Official Luthiers Forum!
http://www.luthiersforum.com/forum/

Need someone to rescue my florentine bend screwup
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=33993		 Page 1 of 1
Author:  Paul Burner [ Sun Oct 23, 2011 5:25 pm ]
Post subject:  Need someone to rescue my florentine bend screwup
I screwed up a florentine bend for a build and need someone to possibly rescue me before I have to start over.

Here's the story:

I've made a florentine bending jig similar to the one Tony Karol show's here: viewtopic.php?f=10101&t=33051

I did three or 4 test bends and had three turn out fine - one was some highly figured hog and didn't behave well. So, I went to bend a piece of African Ebony for a build for a friend - and forgot to thin the board down more before I did the bend - gaah. (Plus I hear that Afr. Ebony can be problematic.)

The wood on one edge of the curve is nice and smooth - but on the other side is faceted some with some cracking on the back side of the bend.

I'm looking for a bending iron expert here to see if they can rescue this piece of wood for me as I really don't want to have to start from a new set of sides unless absolutely necessary. My thought is if the bend can be made to work I can always add some backing to the area(s) that have the cracks to give them structural support for the long haul.

If it doesn't work and the wood can't be salvaged, I'll just start over - but would love to have someone give it a go for me if possible.
Author:  DennisK [ Sun Oct 23, 2011 5:50 pm ]
Post subject:  Re: Need someone to rescue my florentine bend screwup
Ouch! I've been lucky enough not to crack any sides yet, but my first instinct when I saw that was to bend it back flat again, thin it down to veneer thickness, laminate with a piece of some other wood, and try again. At least the show face is on the compression side, so the facets shouldn't show up again.

My second thought was to use a different kind of wood in the cutaway. I've seen a few other builders do it, and it can be hit or miss, but it is an option. Especially if you have a small piece of some extra pretty and unusual wood, so it looks like inspired use of something that doesn't come in full guitar size :mrgreen:
Author:  truckjohn [ Sun Oct 23, 2011 7:18 pm ]
Post subject:  Re: Need someone to rescue my florentine bend screwup
Unfortunately, African mahogany can be tough stuff.... Runout in the wood can make for wood that just won't bend at normal thicknesses.....

Once it has cracks in it - it can be hard to salvage.... Perhaps you can find an expert here to do it....

Too thick when bending causes all sorts of trouble.... My own thoughts are to get another piece... Thin it down to the correct thickness and go from there....
Author:  Rod True [ Sun Oct 23, 2011 7:27 pm ]
Post subject:  Re: Need someone to rescue my florentine bend screwup
I've never had good luck bending african ebony, mac ebony yes, but not african.... This will be hard if not impossible to salvage, those cracks of course have weakened the wood and bending back straight will most likely just break the piece more...

If starting over (my suggestion here) bend at 0.075" but you need to get ebony much hotter to bend, like in the 350*F range, keep the blanket on full till the bend it done... should get you there. Also, put the blanket right on the bending form then the wood then slat to pull it over.

Again, I hate bending ebony [headinwall]
Author:  Don Williams [ Sun Oct 23, 2011 7:53 pm ]
Post subject:  Re: Need someone to rescue my florentine bend screwup
The other option is to thickness the wood down really thin and soak it really good and laminate with a caul and perhaps vacuum, creating a 2-3 piece lamination with epoxy. Might be easier to do that....
Author:  peterm [ Sun Oct 23, 2011 9:18 pm ]
Post subject:  Re: Need someone to rescue my florentine bend screwup
Best advise I can give:

Get a heating blanket on the wood and let a weight flatten it back to normal.
Carefully wick in CA and close all cracks/gaps.
Glue a piece of rosewood to the inside of the piece using original titebond.
Thin each side to about .045" (after gluing)
Soak the wood in cold water and let it dry.
Mist the ebony area and go for the bend again. (I would bend at about 350 for ebony)
Take it slow but not too slow so you won't over dry the wood and cause it to become brittle.
Pray...

Don't ask me how I know but I have seen great success with this method for same situation...
Author:  Jim Watts [ Sun Oct 23, 2011 9:59 pm ]
Post subject:  Re: Need someone to rescue my florentine bend screwup
I won't ask how Peter knows ;) but his advice sounds reasonable to me.
Author:  alan stassforth [ Sun Oct 23, 2011 11:09 pm ]
Post subject:  Re: Need someone to rescue my florentine bend screwup
Why don't you sand the "show side" of that piece, and wipe some thinner on it to see if you can see the cracks,
then, if it looks okay,
sand the backside, a lot,
then laminate another layer on it.
Author:  B. Howard [ Tue Oct 25, 2011 7:36 pm ]
Post subject:  Re: Need someone to rescue my florentine bend screwup
I can see the facets in the first pic, they are the cracks. They are not open because they are in severe compression, but the cracks do go through, thus the sudden tangents. Never tried the super glue thing but I have my doubts as to being able to get all those fibers back together tight enough to not be seen. Half the fibers were torn apart, the other half were crushed together and will open up if you flatten the piece.
Author:  jsmith [ Wed Oct 26, 2011 11:32 am ]
Post subject:  Re: Need someone to rescue my florentine bend screwup
Paul, you've gotten some good advice from folks already. There's a really good chance that you won't be able to salvage the cutaway section and will have to start with a completely new set. Then again you might consider talking to your client about making the cutaway section from a completely different, contrasting wood, a sort of accent piece. Whatever you do, I have this bit of advice. What makes a craftsman is that he learns from his mistakes, and he's the one to rectify whatever mishaps occur. We fix our screw ups. I think it was a vignette from Overholtzer's book that made this point: It's not that a craftsman doesn't make mistakes; it's that he knows how to fix those mistakes. So, I urge you, not to ask someone else to rescue you. Feel free to seek advice, but if you're putting your name on a guitar (especially as a professional guitar maker), you should be the one fixing your mistakes."

Just my opinion.
Author:  mcgr40 [ Wed Oct 26, 2011 12:02 pm ]
Post subject:  Re: Need someone to rescue my florentine bend screwup
jsmith wrote:
Paul, you've gotten some good advice from folks already. There's a really good chance that you won't be able to salvage the cutaway section and will have to start with a completely new set. Then again you might consider talking to your client about making the cutaway section from a completely different, contrasting wood, a sort of accent piece. Whatever you do, I have this bit of advice. What makes a craftsman is that he learns from his mistakes, and he's the one to rectify whatever mishaps occur. We fix our screw ups. I think it was a vignette from Overholtzer's book that made this point: It's not that a craftsman doesn't make mistakes; it's that he knows how to fix those mistakes. So, I urge you, not to ask someone else to rescue you. Feel free to seek advice, but if you're putting your name on a guitar (especially as a professional guitar maker), you should be the one fixing your mistakes."

Just my opinion.


Same advice given to me 30 years ago in engineeriing school by the head machinist. I wasn't there to be taught how to be a machinist, but I certainly learned a lot when he told me that.
Page 1 of 1 All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/