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| Unbend, reverse and rebend a side -- tips? http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=51405 |
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| Author: | Bryan Bear [ Wed Jan 02, 2019 2:30 pm ] |
| Post subject: | Unbend, reverse and rebend a side -- tips? |
Yep, I did it. I bent two bass sides. I want to keep the bookmatch at the tail so I have to either get new sides or straighten and rebend one of them. The sides are cherry and bent really easily so I'm sure I can do this but not sure of the best approach. Do I need to wait a wile for it to take on moisture again now that I have cooked it in the bender? That is the best way to flatten it? Should I really fuss about getting it perfectly flat before I bent the other direction or will the bender take care of wavy/close enough to flat? I could use SS2, I didn't the first go round and it went easily. Should I bother with it for the flattening and/or rebending? What else am I not considering? |
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| Author: | phavriluk [ Wed Jan 02, 2019 4:04 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
I have never had any association with trying to do this. Having said that. is there a piece of scrap that OP can run through the bender experimentally? Might yield up some information. If no scrap, then perhaps trying to unbend a side with a pipe and seeing if OP winds up with more than 1 piece of wood. If that works, then maybe a return visit to the bender and see what happens. Sounds like there's no downside to experimenting, as the side being reworked is not useful in its present state. I have no idea as to how much fiber damage is done during bending. Maybe some veneer softener could help? |
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| Author: | Bryan Bear [ Wed Jan 02, 2019 4:13 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
Sadly, I have no more cherry to resaw for sides. This side pretty much is the practice on scrap; if it doesn't work, I'll have to go out and buy more material to make some sides. So in that regard, there is no harm in trying. I'd just like figure out a method that offers the best chance of success. |
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| Author: | J De Rocher [ Wed Jan 02, 2019 5:50 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
This doesn't answer your questions directly, but the standard procedure that the builder I learned guitar building from used to make Venetian cutaways was to bend the side to the non-cutaway shape in his bending machine and then fully reverse the upper bout bend into the cutaway shape on a hot pipe. He did this immediately after the initial bending in the machine so no recovery time for taking on moisture and he didn't use SuperSoft. It worked fine on the guitar I built in his course which had highly figured Macassar ebony sides. I would be inclined to flatten the side on a hot pipe and then decide based on how the wood behaved during that unbending whether to proceed to bend it to the correct shape on the hot pipe or in the bending machine. |
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| Author: | bluescreek [ Wed Jan 02, 2019 5:54 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
get a cloths iron and paper towels forget supersoft 2 windex works great the ammonia in it helps to get the cell to move with the wet paper towels keep wet between the wood and iron just heat it and rebend . |
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| Author: | Bryan Bear [ Wed Jan 02, 2019 5:55 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
Thanks, that is good to know. Right now, I am leaning towards getting it reasonably straight on the hot pipe and going directly to weighting it flat on the bench with the heat blanket. I got almost no springback the first time so I'm hoping that will get it flat enough that the bending machine won't leave any wiggles. If not, I'll do it all on the pipe. I guess I was just worried that you could overwork a side. |
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| Author: | Bryan Bear [ Wed Jan 02, 2019 5:56 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
John, you posted while I was typing. A clothes iron is a wonderful idea! |
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| Author: | mountain whimsy [ Wed Jan 02, 2019 6:07 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
Yup. An iron for getting it flat. Or in my case, a ski waxing iron. I had to do this on a mandolin with walnut sides. No problems. Just added moisture to the foil wrapped package before rebending. I think I did it the next day after cursing on day 1. |
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| Author: | Bob Shanklin [ Wed Jan 02, 2019 6:17 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
A steam iron works great for flattening bent sides. A dedicated steam iron is a must for the shop. Dedicated, because the base will stain and those stains will transfer to clothes, and your spouse will .........(her favorite threat here) Bob |
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| Author: | phavriluk [ Wed Jan 02, 2019 6:21 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
Parenthetical question: Is worth a try to use a clothes iron + wet paper towels to flatten out some cupping? |
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| Author: | Bob Shanklin [ Wed Jan 02, 2019 7:32 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
Every stinky set of Zebra wood I have bent cupped and I used the trusty iron to flatten the cupping successfully. Bob |
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| Author: | bcombs510 [ Wed Jan 02, 2019 7:41 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
I wanted to wait until you got good answers before posting... and this may need its own thread, but... In the last three years of building guitars I’ve made about every possible mistake. For some reason I’ve never made this one (bending two of the same side). I *think* this is because I turn the bender 180 between each side so that I always have the non tapered (top side) of the side wood pulled toward me. I do this to be sure to keep it square to the side of the bender and also so that the mark with the waist is toward me. Anyone else do that? I don’t even know why I started doing it specifically, other than I wanted to be 100% sure the non tapered side was pulled firmly against the side of the bender. Brad Sent from my iPhone using Tapatalk Pro |
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| Author: | phavriluk [ Wed Jan 02, 2019 8:05 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
Sure wish I'd had the presence of mind (or the experience with bending) to use a clothes iron when I bent a set of 'Boire' sides. Cupped like crazy and a nightmare of a time with the side struts to flatten the sides enough to sand flat. Good experience, I guess. And a clothes iron was five feet away on a shelf. Learn something every day. |
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| Author: | Bryan Bear [ Wed Jan 02, 2019 9:09 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
Some great info here, thanks guys! Tony, that’s exactly what I wanted to hear! Brad, in my case it was because I had a 5 year old little girl hanging out with me in the shop the entire holiday. It was a welcome distraction to be sure but I was feilding a million silly questions at the time I was marking out inside/outside, bass/treble. I marked it wrong and blindly followed my marks and he. Loading the bender. . . |
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| Author: | Woodie G [ Wed Jan 02, 2019 11:26 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
We've done this a few times, including a very old set of Brazilian discarded by a builder after a 'spooned' set of sides. For rosewoods, water and a clothes iron until flat. For mahogany or other more challenging woods, SuperSoft 2 and 12 hours to dry, then work with clothes iron. |
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| Author: | Bryan Bear [ Thu Jan 03, 2019 12:09 am ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
Well, it’s bent back the other way. I’m going to let it sit in the bender overnight. Running my gloved hands over the slats, I think I may be able to feel a slight hump where the bouts changed direction (I didn’t get it perfectly flat with the iron). Hopefully, I’ll be able to touch it up with the hot pipe. I used the iron and the hot pipe to flatten it. As I was taking out the bend on the lower bout with the hot pipe, I had a flashback. I had done this before on some African mahogany for a woodtop banjo I made about 10 years ago. I can’t remeber why I had to unbend it though. |
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| Author: | Bryan Bear [ Thu Jan 03, 2019 11:01 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
I’m happy to report that the side came out of the bender in great shape (pun intended). There were no waves at all like I feared. I did get a fair amount of springback; the previous bends had virtually none. I’m not sure if that means it didn’t bend as well after being bent, straightened and rebent, or if it was just because I didn’t cook it as long the second time (I was afraid of scorching). The spring back is not bad at all. I can push it into the mold without much force on the spreaders; a little tough up with the hot pipe and it’ll be all set (pun not intended). |
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| Author: | mountain whimsy [ Fri Jan 04, 2019 10:34 am ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
Well done! |
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| Author: | bcombs510 [ Fri Jan 04, 2019 10:50 am ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
Yep, nice save! Sent from my iPhone using Tapatalk Pro |
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| Author: | Joe Beaver [ Sat Jan 05, 2019 2:01 pm ] |
| Post subject: | Re: Unbend, reverse and rebend a side -- tips? |
I did that once. As John said, I just ironed it flat with a regular household steam iron. It went very well. Easy actually |
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