knox glue

[WhistlingBadger]

Hi, all.  I'm about ready to stick some rawhide on this new bow.  The heat treating on a caul actually worked, by the way!  yippee!  Thanks to everybody that gave suggestions about that.  I might try reverse bracing for the next one.

Anyway, I'm reading a lot about knox gelatin glue.  Sounds like I want about 1 part powder to three parts cold water, let it soak for an hour or two, then heat it gently to about 140F until it melts.  "Size" the bow with a thin layer of glue, let dry for a few hours while hydrating the rawhide strips, wring out and stretch the hide, glue it in place, wrap it with an ace bandage for about 24 hours, then let it cure for several days before bending it.  Sound right?

Couple questions.  At room temperature, say 70-75F, how long does this stuff take to set up?  I'm afraid it will gel before I can get the hide on and wrapped.  Any tips about that?

TBB1 says tannic acid can make the glue more water-resistant, but gives no further details.  I'm all for water resistance.  Anybody ever tried this?  How does one go about it?  I'm thinking about boiling up some hickory bark solution to use with the gelatin instead of water, but I don't want to get TOO experimental on this one.  Thoughts?

OK.  Thanks, as always.  I sure appreciate the opportunity to bounce things off all you experts instead of figuring it all out for myself.  That's kind of fun too; it just takes too long.   

[HanibalLecter(InnerSmile)]

Truly effective sizing is a lot of work. It takes 20-30 coats of thin glue on the surface to get it soaked deep in to the cells of the wood, before the surface becomes glossy and rubbery. If you get a glossy surface with less than 20 coats, you're using too thick glue. That "sizing" won't last on the wood and will be sucked up by the rawhide. A true sizing is a deep intracellular composite material.


You'll probably want to do the sizing over a period 5 days, taking an hour to apply around 5 coats.  Don't add a coat if you still see liquid glue pooling on the surface -- let that sink  in to the wood pores before getting your brush wet again. When you size properly you get a product that is something other than wood. It's amazingly strong and resilient.

I've never broken a bow in my entire life. This is one thing you shouldn't skimp on.

[mmattockx]

Anyway, I'm reading a lot about knox gelatin glue.  Sounds like I want about 1 part powder to three parts cold water, let it soak for an hour or two, then heat it gently to about 140F until it melts.

I never let it soak when I used it, I just mixed the powder with the water until it was a slurry then put it into the double boiler to heat. Of course, this could be completely wrong...

I would suggest starting with less water and working in to the consistency you want. It is easy to add a few drops to thin it, but it takes a long time to burn off excess water if you get it too thin.

Couple questions.  At room temperature, say 70-75F, how long does this stuff take to set up?  I'm afraid it will gel before I can get the hide on and wrapped.  Any tips about that?

I was doing a patch of synthetic fibres over a pin knot on the back of a bow, so it was a small area. The glue started to set up pretty quickly, certainly in less than a minute. You can stretch that by dabbing some more glue onto the surface as you go and I think warming up the bow would also help slow the set. It is not like working with wood glue or epoxy, though. There is no pot time or point where you can't reactivate the glue by adding a bit of warm water or more warm glue. It softens up again with no problems until after it has really gelled and set hard a day or two later.


Mark

[WhistlingBadger]

Truly effective sizing is a lot of work. It takes 20-30 coats of thin glue on the surface to get it soaked deep in to the cells of the wood, before the surface becomes glossy and rubbery. If you get a glossy surface with less than 20 coats, you're using too thick glue. That "sizing" won't last on the wood and will be sucked up by the rawhide. A true sizing is a deep intracellular composite material.


You'll probably want to do the sizing over a period 5 days, taking an hour to apply around 5 coats.  Don't add a coat if you still see liquid glue pooling on the surface -- let that sink  in to the wood pores before getting your brush wet again. When you size properly you get a product that is something other than wood. It's amazingly strong and resilient.

I've never broken a bow in my entire life. This is one thing you shouldn't skimp on.

Interesting!  Your style of sizing sounds like an admirable and effective pursuit.  Also, exceptionally time consuming.  Since I am a mere mortal with a family and assorted non-bow jobs that occasionally require my attention and/or abilities, I will probably do a single coat of sizing and hope for the best.

I'm still interested in knowing a bit about set-up time and tannin additive.  I'd like to be armed with some understanding of that before I start brushing glue on.

[WhistlingBadger]

There is no pot time or point where you can't reactivate the glue by adding a bit of warm water or more warm glue. It softens up again with no problems until after it has really gelled and set hard a day or two later.


Mark

Thanks, Mark.  So, if it does start to set up, I can just rub a little warm water on it with my finger and that will re-liquify it enough to get the hide on?  The hide will be warm and a bit damp too, so maybe that will buy some time?

[PatM]

Just paint both surfaces and lay the two together  and then warm everything up with a hair drier as you press it in place and work out any bubbles.   Any waterproofing can be tackled with a surface coating.

  While you are waiting  for it to dry and cure you can ask Tom to post pics of his bows.

[WhistlingBadger]

Just paint both surfaces and lay the two together  and then warm everything up with a hair drier as you press it in place and work out any bubbles.   Any waterproofing can be tackled with a surface coating.

Ah, I've read about that, too--heat re-liquifies this stuff, too.  That shouldn't be surprising seeing as how it's jello.  By the way, I love that I'm gluing my bow together with jello.  My daughter gets a kick out of that idea, too.  Anyway, good tips.  Thanks.

  While you are waiting  for it to dry and cure you can ask Tom to post pics of his bows.

Now, let's stay on topic, shall we?     I have seen several threads thus hijacked, and I would prefer to avoid that here.  That said, there are two possible reasons that one might be able to honestly say one has never broken a bow.  I choose to reserve judgement on which reason is at play here.   

OK, enough silliness.  Now...tell me more about this wondrous jello glue!

[HanibalLecter(InnerSmile)]

I highly recommend just doing 1 coat a day for the sizing, for a 20-30 day period. That way you lose maybe 5 minutes off your day. One thing I have noticed is that it's way more economical to size multiple bows or multiple bow components at a time, providing incentive to make bows as an "industry" and also to make bows from many different components. This bow making stuff is a long haul game.


And yes tannins extracted from bark or gall add some water resistance and also micorbial reistance to your glue.



To increase the time before gelling/setting, add glycerine to glue. This also keeps glue plastic for longer snd prevents it from becoming too hard/brittle long term. Ancient Chinese bowyers added lead sulphate to their glues for a similsr effect.

[BowEd]

Whistlingbadger.... .Speaking from experience as far as water and microbial or pest resistance smoking your sinewed bow will achieve the same thing as tannin additives.

[Eric Krewson]

Sound like a lot of work with your method.

I have never put rawhide on with it, only sinew. I don't measure anything, I mix the hide glue with water until it is the consistency of thin syrup, put a coat on the bow and, dip the sinew in the thin glue, squeezes out the excess and lay it on the bow smoothing it down with my fingers.

I have an old crock pot that I bought at a thrift store for $2 that I fill with water I float bowl of the glue in to keep it warm.

[AndrewS]

 So far, I have always glued on rawhide with a carpenter's glue as backing ( I know that hide glue is more traditional )
For sinew, I have so far only used hide glue but that is another theme.

Gluing the rawhide with carpenter's glue is a simple matter:
1. Place the rawhide strip completely in lukewarm water for a minute or two.
2.then wipe off the excess water between two fingers, and
3.brush the rawhide very thinly with some glue.
4.brush the back of the bow with glue and
5.place the rawhide with the glue side on the back of the bow.
6.Fix on the grip area with a clamp and then towards the nocks smooth the rawhide and brush out air bubbles so that the rawhide rests well on the back.
Wrap tightly with gauze bandage and do not move the rawhide by pulling on the gauze bandage.
Allow the wrapped sheet to dry for one day and then remove the gauze bandage and the clamp on the handle.
9. Trim the edge with a sharp knife.
10. let dry through for another day (maybe one more day if the rawhide was relatively thick -.
I like to use thin raw goat skin, which is also used for making drums).
12. the bow can then be tested and the rawhide can be painted, varnished, oiled - just as you like it....

So far, I havn't had a problem with thin rawhide backings. One bow is broken, but there was a mistake on the belly and the rawhide holding the bow together, so it doesn't explode.

[Pat B]

I go through the same process with hide glue and rawhide as with my locust bow redo. I'm bring that post back up to the top. Since I started going through the washing and rinsing the limbs with boiling water and washing and rinsing the backing with warm water I've had great success with sinew and rawhide backing. I'm using hide glue but I believe Knox would work with the same process.

[BowEd]

Sound like a lot of work with your method.

I have never put rawhide on with it, only sinew. I don't measure anything, I mix the hide glue with water until it is the consistency of thin syrup, put a coat on the bow and, dip the sinew in the thin glue, squeezes out the excess and lay it on the bow smoothing it down with my fingers.

I have an old crock pot that I bought at a thrift store for $2 that I fill with water I float bowl of the glue in to keep it warm.

You mean smoking it?Not if you have a tipi.If you've got a smoke shed it's easy too.

[Eric Krewson]

Smoking and teepees, what is that supposed to mean.

I have applied at least 50 snakeskins and only wrapped the first couple because people said that is what I was supposed to do. It is an unnecessary step, your thumbs can get rid of any air bubbles and excess glue as the glue sets and put way more pressure on the item being glued to the back than any bandage wrap. About 10 minutes per limb and the glued on skin will be as tight as a drum.

[BowEd]

Excuse me but I thought you said smoking a bow was a lot of work.