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Guys I've just been watching John Mayes DVD on side bending and he says that using only one blanket in a side bender is akin to using just light bulbs, so I was wondering how many here use 2 blankets when bending.

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Formerly JJH

I learn more from my mistakes than my successes

I use only one blanket, but my guess is that maybe 10-15% use two. One blanket is far from being kin to using light bulbs. When using light bulbs until you have the sandwich closed around form a large part of the heat is escaping into the atmosphere. The waist will receive more heat than any other section and trying to variable control the heat is a slower process with far less precision. As where the blanket provides the heat directly in contact with the wood contained in the sandwich the whole time and as long as the blanket is in good condition the heat is distributed evenly the full length.

The only advantage I see to 2 blankets give is a tad bit quicker to temp, but one blanket can get the wood to temp in less that 2 min. So in my eyes that no big deal.

I don't see why John would say that. I have never broken a side in my Fox bender, using a single blanket. Maybe he uses thinner sheet metal that doesn't retain as much heat?

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

I have done both in my own shop and one in other shops. I tend now to just use one. Nice to have the second one though if one goes bad. I started with light bulbs and did fine there also, 1 blanket was just better.

Speaking of blankets going bad. After 4 years mine finally is developing hot spots. time for a new one

Are you sure I said that? I don't remember saying that. If I did say that I was on drugs so I don't take responsibility for that I think two blankets are FAR superior to one blanket, but one blanket is light years better than bulbs.

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John Mayes
http://www.mayesluthier.com

I just went back and looked... I DID say that one blanket was kind of like light bulbs, BUT the meaning behind it was that with one blanket you have to move a little slower and cautiously sort of like light bulbs. Where as with two blankets it goes a lot faster/smoother in my opinion. Sorry for the confusion...Sometimes I think it perfectly in my head but that doesn't' always come out....

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John Mayes
http://www.mayesluthier.com

I was a little confused John but was going to go the blanket route as a luthier friend and I are going to share the costs silly things like getting the springs here and the screw are difficult, I've found a go kart spare place the sells 5" tension springs otherwise it's £25 for 8 from a spring manufacturer and the screw I'll use studding for. Should all work ok fingers crossed.

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Formerly JJH

I learn more from my mistakes than my successes

JJH, what are you doing about the 110v blanket problem?

John at Blue Creek sells either 240v blankets or 110v blankets and controller and timer with a voltage converter

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Formerly JJH

I learn more from my mistakes than my successes

I've been using two blankets for a while now and in my hands it does go smoother and faster as John said. I have a lot more confidence I won't break something. I wouldn't go back to one. Obviously many highly experienced builders use one and do just fine.

Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.

JJH, I'll have to look at Blues Creek again, I seem to remember there was a problem when I enquired. Perhaps it was just that the controller and timer weren't available in 220/240v.

I read somewhere recently (probably here) that wood bends easiest with the heat source on the inside of the bend. this is why Taylor bends sides in 2 stages. First the waist on one machine, then the upper and lower bouts on another. Using 2 blankets gives you this.

Not all heating blankets are the same. I tried 2 but use just 1. I bend on average 6 sets a week. If your steel is too thin you don't get a good thermal mass or support. Also wattage is important. There are blankets that are 2 1/2 watts pper inch and 5 watts per inch. I use only 5 watters. They have the power to overcome a thermal load.
In 5 years of bending I have lost 4 sets to cracking , all of them highly flamed maple. The key to successful bending is matching the temp to the wood. Also waiting too long will case harden the wood and you most likely will have some issues. From the time I plug in the blanket to the time I am finished bending is about 4 minutes.
Find the technique that works for you.
john hall
blues creek guitars.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it