Acoustic Guitar Construction

Hi All,

Any recommendations for bending temps for rosewood sides? For maple sides?

Many thanks!
-rick

Hi Rick

I bend both Indian rosewood and maple at 275 degrees.
On a Fox style bender I start cranking down the waist at 250, slowly and almost l the way down. When the heat hits 275 I start bending the lower bout.
Then I bend the upper bout, then I crank the waist the rest of the way down.

I cook it at 275 for about 15 minutes. Turn the heat off, let it cool to about 100, turn the blanket back on and heat it back to 275. When it reaches it I turn the heat off and leave it until it reaches room temperature. If you have time, leave it over night and the bend will be set pretty good with little to no spring back.
The whole heat up and bend only takes about 6 or 7 minutes.
I spritz my wood with water and wrap it in kraft paper(the rosewood) to keep the oils from transferring to the slats and the heat blanket.

The maple doesn't need to be wrapped.
I used to also wrap in the paper and the aluminum foil....I think it helps hold the moisture in longer which helps with the bend but it's probably not necessary.

I hope this helps you.

Kevin

Many thanks for the valuable info Kevin. I've only bent mahogony so far in my Fox bender (with mixes results lol). I read somewhere, I think John from Blues Creek, to take mahogony up to 325F. I'll try w/ 275F for the rosewood/maple. Thanks again!

I'm still using a HF router speed controller with my blanket and by the time I finish the bend it's usually up to 300+. I usually am able to hold 285 to 300 by closely monitoring the dial for about 10+ minutes before the timer shuts off. I cut pieces of kraft paper 6" x 36" and slide them through a tray of water to wet them as I build the bending sandwich. I spray the wood with Windex (with ammonia) just before bending. Sandwich is slat, paper, side, paper, aluminum slat, heat blanket, slat. Haven't broken a side since some Bocote years ago and the seller (Aaron Hix) said I probably got it too wet. A little hotter than Kevin's way but mostly the same on timing. I've bent EIR, Maple, Chechen, Afrormosia, Pau Ferro, Black Walnut, Mahogany, White Oak and lots of Maple and Manzanita binding.

Thanks you for the response Carl. I've been using just (2) slats - spring steel from Blues Creek. I've tried from bottom to top:

slat - paper - side - paper - slat - heat blanket

and also

slat - paper - side - paper - heat blanket - slat

I'd like to try a third slat the way you are doing it. Do you think this aluminum flashing is ok? https://a.co/d/85GoELI. I'm guessing you need to flatten it back out for each side? Actually, looks like this aluminum is only 0.007" thick. Probably way too thin...

Thanks again,
-rick

That's what I use. And I've been using some 6" x 36" galvanized steel flashing for the other slats for about 10 years. They came with the homemade bender I bought on ebay. I have to straighten them out every time too.

Thanks for the info Carl. I ended up ordering another slat from BluesCreek since the 2 I have work so well. He no longer carries the spring steel so hopefully the stainless one I ordered works ok. For now I stuck w/ 2 slats and the heat blanket on top. I'll try the 3rd slat above the heat blanket when it arrives. I feel like it could trap the heat more? My blanket came with a crude dial, I just manually twist the thing to roughly hold the desired temp...

I met in the middle between your schedule and Kevin's - did my best to hold 285F and the maple and rosewood bent just fine. Minimal if any springback too. Thanks much!