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Binder and Purfling bending for classical guitars and ukes
Posted: Sat Jul 14, 2012 11:35 am
by Bill Dillon
I need some help, hints, advice. I'm new at lutherie and after building one perfectly satisfactory classical guitar at a lutherie school in Vermont last year, am now working on two ukulele's and one classical guitar. I've reached the point where I have cut/routed the channels for the purflings and bindings and am now attempting to bend them to the correct shape. I'm using an LMI teardrop electric bending iron (which worked fine on bending the sides) and having a bad time with the bindings breaking as I try to bend them. The bindings are rosewood 0.080. I've tried bending them dry and wetting them. Once or twice I've been able to "feel" them let go a bit and bend. but then the break before I get them bent enough to fit the uke waist. Any suggestions any of you might have will be most appreciated. Thanks, Bill
Re: Binder and Purfling bending for classical guitars and ukes
Posted: Sat Jul 14, 2012 11:58 am
by Mark Swanson
That's quite thick to bend at such a sharp curve as in a uke side.
Re: Binder and Purfling bending for classical guitars and ukes
Posted: Sat Jul 14, 2012 12:17 pm
by John Sonksen
Bill Dillon wrote:I need some help, hints, advice. I'm new at lutherie and after building one perfectly satisfactory classical guitar at a lutherie school in Vermont last year, am now working on two ukulele's and one classical guitar. I've reached the point where I have cut/routed the channels for the purflings and bindings and am now attempting to bend them to the correct shape. I'm using an LMI teardrop electric bending iron (which worked fine on bending the sides) and having a bad time with the bindings breaking as I try to bend them. The bindings are rosewood 0.080. I've tried bending them dry and wetting them. Once or twice I've been able to "feel" them let go a bit and bend. but then the break before I get them bent enough to fit the uke waist. Any suggestions any of you might have will be most appreciated. Thanks, Bill
I recently learned how to bend binding and successfully bent some bocote that was thicker at a much tighter radius then you are attempting for a uke. I would say it became easier after I removed water from the equation as it seemed to weaken the fibers of the wood. It' a tricky thing though as the lack of water can and will lead to scorching. What I found was rather than actually try to bend the wood using any kind of force, you really want to hold it on the iron until it kind of lets go and then just use the weight of your hands to pull it down. Even this is a bit of a misrepresentation, it's not the full weight of your hands, it's the idea that you're not trying to bend the wood, you're trying to simply not let it bend too fast.
I'm finding it pretty hard to describe actually, and the truth is you'll start to understand as you practice it. I don't think it's possible to learn how to bend without ending up with a little bone pile of broken pieces. The real trick is finding the patience and the perseverance to keep going. It can be very frustrating, especially when you're dealing with expensive pieces of wood.
Good Luck!
Re: Binder and Purfling bending for classical guitars and ukes
Posted: Sun Jul 15, 2012 8:39 am
by Dick (DT) Trottier
Hi Bill,
Sometimes the problem is the binding wood itself, how it was cut. Look at the broken end of the wood: if the break is any steeper than say 30 degrees it's got too much runout for bending by hand.
Good luck...
Re: Binder and Purfling bending for classical guitars and ukes
Posted: Sun Jul 15, 2012 11:54 am
by Mike Hammond
A product called "Supersoft II" can help to an amazing degree...
Mikey
Re: Binder and Purfling bending for classical guitars and ukes
Posted: Mon Jul 16, 2012 5:35 pm
by Steven Williams
Are you using flexible metal like stainless steel to support the bend? I've also used aluminum flashing with success. For really tight bends I make a "binding sandwich", with the binding between two strips of metal. The top strip helps to prevent fractures and the bottom strip helps to prevent burn marks especially on maple binding. I use just a light spritz of water. It works very well on my ukulele binding even with extremely curly wood.
Steve
Re: Binder and Purfling bending for classical guitars and ukes
Posted: Mon Jul 16, 2012 7:14 pm
by Bob Matthews
Hi Bill, I have to agree with DT, it's most likely runout on the bindings that's causing the problems. You could try a metal backer to see if that helps, but ultimately it may be best to acquire some new bindings and have another go.
0.080" ought to be ok with rosewood, ebony though is a different beast at that dimension as I found out to my frustration whilst binding a headstock.
Bob
Re: Binder and Purfling bending for classical guitars and ukes
Posted: Mon Jul 16, 2012 9:12 pm
by Steve Senseney
Ebony breaks easily, but when it does, you can hide the break.
However, when you use the polished black ebony, every body just assumes you used black plastic binding.
Re: Binder and Purfling bending for classical guitars and ukes
Posted: Thu Jul 19, 2012 11:11 am
by Bill Dillon
I posted this request on three forums and received several excellent and useful suggestions. THANK YOU, EACH OF YOU, FOR YOUR HELP!
Re: Binder and Purfling bending for classical guitars and ukes
Posted: Sat Oct 04, 2014 2:04 am
by Hugh Anderson
You can hide the break in ebony, but it only helps if you got the bend completed.