When is it too hot in temps for sinew backed

[StickMark]

At what temperature, say around 15-50 relative humidity, does a sinew backed bow suffer loss in draw weight? I have heard some Arizona archers mention this before.

[bownarra]

If I lived somewhere with that r.h. range I'd make a lot more sinew backed bows
Sinew will shine in low humidity like that. Design your bow from the outset for the conditions you intend to use it in. Any bow would 'soften up' a bit in high temp, sinew wouldn't make that change worse.

[Tom Dulaney]

Bows become less stiff in the heat. To get around this, simply build your bows bigger for hot weather. The best design for hot weather is wide, thin limbs, at least 2½ inches wide, preferably over 3 inches. Make them as thin as cardboard. Such a bow conducts heat well, but also loses it more quickly. I have some bows that are 4 inches wide that are impossible to string without heat. If the weather isn't hot, those monsters have to be warmed by a radiant heat source. And I always store them in a high humidity environment.

Bows are less likely to break in hot weather as long as they aren't too dry (most people keep their bows way too dry). Any glue on the bow can fail in hot weather, hence why I build hot weather bows wide and thin to radiate the excess heat away quickly.


One thing that is often neglected is sunlight. UV destroys wood and sinew. The ancients painted their bows for a reason, and it wasn't for pretty looks. They were aware of the destructive and oxidative nature of sunlight.

The question is: how do we paint our bows without adding too much weight?

[Marc St Louis]

At what temperature, say around 15-50 relative humidity, does a sinew backed bow suffer loss in draw weight? I have heard some Arizona archers mention this before.

Never heard that one before.  It gets very dry in my house during the winter here, right now it hovers around 30% RH, and I have always had great success with sinew in the winter

[gutpile]

my understanding is that is when sinew shines the best.. you can take a hickory bow made in the south unbacked , take it out west and it will increase in poundage ... that is what a few have experienced... gut

[StickMark]

I should have been more specific, perhaps.
Would 95 to 110 be too hot for the hide glue matrix to be at its best?
I will not leave it a car in summer desert. But, for ambush hunting in summer, where Temps are 95 to 115, I wonder....

My sinew is on hickory stave, fwiw

[PatM]

  Cured Hide glue  does not suffer from heat,

[Tom Dulaney]

  Cured Hide glue  does not suffer from heat, 

Oh yes it does.

[Marc St Louis]

  Cured Hide glue  does not suffer from heat, 

Oh yes it does.

Sure if you throw it in the fire it will burn but that's not what we are talking about here

[Tom Dulaney]

  Cured Hide glue  does not suffer from heat, 

Oh yes it does.

Sure if you throw it in the fire it will burn but that's not what we are talking about here

If the surface of the bow heats up beyond 105 degrees farenheit, glue is going to soften up considerably. That can easily happen in a quiver exposed to direct sunlight south of the 35th parallel, particularly if the quiver is animal skin.

[PatM]

Stop making up stuff, Tom.

[Marc St Louis]

  Cured Hide glue  does not suffer from heat, 

Oh yes it does.

Sure if you throw it in the fire it will burn but that's not what we are talking about here

If the surface of the bow heats up beyond 105 degrees farenheit, glue is going to soften up considerably. That can easily happen in a quiver exposed to direct sunlight south of the 35th parallel, particularly if the quiver is animal skin.

105 F.  Really?  I have done a mild heat-treat on a sinew backed bow with no adverse effects to the hide glue and that was a heck of a lot higher temp than 105 F.  You must be thinking of those people that use TB3 with their sinew to back bows and even then it would take a lot more than 105 degrees, maybe 105 degrees C. 

Spreading false information doesn't help anyone

[StickMark]

Thanks for the replies. I am looking for what you guys are sharing.

Here is a more detailed explanation of why I ask.
Now that spot and stalk mulie rut season has come and gone, and as I am not harvesting smaller ones, it is prep-time for summer velvet season. I never killed a deer from ambushing, and I plan on that this year.

My interest is in hunting bows that can handle the long periods of being "strung up." You may recall, I go on and on about the wide range of humidity and temps in beloved southern Arizona. I have had reservations about using some non-primitive techniques, like spar poly sprayed over the tru-oil'ed sinewed back for moisture protection. But then, buck only tags and seasons are not exactly primitive either, not one bit. In any case, I know that temps get really high at time, close to 100, over 100, even at 4500 feet elevation.

From what I read, the Chiricahua Apache band built their gull wing bow often without a sinew layer, and I wondered "why is that?" I am looking for the source, but that is what I recall reading from last summer.
 

[JW_Halverson]

  Cured Hide glue  does not suffer from heat, 

Oh yes it does.

Sure if you throw it in the fire it will burn but that's not what we are talking about here

If the surface of the bow heats up beyond 105 degrees farenheit, glue is going to soften up considerably. That can easily happen in a quiver exposed to direct sunlight south of the 35th parallel, particularly if the quiver is animal skin.

That's patently false.  I have left a sinewed backed osage bow inside a closed up vehicle in direct sun where the temps rose in excess of 145 degrees. The hide glue was absolutely unaffected in any way, shape, or form, except to maybe cure what little residual moisture it may have absorbed in the more humid part of the year!

In fact, there is quite a lot of literature regarding competition shooting of Turkish composite bows with sinew and hide glue backs being purposely kept in a hot box prior to shooting!

I have to question whether you have experience with actual hide glue.

[PatM]

I want to see Tom's four inch wide bows.  And his hot sinew backed bows in a skin quiver too.