Official Luthiers Forum!

OK, here's the situation:

After watching John Mayes' 2 blanket bending setup, and admiring the absolute ease with which it was all done compared to my single-blanket, no controls bending setup, I've wanted to upgrade the setup. 1 blanket worked just fine and dandy with EIR mind you, but the Khaya decided it would be a little more finicky. And I don't have any temp controls, and switching on and off and on and off gets a little bit nerve-wracking after a while, and isn't necessarily the most accurate method of doing things.

Which brings me to the following: I've just found out a surplus store 'round the corner from me is selling new 220-110 setpdown transformers rated at 1500 watts for E35. They've also got a Variac (first time I've ever come across one here) rated at 1700 watts for 90, which would allow me to control the LMI heat blanket I've got right now pretty accurately (it's a big, big unit, also brand new). But I've still only got the one blanket, and I'd like 2, particularly since I've got some woods in my stash that I'm a bit nervous about (that Macassar Ebony, and Bob's Quilt Sapele).

Now, if I've got it calculated about right, John Hall sells 110v blankets, controller included, for about 115 bucks (E 90 right now, make that about 110 after taxes and shipping). As I see it, I've got two options: get 2 blankets from John Hall (advantage: identical units, work the same way, same temps, etc.) and 2 stepdown transformers, or get 1 blanket, 1 transformer, and the variac unit.

Option 1 would set me back about E300, while option 2 would cost me about E235. E65 difference, so it's not minimal, but I would then have 3 blankets. I could either choose to keep the 220 I've got for stuff like heating fingerboards and whatnot, or simply try to sell it on to someone in Europe who might be interested (it's been used to bend 4 sides, and binding for 2 guitars. The silicone's very, very slightly damaged in one spot, but it works perfectly).

What would you guys do, and why?

I can't help you much on the transformer end of things, but I would suggest that **IF** you go to the 110V blanets that you might want to look at John Hall's offering. I think that will save you some $$$ over the LMI set up.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Check out the MInco blankets. I just bought two of them at $61.90 each.
They are 5" X 34" and work great. Their telephone number is (763) 571
-3121. My order number was: Minco #: 8-HR6686R16.5L12A (D). The
person I dealt with was: SharonCross@MINCO.COM. Good luck.

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Sylvan
http://www.wellsguitars.com

Brock: I was looking at John Hall as one of the options for 110v blankets, since the deal's a whole lot better than LMI's, less cash and including temp control

Sylvan: thanks for the tip, I'll check that out ASAP!

Am I correct in assuming 'standard' router speed controllers work well as temperature controllers?

Mattia,

I just use the one blanket that I have had for years. However, if I have a 'trickier' wood to bend I use 3x150W bulbs underneath, as well, so that I'm heating from above and below. Very cheap no controllers needed. In fact just like the old Fox bender.

If you anyone ever does use bulbs inside their bender please make sure to use metal bulb holders, it gets way too hot under there for plastic holders! Believe me I found that out.

ColinColin S38389.5410069444

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

The way I've got my molds designed makes it impossible to use lightbulbs, sadly; I find that a fully supported bending mold works well (no slats/bars going between a pair of mold pieces, but pretty much a solid surface). That, and I kinda like the elegance of the dual blanket approach, which makes a lot of sense to me.Mattia Valente38389.5532060185

Do the Minco blankets come with controls or just the blanket?

Just the blanket.

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Sylvan
http://www.wellsguitars.com

     I know some of you guys like the 2 blanket theroy but I tried that and to tell the truth , temp is temp. I use a thermomter that has a probe so I can see what is happeing at the wood level. If you do go the 2 blanket rout then you need to adjust your bending jigs.
      I use 2 steel slats to support the wood and found that was more important than anything. The wood get hot in a few minutes and while I am not knocking anyones postion I like the fact the steel sandwiches the wood and press bends it better.
   This supports the wood fibers and since I started using this system I have broken 1 side in 5 years. I bend on average 10 sets a week so I think it is safe to say support of the wood is important also.
     Also a router speed control is actually a variable resistor and will work to control the voltage , thus the temp on blankets. I have my set so Ihit 270 degrees and it holds that pretty darn good.
John Hall

Sylvan, when did you order the blankets? I've just received a price quote from Minco for 2 items, same product number, at $78 dollars each. Bit odd, that. Might have something to do with the fact they do have a distributor here. I suppose I should check in with them as well.

Either way, it's a bit weird..

I'd suggest CERAMIC light sockets...I've used them for 6 years now, running 3-300 watt bulbs (on dimmer and timer switches). A lot safer than metal holders as far as heat related problems. The bending slats heat up in about 2 minutes, then I "throttle" back to bend. I have cracked only one side (in 120 guitars) and that was my fault for trying to "reclaim" a set of sides that were marginal to begin with.

Has anyone here ever tried the heating blankets from Omega?

http://www.omega.com/pptst/SRMU_HEATER.html

They make a 6" wide blanket versus the 5" wide ones from Minco. They don't look like they have the plug built in, but maybe that's okay as there wouldn't be the "bump" in the blanket where the cord would be.

Ray

I have the 5W sq in. 6x36 Omega. It works just fine. I use a router speed control and a timer. I only use one blanket. My router speed control only gets the blanket up to 280 or so but I've had no problem bending at that temp.

Have you looked at Bruce's "combo" bending jig? It seems like you could keep the solid form method you prefer, and retool rather inexpensively.

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DES - Shepherd, MI

Um, when I said 'solid' I meant 'solid'; there's no 'air' under the side anywhere on the bending form, fully supported everywhere. Ergo the no lightbulbs issue. Thanks for the tip, though!

Oh, I understood that well enough. What I poorly suggested was that Bruce's design seemed simple enough so that building another jig wouldn't feel like starting over completely. I'm still deciding which method/style to use whenever I get around to my first!

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DES - Shepherd, MI