Author Topic: Rawhide backing, dry time?  (Read 9533 times)

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TurtleCreek

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Rawhide backing, dry time?
« on: November 05, 2011, 04:31:01 pm »
  When backing a bow with rawhide, how long should one wait before bending the wood?  I understand that you should definitely wait until it's dry to the touch, but should it be given any more time than that?

Offline Hrothgar

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Re: Rawhide backing, dry time?
« Reply #1 on: November 05, 2011, 04:37:17 pm »
Its been several years since I've used rawhide, but I would give it a couple days to dry out completely before bending it--and the thicker the rawhide the longer the drying time. Did you use Titebond?
" To be, or not to be"...decisions, decisions, decisions.

TurtleCreek

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Re: Rawhide backing, dry time?
« Reply #2 on: November 05, 2011, 04:45:42 pm »
  The "bow" right now is roughed out and floor tillered and ready to be sized with glue.  I do plan on using titebond III.  The rawhide that I want to use on this particular project is some antelope rawhide, which is about as thin as paper and tough as nails.  It's much thinner than the white-tail rawhide I have.

Offline sweeney3

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Re: Rawhide backing, dry time?
« Reply #3 on: November 05, 2011, 04:48:45 pm »
I give it a couple days, then unwrap, cut, file, and check for missed spots.  I also use TB3. 

TurtleCreek

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Re: Rawhide backing, dry time?
« Reply #4 on: November 05, 2011, 05:00:52 pm »
Thanks guys for the quick responses.  This will also be the first bow I plan on posting on here.  I look forward to sharing the process with you all.

Offline Pat B

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Re: Rawhide backing, dry time?
« Reply #5 on: November 05, 2011, 05:46:24 pm »
You have to consider the wood absorbing moisture from the glue also. If you put a thin layer of TBIII on the bow first and let it dry overnight it will act as a moisture barrier so when you put the rawhide down the wood shouldn't absorbe any moisture.
  With thin rawhide you may not need to wrap it after glueing. Size the bow and the rawhide with glue and lay the rawhide down on the bow(I like to work with 2 pieces overlapped at the handle). Work any air bubles or excess glue out with your fingers and let it set for an hour. At that time trim the excess rawhide off with a sharp razor blade then let the glue cure completely, about 24 hours, then file and sand the edges of the rawhide until smooth. I'd give it a few days to release any moisture that might have been absorbed into the wood before sealing the bow.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

TurtleCreek

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Re: Rawhide backing, dry time?
« Reply #6 on: November 06, 2011, 04:29:24 am »
  The rawhide is pretty darn thin, as thin as a page from Primitive Archer magazine.  It has consistent thickness the entire length of the strips.  Is it required that I overlap at the handle, or would using a butt joint wrapped tight with sinew or silk thread be good enough to anchor it down at the handle?

Offline Pat B

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Re: Rawhide backing, dry time?
« Reply #7 on: November 06, 2011, 12:24:54 pm »
Its not necessary to overlap at the handle. A butt joint will work and even ending at the handle if you put a wrap at the end of the rawhide. Actually you only need it over the working portion of the limb but you have to secure it somehow. If you have enough hide to overlap it at the handle it will eliminate any chance of  problems.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline Cameroo

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Re: Rawhide backing, dry time?
« Reply #8 on: November 06, 2011, 01:13:44 pm »
I have never sized any of my rawhide-backed bows.  I just soak the rawhide in warm water for about 15-30 minutes, lay it out on paper towel and dab the excess moisture off of it, apply a thin layer of TB3 to both the rawhide and the bow, and then lay it out on the bow.  I have overlapped it at the handle, and also used a butt splice.  Both ways work just as well.  I think that as soon as the glue starts to set up, it makes a moisture barrier that forces most of the moisture in the rawhide to evaporate off the back side.  I usually leave it for a day, then unwrap it and leave it for another day before working the bow.  48 hours is plenty of time in my experience, but there's no harm in leaving it longer if you're unsure. 

I'm not sure if your back is flat (board bow), but if it is, adb did a great holmegaard build along that shows the glue up procedure that I've been using.  Here's a link if you want to check it out:
http://www.primitivearcher.com/smf/index.php/topic,5129.0.html

Offline JW_Halverson

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Re: Rawhide backing, dry time?
« Reply #9 on: November 06, 2011, 02:28:13 pm »
Like Pat said, size the bow with the TBIII first and give it 24 hours to cure up.  Give it a light once over with coarse sand paper before putting on the rawhide. 

I use tacks to stretch my damp rawhide strips on a board as I rub the TB glue into it.  I also use a rubber spatula to lay a very thin layer over the bow limb before laying on the rawhide. 

Start at the handle.  Use string or rubber banding to hold the rawhide down in the middle of the handle and start laying the rawhide down a little at a time using your fingers to smooth out any air bubbles that might be trapped.  When you get to the tip, put gentle stretching pressure on the rawhide with one hand and with the othe rubbing the rawhide in long strokes from the handle toward the tips.  This action will stretch the rawhide and work out any excess glue and/or air bubbles.  When you are satisfied that the rawhide is stretched and bubble free, use a tack or pushpin to hold the rawhide in place.  Push the tack in thru the rawhide into the belly of the bow right about where the nocks are.  Small hole, no damage to the bow, really.

Now start at the handle of the bow and using your thumbs, strecth the rawhide down over the sides.  This squishes out some more excess glue.  Have a wet washcloth handy and a bowl of warm water.  Wipe up any excess glue.  When you have 6 inches of limb done, wrap with Ace bandage and go do the next 6 inches.  Getting the glue off will help get the Ace bandage off later, trust me, and don't ask how I know this.

Once the limb has dried for about an hour, take off the Ace bandage.  Take a fresh bowl of warm water and a clean washcloth and wipe down the whole rawhide side of the limb.  You can use plenty of water at this point because the PVA glue that makes up TB II and III will not re-wet at this point.  But you are plumping up the rawhide again, you want it good and wet so that it swells up and gets rid of the fabric pattern of the wrapped Ace bandage.  Wipe down with a dry paper towel and let it cure overnite.  Repeat on second limb next day.

I've been meaning to take photographs of this process and do an article for PA because I have gotten some really nice comments on my rawhide backings. 
Guns have triggers. Bicycles have wheels. Trees and bows have wooden limbs.

TurtleCreek

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Re: Rawhide backing, dry time?
« Reply #10 on: November 06, 2011, 04:28:35 pm »
Would it help if I trimmed the rawhide strips to a hair over what the front view limb profile will be before I apply them to the bow?

Offline Gordon

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Re: Rawhide backing, dry time?
« Reply #11 on: November 06, 2011, 05:34:22 pm »
I give rawhide backing 24 hours to cure.
Gordon

Offline Pat B

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Re: Rawhide backing, dry time?
« Reply #12 on: November 06, 2011, 05:41:07 pm »
You don't want hair on the rawhide you use for backing. The excess weight of the hair will slow the limbs considerably.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline JW_Halverson

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Re: Rawhide backing, dry time?
« Reply #13 on: November 06, 2011, 11:23:35 pm »
Would it help if I trimmed the rawhide strips to a hair over what the front view limb profile will be before I apply them to the bow?

As long as that hair is about a quarter inch wide, that's a great idea!
Guns have triggers. Bicycles have wheels. Trees and bows have wooden limbs.

TurtleCreek

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Re: Rawhide backing, dry time?
« Reply #14 on: November 07, 2011, 02:48:42 am »
  I didn't mean I would leave the "hair" on Pat...  What I meant to say was-  Would it help if I trimmed the rawhide strips to the profile of the limbs, but only a little bit wider so there wasn't so much excess hanging on the edges