Backbow Suggestions Needed

[Robbie Collins]

I just refretted a Les Paul Custom.  With the strings off, an 1/8th of a turn of the truss rod nut straightened the neck. With the strings on, only slightly more tension. Not good, but it had .009's and I would restring it with .010's so I didn't worry about it.

The ebony fingerboard was problematic...very flakey and frets didn't want to stay down. After I refretted it I put it in the case for a few days. When I pulled it out to set it up, quite a few frets had unseated themselves. So, I refretted it again.  I had to pull, crimp, and re-seat almost every fret to get them to stay down.  I superglued the frets each time. The second time I also clamped them while the CA dried.

So, yesterday I leveled and polished the frets. Today I made a bone nut and began the setup. Now the guitar buzzes over a wide area in the middle of the neck.  I played with the truss rod but and, strung to pitch with the .010's, it is straight with the TR nut almost loose.  I suppose my crimping did some neck compression.

I'm thinking I need neck relief. Obviously, I'm over-invested in this repair and would like to find the simplest method of fixing it, but I will do what ever is necessary. The options I see are

1) Tighten the TR nut, put the neck into a slight backbow, and re-level the frets.

2) Pull the frets, tighten the TR nut to create backbow, level the fingerboard, etc

3) Heat the neck until the bottom of the neck is hot, put a block at about the 6th fret, lay a square steel tube on top, clamp at the first fret and near the body, and leave overnight.

4) Same as three but pull the frets first and refret afterwards.

[Mark A. Kane]

In my view, slipping the neck in this case was only an attempt to avoid refretting the guitar a third time (the proper repair IMO, as outlined in my earlier post). It didn't need the neck slipped before you re-fretted it, did it? The idea of slipping the joint tempted you into thinking you could avoid the refret. We've all been there. All that work, and the thought of having to do it over yet again.

I have my own opinion about heating a glue joint with an end toward repositioning two pieces of wood. Lots of folks do it with some degree of success, but I don't like the idea of destroying an aliphatic resin-type glue joint with heat and expecting that toasted glue to hold anything for very long. Maybe hide glue is different. I don't have the experience to tell. Nonetheless, it seems tenuous and wholly unpredictable at best. For safety's sake, and to keep from making any job more complex, I refrain from utilizing that method and figure out other, more predictable (in my mind) ways to finish the job. Others will no doubt disagree, but I like playing it safe with customer guitars.

I'd bet your customer would be very unhappy with the knowledge of what his guitar has been through at this point. Not that you have to clue him or her in, just that it better be perfect when you hand it back, so as to avoid that conversation altogether. Good luck!

[Robbie Collins]

Mark...In general my modus operandi is to try to repair a guitar so that no one can tell I've worked on it.

That being said, this guitar was a 2nd from the factory and a prior repairman bungled a refret. They removed the nibs but left pieces sticking up. They sanded a deep radius on the fretboard extension, but only on the left hand side. They rolled the edges of the fretboard making it difficult to seat fret ends. Add to that the flakiest board I've encountered so far (this is my 26th fret job) . The fingerboard was also unevenly planed.

So...living up to my standard will be difficult.  I probably should have sanded the backbow out in the beginning. Because of the excessive planing the last guy did I was worried about making the board too thin and destroying the inlays.  I've had a couple of guitars with similar necks and I was able to successfully refret them without trouble. From now on, if it's iffy I'll take care of it to better guarantee the outcome.

I try to be upfront with customers and tell them when I've run into problems.  I don't go into the gory details, but I try to be honest.

As for the reliability of slipped fretboards, surely someone has info on whether they last and whether they create problems down the road.  I learned about it from Hideo Kamimoto's book and the Dan Erlewine advanced fretting DVD.  No much about it on the web. 

Thanks for helping me understand current best practices and strategies for successful repairs.

[Mark A. Kane]

No problem. My suggestions and opinions are just that. There are many ways to skin the cat. One suggestion for next time: if you have to remove a lot of material to get a neck into shape and are worried about the inlays, take them out. It's fairly simple with a little heat. Plane away, then cut the inlay pockets deeper and re-install. 

[Lee Gendvilas]

Hi Mark, would you mind explaining how much is a little heat? I had a vega #9 5string that had a back bow. Since I've never had an opportunity to work on back bow and I didn't want to mess up the inlays.  I gave the instrument back to the owner. It would not have taken much to plane/sand it to flat. You're comment above seems like a solution I might be able to handle.

[Mark A. Kane]

"A little heat" = "not an exact science". ;)

I've had success using a heat lamp targeted at individual inlays for short amounts of time, maybe 1-2 minutes. I mask off the rest of the neck with foil. I work on the inlay with an exacto knife to lift a corner or edge, slowly. I've also used a heat gun, but I think I prefer the lamp for most jobs. Patience is rewarded! 

I learned (the hard way) to be very careful about sanding through inlays. I approach all jobs with an eye toward not creating work for myself for which I won't be paid!

[Thomas James]

I've been using a soldering iron over a piece of wet cloth to steam out inlay. Works well for blocks and dots. Not sure about smaller pieces. Yes, with a lot of patience added.

[Andrew]

Mark, I tend to agree with your opinion about slipping the neck/fingerboard and I would avoid it. However, I have an 83 bc rich stealth that we performed the technique on at my guitar construction course 8 years ago to remove (slight) backbow, and it has been fine since, even though I keep it in a standard D tuning. I have to mention however that the neck was only heated for a half hour and clamped straight, not into relief. Also its hardly a collectible instrument (love it though, even though I dont play it enough). So there are situations where its a method worth considering, and not necessarily as a last ditch. Still, Ive never seen it as the ideal treatment.

[Robbie Collins]

Thanks to everyone who participated in this thread. I learned a lot.

If you're wondering about the final result, I returned the LP Custom to it's owner today who, after playing it, said with a big smile "How'd ya get the action so low without buzzing?"  I told him about my ordeal (short version) and he had no concerns.

The last fret job was a doozey with dozens of large ebony tear-outs. I spend 8+ hours getting it back in shape as I had to fill many of the divots 3 or 4 times. The superglue from the divots, even with the Teflon slot pieces, narrowed the slots. So, after running a refret saw through them and thoroughly cleaning them out, I was able to put in all but one fret in without crimping. I cut a bone nut and, after touching up the finish on the side of the nut, the neck looks virgin, except for the nibs but they were gone before I got my hands on it.

Now back to the custom metal-flake pink & purple sunburst electric I'm making for a doctor's daughter.