Heating blanket for bending sides

[Max Girouard]

Anyone know where I could obtain one appropriate for mandolin side bending? I have access to a bending iron but the blanket method looks better and safer to me.

[Stephanie Reiser]

There is a company in Grass Valley CA that makes heating blankets for guitar side bending. Maybe they do for mandolin sides, too. Look for Benchmark Thermal . Also in the central US look for Watlow.
Why not use a hot pipe?

[MikeEdgerton]

Check out Blues Creek (http://www.bluescreekguitars.com/catalog/index.php?main_page=index&cPath=8&zenid=24ed466c66eb31df695625af3da31a37). NFI.

[amowry]

There was another thread about this recently that you could search for-- I get them directly from Watlow, and they're very reasonably priced. If you download the Watlow catalog from their site it will list your nearest dealer.

[MikeEdgerton]

Here (http://www.mandolincafe.net/cgi-bin/ikonboard.cgi?act=Search&CODE=02&SID=485f02e85c2d1e1a) are several threads that contain Watlow.

[craigw]

Try Tom Durr of Doc's Mandolins. He was selling plans for a heat blanket bending system on the Cafe about four years ago. I built my system with his plans and got the blanket direct from him as well. I really like the way mine works. Tom's Cafe moniker is Mandomaniac and he posted a thread about the system titled: "Heat Blanket Pictorial" on July 5, 2004. You may wish to do a search for that thread in the archives. It goes into some detail how it all works.

[MikeEdgerton]

Try Tom Durr of Doc's Mandolins. He was selling plans for a heat blanket bending system on the Cafe about four years ago. I built my system with his plans and got the blanket direct from him as well. I really like the way mine works. Tom's Cafe moniker is Mandomaniac and he posted a thread about the system titled: "Heat Blanket Pictorial" on July 5, 2004. You may wish to do a search for that thread in the archives. It goes into some detail how it all works.
That thread is here (http://www.mandolincafe.net/cgi-bin/ikonboard.cgi?act=ST;f=7;t=15548;hl=mandomaniac).

[Bill Snyder]

Actually the thread Craig refers to is This One. (http://www.mandolincafe.net/cgi-bin/ikonboard.cgi?act=ST;f=7;t=16657;hl=heat+and+blank et+and+pictorial)
It has more photos of the process. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

[MikeEdgerton]

OK then. I should have read farther down the list.

[brunello97]

Bill, Mike: Great photos, thanks for the links. A few steps in this process have mystified me a bit since I've never seen it first hand. Bill, in the series you linked to is the blanket 'folded' over the wood-wet paper-aluminum foil 'sandwich', so that it heats both sides? I can't quite tell from the pictures.

Thanks to you guys, I've almost got it clear.....

Mick

[craigw]

Mick, you won't get your blanket to fold over. If it's like mine, it will be on top of the "sandwich which includes the side material (wrapped with wetted paper towel material then wrapped with aluminum foil sealed with aluminum tape to prevent any steam leakage)and strips of steel shimstock on both sides. The shim stock should conduct enough heat to cook it all evenly. I preheat my sides flat for 15-20 minutes then transfer to the bending form and start bending slowly and evenly after another 10-15 minutes or so on the bending form. I used Tom's hinged clamping cauls on the first few bends but now use a caul riding on a t-track to make the first big bend. I also use a long twist handle clamp so I can get slow, even pressure as it's tightened. If I can locate some pics I'll posty them a little later.

[brunello97]

Thanks, Craig. I think I have it now. The blanket is to the 'outside' of the sandwhich....It looks and sounds pretty foolproof once you get it all set up. I kind of have the jig maker menality anyhow. The bending-over-a-hot-tube looks pretty tricky to me.

What gauge steel do you use for your shim-stock. I thought I read that someone was using aluminum flashing in one of the earlier threads. Is that thick enough? If you have more pictures you can post I would really appreciate seeing them.

Thanks again!

Mick

[craigw]

Mick, you need to use shim stock because it's made out of spring steel and bends fluidly as well as returning to original shape after bending. The stuff I use is about .0010" thick and is blued but I believe you can get it in stainless. Since you are bending the "sandwich" including the inner and outer pieces of shim stock as a unit you need this flexibility and longevity that you won't get with flashing material. I also insert a couple of temporary keepers (you need to be inventive) to hold the inner piece (shim stock) to the bending mold once it's all bent into shape. This keeps it from trying to straighten your bent side back to it's original shape. I got my shim stock from an industrial supply company in Nevada but can't recall the company name off the top. I had to take it to a metal fabricating shop to have it sheared to the width I wanted.

[Michael Lewis]

In the long run it is easier to bend over a hot pipe or electric heated bender. Granted, it takes some learning and skill, but it is much quicker once you learn the necessary skills.

[brunello97]

Thanks, Craig. That is helpful. I'll hunt around here for the proper steel. Not sure what you mean by 'keeper', but I guess some kind of stay or small bracket to help hold it in place? (Wouldn't the other side of the mold do most of that work?)

Michael: I know you are probably very right viz the hot pipe....By the look of your instruments there is no doubt. I love the design work. Really, really beautiful and Timeless.

Mick

[craigw]

Michael, you're probably right but I got started in this game a little later in my life and wanted to get up and running as quickly as possible. It's fairly quick to learn and I'm pretty comfortable with the heat blanket method now. With the myriad of other things one has to be a master at related to mando building and now with building orders to fill I just don't see enough incentive to change over now. Maybe you'll convince me otherwise at some point but for now it works for me.

[Peter LaMorte]

Wow, Just priced a Watlow 3" x 30" is $58 and a guitar size 5" x 35" is $109 plus shipping. More than I would have thought. Do this prices seem in line?
Thanks
Peter

[Bill Snyder]

From the prices I have seen those seem about right.

[Steevarino]

Gotta say, I'm with Michael on the Hot Pipe thought. #Have you guys tried bending over a hot pipe? #In my short, but whirlwind experience of instrument building, I feel this step is about the most Luthier-Like operation in the whole process of building a stringed instrument. #Very tactile, very "Old World", and very satisfying. #Scared me at first, but then I realized it's not all that difficult. #You can experiment with soaking, steaming, or just wetting the wood, figure out the best material for a metal backing as you bend, if you should wear gloves or not, all that. #The aroma that comes off of the pipe is worth it all. #The feeling of the wood "giving in" under your hands when you do it right, man, it's just so rewarding!

And, it looks like you'll save about $100 bucks if you don't have to buy the blanket! #I use a propane torch to heat my pipe. #I bent 12 guitar sets with one propane canister, that I bought at a cheap tool place for $1.00. #That's not very much $$ per guitar!

Steve Smith
http://www.CumberlandAcoustic.com
http://www.RedLineResophonics.com