Heat Treating Question

[Weylin]

Im finally ready to heat treat my bow. I have done my homework and gathered my tools. The only thing that im unsure of is, what, if anything I need to use to rub or brush on as I heat it. The article in TBB4 suggests several oils and varnishes none of which I have. Is it imperative to use something or do people heat treat without. Do things like olive oil or canola oil work or are they a bad idea. If it matters, I have a Hickory stave flat bow. Let me know what you guys think.

Thanks,

Weylin

[Jesse]

I think olive or canola oil will be just fine. Its just to keep the wood from scorching and help distribute the heat a bit.

[Jmilbrandt]

I have heat treated a few bows without the varnish or oils and had good results. I think it is much safer and better with though.

[Pat B]

Are you heating the wood to correct a problem or are you heat treating(tempering) the belly to add compression strength? These are 2 different animals altogether.
  When I correct problems in a stave, ie. crooks and bends or adding recurves, I use oil on the wood to keep from scorching and I believe it helps distribute the heat evenly and hold the heat longer.
   When tempering the belly I use no oils because I want to scorch the belly to solidify the oils and resins in the belly wood thus increasing the compression strengths. Once this is done however you should not stress the bow at all until the wood has had time to rehydrate. This could take a week if the humidity is low. Also, don't temper the back as it will make it brittle and prone to breaking.

[sailordad]

yup just like patb said

and olive oil smells real good on hickory,so does crisco

[Jmilbrandt]

So you guys use no oils or protection for the backs?

[sailordad]

i dont apply direct heat to the back so why grease it

[Jmilbrandt]

I have always heard the heat can reflect off your forms and damage the back unless it was protected. But like I said before I have done it a few times and had no problems so it's probaby fine.

[Gordon]

Weylin, there is no need for oil or grease if you are tempering the belly.

I use leather shims to help protect the back from heat reflecting off the form.

[Weylin]

Thanks everyone for your input. I went ahead and treated it tonight and I brushed a little olive oil on behind me as I went. Sorry Gordon, I didnt see your suggestion until I was finished, I hope it wont hurt anything. Everything seemed to go just fine, it is holding the reflex that I added. I know that I am supposed to wait for the bow to reach MC equilibrium before I start flexing it again. It is a hickory bow in Portland with a relative humidity of 70-80%. How long should I wait?

[Marc St Louis]

If your form is wider than the bow then the heat will bounce off it and scorch the back.  Wait a couple days at that RH

[Gordon]

What Marc said. And don't worry about the oil, it won't hurt a thing.

[Weylin]

Thanks Marc and thank you for the great heat treating article in TBB4, that was indispensable.

[cracker]

I thined my form down to less than the width of the bow all the way out to the tip.Ronnie

[Weylin]

Gordon was gracious enough to lend me his caul. Only the last 8 or so inches of the tips were narrower than the form so hopefully there wasnt to much damage to the back.