How wet should ebony binding be for hot-pipe bending?

[Toby Park]

Thanks,

For any other beginners who stumble across this thread looking for info, I will answer my own original question -

With the 2mm thick strips of ebony, I wetted them thoroughly just before bending, i.e. used a soaked cloth and wiped the ebony so that there were no dry spots on either sides or edges, although it had virtually no time at all to soak in so I wouldn't consider the wood as being saturated, just wet on all the surfaces.

For the hot pipe, I did not have a propane torch, and the electric heat gun I had was a bit too localised, i.e. it would heat a small section of the metal pipe to a very high temperature without really heating the whole pipe evenly, so was a bit unreliable. So what I ended up doing was baking the metal pipe in the oven. Oven on full heat (220 degrees Celsius) ended up being pretty spot on and upon taking the pipe out of the oven, it worked well with a freshly wetted strip of ebony for about 5 minutes, after which the pipe had cooled a bit and the bending became much more difficult, so back in the oven it went for another 15 mins of heating.

I suppose this makes for a rather slow technique but actually it was great as the gradual cooling of the pipe really helped me get a feel for the wood at different temperatures. With the wood wet, I would press it against the pipe and gradually the heat would come through the wood and show on the topside (i.e the side not being pressed against the pipe would gradually dry, and at the exact moment the water started evaporating on that topside, it would plasticise and bend reasonably well). So if anything, the water was most useful as it gave a visual aid to the rate at which the heat was penetrating the wood.

I did try and bend a bit completely dry but it did not want to bend at all, so the water must be doing something as it is heated up and steams through the wood.

My pipe was just a piece of steel I found lying around in the tool shed, with a diameter of about 50mm and a thickness of about 3-4mm. For the tighter bends this was too big so I actually used the shaft of a soldering iron (!). The good thing about this is the closer to the tip of the iron you move, the hotter it is, so its quite easy to control the temperature. Whilst this worked quite well for the tighter bends, if anything I think it was too hot and I did burn the wood slightly. Also, it became apparent that with excessive heat the wood doesn't so much as split when bending, but crumbles (it really just turns into charcoal surprisingly easy). Another point worth noting is that with a much smaller pipe, i.e. the soldering iron, it heats a very localised part of the wood whereas really you want to heat a larger section of the wood either side of the bend, since this area also needs to stretch and compress with the bend. In other words, a bigger diameter pipe works better where possible.

Another interesting use of the soldering iron was to press the wood into shape after fitting it to the guitar. For example, with my f-hole pictured above, the tight curve closest to the camera wasn't quite fitting snug against the ash, so I simply poked the iron through the f-hole and pressed the wood against the ash. It worked well although be careful not to burn it.

Oh and for more severe bends, after the wood had dried through, if I needed to bend it some more I would re-wet it.

And I took everything very slowly. This binding took me about 2 days all in, pretty much as long as making the entire guitar body!

[Chuck Tweedy]

Great follow-up! Thanks Toby.

[Simon Magennis]

--- So what I ended up doing was baking the metal pipe in the oven. Oven on full heat (220 degrees Celsius) ended up being pretty spot on and upon taking the pipe out of the oven, it worked well with a freshly wetted strip of ebony for about 5 minutes, after which the pipe had cooled a bit and the bending became much more difficult, so back in the oven it went for another 15 mins of heating.

It might amuse you to know that you have basically re-discovered what traditional Germany builders did in years gone by (even post-WWII). The workshops had a stove (most likely wood burning) going all the the time. Glue pot on top, and the bending pipes heated up in the stove. When one cooled too far it was replaced with a fresh one and put back to reheat. I think they got a bit more than five mins. When it was really hot they would bent one sort of wood, lime (basswood ) or willow for linings first as scorch marks wouldn't be visible, then as it cooled down they would bend something else that needed less heat and the was going to be visible. I don't know kind of pipes/irons where used.

The story comes from G.K Hannabach a few years a back. Hannabach the guitar maker and Hannabach the string maker are cousins both from the Schönbach tradition, and who were forced to re-located after WWII.

[Toby Park]

--- So what I ended up doing was baking the metal pipe in the oven. Oven on full heat (220 degrees Celsius) ended up being pretty spot on and upon taking the pipe out of the oven, it worked well with a freshly wetted strip of ebony for about 5 minutes, after which the pipe had cooled a bit and the bending became much more difficult, so back in the oven it went for another 15 mins of heating.

It might amuse you to know that you have basically re-discovered what traditional Germany builders did in years gone by (even post-WWII). The workshops had a stove (most likely wood burning) going all the the time. Glue pot on top, and the bending pipes heated up in the stove. When one cooled too far it was replaced with a fresh one and put back to reheat. I think they got a bit more than five mins. When it was really hot they would bent one sort of wood, lime (basswood ) or willow for linings first as scorch marks wouldn't be visible, then as it cooled down they would bend something else that needed less heat and the was going to be visible. I don't know kind of pipes/irons where used.

The story comes from G.K Hannabach a few years a back. Hannabach the guitar maker and Hannabach the string maker are cousins both from the Schönbach tradition, and who were forced to re-located after WWII.

Great story, thanks! I did not realise this. I assumed it was more 'normal', and even traditional, to have a continuous source of heat on the pipe whilst bending. Glad to hear my idea was not so crazy after all.