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Sapele bending help

Posted: Sun Sep 01, 2019 6:37 pm
by Alan Sanders
I would appreciate any advice. I am attempting to build a guitar using Sapele. I’ve spent countless hours reading and watching videos. The problem that I’m having is spring back. I’ve successfully bent other species in the past but I’m baffled by Sapele.

Using a fox style bender with heating blanket. Spring steel slats. Thickness of .080. I’ve tried soaking the sides as described in Eric Schaefer’s video. I’ve tried a light mist. High heat, low heat. Short times, long times. Second heating after letting it cool first. I haven’t cracked any sides or scorched anything yet. I purchased some practice sides - unsure of species - and they bent perfectly.

Is there some secret to bending this wood? I’ve bent 3/4” white oak for other projects that has less spring back than 2mm Sapele. Thanks in advance.

Re: Sapele bending help

Posted: Mon Sep 02, 2019 11:37 pm
by Marshall Dixon
I use the same bending set up as you do, but never with sapele. All wood seems to spring back a bit, as you know. Does yours straighten out completely? Maybe try to get an idea of the amount of spring back and design your form to be a more extreme curve, trying to anticipate where it will end up.

Sound as if you made too extreme a bend you could just wait a while for it to relax back to where you wanted it.

This is interesting. I wonder what kind of effect this has on the damping quality?

Re: Sapele bending help

Posted: Wed Sep 04, 2019 11:52 am
by Alan Sanders
No, it doesn't straighten completely, but it's getting to maybe 75% of where it needs to be. All other species are dead on. Close adaptation to the mold straight out of the bender. The sapele - not so much. I've had great success with rosewood, walnut, etc. with minimal springback. I thought I was losing my mind so I bought some practice wood of unknown species and it bent perfectly. I've used sapele in numerous pieces of furniture and thought I would try it for my next guitar build. Is it known to springback more than other species?

Re: Sapele bending help

Posted: Wed Sep 04, 2019 12:15 pm
by Bob Gramann
I bend sapele (and all of my sides) on a hot pipe. I’ve not had springback issues with sapele, but I probably overbend getting it to match the mold it will go into. The curly nature of the grain does seem to make it resist bending. I have often cracked a side attempting to bend it. Fortunately, it is not too expensive.

Re: Sapele bending help

Posted: Wed Sep 04, 2019 12:19 pm
by David King
Alan,
I know nothing about the spring back issue but I can say that i've seen considerable variation in the sapele I've used over the years. I wouldn't make any generalizations about any species without at least two samples to draw from. I suspect you may have come across a particularly recalcitrant example.

Re: Sapele bending help

Posted: Thu Sep 05, 2019 8:03 am
by Alan Sanders
Thanks all. I'll try the hot pipe method. Following up on David's comment, I have read several times that there is great variability in sapele. That may be part of the problem as well. After my first attempt with it, I thought I had gotten ipe by mistake instead of sapele.

Re: Sapele bending help

Posted: Thu Sep 05, 2019 2:33 pm
by John Tuttle
I have experienced spring back with Sapele and found that my pipe temperature was too low. Something to do with the lignin in there, I suppose. I have to bend Sapele with a much hotter pipe than anything else to avoid the spring back. This, of course, increases the odds of burn marks if you're not moving the wood enough.

Re: Sapele bending help

Posted: Sat Sep 07, 2019 12:34 pm
by Brian Evans
I have used sapele, and since I hand-bend I can feel when the wood goes plastic. If you aren't getting it to that stage, possibly insufficient heat.

Re: Sapele bending help

Posted: Thu Sep 12, 2019 8:43 pm
by Alan Sanders
Thanks all. Tried a hotter temp of about 330-350 and it went well.