Primitive Archer

Main Discussion Area => Bows => Topic started by: redhillwoods on February 13, 2021, 10:29:41 am

Title: re-hydration time after tempering ?
Post by: redhillwoods on February 13, 2021, 10:29:41 am
I've always waited about 2 weeks after heat tempering to resume working on a bow. I know it depends on the environment but i think this may be longer than necessary. I live in Southern Ontario and the bow is in an unheated addition built onto a heated workshop. I'd like to resume work on the bow sooner. What do you all recommend? Thanks
Title: Re: re-hydration time after tempering ?
Post by: PatM on February 13, 2021, 10:36:53 am
I usually just give it a couple of days.  You can always just put it in  a slightly more humid area for a few days more humid area.

 Or swipe  the back with a wet cloth to give it a little help along.
Title: Re: re-hydration time after tempering ?
Post by: RyanY on February 13, 2021, 10:43:29 am
I usually wait 5-7 days depending on how antsy I am. I know some guys will work their bows as soon as they cool down. I've done that without detrimental results but even if the back of the bow isn't so dry that it breaks, you can't be certain that the wood is behaving how it will when its finished if the MC doesn't return to equilibrium.
Title: Re: re-hydration time after tempering ?
Post by: bradsmith2010 on February 13, 2021, 10:57:47 am
moisture meter,,??
Title: Re: re-hydration time after tempering ?
Post by: Selfbowman on February 13, 2021, 11:20:15 am
You will get a lot of different opinions about this. Mine is when it cools to the core say two hrs . Go back to work if you want.  Arvin
Title: Re: re-hydration time after tempering ?
Post by: bjrogg on February 13, 2021, 11:32:53 am
I guess I usually wait three days. Haven’t had a problem. Usually takes me another day before I have it bending very far.


If I glue skins on I usually wait a couple weeks but not sure it’s necessary. I guess I just worry more about to wet than to dry. Maybe if I broke one I might change my mind.

Bjrogg
Title: Re: re-hydration time after tempering ?
Post by: bradsmith2010 on February 13, 2021, 12:03:59 pm
I glued a snake on a sinew bow,, couple days later it was 18%
Title: Re: re-hydration time after tempering ?
Post by: Selfbowman on February 13, 2021, 01:30:41 pm
Wow! Brad  that’s interesting and good to know if I ever try skins again. Arvin
Title: Re: re-hydration time after tempering ?
Post by: RyanY on February 13, 2021, 01:46:45 pm
I glued a snake on a sinew bow,, couple days later it was 18%

What kind of glue did you use?

PVA glues basically work by having the water evaporate or drawn out of them by the wood. I learned from a Titebond employee that when you glue up a tabletop it's a good idea to wait a week or two for the wood to loose that moisture from the glue. Sometimes what can happen in a table top is the glue line appears raised from the moisture so people plane it down and finish it. When the wood finally dries out there's a recess along that glue line from the wood shrinkage. Definitely noticeable difference that moisture can make from the glue.
Title: Re: re-hydration time after tempering ?
Post by: bradsmith2010 on February 13, 2021, 02:29:26 pm
I used heavy Gel Medium,, its like an acrylic paint but clear,, I think the snake skin was holding the moisture in from the glue,, just like it holds moisture out, once cured,, ??
Title: Re: re-hydration time after tempering ?
Post by: bjrogg on February 13, 2021, 02:52:17 pm
I used heavy Gel Medium,, its like an acrylic paint but clear,, I think the snake skin was holding the moisture in from the glue,, just like it holds moisture out, once cured,, ??

I agree Brad. Just like it keeps it out, I think it also holds it in

Bjrogg
Title: Re: re-hydration time after tempering ?
Post by: PatM on February 13, 2021, 04:32:43 pm
Snakeskin and birch bark both do that.  You have to wait while they dry through the waterproofing qualities.  Whether it  goes out through the layer or down and out through the wood, or a bit of both, it's going to take a bit of time.

 Unless your bow and backing is  overly dry and can use a bit of added moisture.

 Jay Massey mentions the effect of this in his book when he put a dried skin on one limb and a green one on the other limb.    The bow slumped in tiller but recovered by just being left to dry properly.
Title: Re: re-hydration time after tempering ?
Post by: Del the cat on February 13, 2021, 04:58:39 pm
Maybe it depends where you are?
In the UK, overnight does the job.
Del
Title: Re: re-hydration time after tempering ?
Post by: bassman on February 13, 2021, 05:04:21 pm
What Arvin said and even less time than that.
Title: Re: re-hydration time after tempering ?
Post by: scp on February 13, 2021, 08:06:12 pm
I just measure the bow's weight before and after and wait after heat treating, until the current weight is either steady or very close to the weight before. I usually wait for another day even after that, for the full draw. It helps to be patient and work on several bows all at once.
Title: Re: re-hydration time after tempering ?
Post by: organic_archer on February 16, 2021, 09:12:20 pm
Overnight for me. 12 hours or so. I'm in the Midwest. Never had one break from a heat treatment.
Title: Re: re-hydration time after tempering ?
Post by: Pappy on February 17, 2021, 09:32:46 am
Usually a couple of days depending on the weather, I am never in that big of a hurry anyway. :) I don't normally do what you would call heat treating but do do a lot of heat corrections and on some staves that is a lot of heat and I will give them a day or 2.
 Pappy
Title: Re: re-hydration time after tempering ?
Post by: Digital Caveman on February 17, 2021, 09:56:59 am
How long should  I wait after steaming?  I just mildly heat treated part of a bow, but when I couldn't bend it I steamed it for about 10 minutes.  Should I wait a day, 3 days, or longer?
 
Thank you,