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bending temps
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10102&t=7987		 Page 1 of 1
Author:  bob J [ Mon Aug 14, 2006 1:28 am ]
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I know this might be a touchy subject because many of you learned bending temp. from trial and error, ruining many a beautiful side.

I have Universal Bender w/blanket and thermostat.
For those using the above system or any other bending mach. set up, would you please set for the bending temps. for woods you have worked with and please relate amount of water, if any, and what you wrap the side in before bending.
Thanks to all that reply or have had a peek at the post.
Author:  letseatpaste [ Mon Aug 14, 2006 1:40 am ]
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If you want to go low-tech... In Harry Fleishman's class we made it hot enough to just sizzle water on the outer slat. If you spray a little water and the water just sits there beaded up, it's too cold. If you spray it and the water is immediately vaporized, then it's too hot. If you spray and it gets a little sizzle for a second and then evaporates, that's about right.

Most of the time, we'd lick our finger tip and touch it real quick and you could feel it and hear it sizzle, "tssst." That was using lightbulbs in the bender though, so we weren't as likely to get it way too hot, which is easy on a blanket. With my blanket I use the spray bottle. It's worked well for me so far, but I haven't bent that many sides yet, so I'll defer to someone with more experience if their opinion differs.
Author:  Michael McBroom [ Mon Aug 14, 2006 2:13 am ]
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I use a blanket and mold setup, with the temp regulated by a temp controller. Most of the woods I've used that are easier to bend (EIR, cocobolo, pau ferro), I set the controller to 280F, which seems to be just about right. I wet the woods pretty thoroughly before bending and will usually spritz them at least once more when they're on the mold being bent. If the wood is well-quartered, I don't wrap it in foil or use slats. If it is less than well quartered, I will wrap and slat to minimize the chance of the woods developing ripples.

I've bent one set of claro walnut, which bends easily, but I used a hot pipe to bend it. At about 300F, the walnut scorched, and I was not entirely successful sanding out the scorch marks, so if I were to bend another set of claro, I'd try a lower temp.

Mahogany is not easy to bend, I've found. Less water is better with it. Last set I bent, I wrapped and slatted it, both to retain the minimal amount of moisture I used and to minimize ripples, which I was getting even though the wood was perfectly quartered. As I recall, I was bending the mahogany at about 300F.

I've made a few guitars using padauk, which is even harder to bend than mahogany. I've found that padauk can handle a high heat (325-350) without scorching, and it needs lots of water. Bending padauk is a slow process (if you don't take it slow, it tends to crack), but it will bend, and it tends to hold bends pretty well, I've found.

Best,

Michael
Author:  Michael Dale Payne [ Mon Aug 14, 2006 2:16 am ]
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Mahogany: 275F-280F
Maple: 275F-290F
Curly Maple: 280F-300F
Quilted Maple: 280F-300F
Walnut: 275F-300F
Straight Sapele: 280F-310F
Quilted Sapele: 300F-315F
Koa: 290F-300F
Curly Koa: 300F-315F
Most all others will fall in these ranges. the first temp is the temp I start the waist bend at. I bend the waist 3/4 way then bend lower bout , upper bout or cutaway then finish the waist. This gives a good tight fit. The last Temp is the temp I am at when completed. I drop this temp by 25F and cook for ten minutes.

I lightly spritz all I bend with distilled water and I do mean lightly. wrapped in foil or kraft paperMichaelP38943.4703587963
Author:  RussellR [ Mon Aug 14, 2006 2:16 am ]
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Bob

Here's Mine, I use a single Blanket from the top down Blanket, Slat Wood Slat.

Walnut 275 F Very Little Water
EIR 300 F Good spray each side
Madrose 290F Good Spray each Side
Cocobolo same as EIR
Mahogany 290F Light Spray
London Plane/Lacewood 275F with soaked Paper
Zebrawood same as Mahogany (Have to say I've only ever bent 1 Set)
Satinwood 290F with Soaked Paper
Maccasar Ebony 310F with Soaked Paper (Again I have only every done 1 Set)
Ziricote 325F with Soaked Paper.
Pearwood 275F Light Spray


Hope they help some
Author:  npalen [ Mon Aug 14, 2006 2:54 am ]
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Does anyone bend a cutaway as tight as 1" radius in heavily flamed maple?
Nelsn
Author:  A Peebels [ Mon Aug 14, 2006 2:59 am ]
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Russell When you refer to lacewood, are you talking about Austrailian lacewood? I've had a lot of trouble with this one, and I've got several sets.

Al
Author:  RussellR [ Mon Aug 14, 2006 4:17 am ]
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HI Al

I mean standard Lacewood so not the Australian version, but I imagine it has similiar problems, I find with lacewood it likes to break across the little ripples in the grain the art I have found is not too much heat but plenty of steam.
Author:  RussellR [ Mon Aug 14, 2006 9:05 am ]
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Thanks Todd

I am sureyou are right, Mahogany I guess is a bit too general a term as I think their are many different types, some of which require different handling.
Author:  bob J [ Mon Aug 14, 2006 9:38 am ]
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You guys are GREAT. I am not aware of any other place where experienced , excelent luthiers are so willing to part so easily with such precious information
Thanks so much,
Author:  Serge Poirier [ Mon Aug 14, 2006 11:34 am ]
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Like Bob J said, Thanks a lot folks for sharing this precious input, i saved it preciously too!
Author:  tippie53 [ Mon Aug 14, 2006 12:19 pm ]
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email me and I can send you a file on bending
thanks
john hall
blues creek guitars
The temps above are well within range. the thing most missed on is duration.
   I like to keep things at range temp 275 - 375 depending on wood for about 5-8 minutes. after that 220 for 15 -20 mins to dry and set bends
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