Official Luthiers Forum!

Hi,
I have been tapped by a group of wood workers to do a demonstration and speech on wood bending. H E L P !
I have bent 3 sets of Mahogany and one set of Sycamore on a Bender. I have done some various trim on a Propane/ Copper tube/s set up.
I told the arranger that I was only 3 bends in. He said I was ahead of the room....so please share lol

My thought is spend 10 minutes on how bending is used in the assembly of an acoustic guitar. Then do a bend demo on my Blues Creek Bender.

Then talk about different temperatures and different approaches to the wood based on grain or density. Then whip out my propane bender and bend some binding and such. Please look at the photo. Am I doing it right? Safe?



For reference I will watch my John Mayes Video on bending again.
Any help, advise, cautions, teaching direction..... a list of bending temperatures........... HELP!

Don't forget,

Different properties of different woods
Adding water to bend
Soaking your wood first
Just spritzing your wood
Dry bending
thickness as related to bending
Splintering
Twisting
cupping
temperature
bending machine types

start by making an outline - so your demo is well organnized

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It's this new idea from recent decades that everyone gets a participation award. - MUX

Hi John,

You'll get comments from those with more expertise than me - but here's my two cents anyway.

Are you using propane, or MAPP gas? I switched to MAPP when I was unable to get the pipe hot enough with propane.

That pipe looks like a very small diameter - do you experience the flame going out when putting the torch into that pipe? When I bend on a pipe I bend on a large iron pipe which has a lot of weight to it, so I can use a little pressure without the jig flexing or moving. My setup is literally 1) a large bench vise, 2) 2 blocks of scrap wood roughed out to wrap around the pipe - (I soak these in water previous to clamping the pipe between them, and 3) large pipe elbow. The torch stands underneath the pipe and the flame hits the interior of the pipe just forward of the bend. I also use some aluminum foil on the end of the opening of the pipe to prevent my pants from catching on fire. Sorry - looking for a picture - can't find one.

Other suggestions are - make sure you've got a bucket of water and a fire extinguisher handy. I'd also emphasize using lots of ventilation when using the torch Those things can generate a lot of CO. Don't want one of your students ending up in the police blotter for asphyxiation.

Thanks guys.
Corky, No problem on the pipe diameter the block I have as a "flame sheild" is back far enough to allow air flow. I too use foil, for heat up and to keep flame control. I haven't tried MAPP Gas. It really works that much hotter/ better?
Hey I just signed the lease! Kitchen Guitars and iSimon are growing!

Hey John,

For what it's worth, here is a link to an article I wrote about bending guitar sides. It's aimed at people not knowing anythig about guitar building.

I'm used to seminars and such (I used to be a teacher, then did training/teaching on a high tech software). One suggestion I can make, don't go too much into details. Figure out 2 or 3 major aspect of side bending (I'd stick to: concept of heat and moisture to make the wood flexible, different types of tools used to bend sides) talk for 10 or 15 minutes max, do your demonstration (very good idea by the way), and that's it. Then answer questions. That will cover 30 minutes, which is perfect for this sort of situation. More than this and you will start to loose people (some will yawn, some will start to look at their watch, etc.).

For the demonstration, I'd stick to the fox bender demo, no more. Although you can bring the other tools just to show them.

Hope this helps!

Good luck!

_________________
Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

feel free to call me and I will be happy to help
john

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

YJ: In my opinion your pipe is much too small. Tends to heat in too small and localized area. For me,a 3''O.D. work better in that a larger area is heated and less likely to cause fretting and bumpy sides. An oval pipe is even better but a round one certainly works. I bent for years on a pipe but must say am much happier using a bending jig and blanket.
Tom

_________________
A person who has never made a mistake has never made anything!!!

Man if I had a nickel for everytime I've heard that....

_________________
John Mayes
http://www.mayesluthier.com

Wow! Great replies! Aline! Thank you. you structured my class! John (BC) I'll call you! John Mayes I watched all of my John Mayes videos build on a laptop while soaking in a hot tub. Of course my pipe is small.

John Mayes: Who was it said that to you John.....????

_________________
A person who has never made a mistake has never made anything!!!

More like who hasn't.

_________________
John Mayes
http://www.mayesluthier.com

OK I went and got MAPP gas. It keeps choking out. I guess the 1" pipe is screwing with the air flow? Why wouldn't the foil? Hmmm
I guess I will go back to blue unless my plumbing buddy comes through with some 3".
The class is in a PRO Furniture makers shop. All safety stuff in place!

There will be a ton of info on the actual content of what you will present. What you need to focus on now is the delivery.

Step one in teaching is to determine your objectives, in definable terms. There is no other way to ensure success to determine if your instruction has been successful. The objectives will be affected by the class characteristics (size, entry level, capacity to learn, etc.) and your resources (time available, materials, tools, etc.)

Your objectives and your resources will then determine your methodology. Content is only a fraction of teaching so the objectives should be layered. An objective can be stated as simply as "At the end of the instruction, the learner will have a broader awareness of the techniques involved in bending wood for guitar sides.", or as specifically as "At the end of instruction the learner will successfully be able to bend a set of guitar sides using any one of the methods presented." On the surface, these two statements may not appear to be all that different, but upon reflection you will notice that they are worlds apart. The first describes a global awareness while the other describes basic mastery of a specific skill. The teaching for either objective will be very different.

Once you establish your objectives within the framework of your resources, as well as your method for evaluation (evaluations must be in a direct relation to the objectives), it becomes an easy process to determine delivery.

The most efficient method in terms of content per time interval is traditional lecture.

The most efficient in terms of effectiveness of learning, is participation-"hands on practice".

_________________
Expectation is the source of all misery; comparison the thief of joy.
http://redrivercanoe.ca/

Hmm - interesting that the MAPP chokes out but not the standard propane. Well, if propane workds for you then I'd go with it. Great - have a great class - great way to really learn a topic - teaching it!