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GoodWood

Sides Bent, No Way They Match The Mold!

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Ok, just got my second set of sides off my fox style bender. It was sitting on there for a few days. It matches my first set pretty close, but the bottom bout (pics comming) is really not bent well at all. Id say its (bottom center) 3 inches from where it needs to be. I baked it for 20 minutes at 310, with thin thin aluminium between it and the blanket. This looks like it needs to be rebent on the iron, it did not conform to the mold well, although the center section did.

What is going on??? This will need to fit the mold without much help, right? Grrrr...

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Ok, just got my second set of sides off my fox style bender. It was sitting on there for a few days. It matches my first set pretty close, but the bottom bout (pics comming) is really not bent well at all. Id say its (bottom center) 3 inches from where it needs to be. I baked it for 20 minutes at 310, with thin thin aluminium between it and the blanket. This looks like it needs to be rebent on the iron, it did not conform to the mold well, although the center section did.

What is going on??? This will need to fit the mold without much help, right? Grrrr...

GW-Is there just a little spring back? Will the lower bout conform with just a little force(I mean very little)? If you have clamped the wood to your bending form, and you hit the proper temp for 20 minutes(longer than I bake). It should bend just fine. The other thought that comes to mind is, does your form and mold match properly?

Peace,Rich

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Ok, just got my second set of sides off my fox style bender. It was sitting on there for a few days. It matches my first set pretty close, but the bottom bout (pics comming) is really not bent well at all. Id say its (bottom center) 3 inches from where it needs to be. I baked it for 20 minutes at 310, with thin thin aluminium between it and the blanket. This looks like it needs to be rebent on the iron, it did not conform to the mold well, although the center section did.

What is going on??? This will need to fit the mold without much help, right? Grrrr...

GW-Is there just a little spring back? Will the lower bout conform with just a little force(I mean very little)? If you have clamped the wood to your bending form, and you hit the proper temp for 20 minutes(longer than I bake). It should bend just fine. The other thought that comes to mind is, does your form and mold match properly?

Peace,Rich

Yes they do match, if not the form being "1/4" compensated" a bit for spring back. . LOL, my springback is 3 inches....??? Pics comming....

http://img517.imageshack.us/my.php?image=img0314zn0.jpgimg0314zn0.jpg

They spoon match perfect, so whatever is happening is consistent. I will reverse the heat blacnket and see what happens. The upper bout is actually a pretty good match.

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Ok, just got my second set of sides off my fox style bender. It was sitting on there for a few days. It matches my first set pretty close, but the bottom bout (pics comming) is really not bent well at all. Id say its (bottom center) 3 inches from where it needs to be. I baked it for 20 minutes at 310, with thin thin aluminium between it and the blanket. This looks like it needs to be rebent on the iron, it did not conform to the mold well, although the center section did.

What is going on??? This will need to fit the mold without much help, right? Grrrr...

GW-Is there just a little spring back? Will the lower bout conform with just a little force(I mean very little)? If you have clamped the wood to your bending form, and you hit the proper temp for 20 minutes(longer than I bake). It should bend just fine. The other thought that comes to mind is, does your form and mold match properly?

Peace,Rich

Yes they do match, if not the form being "1/4" compensated" a bit for spring back. . LOL, my springback is 3 inches....??? Pics comming....

http://img517.imageshack.us/my.php?image=img0314zn0.jpgimg0314zn0.jpg

They spoon match perfect, so whatever is happening is consistent. I will reverse the heat blacnket and see what happens. The upper bout is actually a pretty good match.

GW, That is really odd. The bends that would be tuffer to set if the heat was low are set very well. I have never had that happen to me even when I used to use only lamps. Are you thinking the heat blanket is not heating on one side? It looks to me like your technique is perfectly fine. It must be something quirky.

Good luck finding the issue :D . I am sure when you find it you will be in good shape.

Peace,Rich

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[qu

They spoon match perfect, so whatever is happening is consistent. I will reverse the heat blacnket and see what happens. The upper bout is actually a pretty good match.

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I think this problem manifested itself because when I bent the sides, the wood cupped concave pretty bad, I let the blanket heat up on the wood and it took 20 minutes, with nothing on top, or clamped together with the heat blanket. When I finally "flatened" it out in the mold, part of the cup was still there, so it set up a tension in the wood. I just cooked it some more, and it looks like its getting closer, but no potato just yet. I can see that the sides would need a bit of sanding to get 'perfectly' flat. That is probably the issue. Grrrrrr first timers learning curve.

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I think this problem manifested itself because when I bent the sides, the wood cupped concave pretty bad, I let the blanket heat up on the wood and it took 20 minutes, with nothing on top, or clamped together with the heat blanket. When I finally "flatened" it out in the mold, part of the cup was still there, so it set up a tension in the wood. I just cooked it some more, and it looks like its getting closer, but no potato just yet. I can see that the sides would need a bit of sanding to get 'perfectly' flat. That is probably the issue. Grrrrrr first timers learning curve.

First I have never used the fox bender but have constructed one, Just waiting to pay for a blanket but I have used a pipe bender before so I have experience bending sides, not that it helps you.

I'm confused about using aluminum, I was under the impression that you should only use Stainless steel or a spring steel which both return to a flat state after bending. Aluminum bends and generally stays that way, and you say its super thin so how could the aluminum apply the necessary pressure across the face of the side during heating?

I rented a Robert Mays DVD about using the fox bender and he used two blankets (this was his method) and I remember him bringing the wood up to temp several times before he turned off the heat. He was meticulous about the temp being just right and the number of heating cycles, or the wood would not shape properly. It was not the length of time spent in the bender after heating that was a factor in making the bending process work but the number of heating cycles and temperature at the peak and valley of these cycles. Maybe someone can remember the exact sequence.

This post confuses me. Hopefully my confusion has drummed up some answers to your problem.

Woodenspoke

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Hmmm... This is a bit of a mystery. When I did the set for my project around Chrismas of last year. I used heat lamps and suplimented with a heat gun(blankets are easier) with thin aluminum(disposable and very flexable).

set up looked like this-

DSCF0568.JPG

product looked like this-

DSCF0570.JPG

That was with a tight cutoway, and had no issues. I do use a steel sheet over the form to give the wood a firm even base(very important to avoid cupping, wobbles, or woop-de-doos in the sides). The thin aluminum is really nice for the tight cutoway because spring or heavy steel wants to crack the wood when you release the clamps, and aluminum sheets are much more gentle. My gut is telling me this is an insufficient heat issue. Did you use a bit of wet paper or a spritz of water on the wood and then seal the metal sheet(with tape or something) to trap the steam?

Peace,Rich

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Hmmm... This is a bit of a mystery. When I did the set for my project around Chrismas of last year. I used heat lamps and suplimented with a heat gun(blankets are easier) with thin aluminum(disposable and very flexable).

set up looked like this-

DSCF0568.JPG

product looked like this-

DSCF0570.JPG

That was with a tight cutoway, and had no issues. I do use a steel sheet over the form to give the wood a firm even base(very important to avoid cupping, wobbles, or woop-de-doos in the sides). The thin aluminum is really nice for the tight cutoway because spring or heavy steel wants to crack the wood when you release the clamps, and aluminum sheets are much more gentle. My gut is telling me this is an insufficient heat issue. Did you use a bit of wet paper or a spritz of water on the wood and then seal the metal sheet(with tape or something) to trap the steam?

Peace,Rich

Yes, sort of, but it looks like the back part of the blanket may not be heating up to equal temp. The front part was steaming, but the back was 20 or 30 degrees behind,

I need to do a blank run test of the blanket I guess. I was having to put water on the front part and I was getting steam off the wood. Im lucky I didnt scortch it! I will do just the rear end this time. Whew........

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Yes, sort of, but it looks like the back part of the blanket may not be heating up to equal temp. The front part was steaming, but the back was 20 or 30 degrees behind,

I need to do a blank run test of the blanket I guess. I was having to put water on the front part and I was getting steam off the wood. Im lucky I didnt scortch it! I will do just the rear end this time. Whew........

GW- When you say you had to put water on the front part. That makes me think you are not sealing the wood up between the metal sheets. If you seal the sheets up with a little tape around the edges, it will help keep the moisture contained and the steam will roll about inside the sandwhich and give you better protection against burning as weel as even out the heat. I never have had problems with even a hint of burning using this method :D .

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Yes, sort of, but it looks like the back part of the blanket may not be heating up to equal temp. The front part was steaming, but the back was 20 or 30 degrees behind,

I need to do a blank run test of the blanket I guess. I was having to put water on the front part and I was getting steam off the wood. Im lucky I didnt scortch it! I will do just the rear end this time. Whew........

GW- When you say you had to put water on the front part. That makes me think you are not sealing the wood up between the metal sheets. If you seal the sheets up with a little tape around the edges, it will help keep the moisture contained and the steam will roll about inside the sandwhich and give you better protection against burning as weel as even out the heat. I never have had problems with even a hint of burning using this method :D .

Ok, that sounds good. This first set is Padouk, but Im going to go with mahogany until I get the sound I want. The Padouk does not seem to absorb much water.

Doing dry run right now. I may have to send this blanket back.

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Yes, sort of, but it looks like the back part of the blanket may not be heating up to equal temp. The front part was steaming, but the back was 20 or 30 degrees behind,

I need to do a blank run test of the blanket I guess. I was having to put water on the front part and I was getting steam off the wood. Im lucky I didnt scortch it! I will do just the rear end this time. Whew........

GW- When you say you had to put water on the front part. That makes me think you are not sealing the wood up between the metal sheets. If you seal the sheets up with a little tape around the edges, it will help keep the moisture contained and the steam will roll about inside the sandwhich and give you better protection against burning as weel as even out the heat. I never have had problems with even a hint of burning using this method :D .

Ok, that sounds good. This first set is Padouk, but Im going to go with mahogany until I get the sound I want. The Padouk does not seem to absorb much water.

Doing dry run right now. I may have to send this blanket back.

GW- I am not sure you understand what I was saying. Steam is good. If you spray(use a regular spray bottle)your wood with a bit of water(both sides), OR soak paper and cover both sides of your wood with it. Then place the wood between your metal sheets, and seal the edges with tape(all the way around). You will keep the moisture(steam) near the wood. This will both protect the wood and help get even heat throughout the wood you are bending. After you have finished your bending simply split the tape with a razor or knife and the steam and moisture will escape. You will get better results doing it this way.

Bending dry can be done, but you have got to have your heating and clamping nailed down VERY well. Or it will be hit and miss for results, and risky(in terms of burning).

Good luck,

Rich

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Yes, sort of, but it looks like the back part of the blanket may not be heating up to equal temp. The front part was steaming, but the back was 20 or 30 degrees behind,

I need to do a blank run test of the blanket I guess. I was having to put water on the front part and I was getting steam off the wood. Im lucky I didnt scortch it! I will do just the rear end this time. Whew........

GW- When you say you had to put water on the front part. That makes me think you are not sealing the wood up between the metal sheets. If you seal the sheets up with a little tape around the edges, it will help keep the moisture contained and the steam will roll about inside the sandwhich and give you better protection against burning as weel as even out the heat. I never have had problems with even a hint of burning using this method :D .

Ok, that sounds good. This first set is Padouk, but Im going to go with mahogany until I get the sound I want. The Padouk does not seem to absorb much water.

Doing dry run right now. I may have to send this blanket back.

GW- I am not sure you understand what I was saying. Steam is good. If you spray(use a regular spray bottle)your wood with a bit of water(both sides), OR soak paper and cover both sides of your wood with it. Then place the wood between your metal sheets, and seal the edges with tape(all the way around). You will keep the moisture(steam) near the wood. This will both protect the wood and help get even heat throughout the wood you are bending. After you have finished your bending simply split the tape with a razor or knife and the steam and moisture will escape. You will get better results doing it this way.

Bending dry can be done, but you have got to have your heating and clamping nailed down VERY well. Or it will be hit and miss for results, and risky(in terms of burning).

Good luck,

Rich

Ok, it came out ok. I just use an on-off switch and manually keep the heat up for 10 minutes. There is still some "slack" in the sides, id say about an inch and a half. I suppose I should get it down to 1/4 inch or less?

Also, they are a bit wobbley from not being clamped properly before heating. I may just go with mahogany sides.

Thanks

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