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Folks,

Inspired by Tom Durr (AKA Mandomaniac) who is a member here at the OLF but post mostly over at the forum without the "S", I have made a 2 part bending form.

It has a male section, minus side and metal slat thickness, which fits into a female section, minus metal slate and heat blanket thickness.

The female form is hinged in 2 places, one being at a point just forward of the apex of the upper bout, and another at a point just to the rear of the apex of the lower bout. The splitting of the female form allows the waist to be brought to bear upon the male form to start the bending process, and then the 2 bouts can be pushed down into position and clamped as required.

Because I had a sheet of 3/4 ply at hand which I bought real cheap, and did not have any MDF near by, this form has been constructed from ply. It is a SOLID form, with repetitive layers of the 3/4 ply screwed together in succession.

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As you can see, I also got a great deal on a couple of thousand 38mm screws Anyhow, I now wish to seal this form and my thoughts are to force a 2 pack auto body filler into the working edges thereby filling and sealing the exposed end grain of the ply. Then maybe sand lightly, carefully maintaining the forms original shape, and spraying the sealed edge with heatproof exhaust paint.

So, my question is, Wad ya reckon? will my planed process seal the working edge, and handle the heat, or do you have a better idea???

Cheers

Kim

Don't know what advice to give ya mate but it looks very cool and i love that idea, i know Charliewood has built one and also Kathy Matsuchita, i hope they will chime in for advice!

Right on bro!

Kim:
The form I use is solid ply. I didn't put anything on the working edge and haven't had any problems.

D.L.

I have a couple forms which are solid, did nothing to them and they are fine after bending .. no scorching at all.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

DL,

I should have mentioned that not only was the ply cheap, but it was cheap and Asian. It is still rated as exterior ply but is relatively soft in the core, not near as hard as I am use to so I would rather seal it than risk it swelling and going out of shape on me.

Cheers

Kim

any standard wood finish that i know of will not stand up to the heat generated by the heating blanket. the engine paint may, but i don't know if the bogg will. perhaps some if the plastic metal materials would work.

however, i have no finish on my fox bender and i have never had any problems.

and since you will be using a metal slat i don't think any voids in the ply would be a problem.

I look forward to hearing how this bender works for you, Kim. Please keep us posted.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Serge correction: I am working on the bending form now and the timing of this thread couldnt be beter for me - Thanks!
Until now the thickness sander has been pre-occupying my days, when the pillowblocks arrive this week, she will finally be fini, mon ami.
larkim I like the look of your form, its schweet, and coupled with the Mando bending instructions - is supposed to eliminate springback nearly completely, appearantly - Im looking forward to trying it out myself!
I think you should be ok without sealing I have seen a few of these forms on the "other" forum and I dont recall any of them being sealed.
Cheers
Charlie

Having bent wood for about 8 years now , I am allways amazed and the new and different ways. This system will work but you have a few things to be concerned of.
   Watch that the large mass doesn't rob some of the needed heat from the set you want to bend causing warping. With that much mass your heat can be pulled off. Martin tried a few bending forms very similar to this and they had a serious warping problem. The steel slats on a hollow form work best as the heat is conentrated to the wood and the wood didn't suffer the thermal shock.
   john hall

   

Kim, I have two forms that fit in my bender that are solid and I have had great results using them.
I am slowly making all my forms solid. They work great with John Halls bending shoe..

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Lance@LuthiersForum.com

Kim,
The ply you have and the stuff I used sounds similar. It was a fairly low grade of 1/2" plywood. Luan laminate with a birch veneer on one side and plenty of voids in between.

Anyway, We used to use a 2-part hi-temp epoxy for filling gaps in hot forming rolls. I think it was made by Chem-Tech. Best I can remember it was good to about 400- 500 degrees and water proof. Don't know if it is still available or not. Something along these lines should work for what you have in mind.

D.L.

Thanks all,

If this were normal ply I would not bother. But as the core of this ply is so soft and porous, I might just do a real thin wipe with some bog and then follow up with the manifold paint as planed just to be sure.

The core of this ply in raw state looks very fibrous, like a type of cane, hence my concern regarding its potential to be excessively hygroscopic. The bog will simply be pushed into the soft fibrous grain and sanded off much like a grain filler would, there is no voids as such.

The manifold paint is good to around 1500 degrees so that will handle the heat OK and should seal the bog in place within the grain even if it does soften under the finish a little when heated. I will probably paint the blue steel shim stock with the same paint to prevent rusting and stain transferal.

Hesh I think I will skip the burst and go with a Ferrari Red. After taking a year and a half to come this far, I need to evoke as much movement around the shop as possible.

On the bright side, with all the time I have spent here and there watching, researching, learning, and procrastinating, I must by now be among the most informed luthiers never to have built a guitar

Cheers

Kim

[QUOTE=charliewood] Serge correction: I am working on the bending form now and the timing of this thread couldnt be beter for me - Thanks!
Until now the thickness sander has been pre-occupying my days, when the pillowblocks arrive this week, she will finally be fini, mon ami.
Cheers
Charlie
[/QUOTE]

Cool bro, hey man, congrats on the home made drum sander and the side bending jig, wanna see pics of that when you have a chance, aweright?

Kim, i only have a regular type bender with bulbs and blanket but i did not put sealer on the plywood SJ form that i used last, didn't have any problems with the aluminum sheet i nailed on both inner sides, hope this helps!

Kim, I will also be very interested to hear how it works out having the steel painted with manifold paint. I've been pondering the best way to prevent rust, and maybe your idea is it. Forge ahead, brother, and let us know how it works.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

My Hot Rodded Form



Fastest look'in thing that has ever been in my shop

Cheers

Kim

Fast track bender!

I covered the clamping side of my waist caul of my fox bender with an automotive high-temp cork gasket material, works great, conforms to the curve.