tonal benefits, of which I'm not convinced. Anyway, many guitars that have bridges glued on with Titebond sound fine, and many with bridges glued on with hide glue do not. Mario would say that 'all the details count', but I'm sure some of the details count for much more than others.

Well.... If the bridge peeling right off of the guitar effects tone... then gluing the bridge onto the finish *Might* cause a problem with tone....

Good luck

John

Gluing the bridge over the finish is a cheap dodge to manufacture faster. I wouldn't even think of doing it.

Whatever it is - stainless steel frets, hide glue, dovetail joints, gluing the bridge on top of the finish, etc - some people are going to believe it affects tone, and some people aren't... and people will hear what they believe.

I happen to be one of those who don't believe that any of the above, along with a long list of other things some people think matter, affect tone.

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Todd Rose
Ithaca, NY

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

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

Try gluing your guitar together with finish material,lacquer,poly,whatever. See how long it stays together. It isn't fit to glue a bridge over. And,if it takes off a part of the top that wasn't UNDER the bridge when it flies off,you have a BIG problem,don't you?

John,

No what? Woody asked at least 2 questions in his original post... so I am confused what you are saying no to.

This is only the second thread spun off the original HVLP Conversion Gun thread (which itself was spun off of another thread). Lots of good stuff going on here!

Mike

All you guys who are saying no to gluing the bridge on top of the finish go tell Rick Turner that. Heck the guy only has a couple of decades more experience than 99% of anyone else active or lurking here and he doesn't have a problem glueing his bridges right onto his finish. I'm also pretty sure I recall that he uses CA to glue his bridges right onto his polyester finishes.

I know he doesn't post here any more but I think he might say something like..."Don't knock it till you've really given it a good shot!" Just maybe not so politely

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Rick Turner's guitars with the bridge glued onto the finish are a different animal than most of our steel
string guitars. His guitar are hybrid or semi-acoustic models with the strings running all the way through
the body many times.....not with the strings anchored to the top by the typical strng ball end retaining
bridge pins and all of the force being concentrated on the top and the glue joint between it and the bridge.

His configuration creates a whole different set of forces and the pulling up of the bridge is not one of them.

Regards,
Kevin Gallagher/Omega Guitars

About 15 year's ago, my son's new Larivee bridge came right off.

To the best of my knowledge, Rick does his bridges this way on his flat top guitars, too. Randy Muth is doing this now as well. It has to be done right - the right sealer, the right finish, the right prep, the right glue, the right fit of bridge to top, etc. But this is typical of many parts of successful guitar making.

An awful lot of bridges done the traditional way come unglued at some point. This newer method may very well prove itself to be better. From what I've heard about it, it has an excellent track record so far.

Read Randy's post about it in the Emtech6000 thread, and/or search the archives for Rick Turner's posts about it. Whatever you do, don't try it until you understand all the steps of doing it right. Excellent finish adhesion is essential.

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Todd Rose
Ithaca, NY

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

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

without thinking about it too much........it seems to me it may be more work and trickier than the traditional wood to wood glue join............i would never even try it but this is intersting all the same..........this is how progression and evolution happens i guess

I repeat: Anyone want to try using finish material for glue? And,even if the bridge glued directly to bare wood does come off,it leaves a clean area,without taking part of the top outside its footprint with it.

The use of CA glue for putting bridges or bindings on is a VERY POOR idea. CA glues have a finite life.And,I'd like to be able to get the bindings loose cleanly and readily if the top has to be taken off.

Do you have sources for any of that?

Polyester adheres so strongly to the substrate that there's no way I know of save sanding to remove it without also destroying the spruce. It does not chip or peel off, and is both hard and tough. Polyester resin is strong and quite tenaciously adhesive. If it weren't, it would certainly save a lot of companies money on mold release.

I've never seen any evidence of a lack of longterm stability of a cured cyanoacrylate bond (outside of extreme conditions of temperature, which will affect nearly all adhesives). Can you provide a source for the finite life of a cured CA bond?

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

I was Master musical Instrument Maker in Colonial Williamsburg,and Master Toolmaker. Was there for 39 years. We have World class furniture conservationists who say that CA has a life max. of about 20 years. My main reason for not wanting to use it on bindings anyway,is that it makes getting the binding off to remove the top more difficult.

I guess you save the bindings ??? I could care less about that if I have to remove a top - route em off and rebind it -its not like I used some special stuff that I only had 4 pieces of - its just wood - thats the way its going to be if it hits my shop.

BTW .. larrivee has lots (make that 1000's) of guitars out there over 20 years old with CA'd bridges ... my phone should be ringing off the hook next week for repairs then

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

A friend brought a 12 string ovation into the shop that had the finish cracked behind the wings and the back of the bridge.It looked to me that it was a result of gluing the bridge to the finish, and string pull over time.I think I`ll keep gluing bare wood to bare wood.
James

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James W Bolan
Nashville Tennessee

Woody,
I've CA bonded about 6 bridges onto Joe White's finish. I can guarantee you that there is no tone loss.

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Why use glue at all? A bolt-on/off bridge seems like the way forward to me. My latest version weighs less all-in than the equivalent glued-on version so is less of a "tone-sink".

Dave F.

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Cambrian Guitars

"There goes Mister Tic-Tac out the back with some bric-brac from the knick-knack rack"

Yep, I'd use it too after doing the proper systems engineering and accomplishing some relevant testing.

Take with a grain of salt - spoken as a long-time engineer, long-time player, newbie builder.

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Steve Smith
"Music is what feelings sound like"

Dave,
While you will find a lot of support for bolted on necks, and even bolted on fretboard extensions, I don't think there is much love for bolted on bridges. Perhaps you could share your design with us in a new thread. You'd likely get a lot of opinions. You might get some great suggestion also.

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Steve, thanks for weighing in. Did you read Randy Muth's description of his method, in the Emtech6000 thread? Do you have a similar or different method? Any tips to share? Here, I'll just copy what Randy wrote below:

"Here is what I do to glue the bridge directly to the finish. First I sand the bottom of the bridge so that it exactly matches the curvature of the top. This is important and I do this by laying sand paper down on the top and carefully sanding the bottom of the bridge in the area where it will be glued on. It must be a perfect match. I then clean the area with CA solvent and put some thin masking tape on the area of the top where the bridge is going. The cheap beige type. I locate my bridge and scribe the masking tape with a brand new Exacto razor. I peel up the masking tape where the bridge goes and leave the rest (I also locate my bridge pin holes and use small locater holes with brads in the saddle slot). After drilling my bridge pin holes in the top I put masking tape inside the guitar on the bridge plate so no glue seeps through and I lightly scuff up the top where the bridge goes. I put a light coat of thin CA on the bottom of the bridge. This wicks in with no build. I let this cure for a few minutes. I then brush (plastic brush hairs, not natural. A natural hair will cause the CA to react and cure right away) medium viscosity CA glue on the bottom of the bridge and quickly place it into position on the top using my locater holes and brads that are already in the bridge. Hope this makes sense. With one hand inside the guitar and one hand on the bridge I apply pressure for a couple of minutes. I pull back the masking tape and clean up what little squeeze out with CA solvent. That's it.

Here's some of the logic behind it. How fast CA glue cures depends on the pH of the substrate it is in contact with. With woods that are alkaline (high pH), the CA glue cures fast and hot. This is how the accelerator works. With woods that are acidic (low PH), it can take quite awhile. This is the reason why I put a seal coat of thin CA on the bottom of the bridge. Ebony in particular is pretty reactive. For example a mixture of ebony dust and CA will smoke. The KTM-SV must be alkaline because it reacts fast with CA. This is why I don't apply the CA to the finish first, but to the bottom of the bridge. This is also the reason, along with the perfect fit, why you can simply firmly press the bridge to the top to get a good bond. By the time you tried to get a clamp on it, it would be too late and you wouldn't have had the pressure needed during the critical cure time. I have tested this and I cannot get the bridge off without ripping the top apart.

A couple of more tips.

When you sand the bridge don't hold down on the wings, since they are flexible. What I do is attach a block of wood to the body of the bridge with double stick tape to use as a handle. This will insure that you have the correct curvature on the bottom of the bridge without forcing it.

When I glue the bridge down, I again use the block of wood as a handle, but also put some pressure on the wings with my thumb and ring finger. I find the brads through the saddle slot are much more accurate and faster than trying to use the bridge pin holes to line things up. Same technique that is used for locating the fingerboard."

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Todd Rose
Ithaca, NY

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

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