Author Topic: heat treating/ fire hardening and colour change  (Read 6760 times)

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Offline lonbow

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heat treating/ fire hardening and colour change
« on: January 29, 2021, 01:14:05 pm »
Hello together!

I have a question about heat treating/ fire hardening bow woods. Is there only a notable effect if the wood changes its colour, or is it also possible to archive a long mild heat treat with lower temperatures without any colour change?

Thanks you!
lonbow

Offline Jakesnyder

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Re: heat treating/ fire hardening and colour change
« Reply #1 on: January 29, 2021, 03:44:20 pm »
If it doesn't change color at all I would think all your doing is hyper drying it.

Offline Pat B

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Re: heat treating/ fire hardening and colour change
« Reply #2 on: January 29, 2021, 04:33:34 pm »
Heat treating dries and hardens wood. Whether you need to heat to color or not I'd guess it may matter a bit but how much. You can't go exclusively by the amount of color because different woods caramelize at different rates, some woods darken quickly where others color very little over a long period of time.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

bownarra

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Re: heat treating/ fire hardening and colour change
« Reply #3 on: January 30, 2021, 12:33:33 am »
No you want to be darkening it significantly to get any real advantage.

Offline lonbow

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Re: heat treating/ fire hardening and colour change
« Reply #4 on: February 09, 2021, 07:56:23 am »
Thank you for your answers! So I think that my bow was too far away from the glow. How far away would you put the stave over the glow? I´ve watched the fire hardening video on shannon outdoors, but there wasn´t any recommendation.

Offline RyanY

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Re: heat treating/ fire hardening and colour change
« Reply #5 on: February 09, 2021, 08:06:58 am »
Thank you for your answers! So I think that my bow was too far away from the glow. How far away would you put the stave over the glow? I´ve watched the fire hardening video on shannon outdoors, but there wasn´t any recommendation.

I keep my heat gun on high and 4” above the limb.

Offline beast

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Re: heat treating/ fire hardening and colour change
« Reply #6 on: February 09, 2021, 09:38:50 am »
personally i dont have a heat gun. i make a fire and use the coals. the only problem is that wood warps when dries because for some reason wood being cooked shrinks. so find a way to make sure the wood don't move

Offline Allyn T

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Re: heat treating/ fire hardening and colour change
« Reply #7 on: February 09, 2021, 09:59:57 am »
personally i dont have a heat gun. i make a fire and use the coals. the only problem is that wood warps when dries because for some reason wood being cooked shrinks. so find a way to make sure the wood don't move
It shrinks from water loss. Like when you order a 8oz steak that's it's raw weight after it's cooked it's much lighter
In the woods I find my peace

Offline Selfbowman

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Re: heat treating/ fire hardening and colour change
« Reply #8 on: February 09, 2021, 01:18:58 pm »
Heat treating dries and hardens wood. Whether you need to heat to color or not I'd guess it may matter a bit but how much. You can't go exclusively by the amount of color because different woods caramelize at different rates, some woods darken quickly where others color very little over a long period of time.

Well put Pat !
Arvin
Well I'll say!!  Osage is king!!

Offline Selfbowman

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Re: heat treating/ fire hardening and colour change
« Reply #9 on: February 09, 2021, 01:25:07 pm »
personally i dont have a heat gun. i make a fire and use the coals. the only problem is that wood warps when dries because for some reason wood being cooked shrinks. so find a way to make sure the wood don't move

Old ways are ways but new heat is easier controlled. Your and my choices. 😀😀😀
Well I'll say!!  Osage is king!!

Offline Marc St Louis

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Re: heat treating/ fire hardening and colour change
« Reply #10 on: February 09, 2021, 02:36:49 pm »
You can get colour change without heat-treating if you put your bow too close to the heat source.  Then again if you're too far from the heat source then you won't get the desired results.  The temperature needed at the surface of the wood should be about 350~400 degrees F
Home of heat-treating, Corbeil, On.  Canada

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Offline PatM

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Re: heat treating/ fire hardening and colour change
« Reply #11 on: February 09, 2021, 02:40:10 pm »
personally i dont have a heat gun. i make a fire and use the coals. the only problem is that wood warps when dries because for some reason wood being cooked shrinks. so find a way to make sure the wood don't move
It shrinks from water loss. Like when you order a 8oz steak that's it's raw weight after it's cooked it's much lighter

 It's more than just water loss.

Offline Selfbowman

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Re: heat treating/ fire hardening and colour change
« Reply #12 on: February 09, 2021, 02:57:08 pm »
You can get colour change without heat-treating if you put your bow too close to the heat source.  Then again if you're too far from the heat source then you won't get the desired results.  The temperature needed at the surface of the wood should be about 350~400 degrees F

Thanks for that information Marc I’ve been guessing but probably pretty close to those temps.
Arvin
Well I'll say!!  Osage is king!!

Offline willie

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Re: heat treating/ fire hardening and colour change
« Reply #13 on: February 09, 2021, 07:16:03 pm »
You can get colour change without heat-treating if you put your bow too close to the heat source.  Then again if you're too far from the heat source then you won't get the desired results.  The temperature needed at the surface of the wood should be about 350~400 degrees F


Marc,
I guess you are saying it's possible to quickly scorch the surface without getting any penetration of the desired effect?  How do you assure effective treatment depth.




Offline darinputman

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Re: heat treating/ fire hardening and colour change
« Reply #14 on: February 09, 2021, 08:10:50 pm »
Lonbow my experience is if treating over coals its best to start high and check color every few minutes and lower as needed. Really depends on how hot your coal bed is, outside temperature and wind are also variables that can effect the process. Hickory can take a lot of heat, osage can be ruined quickly. Even if you char the belly on hickory I have scrapped it down to good wood and still made a good bow out of it.
   I have burnt up a few osage staves and cauls as it is very different from hickory but plan on trying again. These are the only woods I habe tried so far.