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| EIR binding, bending pipe=Frustration! http://www-.luthiersforum.com/forum/viewtopic.php?f=10102&t=4948 |
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| Author: | Alain Desforges [ Tue Feb 07, 2006 2:50 am ] |
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Hello all. I have a true blue newbie question for you. I'm bending some EIR on the hot pipe. I had done one side (non-cutaway) without too much hassle. Now, however, I couldn't bend the cutaway side to save my life. It seemed that if I didn't apply pressure nothing happened (doh!) but the minute I pressed on them, they would snap like dry twigs... I've read many things about it... bend dry, mist lightly, soak for 15 minutes.... Bend hotter than usual, bend cooler than usual.... Face south, bend over backwards, make a prayer or stick a lucky charm up your .... My shop is pretty dry. It hovers from 30% to 32%. Maybe the binding are too dry to start off? I'm contemplating getting a humidifier for the winter months (propane heating). Truth be told, I was bending a bit hot yesterday if the persistant numbness in my fingers was any indication. Thanks in advance. Regards. Alain |
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| Author: | John How [ Tue Feb 07, 2006 2:59 am ] |
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How thick is the binding material your bending? Mine are usually around .070". |
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| Author: | Rod True [ Tue Feb 07, 2006 3:03 am ] |
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Alain, are you using a backing strap? What this is if you don't know is a piece of metal over the side/binding to support the outside of the bend when bending. This realy helps to support the bend all the way through. 
This pic is off the LMI website. |
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| Author: | Michael Dale Payne [ Tue Feb 07, 2006 3:10 am ] |
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My guess is too much pressure to quick. You need to feel the bend. I assume you are keeping a mister handy as a tight bend like a cutaway will take a good bit more time to bend so you will need to hydrate the wood more often. It has been a while since I have bent on pipe but a soft cutaway is the hardest to do. I used a pipe 1/2" smaller od than the Id of the cutaway bend. Use a back and forth motion with the wood feeling when it started to get playable. It really takes very little pressure and a def touch. the binding has such a small surface area it is easy to snap if you try to force the bend at all. Keeping the wood moving back and forth across the pie keeps the heat evenly dispersed in the area of the bend. cut you some Mahogany strips to binding thickness and length and practice on them to get the hang of it. |
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| Author: | Robbie O'Brien [ Tue Feb 07, 2006 3:21 am ] |
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Alain, Here is something that has worked for me and maybe you can get it to work for you. Try thinning the binding to approx. 1.6mm in the cutaway area. This will help it bend easier. Then when installing the binding put a veneer strip of the same wood in the binding channel as you are gluing it up. This will get you back out to the the edge of the channel again. This works well on darker colored woods. |
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| Author: | Josh H [ Tue Feb 07, 2006 3:46 am ] |
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Alain Here is a little trick that might help. I get a rag and spray it until it is damp. Then I place the damp rag on the pipe and bend the binding on top of it. It seems to force the right amount of water into the binding for it to bend. After a few seconds you will have to remove the rag and spray it again. I have found this to be the best way to bend all my binding. I also use this method for bending some of the more difficult side woods. This method seems to force the right amount of water into the wood without it getting the wood to wet. The EIR binding should bend without to much difficulty, but as others have said you may have to thin it a bit more if your cutaway is really tight. Josh |
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| Author: | Daniel M [ Tue Feb 07, 2006 4:44 am ] |
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Hi Alain; I have had an equally frustrating time the last couple of days. I was bending my first cutaway sides & the EIR side just refused to get maleable. I ended up thinning it way down, but the damage was already done, several areas where the wood either kinked or cracked. No amount of moisture, heat, or patience would make that piece of wood behave! There was a fair amount of runout in the side, compounding the issue. The cutaway area ended up so thin, & was afraid of sanding through to get the little kinks out. I ended up thinning down a piece of an orphan side & re-enforcing the whole cutaway section. Robbie's suggestion sounds like a good one. I have had similar problems with Ebony bindings but once thinned down a bit, they bent easily. It didn't take much to make a big difference. |
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| Author: | Mike Loukakis [ Tue Feb 07, 2006 5:03 am ] |
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Hi Alain, I had/have the same problem with the binding on my 335 style guitars. Somewhere (can't remember) it was suggested to use a clothes iron and actually iron(!) the wooden binding on the bending form. In that way you are constantly backing the wood. I've tried it and it works (until now!). Actually I've ironed the binding on the guitar. But it is risky. You could make a small bending form only for the cutaway if you don't use forms to bend the sides. That way it is very straightforward. Go slow, keep moving the iron on the wood and Good Luck!!  |
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| Author: | Alain Desforges [ Tue Feb 07, 2006 5:18 am ] |
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Thanks for your replies guys. The bindings in question are from LMI. They are .09 thick and do have the basswood laminations. I'm using a 1.5 inch pipe with a torch. Like I said earlier, I think I was a bit over-zealous with the heat yesterday. I remember reading somewhere that too much heat will render the binding more brittle and cause it to snap. At one point my iron was so hot that water droped on it would instantly evaporate with an audible 'poof'...On a side note, I don't know what kind of glue LMI uses to laminate these things but it sure holds up to heat. I will try thining them down, since they are a touch too thick anyway, and I might try using the damp towel method as well... I'm so close to finishing... and yet so far.... I think I can relate to a woman in the later stages of pregnancy.... Well... maybe not... Here's a pic of the back (Cherry wood from Colonial). I don't think the bend is too sharp or exagerated. 
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| Author: | EBarajas [ Tue Feb 07, 2006 5:44 am ] |
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I'd have to second Josh's recommendation. Use a damp rag over the hot pipe and bend over that, I do it all the time with the same bindings. Secondly, be patient and take it slow. Also, you need to be cautious with the damp rag thing and light woods like maple, you might get som discoloration but it's never happened to me. Test on a piece first.2 |
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| Author: | Josh H [ Tue Feb 07, 2006 7:09 am ] |
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Your bend is not overly tight, but it is tight enough. If you pipe is so hot that water instantly vaporizes than you have got it to hot. Usually I like to see the water drops bounce a bit and then evaporate. Cool the pipe, thin the binding a bit and take it slow. You should be all set. And of course let us all know how it goes. Josh |
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| Author: | Serge Poirier [ Tue Feb 07, 2006 9:41 am ] |
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Or come to my place Alain, my bender is ready to use and the shop's humidity is dead on 45 degrees, give me a call later on! Serge |
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