Official Luthiers Forum!

New guy to the forum so be gentle.

I can do basic fret work (leveling & dressing), setups, and wield a mean soldering iron, but have never done any kind of wood working. I was given an Alvarez strat copy that has the tremolo stud threaded inserts pulling though the wood. It's a pretty catastrophic failure.

I know the simple (sensible?) solution is a new body, but it does not appear to have the standard strat pickguard, trem, neck pocket, etc., dimensions. A typical replacement body would likely require all new hardware, possibly a new neck, or at least a lot of modification. It was a gift so it has some sentimental value. Plus it's a bit of a challenge for me to repair and I want to give it my best shot.

My plan is to route out the damaged area wider than the tremolo cavity and glue a new piece of wood in, drill for the stud inserts, etc. The tremolo and pick guard should cover most of the repair and what little that will show I'm not too concerned about. What I am concerned about is choosing a good wood for this repair piece as well as a good glue to use, or if something besides just gluing would be recommended.

Thanks!


Any suggestions would be appreciated.

OK, this is a common occurrence, and not a basic or cheap repair. You'll have to rout out to clean, uncracked wood - and put in a species close to what you already have. Titebond will work well as a glue. Of course, once you're done with all the routing, gluing, drilling, and all that - then you get to touch up the finish. If you've never done anything like this before..... Maybe this shouldn't be your first foray, because it's not for the inexperienced or fainthearted.

_________________
"Act your age, not your shoe size" - Prince

What Chris says. If you don't need a trem you could deck yours and block it in the cavity from the back.

Another possibility would be to install a bridge system that doesn't require the mounting studs. I happen to really like the Kahler tremolo (from an engineering standpoint it is absolutely elegant but quite pricy). It mounts flat on top of the guitar, here is the routing template which you could compare to the hole in the top of yours

https://www.kahlerusa.com/public/pdf/6200RIMA.PDF

If it will fit, here is the unit itself

https://www.kahlerusa.com/guitar-tremol ... teel-steel

My turn! ^^^^ What Freeman says. ^^^^

Kahlers WORK.

_________________
"Act your age, not your shoe size" - Prince

I thought I already responded, but I don't see it. If this ends up as a double post I apologize in advance.

I would like to retain the original trem only because it is original. I'm actually not much of a trem guy and usually don't even put the bar in when playing. If I can't make it work with the original trem I would likely go hard tail with it.

I would still like to try routing out the bad wood and gluing a solid piece in it's place. Chris recommended using similar species of wood but my thought was to go with a stronger tone wood (maple or ash?). My best guess based on what little info on this guitar that I have been able to fine out is that the body is likely alder, which is a fairly weak wood. Why do you recommend sticking with a similar species? Is it a tone thing or something else?

I don't think they type of wood matters that much as long as it is similar density and strength. The same wood will be easier to match finish but you are still going to have some difficulties with that.

Would it be possible to drill the damaged area out and insert dowels? The grain will be running the wrong direction but I don't know if that would be a problem. You can buy maple dowels at any box hardware store. Use a Forstner or brad point bit so you get a square bottom in the hole and glue the dowel in with Titebond.

Dowels DO NOT work. Been there, done that, BIG FAIL.

_________________
"Act your age, not your shoe size" - Prince

That's why we have these discussions, eh?

Dowels wouldn't really be an option here anyway. The whole area between the trem inserts is pulled forward. I need to put a piece at least a 1/2" or more past the trem route on each end.

I'm not too worried about the finish there as most on the new piece will be covered by the pick guard or trem. I'm more concerned about using a strong wood for structural reasons, but assume I want to stick to a tone wood. I'm even thinking about adding a steel or aluminum plate/angle in the pickup cavity for added strength, if there's room.

Any suggestion on a structurally strong wood for this? I don't have any hands on experience with the various woods, other than playing guitars made from some of them. I was Googling the strength of different woods and found this:

http://workshopcompanion.com/KnowHow/Design/Nature_of_Wood/3_Wood_Strength/3_Wood_Strength.htm#strengthchart

On this list hickory and bubinga look the strongest, but I don't see hickory being used in guitars and bubinga doesn't seem like a wood I'm likely to find locally. Maple and ash look like pretty strong and are fairly common.

I would use the following criteria to select the wood

- If appearance is important I would try to match what is there. Most likely if its a strat copy that would be ash or alder
- I would choose one of the denser stronger woods - maple and ash are good, I would consider mahogany. Spruce, cedar, and basswood are out.
- I would look in my scrap box and see what I had in the right size - I've got lots of maple, mahogany, some koa, lots of spruce, some doug fir.

So that narrows it (for me) to ash or maple. Since I don't have any ash I would have to go to my local lumber yard and score a small piece. I sure as heck wouldn't buy a board just to do this repair.

When you route out the cavity make a really good jig and use that for both the routing and cutting the insert. The vertical corner will be radiused at whatever diameter router bit you use - making the corners of your jig the same radius will help you make the insert to fit perfectly. Think about how you will clamp it in place - it looks like when you take the p/g off and remove the pickup you can put a clamp into the pickup cavity and pull it forward - if there is through body cavity for the trem you can probably clamp it there, otherwise you may need a very deep clamp for the vertical.

If you are trying to match the existing wood then you need to run the grain lengthwise with the guitar. If not I would run the grain crosswise - your insert it probably going to be 2+ inches wide and one or so inches deep - I would want the grain on the long dimension.

Also measure the centers of the stud holes very carefully - you want to duplicate that when you drill the new holes. Reference them both from the center line and from the fretboard or nut - that determines the scale length and compensation - it needs to be dead on. Those holes need to be carefully laid out and drilled on a drill press. When I'm laying out anything to do with a bridge I put a lot of blue tape on the top of the guitar and draw lots of little lines





That jig is a one time thing made out of some scrap plywood. It does have two flathead screws going into holes where this particular trem will mount as well as the clamps. In theory you can use double sticky carpet tape to hold it down but I like to add screws and clamps.

edit to add - once you've figured out how big your insert needs to be and if you don't want to try to source the wood locally, shoot me a PM and I'll look thru my scrap box. I can probably find a few different things that would work - wouldn't cost more than a few cents to send them too you. If you want to source it locally just go to a cabinet shop and see what they have for cutoffs.

Freeman, thank you for the offer!

I had a chance to disassemble it completely and the damage is actually worse than I thought!

As you can see in the pics, not only have the trem insert holes failed, but the entire section where the trem inserts are has moved forward. It even looks like someone tried to use wood putty (or who knows what) to "fix" it. Part of the issue may be that it appears to be a two piece body and the failure is right along the seam. The smart move is obviously to get a new body, but I still want to try and fix it, it's not like I can make it much worse! It looks like I would need a repair piece at least 1"x1"x5", although longer would be even better since it would let me tie into more solid material. My plan is to the replace the section I marked in red in the last image (with radiused corners of course).

Freeman, do you have something laying around that big that might work?

Thanks!

I've fixed stuff worse than that... I had a Flying V in the shop once that had endured several Floyd and Kahler installations and finally collapsed from front to back between the bridge and neck. Someone glued in large pieces of broom handle... I routed a swimming pool size hole in it, filled with a brick sized slab of mahogany, and started over. Charged a truckload of money for the repair and touch-up, but it's still going strong 15 years later out in San Francisco last I heard. Measure everything carefully, take pics and measurements - drive on. You can do it. Bend it to your will.

_________________
"Act your age, not your shoe size" - Prince

IMO, routing out the damage and replacing it with a rectangular piece is basically impossible...

1: it would require a PERFECT fit
2: just how would anyone plan on getting a proper glue joint as one would be pressing a new piece in as opposed to pressing it together

what I'm seeing from the pictures is one of the studs appearing to be pushed in as opposed to pulling out, which implies it was dropped on its face and the trem took the force and transferred it to the body...

on second thought it would be possible if you could machine a hole and patch that are wider on the back side (e.g. taper kind of like a dovetail joint) so that when pressed in glue adhesion is possible and too boot the geometry of it all means that any forces being transferred from the front side are going to actually suck the joint tighter...

either way, a royal PITA to pull of with any alacrity...

I see that apparently Chris has pulled off something similar (posted whilst I was responding), but this level of woodworking is certainly not for the faint of heart, or for a person who tries for anything but perfection (one will NEVER be "perfect", but if you don't try you won't even be in the ballpark)

Lee, I've got several things that might work. 1-1/2 x 2 x 5 mahogany, 5/8 x 1-3/4 x 11 mahogany, 5/8 x 3 x 9 maple. The 5/8 pieces could be laminated and there is nothing wrong with that - all of my necks are laminated. If you wanted to PM me an email address I could send you a picture or you could give me a snail mail addy and I could drop them in a box on monday.

All of these would have the grain running across the guitar - I think that might actually be much better (eh Chris?)

And explain that third picture - which cavity is that and exactly what are we looking at? Is the dark thing a cover from the back? If so I think you should route all that cracked wood out. What is the total depth there?

I guess I think it is worth a try. I would route a little wider than Lee shows with his red line - maybe another inch into the bass side - that sound give fairly good support on the guitars long axis. The router bit will leave a radiused corner on that side - the insert will have to be the correct width to fit the slot and have radii on that end - that isn't hard to do. The end that extends into the control cavity is not critical - make it over long and route or chisel back. I would make the insert to stand slightly proud, then plane back level with the top. Carefully drill for the studs - you'll have just as much wood as the original guitar and the grain will be running in a better direction.

Personally I would disable the tremolo so you don't have the rotational stress on the studs (but then I'm a non-trem sort of guy anyway LOL).

One big problem will be to restore the finish - I would at least shoot a couple coats of lacquer on the insert. A new pick guard could be fabricated that would cover the insert on the bass side or you could just leave it to show off your repair chops.

Anyway, at this point it costs basically nothing to try.

It's the rear spring cavity. The "dark thing" is the table top.....

_________________
"Act your age, not your shoe size" - Prince

That sounds great. I will PM you. Thanks!

Chris is spot on regarding the third pic. That's the table pad on my kitchen table. The depth from the top of the body to trem cavity is about 1 inch.

OK, I'll send you a picture of some wood and drop it in the mail tomorrow.

The fact that the tremolo cavity goes all the way thru to the back makes clamping really easy - a couple of quick clamps or c-clamps should work nicely. I was worried about clamping in the long direction but the way you are going to route makes that unnecessary.

As far as Mike's concerns - here are my thoughts. First, routing a rectangular cavity with radiused corners and fitting a piece in it is no more difficult than many of the other wood working joints that we make every day. All of my Fender style neck pockets look like that and any decent wood worker makes M&T and box joints and dovetails that fit.

Second, the glue joint will be strong enough - it will be clamped against the bottom and if the insert is well made it will be a tight fit on the sides. I don't see any problems there. Again, look at a normal Les Paul style M&T - its a very similar joint and they are under a lot more stress than this will be.

Get yourself one of these: https://www.mlcswoodworking.com/shopsit ... outer.html.
For $100 you get a standard base, a plunge base and an adapter ring. Variable speed, on/off switch is easy to access, easy to one hand shallow cuts.

I actually have a router with many accessories, including a plunge base, given to me by my father shortly before he passed. I've never really used it and I think this will be a a good project to learn on. Obviously I'm going to be doing a lot of trial and error experimentation on random paces of pine I have laying around left over from home improvement projects before cutting on the actual guitar body.

A router is one of the most important tools in lutherie. Its also one of the scariest.

I think the "record" is a bit murky...

I think, know for a fact actually, that routing out the body and making a nicely fitting piece of wood for a patch is very possible and done many times...

what I worry about is actually getting a good glue joint with a nice tight fit (hence my wording of pressing IN as opposed to pressing TOGETHER)...from what I'm seeing in the pictures, the amount of wood that will be glued to is fairly small and I think a "perfect" glue job is going to be required. to be more clear, there is the thought that as you push this patch in you are also pushing the glue away (even if you've properly applied glue to both the hole and the patch)

perhaps (most likely in retrospect) I am misunderstanding the whole plan of action as I currently look at it and see the possibility of just routing halfway or so into the body as opposed to all the way through...in the halfway case you will have a new glue joint, and that being on the "bottom" of the route (which, yeah, is on the sides of the back routing for the springs)

My plan is to route about an 1" deep into the body, just far enough to be even with the trem spring cavity. That will give me an area to glue the bottom as well as the sides in the area were the patch extends past the trem route. Freeman has sent me material for the patch and I will post pics as I go. I appreciate any feedback as I go. If I feel that the glue is inadequate I will add some metal bracing in the pickup cavity. Unlike tone woods, I have plenty of steel and aluminum plate and angle laying around the garage.

I just assume that Lee wasn't going to route all the way thru and thus there would be a bottom to the cavity that he would glue against. That why I asked about the picture of the back cavity - that tells me he can get a normal clamp in there and pull the insert tight against the bottom. He also stated that he needed a piece of wood approximately 1 inch by 1 inch - since the usual depth of a solid body is at least 1-1/2, again, that tells me it won't go all the way thru.

I'm not too sure about how the trem spring cavity will end up but as long as the insert is 5 inches long as shown in the marked picture he will have lots of solid wood to glue to. I'm quite convinced that the repair will be sound.

The wood Freeman sent arrived yesterday. Thanks!

I'm going to give it a go this weekend and was wondering what size router bit would you suggest? It looks like 1/2" is the most common and would leave a 1/4" radius in the corners. That seems good to me but wanted to check with you guys.

Thanks!