Sometime ago I saw a video (which I cannot find on Youtube) where polymorph pellets were used to make a caul that would fit around part of an instrument neck that couldn't take a standard G or other clamp.
I have a situation where I need to make something for the alignment of a banjo neck to a pot where a clamp cannot fit.
Can anyone point me to some videos that show it being done?
I've never seen a video on it, but I followed the approach in this photo essay at Frets.com to make a caul for clamping a headstock on which I was gluing a crack.
Photos here are my caul-making.
Friendly plastic
I've used the method from frets.com mentioned by Ken several times. It works great. Very easy. No video needed those photos are about all there is to it.
Product I used is Polydoh moldable plastic.
Thanks for the input. Its just what I wanted.
Note the title of one of my photos: "finished caul - with wood clamping pad"
About that clamping pad: As the "making caul" photo shows, I clamped the malleable plastic and the face of the headstock between two small, flat, pieces of wood (scraps of finished window casing).
The piece that was pressed against the plastic ended up stuck to it. Hence, the finished/volute-shaped caul has its own integrated wood clamping pad.
And finally: While this caul was made specifically for a 1970s Kasuga neck, it was close enough to clamp a Rover RB35 neck on which the fingerboard was separated from the neck near the nut area and a hairline crack was developing on the opposite side.
quote:
Originally posted by Old HickoryNote the title of one of my photos: "finished caul - with wood clamping pad"
About that clamping pad: As the "making caul" photo shows, I clamped the malleable plastic and the face of the headstock between two small, flat, pieces of wood (scraps of finished window casing).
The piece that was pressed against the plastic ended up stuck to it. Hence, the finished/volute-shaped caul has its own integrated wood clamping pad.
And finally: While this caul was made specifically for a 1970s Kasuga neck, it was close enough to clamp a Rover RB35 neck on which the fingerboard was separated from the neck near the nut area and a hairline crack was developing on the opposite side.
So the plastic sticks to wood? Should I use a piece of plastic bag between the polymorph and the instrument wood to stop it sticking there? Also, can the formed polymorth be reused by heating it in hot water?
quote:
Originally posted by banjonzSo the plastic sticks to wood? Should I use a piece of plastic bag between the polymorph and the instrument wood to stop it sticking there? Also, can the formed polymorth be reused by heating it in hot water?
The wood block appeared to me to be stuck. I don't remember how hard I tried to free it.
Yes, plastic bag or good thickness wrap for protection is necessary, I think. The moldable plastic will have just come out of water and will have water on it. The plastic wrap I used on the banjo neck is visible in my photo.
It's my understanding this stuff can be reused by putting it back in hot water.
I found the discussion from 2017 in which I was asking for advice on gluing a peghead crack that could only be opened a little. At the end, after I did the repair, I shared the same photos of my caul-making plus photos of clamping and the repair. I added these notes to describe a few things not obvious in the photos:
Shiny stuff you see in the photo of making the caul is plastic wrap that I wrapped around the peghead and top of neck to keep the neck dry. Don't want water seeping into the crack.
The shiny surface inside the caul is plastic wrap that got molded to the thermo-plastic. No getting it off. No harm.
The wood on one side of the finished caul is the small clamping block for that side, which also got permanently stuck to the thermo-plastic. Again, no problem.
In making the caul I tried molding the plastic so that the two wood blocks would be parallel. Failed at that. But even though they're not parallel when clamping, the swivel piece of the clamp adjusts enough to put good pressure.
This is the only time I've used the stuff. It was 7-1/2 years ago.
Good luck.
quote:
Originally posted by Old Hickoryquote:
Originally posted by banjonzSo the plastic sticks to wood? Should I use a piece of plastic bag between the polymorph and the instrument wood to stop it sticking there? Also, can the formed polymorth be reused by heating it in hot water?
The wood block appeared to me to be stuck. I don't remember how hard I tried to free it.
Yes, plastic bag or good thickness wrap for protection is necessary, I think. The moldable plastic will have just come out of water and will have water on it. The plastic wrap I used on the banjo neck is visible in my photo.
It's my understanding this stuff can be reused by putting it back in hot water.
I found the discussion from 2017 in which I was asking for advice on gluing a peghead crack that could only be opened a little. At the end, after I did the repair, I shared the same photos of my caul-making plus photos of clamping and the repair. I added these notes to describe a few things not obvious in the photos:
Shiny stuff you see in the photo of making the caul is plastic wrap that I wrapped around the peghead and top of neck to keep the neck dry. Don't want water seeping into the crack.
The shiny surface inside the caul is plastic wrap that got molded to the thermo-plastic. No getting it off. No harm.
The wood on one side of the finished caul is the small clamping block for that side, which also got permanently stuck to the thermo-plastic. Again, no problem.
In making the caul I tried molding the plastic so that the two wood blocks would be parallel. Failed at that. But even though they're not parallel when clamping, the swivel piece of the clamp adjusts enough to put good pressure.
This is the only time I've used the stuff. It was 7-1/2 years ago.
Good luck.
Thanks Ken.
