Bending Machine vs Bending Iron

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donnercruz

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Is there a reason to go for one over the other?

There seems to be a learning curve with a bending iron and cost for a commercial one is higher than the cost of a heat blanket + parts. However, I just saw a video where the luthier talked about connection with the wood and feeling how it bent and was decidedly against bending machines.

It almost seems like an argument between traditional and new methods.
 
There is a learning curve involved using either method. One is not easier than the other, they both take practice.
If you want to make only a few ukes, the pipe will serve you well.
You want to go into production, save time and get consistent results, spring for the heat blankets and bending form.
Having said that, I believe anyone building acoustic instruments needs to know how to bend on a pipe. It comes in handy in times when using a bending form isn't possible, convenient or even necessary.
Good luck.
 
We live in an 'instant results, fast everything' age and the heat blanket appears to be the short cut to getting it right. I only bend my soprano shapes using a heat blanket because the curves are so severe. It takes me 18 minutes to hand bend a set of sides in curly koa and they always fit the mold, stay where they are bent to and look right. Chuck has it right. What I'd add is this is - the expense:
  • Heat blanket: $80 US
  • Fox bender frame: $40 US + time making ~ 3 - 4 hours
  • Forms : $30 US + time making ~ 2 - 3 hours each mold
If you factor it all in, they come out costing the same. However, with a bending iron you have a versatile tool that will give you a sense of triumph every time you bend a set of ribs with it.

From a Zen point of view - it is right of luthiery passage to learn the pipe bend...
 
Bending on a pipe can also save you on wood as well. When you bend on a pipe you can keep your eye on things and take your time. When you use a heat blanket it all goes pretty quick and you won't know you've fried or cracked your sides until it's too late. One burnt or broken side means the entire set is toast!
It all takes practice. Unless you are Taylor Guitar, there's no magic machine available for the small shop where you stick your side into a slot and it comes out perfectly bent.
 
Glad you refered to taylor Chuck. I've watched those videos regularly and in the bending one Bob confesses that it took a full year to develop those machines. Just think of the number of permutations they had to go through to calculate the overbend... And yes, that is the reason to hand bend - control. We should start a Guild of Hand Benders... lays way open for lewd and side splitting comments!
 
Thanks for the replys guys, I appreciate the input. I'm going to start working up the jigs, forms and templates I'll need either way, and then pony up for a bending iron.
 
Lower Cost Heat Blankets

I got my heat blanket from MSC supply where they have a large selection of sizes and wattages. I thought mine was 24" x 3" 360W, but I didn't see that size listed on thier web-site just now. They do have a 18" x 3" 270W for $35. Link: http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=4627382&PMT4NO=74053728

You do have to wire a plug to it, but I really like the 3" width over the 6" ones you get at the luthier supply stores. No re-use for guitar side bending though.

If you order one from them, make sure it's not one with an adhesive back.

I also got my stainless steel bending sheets there as well at a good price if I remember correctly.

I did bend my first one using a pipe heated with a torch - no cost at all. then went to the light-bulb heat form. But now prefer the heat blanket for consistancy.

-darrel
 
I've tried a lot of things, but never a heat blanket. I can say that pipe bending really isn't that bad. There are exceptions when it's AAAAAAAAAAAA curly koa or ebony, but those are extreme bending nightmare cases.

The thing to remember when using a pipe is to make small, even bends. A lot of beginners try to nail the perfect shape in as few bends as possible. Not going to happen. I can't even keep track of how many sides I've bent on a pipe, but I still take my time. If it's not bent enough, you can always go back and work the bend. Once you get that, it's easy squeezy lemon peezy.

Pipe temperature is also a very important factor. You want your pipe to be almost hot enough to start burning the wood. Any cooler, and you'll take forever and/or possibly crack a side. Hotter and you burn too fast. It takes a little practice to know when the pipe is just right.
 
Ok, here's a question, kinda sorta related--

Lets say I had my uke sides at the appropriate thickness, and I soaked them for a while till bendy (not unlike soaking cane for a chair)

then, I shaped it over a form, with it held in place, then placed it in a cool-ish (180-200degrees F) oven till dry (a day or so). Is that essentially the same idea as the heating blanket, or not really?
 
cashew said:
Ok, here's a question, kinda sorta related--

Lets say I had my uke sides at the appropriate thickness, and I soaked them for a while till bendy (not unlike soaking cane for a chair)

then, I shaped it over a form, with it held in place, then placed it in a cool-ish (180-200degrees F) oven till dry (a day or so). Is that essentially the same idea as the heating blanket, or not really?
Click to expand...

I have a friend that does precisely that. He soaks the wood a couple hours and then puts it in a fox style bender without any source of heat to dry. Sometime he'll put it in front of a fan to expedite it, but the sides are so thin they dry quickly anyhow. He tried a heat blanket and just couldn't make it work, so he decided to stick with this system. He used to bend on a pipe but he just doesn't have the strength in his hands to do it anymore. He primarily bends mahogany and walnut, so I can't say that it will work with other woods.
 
I don't know what a fox bender is. I'm going to assume it's a form with the screw down clamps.

As long as you can get the wood to bend to the form, you can let it dry in the air or in an oven. Without heat, it will have more spring back. A little spring back is not necessarily a bad thing. It adds some natural tension to the sides, which should make them slightly stiffer. Too much spring back is definitely bad. Over time, glue joints will weaken and you could have potential separation at the seams.

The tricky part is bending without heat on the fox bender. Water helps soften the wood, but the heat is critically important for setting the bends. Without some kind of heat source, the wood will want to spring back. Unless you over bend, which would be impossible to do, without cracking the sides.
 
The principle element in wood is cellulose - cellulose is a 'thermo plastic' and that is why heat works with it. It is also why cellulose is a more natural choice than other finishes when it comes to 'compatibility'.
 
Pete Howlett said:
The principle element in wood is cellulose - cellulose is a 'thermo plastic' and that is why heat works with it. It is also why cellulose is a more natural choice than other finishes when it comes to 'compatibility'.
Click to expand...

Pete, actually, I was thinking about that 'thermo-plasticity' with the hot oven--

The image that sprang to my mind (and don't laugh) was actually the process of setting hair in curlers.

If you set cold damp hair in curlers, it'll curl sure, but, it won't be as defined or hold up as long.. Now, if you set that same head of curlers under a hot hair dryer, you get curls that stay. (Hair works in that plasticky way too)

Glad to know it would work. :)

Thanks Folks!
 
Pete Howlett said:
The principle element in wood is cellulose - cellulose is a 'thermo plastic' and that is why heat works with it. It is also why cellulose is a more natural choice than other finishes when it comes to 'compatibility'.
Click to expand...

Celluloid is a thermoplastic and cellulose is an ingredient for making celluloid. I'm not sure about the compatibility statement but lacquer is most often made from nitrated cotton.

I forgot to mention that my friend uses ammonia in his dip tank which acts as a softening agent for the wood then evaporates and leaves the wood in its bent shape. At least that is his claim. Anyhow, here is an excellent article on various forms of bending wood as well as on wood ductility. Wood Bending
 
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