Hey, Just joing the fun.
Have you popped that sucker in the oven periodicaly?
The internal strain can somewhat be alleviated if you can figure out the annealing temperature.
On the other hand, if you randomly choose a temp you may "age" it into a more brittle material.
Annealing doesnt reverse the deformation, but gives you a new starting point. AS Jeff pointed out, strain caused by plastic deformation is accumulative...
Cold working metal makes it stronger, but it also makes it more brittle. So the more you move that without any annealing, the more brittle it will be.
Bridge lift on the 4003S/5 SPC - advice, please!
Moderator: jingle_jangle
Ah, the advantage of being a chemist! At the place I work, I could (with minor difficulty) heat it up in an oven with a slow nitrogen purge, with or without vacuum applied.
I don't know whether I want to gamble with a procedure with two unknowns at this point, but thanks for bringing up that point, Josh.
I don't know whether I want to gamble with a procedure with two unknowns at this point, but thanks for bringing up that point, Josh.
It is better, of course, to know useless things than to know nothing. - Seneca
the black coating may not like the oven ...
The powder coat will probably just become soft and possibly get to the point that it flows again. It probably won't hurt it as long as it stays within the working temperature range of the paint and it is not disturbed. We have done this to 500 degrees F with no problems.
"The best things in life aren't things."
well a quick Google and it appears that pure zinc's annealing temp is below rm temp. ~50 degrees F.
Theoretically this means it cant be strain hardened (assuming its reasonably close to pure) and that you have nothing to worry about.
On the other hand judging form the data you presented (pictures) I would say that it has been hardened. The arch in the middle is why I say so. The section that was bent the worst wanted to bend back the least (if you follow my logic) So the result was that the sections that weren’t all that bent in the first place were more willing to bend do to your clamping. This makes me think that the metal does contain internal strains.
since we can assume that the annealing temperature is quite low (although not below rm temp) and we know the danger to the finish I would say the danger to the part is marginal.
The aging temp will be substantially below the annealing temp so that is no longer a problem.
If it were mine, I would heat it to about 4Xtheoretical (50F) = 200degreesF ~1hr and then allow it to cool very slowly (Leave it in what ever you heated it in and let the whole system cool down)
Theoretically this means it cant be strain hardened (assuming its reasonably close to pure) and that you have nothing to worry about.
On the other hand judging form the data you presented (pictures) I would say that it has been hardened. The arch in the middle is why I say so. The section that was bent the worst wanted to bend back the least (if you follow my logic) So the result was that the sections that weren’t all that bent in the first place were more willing to bend do to your clamping. This makes me think that the metal does contain internal strains.
since we can assume that the annealing temperature is quite low (although not below rm temp) and we know the danger to the finish I would say the danger to the part is marginal.
The aging temp will be substantially below the annealing temp so that is no longer a problem.
If it were mine, I would heat it to about 4Xtheoretical (50F) = 200degreesF ~1hr and then allow it to cool very slowly (Leave it in what ever you heated it in and let the whole system cool down)
The final chapter.
Here is a picture of the tailpiece after a lot of slow clamping and a 'heat treatment' of sorts:
The gap has been reduced to about 4 mm, and the bridge looks more-or-less normal. It also has a clear ring to it, no dead spots which would indicate a crack.
I made a template for the new holes using my 4003S Redneck (which has the two extra tailpiece screws):
After marking the spots with a silver Magic Marker, I used a nail to make a dent to guide the drill bit:
I checked what size bit to use using the Redneck again, and after using a small bit to make starting cuts, I drilled the holes:
I then countersink the holes a little:
I then clamped the end back down and put in two temporary screws:
Virtually no gap is left at this point. I removed the clamps and gave the bridge a heat treatment of sorts: I heated the oven to 140-150 °F, turned the oven off, then put the bridge and plank in overnight.
After the heat treatment, the gap was about 1-2 mm:
I then put the bridge back on the body and drilled pilot holes for the new screws. I used the clamps again to pull the back of the bridge down before installing the new screws. This is what it looked like when done:
The gap is about 1-2 mm. Good enough, I think! I chose to use two #8x1" black decorative screws instead of chrome or stainless ones, to make the change more "stealthy" (ha ha).
Here it is with the initial restringing (not to tune, but with some tension to get the neck accustomed to tension again):
I'll have to check the intonation once I get it back to tune, but it looks like it's back to playable condition - which it wasn't when I got it, if you remember ...
Again, many thanks to everyone who contributed their thoughts, advice, and opinions in this thread.
Here is a picture of the tailpiece after a lot of slow clamping and a 'heat treatment' of sorts:
The gap has been reduced to about 4 mm, and the bridge looks more-or-less normal. It also has a clear ring to it, no dead spots which would indicate a crack.
I made a template for the new holes using my 4003S Redneck (which has the two extra tailpiece screws):
After marking the spots with a silver Magic Marker, I used a nail to make a dent to guide the drill bit:
I checked what size bit to use using the Redneck again, and after using a small bit to make starting cuts, I drilled the holes:
I then countersink the holes a little:
I then clamped the end back down and put in two temporary screws:
Virtually no gap is left at this point. I removed the clamps and gave the bridge a heat treatment of sorts: I heated the oven to 140-150 °F, turned the oven off, then put the bridge and plank in overnight.
After the heat treatment, the gap was about 1-2 mm:
I then put the bridge back on the body and drilled pilot holes for the new screws. I used the clamps again to pull the back of the bridge down before installing the new screws. This is what it looked like when done:
The gap is about 1-2 mm. Good enough, I think! I chose to use two #8x1" black decorative screws instead of chrome or stainless ones, to make the change more "stealthy" (ha ha).
Here it is with the initial restringing (not to tune, but with some tension to get the neck accustomed to tension again):
I'll have to check the intonation once I get it back to tune, but it looks like it's back to playable condition - which it wasn't when I got it, if you remember ...
Again, many thanks to everyone who contributed their thoughts, advice, and opinions in this thread.
It is better, of course, to know useless things than to know nothing. - Seneca
