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 Post subject: bending figured koa
PostPosted: Tue Jan 03, 2017 10:34 pm 
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Mahogany
Mahogany

Joined: Sun Jan 10, 2016 10:13 am
Posts: 78
First name: Thomey
Last Name: Dertien
City: Sioux Falls
State: SD
Zip/Postal Code: 57106
Country: United States
Focus: Build
Status: Amateur
So i Just got my koa in the mail today and it is pretty highly figured. more than i thought it would be. i have never bent figured wood before but i did buy some mahogany from the local lumber yard to practice with. it definetly bent harder than the other woods ive bent. i use a heat blanket and a form. i was doing slat wood slat blanket but just stared putting the blanket on top of the wood so from bottum up slat wood blanket slat and it seems to work better for me. i do wrap the wood in paper and then tin foil too. I thinned the koa down to .75 tonight and sprayed both sides with super soft 2 and wrapped them in wax paper for 10min. now they are drying overnight and ill bend them tomorrow night after work. so do i just bend it normal. start bending when i see steam and see and feel the wood relax and then go at it or is there something else i should be doing with highly figured wood. im pretty nervous it was alot of money and i dont want to brake them. some good advice would maybe help me sleep better..lol


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 Post subject: Re: bending figured koa
PostPosted: Tue Jan 03, 2017 11:06 pm 
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Posts: 4820
Hi Thomey. I'd be nervous, too! However, I don't think you need to be. My current guitar is highly figured koa as well. I did exactly what you described with the Supersoft, and the sides bent like a charm. Granted, mine were .06 because I use double sides, but bending couldn't have gone any smoother following my regular routine of starting the bend around 230° F.

Have fun! [:Y:]


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 Post subject: Re: bending figured koa
PostPosted: Tue Jan 03, 2017 11:24 pm 
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Mahogany
Mahogany

Joined: Sun Jan 10, 2016 10:13 am
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First name: Thomey
Last Name: Dertien
City: Sioux Falls
State: SD
Zip/Postal Code: 57106
Country: United States
Focus: Build
Status: Amateur
Should I we the sides with water and wet the paper or is that to much water. Also I've seen people post about stains from super soft or discoloration from the wood. Hopefully that doesn't happen. The people that have had that issue seem to have the same story of wetting the wood with super soft and letting them sit over night In wax paper or they bend before they dry from the super soft.


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 Post subject: Re: bending figured koa
PostPosted: Tue Jan 03, 2017 11:39 pm 
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Joined: Mon Aug 23, 2010 11:42 pm
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First name: John
Last Name: Parchem
City: Seattle
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I use highly figured koa a lot and generally bend venetian cut-aways. It is not horrible to bend. I use a fox style bender. I have the heating blanket on top of the wood. I do not use wax paper I use either craft or parchment paper (no wax) I spray the super soft 2 wrap and let it sit overnight and just bend. I start slowly bending the waste when the wood is around 250-260. It starts heating up fast at that point. If I do a cutaway I usually use a heat gun to heat the underside of the cutaway while I bend. The bouts I just bend.

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 Post subject: Re: bending figured koa
PostPosted: Wed Jan 04, 2017 6:02 am 
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Old Growth Brazilian Rosewood
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Posts: 13634
Location: Ann Arbor, Michigan
First name: Hesh
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Avoid metal such as foil or a slat being in direct contact with the wood. We've had reports through the years on this forum that Koa can turn a bit green when in direct contact with metal.

Beautiful wood, a favorite of mine. I never used SSII when I was still building for Koa but I would have had I had it.


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 Post subject: Re: bending figured koa
PostPosted: Wed Jan 04, 2017 6:09 am 
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Koa
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First name: Willard
Last Name: Guthrie
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We do pretty much as others have suggested:

- We treat with SuperSoft 2 by spraying both sides of the wood, then allow it to fully dry - usually about 6-7 hours - and bend within 36 hours.

- We avoid the use of most parchment paper because it is loaded with silicone as a release agent. Non-silicone parchment paper usually has to be mail-ordered, but it works as well as aluminum foil for isolating the rust-prone spring steel slats from wet paper. Unless the parchment paper is specifically labelled and sold as as 'silicone-free' it is not going to be, and to further confuse the matter, the 'Earth-Safe, Natural, Good for Mother Nature' stuff is the silicone-loaded variety, while the silicone-free parchment is considered environmentally damaging due to the nature of the coating used for the surface treatment.

- We've found either 40 lb. brown or white kraft paper (white for light-colored woods like holly) may be used as a moisture reservoir to control the amount of water added to the stack, and has the added benefit of wicking away resins and oils when bending woods like cocobolo, reducing cleanup on the sides or bindings and on the slats.

- We use a stack (from bottom to top) of: spring steel slat/aluminum foil/wet kraft paper/wood/wet kraft paper/foil/slat/blanket/slat. We use separate sheets of foil and paper, rather than an envelop approach - this limits the marking seen on softer woods like koa and mahogany associated with wrinkling on the insides of the bends seen with an envelop approach, and we see faster, more consistent drying when the edges of the stack are open.

- Figured koa and mahogany both seem to show more fiber collapse in tight bends when there is more water in the bending stack, so we calibrate that amount by using kraft paper - after soaking the paper for a minute in warm water, we use the edge of the bench to strip the excess until the surface appears to be semi-gloss for these woods.

- We start bending as soon as steam is seen, which is fairly fast with a 5 watt per square inch blanket running flat out (FULL on our blanket controller) - there seems to be no advantage to waiting longer, and there is a real possibility that the water needed to produce the steam is exhausted prior to the bending being completed. As soon as the bending is completed, we wait for the steam to end, then use the blanket controller (a router speed) to throttle the blanket to produce about 270-280 degrees F during a 30-40 minute drying cycle, followed by an overnight rest in the bender.

There are some good videos on YouTube describing the process for bending figured woods, including ones from John Hall at Blues Creek Guitars and the 'Bending Figured Mahogany with the Fox Bender' series.

Good luck!

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 Post subject: Re: bending figured koa
PostPosted: Wed Jan 04, 2017 8:04 am 
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Mahogany
Mahogany

Joined: Sun Jan 10, 2016 10:13 am
Posts: 78
First name: Thomey
Last Name: Dertien
City: Sioux Falls
State: SD
Zip/Postal Code: 57106
Country: United States
Focus: Build
Status: Amateur
i just bent them this morning before work. the bend went really good the lower bout almost fell it the form at 220 degree before i even started bending. i did get some staining that will be fairly easy to sand out i think. i used brown craft paper that has to be the reason why. i use distilled water so i have no idea how the stains would get there other than the paper. i use tin foil between the paper and slats too so thats not it.


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