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Top Delaminating On Guitar Build


fookgub
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The top is delaminating on one of my guitar builds. It is a maple top on a mahogany body with a garolite contrast strip. The layers are glued with epoxy. The maple is coming off, but the mahogany/garolite joint seems solid. I've already tried to wick superglue into the gaps, but it didn't hold. The pictures shows just one particular spot, but the top is coming off in multiple places.

I figure I have two options:

1. Try to separate the top, possibly using heat. Clean up the surfaces, and glue it back on.

2. Plane off the top, buy a new one, and glue it on.

I used hardware store epoxy for this joint. This is the last time I will use that stuff for anything serious. I've already hosed a neck using cheap epoxy, and now it looks like I hosed a body, too.

What do you guys think?

http://www.ece.utexas.edu/~wrobert/tm2-top1.jpg

tm2-top2.jpg

Edited by fookgub
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Well...epoxy is the wrong kind of stuff to use in this application...it doesn't have any give and those woods will all move a different amount...especially if unfinished and can absorb moisture. A wood glue is designed for wood and this is what it is good for, especially with such a wide surface area to glue with.

There are some bad epoxies...but you need a long setting time epoxy and understand the stuff too...it's a chemical reaction...it will start to go off immediiately...it will go off even faster if stirred and you would have used a fair bit on this...by the time you got to the maple I suspect it had already done most of it's chemical reaction.

OK...so the cure...

It looks like it hasn't stuck that well...If you use a domestic iron with a bit of cloth over it so as not to mark the wood...you might find the epoxy softens up or cracks the top off completely...go easy not to crack the top.

Tidy it up a bit and make sure the new glue has some timber to stick to and glue the top down again...

pretty much as you suggest...

and be happy it happened now, not after you finished or a few months later...

Epoxies can be great but there are many different types and they require some experience t get the best of them. Hardware store stuff tends to be fast setting and designed for small joins, not this kind of thing...and they do not tolerate a lot of movement in the materials which is why wood glue has a bit of a give to them...

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Good points, Pete. I did actually use a slow setting epoxy, but it was cheap stuff. I got good squeeze out, and the epoxy was still nice and fluid when I clamped the top on. I think West Systems or some other "good" brand would have worked better. I'm not so sure wood glue is good choice, though. Garolite is a synthetic, non-porous material. When I glued this up, I scuffed both surfaces with 80 grit, but the glue just didn't stick. I'm considering Gorilla glue for re-gluing the top. I've had pretty good luck with that stuff so far.

Anyway, given that the glue is really not sticking well, I'd like to try to break the joint without heat. I'm worried that using heat will affect the garolite/mahogany joint, which seems to be holding quite well so far.

Edited by fookgub
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I think West Systems or some other "good" brand would have worked better. I'm not sure sure wood glue is good choice, though. Garolite is a synthetic, non-porous material.

Yeah, I think you just got screwed with that bad epoxy. I have bought my share of bad epoxy in the past. I just loved it when I took it back for a refund and the clown clerk comes off with " you probably just didn't mix it right ".

Doesn't PRS glue tops on with epoxy ?

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They polyurethane glue is brittle and I don't recommend it on a guitar. If it is to fill a gap it will certainly do it. However if the top has already failed then what else will go wrong down the line. I have used this glue only on projects for outdoor use. The glue is quick to harden in the tube once its open. Also it does squeeze out rather liberally and you cant clean it until its dry. Wear gloves.

I did use epoxy once a long time ago to attach a fingerboard I thought I was smart, Hah.

I use the 5 minute west epoxy sold by most suppliers but rarely use it except to repair jigs and some other surface imperfections. I never had a bad batch. I do have some cheapo epoxy which I use for home fixes when I don't want to use the good glue.

I haven't seen the reason to spend extra money for a glue which does not improve any build. If down the line your 30 year old guitar needs some major repairs then someone will be in for a shock. I can already see the cursing directed toward you.

Good old original Titebond (not II or III) is what you should have used in the first place. Or if you like to spend money the LMI white glue is also very good. I have never had a joint fail or creep; plus no mixing; and squeeze out is easy to clean up. What more do you need.

I guess if you want to fix it try Pete's method. You may be able to pry off the top with this method and save the piece.

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Garolite is a synthetic, non-porous material.

oh...well just goes to show, I have never heard of it, I assumed it was a type of wood. All the same, a domestic iron will not apply too much heat and maybe worth a try, but if you don't mind likely sacrificing the top, it will probably pry off ok.

I have played with epoxy for a number of different things and all are kind of different...there are some things that epoxy won't stick to...although the mahogany seems to have stuck ok. If it is non-porus, then epoxy was the better choice over wood glue perhaps...not sure what gorilla glue is, but if it is for laminates, it might be ok.

I am a bit of a fan of west system for a lot of things myself...I use an accelerator for the kinds of things I generally do (small stuff)...but on this kind of thing, slow is often better...climate affects it, however...

I guess another possibility is to do what nature does to crack open a rock...extreme change in temperatures and moisture. I think this is some of the reason why it has given way, a slight shrinkage compared to the synthetic below with the thin top...the thicker mahogany body having less of the effect.

It might sound crazy but a few ways to do this is to perhaps try and soak the top to get it to expand, cracking the join between it and the synthetic (which will resist moisture to the mahogany)...to really accelorate the effect...freeze it, the top will perhaps crack off it....believe it or not that is one of the secret processes to making a special kind of sustainer coil I have been working on, I literally crack it out...hehehehe

On the other hand, if the top is going to be sacrificed, then a really thin sharp blade may well do the trick...in fact a blunt very thin metal might be better...a blade will often cut into the wood while a blunt but thin edge will prise a joint open as often as not...I suspect that the weak link is the glue join to the synthetic veneer and this will give way first and the top may be saved yet...

good luck!

pete

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pete - I doubt wood movement is the issue. This joint was never good from day 1. It's been sitting in my shop for a while waiting for me to deal with it, and I been watching the garolite/mahogany joint to see if it comes apart. I think the surface prep on the maple may not have been good enough. I roughed it up with 80-grit in the orbital, but it still seemed pretty smooth to me. Maybe the epoxy just couldn't find anything to hold on to. I'll inspect it if I manage to separate the top.

wes - I know you ordered some garolite a while back when we were having a discussion about it. Did you ever end up using the stuff for anything?

Woodenspoke - I'm going to try Titebond I & III and Gorilla glue on a couple test pieces before I decide what to glue the new top on with. I understand your comments re PU glue, but I've been using it more and more lately, and I've started to like it quite a bit. Have you had any experiences gluing up phenolic with Titebond or white glue? It doesn't seem like it would stick well, but I guess you never know.

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>snip<

Good old original Titebond (not II or III) is what you should have used in the first place. Or if you like to spend money the LMI white glue is also very good. I have never had a joint fail or creep; plus no mixing; and squeeze out is easy to clean up. What more do you need.

>snip<

+1 on the Titebond and it will adhere to the garalite if you will wipe it down with acetone first and let it cure for 24hrs. not the normal 20 mins and move on.
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wes - I know you ordered some garolite a while back when we were having a discussion about it. Did you ever end up using the stuff for anything?

I never have used it...I was interested in it as a substitute for ebony on finger boards...but it seems much too flexible for that.

I still have it,but I don't know what I will use it for....

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