Heat neck clamping for how long?

phangtonpower · #1 03-03-2013, 01:04 AM

I know this maybe a temporary fix, or might not work at all, but I'm trying it anyways since I don't have money to buy a new neck. And if I have to buy a new neck anyway, might as well give it a try.

Anyway I bought a MIM 70'ish block inlay, bounded, bullet truss rod from stratospher ebay a few years back. It's relief at about 1mm has always been a little much for me. I tried washers and it helped a little, but not much.

I live in Japan and since they don't have central heating in houses, people use a table covered with a blanket and a heater inside to keep warm. Similar to this

I have my necked clamped with a back bow hanging under the table as close as I can get it to the heater. It's about 120 degrees on the surface of the neck.

How long should I keep it under there? I was thinking about a month since it will probably be warm enough to not have to use the table anymore. We usually leave it on 24 hours a day. Anything I should look for to know that it's done. And should I tighten the truss rod after it's cooled down still clamped, or slowly tighten for how ever long it's under there?

phangtonpower · #2 03-03-2013, 07:12 PM

Anybody?

202dy · #3 03-03-2013, 08:46 PM

It's not how long. It's how hot. One hundred twenty Fahrenheit isn't going to get it to where it needs to be.

However, you've not exhausted typical remedies.

Loosen the truss rod nut. Use the clamping rig you were going to use with heat. Place the neck into a back bow. Sock the truss rod nut down. Take the clamping rig off. If the neck is in a backbow, loosen the rod. If it is not, try again with the washers. This method may take a few tries, but it beats babysitting a neck coming up to temp.

phangtonpower · #4 03-03-2013, 10:54 PM

Quote:

Originally Posted by 202dy

It's not how long. It's how hot. One hundred twenty Fahrenheit isn't going to get it to where it needs to be.

However, you've not exhausted typical remedies.

Loosen the truss rod nut. Use the clamping rig you were going to use with heat. Place the neck into a back bow. Sock the truss rod nut down. Take the clamping rig off. If the neck is in a backbow, loosen the rod. If it is not, try again with the washers. This method may take a few tries, but it beats babysitting a neck coming up to temp.

As I mentioned I've already tried washers and I've tried the jig. Guess this neck is toast. That was a waste of 400+ bucks!

202dy · #5 03-04-2013, 05:51 AM

Quote:

Originally Posted by phangtonpower

As I mentioned I've already tried washers and I've tried the jig. Guess this neck is toast. That was a waste of 400+ bucks!

How many times did you try back clamping and tightening the rod? It can take multiple attempts. Sometimes five or six.

As mentioned before, 120F is not hot enough to heat bend the wood. Toast occurs when the sugars in the wood caramelize.

It is very possible that you may need to seek the help of a professional for this task.

phangtonpower · #6 03-04-2013, 06:35 AM

Hmmm. There are no techs were I live. It took about 2 months to do a fret level because they had no idea what I was talking about. And still they didn't do it right.

I thought the purpose of heat treating was to reset the glue.

Anyway I tried inducing a back bow by hand with a friend helping, but it would always spring back under tension. Thanks for the tip. I'll try with the clamp a few times.

202dy · #7 03-04-2013, 08:42 AM

Quote:

Originally Posted by phangtonpower

Hmmm. There are no techs were I live. It took about 2 months to do a fret level because they had no idea what I was talking about. And still they didn't do it right.

Seek different helpers with the aid of a translator.

Quote:

I thought the purpose of heat treating was to reset the glue.

That is the primary idea. And once again, 120F is not hot enough to break the bond. White glue releases somewhere in the neighborhood of 170F. All of this is moot if the fingerboard is a veneer less than 1/8". It is not strong enough to hold the neck in position.

The secondary idea is to enable the wood fibers to release the set and and take a new one.

Quote:

Anyway I tried inducing a back bow by hand with a friend helping, but it would always spring back under tension. Thanks for the tip. I'll try with the clamp a few times.

Of course it will. The two of you cannot generate the generate the deflection that is necessary over the period of time it takes to tighten the nut. The right amount of deflection looks pretty extreme. Use a clamp, bar, risers, and a caul.

phangtonpower · #8 03-04-2013, 10:23 AM

Quote:

Originally Posted by 202dy

Seek different helpers with the aid of a translator.

There is only one tech, who probably has as much knowledge as me, and I brought two people to help translate. One was a guitar player ><

You've been a big help

One last question. You said that it may take a few times tightening the truss rod when back clamped. Should I loosen the truss rod every time I try to back clamp and re-tighten if the truss is already maxed out?

202dy · #9 03-04-2013, 12:49 PM

Quote:

Originally Posted by phangtonpower

Should I loosen the truss rod every time I try to back clamp and re-tighten if the truss is already maxed out?

Yes. Completely slack before each attempt.

phangtonpower · #10 03-07-2013, 08:33 PM

Quote:

Originally Posted by 202dy

Yes. Completely slack before each attempt.

Took your advise. Its been a few days and its been holding at .3mm relief like Fender recommends

I did leave it under the table for a few days as close to heater as possible, but I took it out and did what you recommended. Its also starting to warm up here, so I don't know if its the combination of things that's keeping the neck where I want it. Regardless, I've never had the neck this straight before

Thank you for all the help!

202dy · #11 03-07-2013, 08:39 PM

It wasn't the heat.

You're quite welcome.