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Bending Purfling for Sides
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=29683		 Page 1 of 1
Author:  George L [ Wed Oct 27, 2010 6:36 pm ]
Post subject:  Bending Purfling for Sides
I'm not having much success getting laminated wooden purflings to bend sideways, so they lay flat in the channel below the binding (along the side of the guitar). I'm using the b/w/b 3/32" x .060" material from LMI. Anyone have any pointers on how I can get past this obstacle?

Thanks in advance,
Author:  Rod True [ Wed Oct 27, 2010 6:53 pm ]
Post subject:  Re: Bending Purfling for Sides
George, sandwich them between your binding when you bend the binding. I tape my 4 binding pieces together with two side purfings between the binding. This keeps the bindings on the correct edge when bending.
Author:  WaddyThomson [ Wed Oct 27, 2010 7:03 pm ]
Post subject:  Re: Bending Purfling for Sides
Yeah, that's the ticket! Then, when they do buckle a little you can iron them flat after they are bent.
Author:  George L [ Wed Oct 27, 2010 7:43 pm ]
Post subject:  Re: Bending Purfling for Sides
Aha, clever. Banding them together. Okay, I think I've got it!

Thanks,
Author:  Glenn LaSalle [ Wed Oct 27, 2010 8:17 pm ]
Post subject:  Re: Bending Purfling for Sides
Hi George,

John Hall has a video on this very same subject here:

http://www.youtube.com/watch?v=YLkOOOOnAfI

Glenn
Author:  Tom West [ Wed Oct 27, 2010 9:13 pm ]
Post subject:  Re: Bending Purfling for Sides
George : I glue them to my bindings and then put purfling to purfling in a pair. Tape the pair together using masking tape especially at the tight bends.This helps to prevent the buckling and crimping. Then bend at least two pair in the bender.
Tom
Author:  George L [ Wed Oct 27, 2010 9:43 pm ]
Post subject:  Re: Bending Purfling for Sides
Great tips. Thanks all!
Author:  dunwell [ Thu Oct 28, 2010 7:41 am ]
Post subject:  Re: Bending Purfling for Sides
If you are pipe bending use some side restraints. I made some strips about and inch wide and 1/8" thick of aluminum flat stock and then bent them to the curvature of my pipe. I use hose clamps to hold them in place on the pipe leaving a small channel between that is wide enough to feed through the purflling strip. This also has the advantage of heating the sides of the strip that are not in direct contact with the pipe itself and allowing it to get warm enough to bend without kinks or breaking. I usually don't get more adventurous than a B/W/B type strip, usually for that type of bottom strip for the sides I just use a B/W strip. 3/32" tall should bend just fine with this rig. If I have taller purfling strips I will trim them down a bit if necessary but don't make them less than your binding thickness or they can get in "under" the binding when you glue up unless you glue them to the binding first.

FWIW,
Alan D.
Author:  Joe Sustaire [ Thu Oct 28, 2010 7:59 am ]
Post subject:  Re: Bending Purfling for Sides
That's a neat tip for us pipe benders Alan!
I like the idea of that heated channel.

Thanks,
Joe
Author:  WaddyThomson [ Thu Oct 28, 2010 9:11 am ]
Post subject:  Re: Bending Purfling for Sides
That is a good tip. Wish I'd thought of it! :D
Author:  Ken C [ Fri Oct 29, 2010 9:28 pm ]
Post subject:  Re: Bending Purfling for Sides
Actually, this evening I bent some curly maple and some purfs for a J-185 build. The sandwich consists of 4 maple bindings, 6 BW purflings, and 2 BWB purflings. No ironing needed and ready for installation. Here's a pic of what folks are talking about:
Attachment:
DSCN3937.jpg

Attachment:
DSCN3938.jpg


Ken
Author:  George L [ Fri Oct 29, 2010 11:31 pm ]
Post subject:  Re: Bending Purfling for Sides
Still struggling with this, but getting better. Hopefully tomorrow I will achieve better results. I really enjoy the challenge of learning how to tackle new steps in the building process. Thanks for the pics, Ken. That helps.
Author:  Daniel Minard [ Sat Oct 30, 2010 2:35 am ]
Post subject:  Re: Bending Purfling for Sides
Yeah, what Alan said. The side supports make edge bending wide purflings easily into tight turns.
Lots of moisture & work quickly as you can. You don't need a lot of heat. The bends don't have to be perfect... Close is good enough.
I have much better luck with mitres if I put the purflings in separate from the bindings.
Author:  tlguitars [ Mon Nov 01, 2010 11:26 pm ]
Post subject:  Re: Bending Purfling for Sides
Don't use your binding for your side purfling: Two alternative ways.

1. I did for a while and now I cut and thickness some scrap fat binding. My WBW is around .096 tall (ish). And my binding is .080-.090 depending on the guitar. (ish!)

Purfling that is .096 and binding that is only .090 will/ can result in squished sections or scorching.

What I do is I cut and thickness some scrap "binding" (walnut or Mahog) and thickness it to .100-.101 (width doesn't matter), tape it like you would in the above photos and that way when I bend the .096 purfling my clamp and steel doesn't touch the purfling. I get the bend but there is no chance of warping, wobble or scorching because there is no hard contact, just heat and pressure.

(I do use binding when bending my top and back purfling as the purfling is .060 (plus glue) on it's side)

2. (The up grade) I recently was in a shop where the builder had 2 heat blanketed jigs. The 1st looks like a cutout from a cutaway, it's job is to set the waist. This is wrapped in a heat blanked and 4 pieces of purfling are just pressed around the curve of the cutaway (the side waist) and then the pieces are transfered to a second jig that is the full shape of the side (with another heat blanket) and the waist is clamped into place, and the purfling is then hand heat bent and clamped into place. They are clamped for maybe 2-3 minutes and then pulled and set aside. Perfect WBW, no warp no scorch and you can do 25 guitars worth in a couple of hours. Genius!
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