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I'm a newbie to this so if this is a stupid question, go easy on me.

I've never seen a steam box used for bending guitar sides but it's used all the time to bend wood for other purposes. I was just wondering if it's ever been used to bend guitar sides and if so, how does it compare to normal methods?

Thanks,
Julie

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Julie Moriarty
http://JulimorCreations.com

It's not a stupid question, but I think you are better off thinking about a steam box as a precursor to the normal processes, instead of a substitute for them. Here's a video:

https://www.youtube.com/watch?v=rqSglfu6xtA

If your goal is to stick the side wood into the steam box, take it out, and just bend it over a form, I think that's not going to work. The wood is too thin and it will break. It needs to be very hot (and at least slightly wet, for most woods) in order to bend without breaking. With wood this thin, the steam saturation from the steam box would not last long enough outside the box to be of much use, other than as "softening up" the wood for insertion into a bender, as the video shows.

Frankly, unless you are working with very picky wood (the use of which is a bad idea on early builds), I don't see the point of a steam box. You still have to bend it with either a bender or a hot pipe, so why bother with the steam box in the first place?

I haven't used a steam box so take this for what it is worth. When I was starting out (and trying to figure out a way to cheat the system because side bending was so intimidation), the advice I got/read was that, as Don said, the side wood is too thin to hold enough heat long enough to bend on a form. Steam bending was much better suited for thicker stock. Further, I was told that steaming figured woods was more likely to encourage them to separate in the figure than regular bending on a hot pipe or blanket type bender; I don't know if that is true or not.

the good news is that bending seems way harder than it is. Yes you will break some wood and yes it will be a little frustrating, but once you get the feel for it, you will wonder why you were so afraid.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

When I started out over 50 years ago I was building all cedar guitars. The sides were put in boiling pans which boiled on the stove top for and hour or so then were clamped to a bending form and stuck in the oven until completely dry. I still have an all cedar guitar that was built that way and it plays fine and the sides are still perfect. I'm not recommending this method since most woods don't do well when treated this way (they tend to ripple). When I started using other woods I switched to a home made bending iron which I still use. P.S. I don't build all cedar guitars anymore even though some of them were very successful.

Thanks for the replies. It makes sense the steamed wood of a side isn't thick enough to hold the heat. (I have the box and steamer and yes, I was looking to take a short cut!)

Watching the video, I'm not seeing any advantage to steaming the rosewood before taking it to the bender. Robbie spritzed the wood and wrapped it in foil then let the heating blanket take it to 350. I can't see how pre-steaming the wood would have helped. Maybe it was so Karen didn't get too nervous.

So now I have another question - I'll be bending sipo (utile) on a bending iron. The sides are .09" thick. Would there be any advantage to wrapping them like one would if using heating blankets? Foil - kraft paper - spring steel forms on either side.

Thanks again,
Julie

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Julie Moriarty
http://JulimorCreations.com

Julie—

No, in my view, that won’t be the best way to use the bending iron. It cuts you off from seeing and feeling when the wood gets pliable, and when it is drying out and/or scorching.

But, it can be useful to use one or both of something shorter and not enveloping. You can use a wet cloth or paper towel between the iron and the wood to create more steam, which aids the bending. You can also use a steel slat on top of the wood right at the iron, to support the wood and help prevent breaks.

I steam bent sides for dulcimers 9-10 years ago. It was hard. I have made several sizes hot pipes the last 2 years and bent guitar sides. They are easy to build and much better for guitar sides. They are much less work than using a steam box.

Steam boxes are great for larger pieces of wood.

First, don’t just go at it on the bending iron with the wood you plan to use for the sides. Make several practice sides and make your mistakes there. You will need to get a feel for how hot you need to get the wood, how to avoid scorching, when it is ready to bend and a few other nuances. It is a feel thing and you will take a few tries to get it down. I know you want to get to building and the last thing you want to do is cut and thickness a bunch of wood that will not go into your guitar. Trust me, I know. I was there. Honestly, the work you’re put into making the practice sides will also help you develop the cutting and thicknessing skills that will serve you well in the future. Getting a consistent thickness is very important to bending success. It will be worth it. Not to mention that you will have to do it anyway when you break your first side.

Second, 0.09” is thicker than you want. I usually shoot for 0.085” sometimes less. That little bit doesn’t sound significant but it really makes a big difference in bending. There is a trade off with side thickness, too thin and you don’t have much material to sand away when you are blocking the sides. Too thick and you get bad bends that need more block sanding to even out. I have read some people here go thinner than 0.08” but I’m not good enough to do that (I sand away a fair amount of sins).

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

I agree with Bryan about the thickness. 0.09” is just a smidge thicker than I like to bend. I also shoot for 0.085”. There are folks who can bend thicker wood, but my sweet spot is 0.085”. Thinner feels too flimsy, thicker feels like it resists the bend.

The same 'cube rule' for beam stiffness applies to side bending. That seemingly minor difference in side thickness between 0.085" and 0.090" - just 0.005" (1.5 times the thickness of a sheet of copy paper) - increases the resistance of the side to bending by about a fifth. Like the others here, we thickness most sides to 0.080"-0.085", with Venetian-cut sides thinned further in the cut area to about 0.070".

SuperSoft II veneer softener is used for some woods to prevent fiber collapse and to reduce stiffness, so especially for mahogany and similar timbers, it definitely reduces cross-grain rippling and fiber failures.

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For the times they are a changin'

- Bob Dylan

Some woods bend easier than others - sipo won't be particularly easy. Walnut on the other hand bends like butter, and even at 1/8th inch thick is quite workable. If you will be using a pipe one thing to keep in mind is to not heat the wood on one spot, but rather keep it moving and heating a broader area, gradually taking a bend and avoiding "facets" - kinks and flat spots.
Bending with a blanket is much easier, and I only use a pipe for "one off" stuff any more.

Jules,

As others have said, steam bending is not the best way to go about it. One reason why is that water (at sea level where you are) will only reach 212 degrees F. It can get no hotter; even the steam will cool down too rapidly to be useful. A pipe or a blanket can get much hotter than that which seems to get to the temp where the cells in the wood will 'relax' and allow bending w/o breaking. A hot pipe is cheap and it works. A pair of welding gloves helps, too.

Steve

Adding water to the wood causes problems, as well as solving them. That is; a certain amount of moisture in the wood seems to be necessary to get it to bend, but too much causes it to cup across the grain, and encourages the fibers to peel apart on the outside of the bend. Usually, when I'm bending, I try to add water to the inside surface, to avoid that latter. With steam you've got moisture everywhere. That, in itself, is enough reason IMO to avoid the use of steam.

The latent heat of vaporization makes steam a potent tool for bending wood - the energy needed to raise a pound of water from 32 deg F to 212 deg F is just one-sixth of the energy need to make a pound of steam from a pound of boiling water. While some woods like rosewoods are happy to bend with just the water vapor trapped in the wood (which is converted to steam) or even just heat alone, timbers like mahogany and walnut need the energy available from that phase change from water to steam for a successful bend. Even though we may not be using a steam box, we are usually still relying on steam itself to help us bend our sides.

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For the times they are a changin'

- Bob Dylan

Thanks for all the great information! Lots of good stuff. I wish I had read all that was posted after my last post before I jumped into the first bend.

Lessons learned:
1) Don't rely on memory for how thick the wood is. I thought I had taken all the sides to .09" a week or so ago. I was wrong. It was .11".
2) Be patient and don't try to force it. (Yes, I wasn't and I did.)
3) The heating iron takes a LONG time to reach bending temperature. The one I have took well over 30 minutes and reached a temperature of between 260 and 290 on the top. As the thermostat cycles, the temperature fluctuates.
4) Sipo doesn't like to bend like other woods I've bent. This was the first time I've had fibers break on me.

I'm going to take the second practice piece down to .085" and see how that works.

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Julie Moriarty
http://JulimorCreations.com

Like I mentioned in your other thread, that bending iron sounds to me like the controller is broken.

If the temps I'm reading are accurate. SM says IR thermometers (which I've been using) don't read iron temps accurately.

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Julie Moriarty
http://JulimorCreations.com