Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

[nexion218]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

DEAR GOD, NO!

Just curious... What makes the apegoo that big of a "NO"?

[GuitarDoc]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

Is there masking tape on the bottom of the truss rod? Leave that in place, it keeps the epoxy from getting into where the actual rod is. The epoxy keeps the truss rod secure so it won't rattle and so it will function properly. You don't need much epoxy, just enough to hold it. Make sure you don't get any on the adjusting threads.

Sounds like you're on your way. Great learning experience.

[ICTGoober]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

Is there anything I need to do with the truss rod to avoid rattles?

The chances of that happening is very low, but epoxy would reduce the risk. However - any repairman who had to deal with such an installation would be perfectly within his rights to hunt you down and kill you. ALWAYS consider how your build techniques will affect any future repairs. There is a LONG thread on this very subject over on the Official Luthiers Forum.

[ehdwuld]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

Well this will probably be the last repair before the guitar meets a fence post

Just saying

[GuitarStv]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

Is there masking tape on the bottom of the truss rod? Leave that in place, it keeps the epoxy from getting into where the actual rod is. The epoxy keeps the truss rod secure so it won't rattle and so it will function properly. You don't need much epoxy, just enough to hold it. Make sure you don't get any on the adjusting threads.

Sounds like you're on your way. Great learning experience.

I'm waiting on the truss rod in the mail, should be here Wednesday or Thursday. It sounds like there will be masking tape on the bottom of the truss rod. I pulled out the old U channel/truss rod to look at it last night, and it was tricky to get back in because the sides fit so snugly. I'm worried that if I epoxy the sides of the channel when I push the truss rod in it will push all the epoxy to the bottom and cause problems. (Also kinda worried about damaging the masking tape and wrecking the rod as it gets jammed in there). Should I put the epoxy on the sides of the truss rod to avoid this happening.

Would the epoxy on the U channel make the neck more solid/stable? There must be a reason the Stew Mac instructions say to do it.

Also, does it matter what epoxy I use for this? I think the stuff I've got in our basement is probably bad (about 10 or 15 years old now) so I'll have to get some more. Might as well get the right stuff.

The chances of that happening is very low, but epoxy would reduce the risk. However - any repairman who had to deal with such an installation would be perfectly within his rights to hunt you down and kill you. ALWAYS consider how your build techniques will affect any future repairs. There is a LONG thread on this very subject over on the Official Luthiers Forum.

So, the Stew Mac instructions are not good?

Run a thin line of epoxy down both sides of the bottom of the slot and install the truss rod with the rounded side (with the masking tape) down. The flat surface of the rod should be facing upward, almost flush with the top of the neck.

Do not remove the masking tape that is on the rod. It prevents the glue from getting into the mechanism, which could cause adjustment problems. Clamp the rod into the slot and promptly remove any glue squeeze-out. Leave your clamps in place until the epoxy has properly cured.

Like I said, it's a pretty tight fit in the channel. I think that only a very tiny amount of epoxy would manage to get between the wood and the aluminum U-channel, not sure if this would be a problem for someone (let's be honest here - me) in the future doing a repair.

Well this will probably be the last repair before the guitar meets a fence post

Just saying

Yeah, there's also that. :P

[ICTGoober]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

I think StewMac and Dan Erlewine should know better than to use epoxy for this repair. The problem is once the wood has been contaminated by epoxy, it's over. You can't get the crap out of there so that it can be glued in properly. You can soften the epoxy with heat, and remove the truss rod.... But there would be no point.

Just because it's not worth the money to do a proper and complete repair, doesn't mean someone COULD fix it right in the future. Like if you donated the guitar to a program that fixes guitars to be given to underprivileged kids? Get it? We don't know the future of anything.... even a cheap POS guitar. I've saved a lot of stuff that didn't deserve it, either to learn or to give away.

[GuitarStv]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

I think StewMac and Dan Erlewine should know better than to use epoxy for this repair. The problem is once the wood has been contaminated by epoxy, it's over. You can't get the crap out of there so that it can be glued in properly. You can soften the epoxy with heat, and remove the truss rod.... But there would be no point.

I'm confused. Why couldn't you just run a file (or some sandpaper) over the epoxy in the channel to remove it? (Assuming that you need to pull the new truss rod out again for some reason in the future.) As mentioned, it's a tight fit . . . there would only be a very small amount of epoxy between the U channel and the wood anyway, just enough to fill any small gaps that exist and hold the rod securely in place.

Just because it's not worth the money to do a proper and complete repair, doesn't mean someone COULD fix it right in the future. Like if you donated the guitar to a program that fixes guitars to be given to underprivileged kids? Get it? We don't know the future of anything.... even a cheap POS guitar. I've saved a lot of stuff that didn't deserve it, either to learn or to give away.

I am doing a proper and complete repair. At least to the best of my knowledge and ability. My intent is to fix it right this time, that's why I've been asking questions. I appreciate the input from everyone. I'm just perplexed that the instructions that come with the truss rod that Stew-Mac has been selling for decades would be so wrong as to cause the instrument to be irreparable in the future. Dan Erlewine has been the source of an awful lot of really good guitar related information over the years. I'm kinda hesitant to ignore their advice out of hand.





Speaking of questions, one more for everyone . . . the current truss rod sits about a mm (or maybe half a millimeter) below the top of the channel that is routed in the neck. I don't like any gap being there in the neck. My inclination is to fill it with wood filler before gluing the fretboard down so that there's a completely flat surface to glue to, and no room for the truss rod to slop around before applying force on the neck during adjustment. Is this a good idea? Is wood filler suitable for this, or should something else be used? (If it was deeper I'd cut a strip of wood or something, but think it's too shallow to be able to do that properly.)

My tracking number says that the order is in my mailbox right now, so I'll get to do a test fit tonight. Exciting!

[ICTGoober]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

Why couldn't you just run a file (or some sandpaper) over the epoxy?

Because the epoxy contaminates the wood. It gets down in the grain, and prevents any future glue from getting a grip.

My comment about the future wasn't directed at you per se. But weren't you told fixing it wasn't worth it? It might be true, but it doesn't make the guitar worthless, that's all I'm saying. It's not trash to be thrown away or burned in a campfire.... I digress, didn't mean to confuse you. I'm glad you are making the effort to restore it to usefulness.

[GuitarStv]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

Because the epoxy contaminates the wood. It gets down in the grain, and prevents any future glue from getting a grip.

Would using titebond on the sides instead of epoxy be a better idea then? I feel like there must be a reason that the recommendation to glue the rod in is there. Does it better distribute the force of the rod?

[GuitarDoc]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

Actually, Titebond is not a good idea because it shrinks as it dries/sets. The epoxy is a better idea. Follow Dan's advice...he really DOES know what he's doing. Probably more than anybody on this forum.

The shrinkage of Titebond makes it a great product for gluing the fretboard to the neck...it actually tightens the connection as it sets.

Besides, you're not worried about the epoxy sticking, or any other "glues" of future repair jobs sticking. That is NOT the purpose of the epoxy or whatever you decide to use anyway. The purpose of the epoxy is as a filler...to fill in all the tiny gaps and to hold the rod secure, to keep it from any movement or flex when it is tightened in the future. For your neck and truss rod to function properly, all components of the neck have to be intimate/as one piece. Epoxy keeps the rod secure and free from any motion or rattle. Glue keeps the fretboard secure to the neck.Each material used in guitar making or repair has its unique application/purpose.

[GuitarDoc]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

Oh, yes. It won't hurt to fill in the gap at the top of the channel. Don't let any excess interfere with the fretboard seating or the glue sticking. Keep it totally within the channel.

[ICTGoober]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

I gave you my opinion, but you're the cat doing it. I'll say no more.

[GuitarStv]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

Truss rod was in the mail as expected. I clamped one end of it and made sure it worked as expected before doing anything else . . . because it would sure suck to get everything back together and realize it all has to come apart again.

So, this should have been super easy and taken no time at all . . . pull old rod out, push new rod in but the new truss rod was just a hint larger in width and depth, and has a nut that was 5 mm longer than the original. Which led to an 'Oh ****' moment before I realized that I had to take the nut off to fit the thing in (not a problem pulling it out with the old nut broken off of course). I did a test fit, and the channel needed a little filing to accommodate it.

Even then, it ended up a very (very) tight fit. There's absolutely no need to add wood filler with this rod and if the reason for epoxy is to fill gaps I don't think there's a point trying to squeeze a couple drops of epoxy in there. There are no gaps big enough to worry about. I was a little worried that the allen key adjustment nut was going to be too long and poke out the bottom of the soundhole, but it just barely tucks away OK. I've put a little oil on the threads of this nut, and it turns very smoothly right now. Should I use some grease on it, or is the oil good enough?

Guitar with broken truss rod:


Truss rod removed and new/old comparison:


Truss rod replaced:




I'm still trying to think of the best way to hold everything together while gluing the fretboard back on.

[GuitarDoc]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

So far so good.

[ehdwuld]

Re: Extreme acoustic guitar surgery - watch me destroy a beloved instrument!

I got faith in ya
You got a degree in something right?
You can do it
Slap that fretboard on and pray

Got a pin nailer?

I got this brad nailer that shoots brads the size of small sewing needles
It would be perfect for this