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Thread: Side bending. Is this worth saving?

  1. #1

    Default Side bending. Is this worth saving?

    Is this side piece worth trying to save? sanding past the burns? or should I scrap it and try again?
    This is my first ever side.
    I'm having a bit of trouble managing the temperature of my homemade bending iron. I think I let it get too hot. You can tell how hot it got by the temper colors. it got to about 700 degrees farenheight in the center at one point
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  2. #2
    The Amateur Mandolinist Mark Gunter's Avatar
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    Default Re: Side bending. Is this worth saving?

    I’d ditch it because of the crack, rather than the scorching.
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  4. #3

    Default Re: Side bending. Is this worth saving?

    Not sure about the depth of the scorch, however Iíd make a few suggestions, if your bending iron is getting that hot you need to control it a better. I have a dimmer switch mounted into a small electrical box that I use to control the heat from my homemade (from a hot water element) bending iron. Also you can get a very cheap non contact temperature meter from Harbor Freight, or even most Home supply stores, and use it to monitor the temperature, Iíve found that Iím able t effectively bend in The 400 deg F range.
    And finally I use a piece of folded over aluminum foil between the wood and iron, and I get almost no scorching. Hope this helps

  5. #4

    Default Re: Side bending. Is this worth saving?

    Quote Originally Posted by Levi S View Post
    Not sure about the depth of the scorch, however I’d make a few suggestions, if your bending iron is getting that hot you need to control it a better. I have a dimmer switch mounted into a small electrical box that I use to control the heat from my homemade (from a hot water element) bending iron. Also you can get a very cheap non contact temperature meter from Harbor Freight, or even most Home supply stores, and use it to monitor the temperature, I’ve found that I’m able t effectively bend in The 400 deg F range.
    And finally I use a piece of folded over aluminum foil between the wood and iron, and I get almost no scorching. Hope this helps
    Thanks. I actually have one of those dimmers but it doesn't have a lot of fine control. I didn't have any way of measureing the temperature accurately. I think I should invest in one of those thermometers.

  6. #5
    Registered User John Bertotti's Avatar
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    Default Re: Side bending. Is this worth saving?

    I wonder about the crack as well. I would be tempted at cutting it out and making an A or two-point to avoid the crack and save most of the side.

    As for the scorch I have seen some nice intentional scorch on wood if it doesn't sand out the way you want you could do an intentional scorch side.
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  7. #6

    Default Re: Side bending. Is this worth saving?

    This is your first one. And I just completed my first one. So I'm coming at this having learned a lot of lessons (and patched a lot of imperfections!). So here are my two cents:

    - The scorch appears manageable, for a couple of reasons: If you plan to apply a darker finish then it may end up being covered or masked by the color. Also, the sides appear (to me, anyway) to be slightly thick. And so if you planned to sand the scrape or sand the sides down anyway after assembly then you may sand past the scorch, too.
    - I agree that the crack is the more worrisome development. That said, my F5 had a couple of places where the grain split or tore away, and I was able to manage it either with CA glue, TiteBond or even filler.

    Anyway, that's just my perspective as a rookie. There are plenty more experienced builders on this site, and I'm sure they have better advice. I considered my first build purely a learning experience and really just lucked out at getting a playable instrument in the process!

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  9. #7

    Default Re: Side bending. Is this worth saving?

    What is the best temperature to shoot for when bending so I don't scorch the wood again?

  10. #8
    Registered User bpatrick's Avatar
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    Default Re: Side bending. Is this worth saving?

    375-400 degrees is optimal. If you have more side wood, I would probably try again due to the crack. You could probably convert your cracked scroll piece into another side piece.

  11. #9
    Registered User bpatrick's Avatar
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    Default Re: Side bending. Is this worth saving?

    If you're not using a thin piece of sheet metal bending strap to back the curves, you should. It will help prevent cracks. The more highly figured the grain, less water should be used. Here's a bending strap I made from a piece of step flashing.
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    Levi S 

  13. #10
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    Default Re: Side bending. Is this worth saving?

    I would clamp the crack with padded rounded cauls and glue it up with hot hide glue. If you do a good job, nobody will know it is there except you. I've seen construction cracks that were a lot worse on 100 year old Gibson mandolins, and they are holding up just fine. If you are concerned about the crack, you can back it with a thin strip of glue soaked linen or thin canvas.

    If the burn marks don't sand out, shade them.

    For some strange reason, a lot of folks actually admire the saw marks that are so common on old rosewood Martin guitars.
    Last edited by rcc56; Jul-25-2019 at 12:09am.

  14. #11
    Registered User fscotte's Avatar
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    Default Re: Side bending. Is this worth saving?

    Use it. When you glue it up on the mold, throw a little HHG in that crack and it will virtually disappear. You'll be sanding the outside of the rim as well which will help hide it even more.

  15. #12
    Registered User sunburst's Avatar
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    Default Re: Side bending. Is this worth saving?

    I agree with the last 2 posters.
    When we have bent curly maple into scroll shapes for 30 years or so we learn that the wood cracks sometimes and we have to repair minor cracks. May as well lean that lesson now.
    The scorch looks like most of it will scrape/sand away and what is left will be covered by a sunburst or other colored finish. If you are trying to make a blonde finished mandolin set the piece aside and save it for a later project (and be advised that a blonde mandolin may not be the best choice for a first build).

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  17. #13

    Default Re: Side bending. Is this worth saving?

    I would use it. I have reclamped bigger cracks and sanded/stained over (much) worse burns. I bend my sides over a steel pipe heated with a blow torch and get scorch marks that make curly maple look like zebrawood if I'm not paying enough attention. It's almost always very superficial.

    Thanks,

    Magnus

  18. #14

    Default Re: Side bending. Is this worth saving?

    Now we know why traditional sunbursts are dark in the waist and around the neck joint. I agree with others that the crack is workable. On the next one, use a backing strap as suggested on the tight bends and perhaps a bit more water. Also, I've read that some builders thin the part of the side on the scroll down farther (as much as down to 0.050") to facilitate bending. Enjoy the journey!

  19. #15
    Registered User j. condino's Avatar
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    Default Re: Side bending. Is this worth saving?

    Throw it in the burn pile and start again. You are on day one....if you keep the "reuse it at any cost and fill the results with superglue and rat turds" mentality just so you can move on to do the next step half a$$ed, what do you think the end result will be??????? Sure, it is supposed to be a learning project, but the idea is to learn it well and then move on. Move on now and all you learned is how to &@$% up a nice piece of wood....

    Take that already broken section and bend & break & burn it ten more times; you will learn a lot and then when you bend piece #2, it will come out perfect.....

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  21. #16
    Registered User bpatrick's Avatar
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    Default Re: Side bending. Is this worth saving?

    Here's a pile of learning. I still think this particular batch of very curly red maple is unbendable.

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  22. #17
    Registered User fscotte's Avatar
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    Default Re: Side bending. Is this worth saving?

    If you discard wood because of mistakes, you'll never finish your mando. Learning how to work with mistakes is what makes you a good builder.

    Loars are full of little mistakes.

  23. #18
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    Default Re: Side bending. Is this worth saving?

    i have a friend who has made 76 mandos to date. I , only 4, and constantly post on here for help. I had a couple scorches, and it being in that top near the scroll area, was very dark on my burst. I like some of the repair it comments on here. The advice my buddy had given me, is that sometimes, when you are done with a portion of the build, you have to stand back, and say," Now how am I going to fix that?" I watched him do some bending, and he wrapped the piece to be bent in wet paper towel, then aluminum foil. He also uses a pipe and torch

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  25. #19

    Default Re: Side bending. Is this worth saving?

    Thanks for all the helpful responses. I've tried sanding the burn marks and gluing the split. I'll post a picture of it later once the glue dries. I'm still not sure if I will be using the piece but It wasn't much work to try to fix it so I gave it a try.

    I'm going to be bending the rest of the side pieces from some of the shorter pieces of material I have. I'll do my best to refine my methods. I might end up redoing the big piece depending on how it goes and how much wood I have left.

  26. #20
    Registered User barry k's Avatar
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    Default Re: Side bending. Is this worth saving?

    How thick are your sides....they look too think to me. Over .080 is too much. I personally like .065 to .070 thick.....anything more is over kill

  27. #21
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    Default Re: Side bending. Is this worth saving?

    I'm in the camp of toss it out and start again. The sides do look thick in the photos. Shoot for .070"- .080".

    I use my bending iron horizontally. I put a cut off t-shirt sleeve over the pipe and mist it occasionally during the bend process. No water directly on the wood. The t-shirt will keep the wood from scorching. My pipe is a solid 2 1/4" piece of aluminum rod with a hole drilled in it for a cartridge heater. Takes a while to get to 375-400 degrees F, but once it's there, it keeps a stable temp. I also use a backing strap.

    When you start getting into figured maple, those cracks will happen more frequently. I make up about 4 pieces (more if I can) and do the scroll first. Sometimes I'll go through 3 pieces that will crack, then I find one with a spot not quite as figured and more flexible on the end than the others and it bends like a charm. It's a frustrating procedure. Plain maple will bend like a wet noodle comparatively. You'll notice most Loars have very plain sides.

  28. #22

    Default Re: Side bending. Is this worth saving?

    Quote Originally Posted by sliebers View Post
    I'm in the camp of toss it out and start again. The sides do look thick in the photos. Shoot for .070"- .080".

    I use my bending iron horizontally. I put a cut off t-shirt sleeve over the pipe and mist it occasionally during the bend process. No water directly on the wood. The t-shirt will keep the wood from scorching. My pipe is a solid 2 1/4" piece of aluminum rod with a hole drilled in it for a cartridge heater. Takes a while to get to 375-400 degrees F, but once it's there, it keeps a stable temp. I also use a backing strap.

    When you start getting into figured maple, those cracks will happen more frequently. I make up about 4 pieces (more if I can) and do the scroll first. Sometimes I'll go through 3 pieces that will crack, then I find one with a spot not quite as figured and more flexible on the end than the others and it bends like a charm. It's a frustrating procedure. Plain maple will bend like a wet noodle comparatively. You'll notice most Loars have very plain sides.
    I'm using a cartridge heater in a steel pipe packed with aluminum foil. I think I got a heater element that is too powerful though because even with a router speed controller turned pretty low it will eventually heat up until it has a deep blue temper color. I think that's around 700 degrees Fahrenheit. it heats up quickly though at least. I'll measure the sides with some calipers when I get home. I can't imagine they're much over .09 though. The wood I got for this is very lightly figured. I specifically asked for lightly figured wood from Bruce at Orcas island tonewoods for my first mandolin so I wouldn't have too much trouble bending the sides. I also think the subtle or understated figure look might end up looking nice.

    - - - Updated - - -

    Quote Originally Posted by sliebers View Post
    I'm in the camp of toss it out and start again. The sides do look thick in the photos. Shoot for .070"- .080".

    I use my bending iron horizontally. I put a cut off t-shirt sleeve over the pipe and mist it occasionally during the bend process. No water directly on the wood. The t-shirt will keep the wood from scorching. My pipe is a solid 2 1/4" piece of aluminum rod with a hole drilled in it for a cartridge heater. Takes a while to get to 375-400 degrees F, but once it's there, it keeps a stable temp. I also use a backing strap.

    When you start getting into figured maple, those cracks will happen more frequently. I make up about 4 pieces (more if I can) and do the scroll first. Sometimes I'll go through 3 pieces that will crack, then I find one with a spot not quite as figured and more flexible on the end than the others and it bends like a charm. It's a frustrating procedure. Plain maple will bend like a wet noodle comparatively. You'll notice most Loars have very plain sides.
    I'm using a cartridge heater in a steel pipe packed with aluminum foil. I think I got a heater element that is too powerful though because even with a router speed controller turned pretty low it will eventually heat up until it has a deep blue temper color. I think that's around 700 degrees Fahrenheit. it heats up quickly though at least. I'll measure the sides with some calipers when I get home. I can't imagine they're much over .09 though. The wood I got for this is very lightly figured. I specifically asked for lightly figured wood from Bruce at Orcas island tonewoods for my first mandolin so I wouldn't have too much trouble bending the sides. I also think the subtle or understated figure look might end up looking nice.

  29. #23
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    Default Re: Side bending. Is this worth saving?

    Too much heat can certainly cause the problems you are having. Get a surface thermometer so you know where you are at to start bending, and if it starts creeping up on you during the process. .090" shouldn't be too thick for plain maple, but you can taper the scroll area down to .070" with scrapers, or sanding blocks. I've found microscope slides make great scrapers. Then you can leave the rest of the ribs at your .090" thickness.

    The first mandolin I built many years ago had plain maple. I followed the Siminoff book and bent it at around .115" or so. Bent perfectly on a pipe with a torch. A few years later, I decided to make another one and bought some fancier maple. I broke every single piece for one set until I came up with the approach I use now.

    Quote Originally Posted by Mandolin_newbie View Post
    I'm using a cartridge heater in a steel pipe packed with aluminum foil. I think I got a heater element that is too powerful though because even with a router speed controller turned pretty low it will eventually heat up until it has a deep blue temper color. I think that's around 700 degrees Fahrenheit. it heats up quickly though at least. I'll measure the sides with some calipers when I get home. I can't imagine they're much over .09 though. The wood I got for this is very lightly figured. I specifically asked for lightly figured wood from Bruce at Orcas island tonewoods for my first mandolin so I wouldn't have too much trouble bending the sides. I also think the subtle or understated figure look might end up looking nice.

    - - - Updated - - -



    I'm using a cartridge heater in a steel pipe packed with aluminum foil. I think I got a heater element that is too powerful though because even with a router speed controller turned pretty low it will eventually heat up until it has a deep blue temper color. I think that's around 700 degrees Fahrenheit. it heats up quickly though at least. I'll measure the sides with some calipers when I get home. I can't imagine they're much over .09 though. The wood I got for this is very lightly figured. I specifically asked for lightly figured wood from Bruce at Orcas island tonewoods for my first mandolin so I wouldn't have too much trouble bending the sides. I also think the subtle or understated figure look might end up looking nice.

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