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Todd and Todd,

You both mention system advantages but don't say what they are. Todd Stock mentions avoiding some of the problems associated with removing finish, like chipping, but all systems have pitfalls and need to be done well.

I have no problem bucking tradition but I make it a point to do so only when there's an advantage that's pretty clear....to me if not to everyone else

So what makes this worth bucking tradition? I'm seriously interested, not arguing. And what are the repair implications in your mind, if any?

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http://www.chassonguitars.com

I have the feeling that I'm the one that opened the Pandora's Box here. Sorry that I haven't posted sooner, I was out hiking the Fingerlakes Trail, NOT to be confused with hiking the Appalachian Trail.

I started doing this based on the work of the highly respected Rick Turner. I am a scientist by training and I admit to being an experimentalist. Some people are not so inclined and prefer to not to risk exploring some of these things. That is fine. This is something that I thought I would try to see if it worked for me. I tested this first before doing it on a guitar and it worked perfectly. I am now building a guitar with a redwood top, and I will again test this method to make sure it works on redwood as well as spruce. I should point out that there have been some ideas of Rick's that didn't work for me, such as the use of Waterlox. Just didn't like it.

First of all, both wood glues and CA glue require a "perfect" fit. In fact, it could be argued that it is more important with wood glue since its cohesive strength is so poor. I believe the cohesive strength of CA is a bit higher. When I would put a bridge on using hide glue, I would carefully rout the finish off the top as well as rout a small ledge on the perimeter of the bridge equal to the thickness of the finish. Still I could not absolutely be sure the bottom of the bridge was a perfect match to the now routed area of the top. Having said that, I used good clamping pressure and technique and haven't had any problems with my bridges pulling off. However, when using CA glue to glue the bridge to the finish, I can be absolutely sure that I have tight fit everywhere.

But why do it? Well once I tried it, it became obvious that this is a very fast, precise and clean way to attach a bridge, with no second guessing as to the fit. It works for me and I like it!

Al, does bring up a good point in part. It may be a good idea to have the glue joint at the bridge be the weakest link. This might be especially useful for those that abuse their guitars by leaving them in a hot car, where temperatures can get well over 100 oF. However, so far I am not concerned about the bridge coming up on its own due to a faulty glue joint to begin with. Bottom line is that the concern is the strength of CA glue, not the weakness of it.

Concerning longevity, I've had guitars strung up for a year now with this system. That is not a very long time, but I believe it is a pretty secure system that is now dependent on how stable the glue and finish are. I guess there is some debate on that. However if the glue should fail in 20 years, then the bridge will come off and it will have to be reglued. Rick has had his guitars out there a bit longer.

As far as being a traditionalist, I use a V-joint to attach my headstock to my neck shaft. I wouldn't trust that newfangled method of using a one piece neck!

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Randy Muth
RS Muth Guitars Website
RS Muth Guitars Blog
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Todd,

I read your post after I posted mine. It is Rick Turner that does this, I'm not sure about Rick Davis.

I agree with Points 2,3 and 4 and talk about them in a more roundabout way in my post. I don't know about wicking the CA glue. Rick and I brush on medium viscosity CA glue.

I did take a bridge off once, not because of problems with the bridge, but because I wanted to refinish the top. I wound up routing it off. This could be considered a downside to this method, but this was the first time I routed a bridge off and it was quite easy. A bit easier than ungluing a bridge in my opinion. Of course, you do have to make a new bridge. CA solvent might work, but I don't see getting it into the glue line as being that easy. I need to talk to Rick to see how he does it. I would bet he routs them off though. He has no qualms with doing things like that.

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Randy Muth
RS Muth Guitars Website
RS Muth Guitars Blog
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John wrote:
"I also ended up somehow with a stick of Mahogany (Sawed straight out of a board) that CA would not cure on... That was weird."

CA requires alkaline, or, at least, neutral conditions to cure. Many woods are acidic. CA often won't cure, or cures only slowly, on walnut, for example. I've found that rubbing in a little dry baking soda, and brushing or blowing off the excess, is a big help. Enough of it stays in the wood to start kicking the CA, and once it starts it cures nicely.

Todd Stock wrote:
"4. Greater bridge contact patch versus leaving the usual 1/16" to 1/8" of lacquer inside the bridge outline, with related stress reduction."

As far as I'm concerned, leaving finish under the bridge is a mistake, whether you relieve the bridge bottom edges or not. By reducing the length of the contact along the line of pull you're greatly increasing the maximum stress along the back edge of the bridge, and inviting it to peel off. Yes, there's more chance of chipping the finish when you clean all the way out to the edge, and you have to be more careful to not score the top when you scribe the outline, but both of these are simply part of the tool chops you should have anyway. Just one curmudgeon's opinion.

Al, as far as relieving the edge of the bridge, it seem it would matter how wide your bridge is. With a 1" wide pyramid bridge, i would hesitate to relieve the edges, but with a 1.5" wide belly bridge, it seems there is adequate width to relieve the edge a little.

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Randy Muth
RS Muth Guitars Website
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Todd,your remark about "experts in 18th.C. restoration" shows that you are completely unfamiliar with what modern museum conservationists do. They do not employ only traditional materials and chemicals in restoration. Much to the contrary,they use the very latest finishing,coloring,and adhesives in their work,but only those which have proven to be the best. For example,they use Orasol dyes in restorations involving stains,colors and paints. I use Orasol metallic salt dyes myself. I learned about them from conservationists. They are the most lightfast dyes available. Invented in Germany for automotive use. They are arc light tested for maximum fade resistance. This is just one example.

I am content to take the benefit of their knowledge because I have seen the depth of their knowledge. They are on the cutting edge of modern methods.

They have been very useful to me in learning about the best products that I can apply to my own instrument making. You simply have no idea the advantages I had in building instruments in a museum situation for 39 years. I was able to have private access to the restoration shops behind the scenes at places like the Smithsonian,the Met.,the Mariner's museum,the Chrysler Museum,and our own conservation shops,which are equal to the best in the World. Williamsburg is the largest outdoor museum in the World. I learned things I would have been unable to learn on my own. I was also able to experiment at great length in several fields of interest,such as varnish making.

I have been building for 54 years,and being where I was most certainly accelerated my education in the peripheral areas of instrument making.

I resent you calling me a curmudgeon which I certainly am not.If you have googled my name in guitar making,I think you will see that. I can find no internet presence about you. Are you an experienced builder? I cannot tell. I suggest you mind your manners.

Todd - Yes that's pretty much what I do, although I have done it without any masking. Clean up is easy with CA remover. I use slow setting, medium viscosity CA, so I have plenty of time to position.
I use #10-32 screws through both E strings to clamp. A little Teflon lube on the threads makes life much easier. I only have the outer 2 holes drilled on the top at this point.

I did need to remove one bridge for a refinish. It took about 15 minutes with ca remover.

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

Todd:I have googled a few minutes about CA glue use in museum restoration work. Ed Mautner of the Smithsonian in remarks concerning the restoration of the Starship Enterprise model,said that because of the short adhesive expectancy of CA glues,they RARELY use it in artifact restoration. He also cites the brittleness of CA in not moving with small dimensional changes in some materials (like wood?) They ONLY use CA in spot gluing items to hold them while they glue the main areas with other adhesives.

I would think that the brittleness,and non movement qualities of CA adhesives would be definite reasons for NOT using them on thin wooden guitar tops,or on bindings,let alone the short life that CA has.

The head conservationist of U.S. Naval models also does not use CA for the same reasons.

The head conservationists I knew at Williamsburg's furniture conservation shops have moved on. One is now head of conservation in a museum in Nebraska,the other is running his own conservation service. I cannot readily get hold of them.

If you would spend some time googling for yourself,you might also turn up some similar answers.

You can post opposing views all you wish. I wish you would do so in a more polite way.

Hi George – I wanted to thank you kindly for your input here regarding the use of CA glues to attach bridges to guitars.

The CA debate has reared it’s head from time to time on this forum and this is not the first time that we have discussed it. Nonetheless I have been on record here as not wishing to use CA glue on my own guitars having in the past sited reasons very much like your own reasons. The lack of data and long term testing results always concerned me when we can see examples of Egyptian chairs that were glued with HHG 1,000 years ago and the bond is still holding.

I Googled CA and read quite a bit about what folks are saying. I’ll add that I have been a wooden ship modeler in a past life (and I still have 2 to complete…) and I never used CA there either. What I find as a result of Google searches is that there are a lot of opinions that support yours but I was not able to find any published testing or data.

Mind you because it can’t be proven does not make it false in my view. The art and science of guitar building is over flowing with things that we believe or don’t believe that have yet to be substantiated beyond a shadow of a doubt.

In the past I have been critical regarding the use of CA for bridges glued directly to the finish. More recently I have had a number of my guitars finished with cat polyester. My experience with cat polyester which included some measurements of weight and film thickness also inadvertently exposed me to how tenacious this finish is in terms of it’s adhesion to a guitar if applied correctly.

So, and sorry for being so very long winded here – it’s my nature…., my opinion regarding using CA to glue a bridge directly to a cat poly finish has changed. Also, as others have mentioned Master Luthier Rick Turner has been using CA for some time now and perhaps 1,000 or more instruments. I know Rick and I also know that Rick would not use CA if it did not do the job. Rick is also very well versed in repair, something that many builders lack experience with.

Would I use CA on a polyester finish – no. Regardless of my own belief that this is a sound practice provided that it’s a cat poly finish AND care is taken to do many of the things mentioned by others here. I prefer to leave these kinds of things to others to try being all too happy using HHG with direct wood-to-wood contact and a well fitted bridge.

Regarding does using CA to glue a bridge directly to the finish have a sonic impact? I can’t answer that question but it does concern me and my preference is to not have finish, no matter how thin, and a CA glue layer between my bridges and my tops. Again, just because it can’t be proven does not make it false. Am I saying that there is a sonic impact – no. What I am saying is that I don’t know… and in not knowing I am not willing to make a break with the best practices of tradition to find out on my customer’s dime.

George I understand the objection to the term curmudgeon. As someone who is a bit thin skinned at times I have been known to misinterpret the intentions of others on this very forum and of course elsewhere too… Had I not been a member of the OLF for many years now I would not know that the term curmudgeon has been used here in the past as a way recognize the experience of another. We even have had a highly regarded Luthier who willingly goes by the name of “grumpy.”

I will go so far as to indicate that in some instances this term, curmudgeon, is almost a term of endearment on this forum. It’s a way to acknowledge someone’s heavy experience while also indicating that perhaps the delivery of said curmudgeon’s message may have been, well…, not as we may have wished.

As it was used here by Todd I would not take it as an insult. I fully understand how you have come to take the use of the term as an insult as I would have as well if I was new here and not up on the history of the forum.

It’s great to have you here and I did Google you and I am most impressed and would encourage others to Google you too. I also won’t be using CA on my bridges so don’t feel like you are the only one here who does not understand why others are doing so.

Thanks

Hesh,thank you for your kind words. I think Todd is still ignoring what highly educated restoration techs have said about CA. If they say it has a short life,I'm taking their word for it. I used to work right beside the furniture conservation shop,and was over there often. Those guys spend a lot of their time going to conferences,and otherwise learning the latest and best available techniques for their work. After all,they are working on objects sometimes worth millions,and they have to proceed very carefully. They also have their reputations to protect in the relatively small World of the restoration community.

I have googled " life expectancy of CA glue,and came up with a few examples of what conservationists have said. I can't recall exactly how I worded my google late last night.There is information out there if Todd wants to look for it.

I feel exactly as you do about hide glue. It has proven itself over thousands of years. I don't want my guitars,violins,harpsichords,lutes,or viola da gambas falling apart in future years.

Changing the subject,Todd,instead of googling information about CA? Now I have learned that NO museum conservators or curators wish to use CA.

As for the builders you cite,they can do as they wish,certainly. If I were a customer,I would prefer tried and proven building techniques to be used on my instrument.

I have not used CA for gluing my bridges....yet. That may change if I decide to go that way. I do use CA for many applications in guitar building and will continue to do so.
Personally I believe many rather stay within their comfort zone and use what they are used to and for some reason end up stuck in the past. Nothing wrong with it.
Do you want to mess around with hide glue? go for it, for me it isn't worth it. We are all entitled to our different opinions and come up with our own methods.

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

My omission;I meant on objects such as antique furniture and other wooden objects. We did not deal with fossils in Williamsburg. CA does not flex to stay intact well when wood moves. We are discussing wood here,aren't we,in different objects yes,but still CA on wood. Don't you really think you are talking apples and oranges?

I'll admit that I am a fossil! However,I am going to have to say that we'll just have to agree to disagree. I simply do not think it is best to use glues about which there is so much controversy. And,I really think that this is the prudent course to take. I can't see how that logic can be denied.

I also think that the best way to glue a bridge down is wood on wood. I believe that hide glue is the time proven and true glue to use. It is also easy to clean up,and reversible. It is good for acoustics.

I do not believe in gluing frets in. Mechanical hold is best,and the easiest to replace when worn.

I believe that spruce is the best wood for tops. I do not think that redwood,cedar,or other woods that are too soft,do not conduct vibrations as rapidly,or could tear loose from the glue line are as suitable. I have tried them in the distant past.

There. Plenty of ammunition for everyone in the forum to jump on me about.

I finish by saying that no one knows enough about making the truly perfect guitar to really dispute anything I have said. It's all opinions in the end,and risk taking when it comes to using controversial materials and methods.

You guys are right. I need to be less passionate about my posts. Thank you for your understanding.