Advice Gladly Accepted

My electric wood bender arrives from Luthiers Mercantile today - a day early. I'm willing to take any advice you have to offer about how to use it.

I'll be bending sides for a traditionally-shaped uke. I have several sets of side wood from Stewmac. I think they are mahogany and cherry.

I'm finishing up modifying a Fluke, so I might not start bending today. I like to practice before doing something important, but considering the price of the wood, I won't be doing that.

Thanks in advance.

Bending can be a tricky thing to get the hang of, so it's a good idea to practice on scrap or cheaper wood you don't care about (In my opinion there are much better and cheaper places to get wood than from StewMac).

The best advice I can offer is to get your wood very thin, you're going to have tons and tons of problems if your wood is too thick (I think for a ukulele 60 thousands (1.5mm) works well)

As far as actually bending, I believe there's two groups of people, those who soak their sides prior to bending and those who spray water on them as they go. When I was making ukuleles more often, I would soak my sides in water for 10-15 minutes before bending and then spray water as needed, however this can cause discoloration in the wood and you have to wait much longer for the wood to dry before gluing blocks or linings. In the violin making world, you very lightly wet the wood and bend it using a metal bending strap to prevent cracking. Having used both methods, I much prefer NOT soaking and using a bending strap, however I've had failures and successes with both methods.

Before bending (and soaking if you choose to do that) you need to make sure your bending iron is hot enough, I have a digital iron I set to 165 degrees Celsius and I know its ready to bend when water rolls around and bounces before evaporating. Once its ready its a good idea to just warm up the wood very lightly before apply pressure and creating the bends, as you bend you'll hear a sizzle, and when that sizzle goes away you need to re-wet the sides.

I think that about covers the basics, as a lot of bending wood is just getting a feel for it, and its definitely something you need to practice before you get comfortable with it.

What I learned is that wood will bend when it is ready. Like so many things in life, don't force it. You will find that when the wood is ready to bend it gets a "rubbery" feeling that is unforgettable once you feel it. Take what the wood gives you and then back off. Technically speaking, the lignin bonds that cross link the wood start to give away and that is what causes that rubbery feeling. I find that I quite like bending wood that I can bend. I cannot bend bloodwood or real ebony so I just don't try and both me and the trees are happy.

About the soaking/water. Some woods are better bent dry and some need some water sprayed on. Some woods will warp and cup badly if you introduce too much moisture, particularly when not quarter sawn. Maple is a good example. You have mahogany and cherry. Mahogany is a dream to bend. Get it thin enough and you shouldn't have any problems. Cherry is fine if well quartered, but can cup if not we'll quartered and you use too much water. Cherry being lighter in colour is more prone to show scorch marks which are likely in your first few attempts. Use a rocking motion and firm but not strong pressure. Check the shape against a template often. Enjoy.

Sam.R.B said:

Having used both methods, I much prefer NOT soaking and using a bending strap, however I've had failures and successes with both methods.

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Thanks for that. My "practicing" will be on the side wood I bought from StewMac. I'll just have to be careful.


So you prefer not soaking, but using a bending strap? I have thin stainless steel I can cut to fit the wood as a strap. I also made a mold for the shape I want - male and female.

Thanks sequoia and Red Cliff!

I have a pipe which I drape a thicker cloth over, think a thinner washcloth. Found a picture I have. It is doubled up. I dampen it in a bowl of water and wring it out so that it is not dripping. Then I drape it over the pipe and when the steam comes off the rag I bend on it. When it stops steaming I move the rag to the next damp spot. It is a little slower than doing the wood directly on the pipe but I no longer have to worry about scorching the wood, I do a lot of light colored wood. On the wood, If the wood has runout that is where the fibers of the wood leave through the sides of the wood. This is where the wood is going to crack and separate. Wood with runout can be bent with a back strap. You do not want to soak the wood with water as it helps to separate the layers of wood. Wood like curly maple is an example of a wood with localized runout. Wood going from quartered sawn to flat is another example of this, early on I got some cocobolo cheap and the section of side that went to flat cupped and fractured.

If you have any powered saws to cut wood with you could tape a trip to your local lumber store (even at these prices) and pick up a 2x4 that is free of major defects and slice it up then plane or sand it down to side thickness. You can then get a lot of practice bending. Softwoods are not as forgiving at times, they do not like tight radius's. Doing tight curves like cutaways are helped out by thinning the section more than the rest of the sides. The tight curves do help stiffen up the area and as long as you have enough thickness after to clean up the outer side you are still good.

printer2 said:

I have a pipe which I drape a thicker cloth over, think a thinner washcloth. Found a picture I have. It is doubled up. I dampen it in a bowl of water and wring it out so that it is not dripping. Then I drape it over the pipe and when the steam comes off the rag I bend on it. When it stops steaming I move the rag to the next damp spot. It is a little slower than doing the wood directly on the pipe but I no longer have to worry about scorching the wood, I do a lot of light colored wood. On the wood, If the wood has runout that is where the fibers of the wood leave through the sides of the wood. This is where the wood is going to crack and separate. Wood with runout can be bent with a back strap. You do not want to soak the wood with water as it helps to separate the layers of wood. Wood like curly maple is an example of a wood with localized runout. Wood going from quartered sawn to flat is another example of this, early on I got some cocobolo cheap and the section of side that went to flat cupped and fractured.

If you have any powered saws to cut wood with you could tape a trip to your local lumber store (even at these prices) and pick up a 2x4 that is free of major defects and slice it up then plane or sand it down to side thickness. You can then get a lot of practice bending. Softwoods are not as forgiving at times, they do not like tight radius's. Doing tight curves like cutaways are helped out by thinning the section more than the rest of the sides. The tight curves do help stiffen up the area and as long as you have enough thickness after to clean up the outer side you are still good.

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Thanks for that. I like the idea of the damp cloth. As for practicing, if I practice on wood other than the type I'll be using, I'll get a false impression of how to bend. I did some bending a few months ago for a uke based on a tennis racket. I used a propane torch shooting into a pipe. This electric bender should be easier to use, especially for control of the temperature.

I made a mold of the shape I want, male and female, and I cut the male section down to allow for the thickness of the side wood.

We all mostly do things our own way..I just bend the waist first before I finish off with the bending machine..and I use a metal shim to keep the heat/steam in check and a wooden block to avoid burning the fingers.
See here https://www.youtube.com/watch?v=vUmyFjC5THI

Thickness is totally critical. I use a rule of thumb its 1.75mm for me. No thicker but sometimes down to 1.65mm if it is rosewood. Your cherry should bend pretty easy. Does this help:

https://www.facebook.com/705786030/videos/10158100826921031/

Timbuck said:

We all mostly do things our own way..I just bend the waist first before I finish off with the bending machine..and I use a metal shim to keep the heat/steam in check and a wooden block to avoid burning the fingers.
See here https://www.youtube.com/watch?v=vUmyFjC5THI

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Thanks. It looks so easy. : )

Pete Howlett said:

Thickness is totally critical. I use a rule of thumb its 1.75mm for me. No thicker but sometimes down to 1.65mm if it is rosewood. Your cherry should bend pretty easy. Does this help:

https://www.facebook.com/705786030/videos/10158100826921031/

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Thanks. According to StewMac -

"Side set dimensions:
Each half is approximately 3-3/4" x 20" (95mm x 508mm)
Thickness-sanded to 3/32" (2.38mm)

Back set dimensions:
Each half is approximately 5-1/4" x 13" (133mm x 330mm)
Thickness-sanded to 1/8" (3.18mm)"

That's for both the sapele mahogany and the cherry

They are nominal sizes..

Jerryc41 said:

Thanks. According to StewMac -

"Side set dimensions:
Each half is approximately 3-3/4" x 20" (95mm x 508mm)
Thickness-sanded to 3/32" (2.38mm)

Back set dimensions:
Each half is approximately 5-1/4" x 13" (133mm x 330mm)
Thickness-sanded to 1/8" (3.18mm)"

That's for both the sapele mahogany and the cherry

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If the sides are 3/32 thick you are going to want to thin them down before bending. Apologies if that is obvious but just in case...

That is exactly my sweet spot also for thickness but I express it in inches as between .060 to 0.070 with 0.065 equal to 1.75mm.

Red Cliff said:

If the sides are 3/32 thick you are going to want to thin them down before bending. Apologies if that is obvious but just in case...

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I'll measure the thickness before I start bending, but my thinning technique is limited to sandpaper. I bent wood from StewMac before, and it worked okay.

Jerryc41 said:

Thanks for that. I like the idea of the damp cloth. As for practicing, if I practice on wood other than the type I'll be using, I'll get a false impression of how to bend. I did some bending a few months ago for a uke based on a tennis racket. I used a propane torch shooting into a pipe. This electric bender should be easier to use, especially for control of the temperature.

I made a mold of the shape I want, male and female, and I cut the male section down to allow for the thickness of the side wood.

View attachment 134399

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I would not have suggested it if I felt it would give you a false impression how to bend. Good luck.

printer2 said:

I would not have suggested it if I felt it would give you a false impression how to bend. Good luck.

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I understand.