Side Bender Questions

[naccoachbob]

I'm considering getting a side bender and trying my hand at that operation.
Looking at the ones John Hall sells. But thought it would be a good topic for discussion and getting ideas from the folks around here. Been exchanging emails with another forum member about it as well. Any other forum members/sponsers sell benders?
What do ya'll think?
There's everything from a pipe with either a torch or charcoal lighter, to a bending iron, to a full growed bender like John's, Fox's, LMI's, etc.
In another forum, someone had one of the first ones that LMI made. He was in Australia, and evidently they use 220 volt there. His burnt up on the first try, roasted the wood, and almost burned down his shop. Turned out they didn't have a voltage regulator on it, and LMI very quickly corrected that problem. Just how safe would one be here in the USA at 120?
With a pipe or iron, you can "feel" the wood respond to the heat. What is a good technique for sensing when to bend and at what speed to bend down on a waist, for instance with a bender? What do you see, smell, hear, feel?
With pipes and irons, how do you keep the bend perfectly vertical? Is it easy to get it off kilter? Or if you're reasonably observant, is it a "piece of cake"?
Just some thoughts and questions. Please chime in, everyone.
Thanks,
Bob

[tippie53]

Hand bending is a good skill to learn. Benders are repeatable . There is no one answer here but to educate yourself. Can you build one ? sure . You would be surprised at how many people try and buy the supplies only to buy the machine .
The design you choose needs to fit your requirements for output and space. Light bulb machines are so unsafe that I will not mention them again . Heating blankets are not just safer but more controllable . Having the ability to control the heat range is important. Heat blanket wattage is also important. 5 watts per inch is a good power range. below that the wattage can't overcome thermal load and takes longer to get the heat into the wood .
I will be watching this so that I can help with my experience .

[kencierp]

My production bending system is very fast and also proprietary so I won’t be sharing a lot of information. Those of you that have purchase our pre-bent sides or built a KMG kit can attest to the fact that our sides snap right into the mold without much need for even a waist clamp. I will say that the molds/forms are totally enclosed and heat is applied to the “inside of the curves” – that is where the compression takes place.

I use very, very thin Stainless Steel supports (actually shim stock) on the cutaway bender. Our standard machines have .020” aluminum supports no stainless steel at all.

All the wiring is silicone shielded

All have temperature controls are actually regulated with one of these gadgets

http://www.energyfederation.org/consume ... bAodrkoIbg
Wattage usage can be converted into output temperatures.

We also use a standard wood burning furnace thermometer to keep an eye on the temp.

And most importantly all have shut down timers – building one without a timer could cost you a house. We do not sell benders --- they are too hazardous.

Bending on a pipe is fun -- where leather gloves -- work slow, you can feel the wood wanting to relax, keep the wood in motion to prevent scorching, use a spray bottle to mist the wood with "distilled" water. And plan on taking a very long time to get it right -- but it is very doable even for the new comer.

I came across a bender plan recently but forgot to add it to my favorite links -- when I find it again I'll post it.

[tippie53]

I do agree about the timer . They should also be used on pipe benders. It is to easy to walk away from any heat source.

[Kevin Sjostrand]

Bob,
You know I don't have alot of experience yet, but here is what I am doing.
I liked the idea of "feeling" the wood. I have not used a bending machine yet. If someone gave me one, I would use it.
However, I am enjoying hand bending. It takes longer, but I like the feel, smell, and hands on approach. I built myself an electric bending iron for about $25. It works great. I have bent sides for 3 guitars so far. I have found it is pretty easy to keep the sides square to the iron. I also have not had much trouble with twisting or cupping, although this last set (macacuaba) wanted to cup, I just wouldn't give in!!!! For me, cause I don't have much experience, I go really slow, but you can feel the wood start to give from the heat and pretty much figure out how much you can begin to force the wood to bend. I like it.
I also have another pipe that I've put a torch in to help make the cutaway bend, and that works too, and is even cheaper if you already have a propane torch.
If you want to try the handmade electric iron, let me know and I will give a list of what I used, and I can put pictures of the rig up here if you like. I think they are back in the old forum.

Kevin

[Kevin Sjostrand]

Hey Tony, our posts went up about the same time. I would like to say that what I have found hand bending is it would be pretty hard to crack a side as long as you pay attention to what you feel the wood doing. Forcing it before it is pliable is cause for breakage, but you really can feel the wood going elastic, and that in turn tells you how much you can push the wood into a bend.
You might just have to get the pipe and torch and try it out.
It is a must if you want, or need to touch up sides to better fit the mold.
Now my sides don't alway fit my mold perfectly, but I like it that way because I don't want any two of my guitars to be exactly the same.....like cookie cutter guitars, I think they might be worth more 100 years from now.

Kevin

[darren]

I bent my koa sides by hand on a pipe, same setup as Ken's, and there was some separation of the 'curl' in the waist. It was probably too wet. As I understand it the same thing can happen on a bending machine. There are lots of posts about broken sides/linings/bindings in bending machines on other forums, so don't think that a machine makes you immune to that. ;)

[kencierp]

Darren's comment is right on the mark --- each piece of wood seems to have a mind of it's own. For this reason KMG does not have a "bending only" service. Even Honduran Mahogany can be a challenge balancing moisture and heat -- the figured stuff can crack in a spot that makes no sense at all. Some woods -- the Mahoganys for sure, have interlocking grain paths which casue sections of the material to "puff up" rather then bend when heat or moisture is applied.

To my previous comment I would add that we have found over the years that a perfect fitting waist caul for each style is a quantum improvement if the goal is consistancy --- setting that curve exactly, tends to minimize spring back.

[tippie53]

I will say that with a machine and blanket I went to less than 1% breakage . I was running about 10% or more with the iron . I do have one and will use it to touch up tricky woods but it all comes down to your building style and investment cash .
Time wise a machine will pay for itself in time saved and wood not broken . AN iron helps in skill of bending and doing the things that you may only need to do once in a while .

[Kevin Sjostrand]

Bob,
No dilema if you have $600 dollars laying around with nothing else to spend it on.

Kevin