MIMF

I just got one of those electric charcoal starters (the kind with a simple loop coming out the front) that I plan to use in a homemade bending iron. As mentioned in a related topic here (and in the old forum), I need to bend it further closed for it to fit in my pipe (2-1/2").

I've read here that this is best done when it's red hot. What should I watch out for while bending it (beside burning myself)? Does it break easily? Bend it slowly? Is it solid metal, or hollow with a wire inside? You guys that have done this...how? Thanks!

My understanding of how they are made--They have a nichrome wire inside, this is surrounded by insulating clay type of material, this is inside of a copperish type of outside metal.

These are obviously manufactured somewhere, and they about have to be made with a straight wire, then bent into the commercial product you purchased. As far as bending hot or cold? I really don't know. I put mine inside a 4" pipe, so I did not have to bend very much.

They can be bent cold, if done slowly and carefully. If you have to bend it a lot, maybe heating would be better. I only had to squeeze mine about an inch narrower than it was, and I did it cold, in a vise without a hitch.

I've bent, straightened and re-bent mine quite dramatically (I needed it for something else at some point), cold. Probably not recommended, but it is still in one piece.

Okay, I'll bend it today....but, since this is closely related, I'll ask it here (if that's a mistake let me know.

What size pipe are you folks using for violin ribs? I was thinking about the tight bends in the C bouts. Is 2-1/2" too big? Thanks!

I'm probably a little late with my comments but... I bent mine cold and got it to fit in a 2.5" pipe. I went slow and pulled it out of the vice a few times when I thought it might crack but no problems. I finally got the tip narrow enough to fit in the pipe and then pushed it in from there.

Thanks for that info! Never too late in my opinion, and that's info I was looking for!

I've bent two cold... the first down to about 2.5" and the second to about 1" (practically flat). Used a vice, nice and slow. No problem.

Okay, it seems like bending these things both cold and hot has been successful for folks here.

Another question about it: Looks like it will have to be bent at both ends; the outer end where the loop around is, and at the handle side. Looking at the handle side, if you place it in a vise at the area where the loop gets wide (see pic below) then the closer parts of the loop going into the handle would get mashed together! No? So would it make sense to put a little block of wood between the element tube to keep this from happening?

I don't think you'll need a block of wood to keep the wand from mashing together near the handle but by all means give it a try - a little security never hurts. You'll find there is a fair amount of resistance as you're cranking the vice. My igniter is a different shape from your sketch, wider at the outer end than at the waste. I started a little below the middle and worked my way toward the tip. The pipe near the handle seemed to just follow along. At no time did it feel like it was going to mash together. Good luck.

Why worry about it. If it breaks, you can get another for $10. It probably won't break.

I have another one I'm building for guitar sides. I'm using a 4" piece of pipe for that one, but the charcoal igniter I'm using for that one (unbent) fits inside pretty loose! I was thinking of using the cooling flange on the igniter to bolt it to the end of the pipe to keep it steady. Make sense?

I think you want the element to contact the inside of the pipe pretty solidly to transfer heat. There's no reason you can't make a big bend on a smaller radius pipe. I do all of my bending on the same 2.5" pipe from the violin c-bout to the sides on the biggest jumbo guitar I build.

Bob Gramann wrote:I think you want the element to contact the inside of the pipe pretty solidly to transfer heat.

Take what I say with a grain of salt, because I'll be Bob uses his bending iron a lot more than I have mine... but I specifically didn't want the hot spot that I thought would be created if the element touched in one place, so I centered mine and "padded" it with BBs. The temperature is even all the way around... but maybe that doesn't really matter.

My pipe is about 1/4" thick aluminum. It heats pretty well all around. I guess a thin pipe could have a hot spot.

I just finished mine today but haven't fired it up yet. The elements lightly touch the pipe, which is about 1/8" thick.

How are you guys controling the heat? Most pics I see are using what looks like a light dimmer switch. But this thing runs about 550 watts. Suggestions on this?

I use a harbor freight router speed control.

http://www.harborfreight.com/router-spe ... 43060.html

They are frequently on sale for a lesser price.

My light dimmer is 600 watts. My charcoal lighter is 500. I mounted the dimmer and the outlet in a metal box just in case but the combination has caused no problems.

A 600 watt dimmer will have a built-in safety factor, also, so it will handle a good bit more, especially for short periods, so it should be perfectly fine. If it gets too hot for your liking, add a heat sink of some type, perhaps scrounged from an old computer or two. Dimmers can also be had with built-in heatsinks and ratings of 1500 watts or higher, but they're not inexpensive!

I'd feel better if your heater didn't touch the thin pipe directly. If you could squeeze it a bit smaller, then loosely pack the cavity with copper(or stainless steel scrubbers?) as suggested earlier, methinks you'd have a much, much nicer, more evenly heated pipe.