Anyone know how to or know of someone who can correct a back bend on a neck through ?

[Casey Jones]

Long story short I have a 1990's Carvin LB 70 Bass which is a neck through with ebony finger board that has a wicked back bow in the neck and just a one directional truss rod. I bought the bass for a good price thinking I'd eventually figure out how to correct the back bow but haven't found a way yet. I heard that there's a company in Texas that can correct this type of issue (don't know exactly how), has anyone heard of them or have contact info?

I've thought about sanding away at the arch in the bend but I'm afraid Id have to take off too much fingerboard material to get it flat and it would be too noticeable in the end that there's a big chunk of the board that's missing.

I've also tried a method I read about which involved stringing it up and putting a wedge around the 7th fret about an inch thick and tightening the strings up for a day or two, this had a very minor affect on the back bow and the back bow actually settled back to it's original state shortly after relieving the tension from the strings.

So I'm at a loss and willing to let someone with the proper experience and facilities to correct this issue. If anyone knows a reputable place to send or take it to in Los Angeles I just might do that because I'm afraid this bass will be a complete loss if it doesn't get taken care of the right way.

 

[kramersteen]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

Its only ever happened to me once. Same story neck through and a single action rod. I Clamped it to a bit of solid flat granite for a month. :18: That fixed it right up ''for me''.

Sorry i don't know more.

 

[Casey Jones]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu



I've starting to think that it's not as bad as I originally thought, but I'd still appreciate any help / recommendations to figure out the best course of action. I'm even starting to think I can correct this in the fret leveling process, just so that I don't have to touch the board. Or a little of both options.

 

[Casey Jones]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

The month part is where I was way off, if that worked for you I'll try again and leave it sitting longer this time. I might actually have the perfect peice of granite for this :18:

 

[kramersteen]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

Have you ever had strings on it?

 

[Casey Jones]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

It didn't have strings on when I bought it, and I knew about the back bow. I only put strings on after I removed the frets to attempt the strings + wedge technique which I was afraid was going to twist the neck if I left in on for too long. I removed them to take the pictures because the auto focus on the camera was focusing on the strings.

 

[kramersteen]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

Well personally i would have tested it myself with strings on before pulling the frets. Especially bass strings i am sure it would have pulled it semi straight over a few months? The pictures dont look all that bad.

 

[Casey Jones]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

Ya, I jumped the gun on that step for sure, the frets were in such bad condition though (rust and crap) I figured a refret was the best option for me at the time and I was very excited to get this bass up and running a the time. You think regular string tension would have fixed it over time? So thats possible still an option? I could have just left regular tension on the strings and it would have corrected it?

 

[King IzzO)))]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

Eh, what Raph said.

Now who's got a solution for tongue lift?

 

[kramersteen]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

Ya, I jumped the gun on that step for sure, the frets were in such bad condition though (rust and crap) I figured a refret was the best option for me at the time and I was very excited to get this bass up and running a the time. You think regular string tension would have fixed it over time? So thats possible still an option? I could have just left regular tension on the strings and it would have corrected it?

I will just look at my crystal ball and let you know :knockedou its hard to say without looking at it properly.

I find it a biit crazy that you didnt put strings on first. Anyway ...........it will be worth fixing.

 

[Casey Jones]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

I thought about it this way, my time would be better spent on a refret rather then trying to scrape rust off of old frets. So onto the refret, but I didn't fully know the solution to the back bow. If I strung it up it would have been buzzing all over, didn't see the point of stringing it up just to hear buzzing frets. :duh: I didn't think that regular string tension would have corrected it, which I don't think I need frets to do, I'll worry about fretwork when the neck is straight. :banana:

 

[ChAoZ]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

Did you try loosening the truss rod ?

 

[Casey Jones]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

Yes of course, first thing I did.

 

[kramersteen]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

I bet the frets were in mint condition and just needed a polish.

 

[Casey Jones]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

Hahaha, thought you didn't have a chrystal ball?! :knockedou

Like I already said pretty clearly, I'd rather put my effort into a refret, also just measured the old rusted frets and found a matching set of Jescar's that will be a nice touch to the bass once it's all done.

Also was planning on planing the neck which still might be an option since there isn't a definitive solution to this yet, which if I recall correctly can't be done with frets attached.

 

[Myaccount876]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

The whole point of a single-action truss rod is to counteract the tension of the strings pulling the neck into a bow. Refret it (too large fret tangs will compress the wood and make it back bow more), and string it up to pitch, and let it sit like that for a while. It should fix itself.

 

[Casey Jones]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

The whole point of a single-action truss rod is to counteract the tension of the strings pulling the neck into a bow. Refret it (too large fret tangs will compress the wood and make it back bow more), and string it up to pitch, and let it sit like that for a while. It should fix itself.

Id personally like to have the neck where zero tension on the truss rod means that there is a little relief in the neck, so that I can counter act that with the truss rod and be able to do the perfect fret job and set up on it that way (I don't like not being able to work without a little relief in the neck when doing this because it just seems counter intuitive, thinner necks with single action truss rods seem to not want to go beyond 0 relief and sometime stay in a back bow when not strung up and I don't like relying on strings to give me the relief that I need in the set up). I do not want to attempt a fret job if the neck is still in a back bow.

The original fret tangs measured .032 inches and the new ones are .036 inches. I don't think 2 one thousandth of 1 inch in the fret tangs will create too much back bow in and of itself (If it turns out that the frets do not want to seat properly after the compression of the fingerboard from the straightening process, I can use a fretting saw to widen the slots and counter act any back bow that may occur from that).

I will try and string it up and let it sit for a long while and if that doesn't bring at least a little relief to the neck, I may also try the clamping method mentioned and maybe even include some heavy foam in the middle of the arch to give it some much needed relief. After I see that the truss rod is near 25-50% tightened and the neck has 0 relief in it, I'll be able to do a proper fret job & set up on it (I think 75-50% of truss rod tightening should be enough to counter act the tension from the strings beyond that point).

 

[jake_xms3_punk]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

Strings will add tension as already said. if it still doesn't work itself out, I have had good results using weights and clamps.

 

[crusty philtrum]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

A heat press is the generally-accepted cure for a backbow when string tensioning and truss-rod loosening are not enough. You can either get a luthier to do it or construct something yourself, I'm sure there would be plenty of ideas floating around on Youtube.

 

[J E C]

Re: Anyone know how to or know of someone who can correct a back bend on a neck throu

IMHO, the best thing to do weather you refret it or make it a lined fretless is to replain the board!
I would start by seeing how much adjustment the T-rod has and that it is functional. Then I would adjust it so the neck has a slight amount more back bow than it has with the T-rod loose. Then replain the FB into the proper shape and refret it. Doing this is the best way to correct the problem, and it insures that the neck will come forward, and be able to adjust the neck shape with the T-rod. This is a good technique to do any time you make or refret a neck.
Nice bass by the way! It's worth fixing properly!