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Gluing purfling to binding before bending. Hints?
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=52218
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Author:  SteveSmith [ Fri Jul 26, 2019 12:54 pm ]
Post subject:  Gluing purfling to binding before bending. Hints?

I've got some real nice curly Koa binding and would like to glue some purfling to the bottom of the binding strips befrore I bend the binding. Several ideas come to mind but since I haven't tried this before I thought I'd see if anyone here has done this and how they did it. Thanks!

Author:  Jim Watts [ Fri Jul 26, 2019 12:59 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

I do this regularly, use titebond III for gluing the purfs to the binding and it'll bend fine.

Author:  meddlingfool [ Fri Jul 26, 2019 1:00 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

I do that on every guitar.

I cut my purflings to .090 x 020.

I sand the sides to .090, then cut off the bindings. Then sand sid s tomwhatever, usually .080-.085.

I use binder clips and titebond 3 the glue the purflings. Then I sand the bindings to .070., which cleans up both sides quite nicely.

Author:  Dave m2 [ Fri Jul 26, 2019 2:29 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

There are two things: the glue you use has to be heat resistant since you will be heat bending the resultant sandwich, hence people's use of Titebond 3 - I use a product in the UK called Cascamite. some sort of resin glue. The second is how you apply clamping force. I have a long jig to push the two components together. Some use a number of small light spring clips. The trick is to keep the binding and pufling in register.

Dave

Author:  SteveSmith [ Fri Jul 26, 2019 2:42 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

Sorry, should have noted that I will use TB 3. Have used that before but I usually laminate flat purfling stock to my binding stock then cut the bindings out so looking for clamping hints mostly I suppose but didn't want to limit the answers.

Thanks again everyone.

Author:  meddlingfool [ Fri Jul 26, 2019 3:31 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

Binder clips. That’s why I rip the bindings at .090. Any thinner and the round ends just pop off. Plus it leaves .020 fir cleanup...Image


Sent from my iPhone using Tapatalk

Author:  Jim Watts [ Fri Jul 26, 2019 3:47 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

I clamp them in a jig, basically two boards that are pushed together. My jig is only about 10-12" long so I have to do a few sessions to go down the whole length. It's cork lined to make up for any unevenness in the binding. I also start with .09 binding and then clean up after it dries, I try to finish at .080. I've used those small plastic spring clamps in the past but had trouble with them popping off, which is why I made a jig. But it appears binding clips work just fine.

Author:  Terence Kennedy [ Fri Jul 26, 2019 4:42 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

Yep, binder clips.

Author:  SteveSmith [ Sat Jul 27, 2019 6:54 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

Ok, I've got a couple a dozen binder clips coming. Thanks!

Author:  Alan Carruth [ Sun Jul 28, 2019 12:30 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

I cheat; I glue the side purfling to the wide side of a piece of binding wood that's about 1" wide by 1/4" thick or so, and then cut off the binding strips. Since I use a bandsaw I have to shoot the edge after each cut. Then I thickness the strips using a drill press planer, running them against a fence on the top side so that the purfing lines won't chip off. I do the gluing in the go-bar deck, using slightly thinned (by 10% or so) T-3. Thinning it out keeps the glue from setting up before I can get all the go-bars on.

Author:  SteveSmith [ Sun Jul 28, 2019 2:41 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

Alan Carruth wrote:
I cheat; I glue the side purfling to the wide side of a piece of binding wood that's about 1" wide by 1/4" thick or so, and then cut off the binding strips. Since I use a bandsaw I have to shoot the edge after each cut. Then I thickness the strips using a drill press planer, running them against a fence on the top side so that the purfing lines won't chip off. I do the gluing in the go-bar deck, using slightly thinned (by 10% or so) T-3. Thinning it out keeps the glue from setting up before I can get all the go-bars on.


I prefer to make my bindings up from a wider piece of wood too but in this case I have some very nice curly koa bindings that need to have purflings attached.

Author:  Pegasusguitars [ Sun Jul 28, 2019 4:08 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

Ideally I would laminate sheets of material to the wider binding stock and slice it, but things never seem to be ideal! I use this jig, made from hardware store 1/8" aluminum bar stock, some 1/4-20 knobs, and 1/4-20 threaded inserts. It works very good. I ran the aluminum through my sander to thin it. You need to keep a trough of water handy because the aluminum gets hot enough to melt the feed belt. One side of the aluminum bar stock has only holes for the knobs, and the other side has slots so that it can slide to close up.. The U shaped pieces on the side apply the force to squeeze the binding and purfling together. I can only 2 bindings at a time, but they only have to stay in the jig for 20 minutes or so. A drawback, if there is one, is having to change the wax paper under the jig every other glue up. I'm going to try waxed melamine as a base next. I've been told TB won't stick to it. Also want to try TB3 because I do sometimes get separations during bending. They can usually be fixed with a hot iron, but would rather not get them in the first place.

Author:  meddlingfool [ Sun Jul 28, 2019 4:30 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

It's about the only thing tb3 is good for on a guitar, but it is very good for that application...

Author:  SteveSmith [ Sun Jul 28, 2019 5:20 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

Nice jig! I was trolling the McMaster Carr catalog looking at UHMW plastic so I could build something similar but since I don't normally glue purflings to individual binding strips I decided to go for the clips.

Author:  doncaparker [ Sun Jul 28, 2019 6:32 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

If you want nonstick gluing fixtures, both UHMW and HDPE plastic are great, but for large, straight pieces, just wood covered with packing tape works pretty well.

Author:  sdsollod [ Sun Jul 28, 2019 6:52 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

My system is not as sophisticated as Bob's but it does the trick. I use packing tape for non-stick. Sorry for the picture size...

Author:  SteveSmith [ Tue Jul 30, 2019 1:06 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

I went with the binder clips. I figured the hardest part would be to get the binding and perfling aligned and clamped. That turned out to be easy. The hardest part was getting an even coat of the watery TB3 on the edge of the binding and that wasn't that bad. Just using my finger to put on the glue turned out to be easy.
Image

Author:  meddlingfool [ Tue Jul 30, 2019 1:25 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

Cover all but the last 1/16" of the bottle cap with tape...

Author:  SteveSmith [ Tue Jul 30, 2019 1:26 pm ]
Post subject:  Re: Gluing purfling to binding before bending. Hints?

meddlingfool wrote:
Cover all but the last 1/16" of the bottle cap with tape...


The finger worked real good on #2. I'll try the tape on the bottle on #3.

Edit: The tape on the bottle worked best of all. Great hint, thanks Ed!

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