When is it too hot in temps for sinew backed

[bradsmith2010]

it would be easy to test ,, just glue some sinew on scrap and heat it up,, I just dont believe everything I read,,,
I have heated lots of sinew bows to correct them as well,, with no glue failure,,but I guess I didnt get it hot enough,,
I think you would have to have a combination of heat and moisture to make the glue fail, but I am just guessing and only self published,,

[Tom Dulaney]

Why would Marc have no way of knowing how the bow would have shot before heating it?  All he had to do was shoot it before and after.

  I have corrected a sinew backed bow many times with high heat on the belly side.

There's no way of knowing now how well the bow would have seasoned up til now.  I have heard of too many broken bows around here. I haven't broken a bow in two years after assuming what I now know about heat, glue and RH. These materials are incredibly sensitive to the slightest change in temperature. After about 130⁰f for longer than a few seconds you are no longer affecting their mechanical properties but merely degrading fiber. Hence why so many bows around here go *BANG* at a 20 inch draw despite lengthy efforts to get a single growth ring on the back; whereas I'm bending violated pieces to the shape of a rainbow without experiencing a single lifted splinter. This wood stuff will love you if you just be gentle with the heat.

[PatM]

Nonsense,  Tom.  You're talking out of a dark place.  Most of the broken bows on here are  poorly selected wood made by new guys.  Others are by guys pushing the limits.

 Wood takes really high heat and Hide glue and sinew can tolerate high temps.   

 Did you figure out the  60C and 140 F thing  out yet?

[Yooper Bowyer]

Well, the consensus seems to be that a sinew bow will not suffer any significant performance loss at temperatures that may reach into the 100-115 range in the noon time.

Yes, 100-115⁰f ambient temperature is fine. That's not the same thing as the temperature on the bow's surface. Heat the surface of a sinew bow to 115⁰f and you may very well slough the sinew off before you get to full draw.

If the ambient temperature is 115⁰f you can bet your bottom dollar that a bow's surface will be the same if it sends any length of time at that temp, maybe hotter in bright sun.  Temperatures equalize.  Also, you can't seriously bend wood with ambient temperatures.

[Tom Dulaney]

Well, the consensus seems to be that a sinew bow will not suffer any significant performance loss at temperatures that may reach into the 100-115 range in the noon time.

Yes, 100-115⁰f ambient temperature is fine. That's not the same thing as the temperature on the bow's surface. Heat the surface of a sinew bow to 115⁰f and you may very well slough the sinew off before you get to full draw.

If the ambient temperature is 115⁰f you can bet your bottom dollar that a bow's surface will be the same if it sends any length of time at that temp, maybe hotter in bright sun.  Temperatures equalize.  Also, you can't seriously bend wood with ambient temperatures.

If the bow is never fired with no wind gusts of any kind, like in a hot car, sure.

If there's wind and you're shooting your bow, no way. Wind blows the heat off the bow and keeps it from assuming ambient temperature, as does the release in shooting.


As for  bending with ambient temperatures this is probably a more serious bend than anyone here has ever done, it was with less than 60⁰c ambient temperature only. Keep in mind the bent sections are approximately 3 inches long, and quite thick.

[PatM]

You'll figure out the C and F thing at some point Tom. I hope.

[bownarra]

Yes JW that is a fact. Around 40 - 45 celcius was the temperature used. 105 - 115 f.
During construction of a hornbow when gluing the horn to the core the horn is heated to around 50 celcius. The horn at this point has many sizings coats of thin glue. The heat is to soften the horn so it follows the cores shape perfectly and with less ressitance. Also during tillering the bow can be heated to 50 degrees for correction of twists. Relatively high heat is the primary tool for correcting twists etc on hornbows.....funny how they don't all fall apart

The original Ottoman hornbowyers never used those stupid lightbulb boxes, for the obvious reason that lightbulbs and accurate thermometers didn't exist in Turkey until the 20th century, when the art was dead. They are a toy of 21st century morons who call whatever is is they do "Turkish archery". Nobody stores a bow at +105 degress farenheit.

Again you have picked some ill explained section from the internet and that is your 'proof'......
Seriously you know nothing about this stuff and your responses prove it. I for one am not going to waste my time with a troll like you. I have been making these bows for quite a few years now.  I KNOW what i'm saying is correct through direct, first hand experience. No cut and pasted quote is going to alter what I KNOW to be the truth. I could go through that section of text and explain what is going on with it but this is the last response you will get from me.

[Yooper Bowyer]

That wood must be waterlogged, or I'll see the documentation otherwise.

If the bow is never fired in a vacuum with no wind gusts of any kind, sure.

If there's wind and you're shooting your bow, no way. Wind blows the heat off the bow and keeps it from assuming ambient temperature, as does the release in shooting.

First:  There is no ambient temperature in a vacuum.

Second: Wind may 'blow off' heat if the temperature of the bow is greater than that of the wind, otherwise the heat will flow from the wind into the bow.  This is a basic law of thermodynamics.

Third: The hotboxes the ottomans used where heated with charcoal

Between these, the question about Ferenhite to Celsius, and some other basic blunders, I have to ask what claims to credibility you have.

[Marc St Louis]

Can't say I've ever seen Tom D post anything of his own making.  It's always quotes from other sources or pics from online

[Tom Dulaney]

That wood must be waterlogged, or I'll see the documentation otherwise.

If the bow is never fired in a vacuum with no wind gusts of any kind, sure.

If there's wind and you're shooting your bow, no way. Wind blows the heat off the bow and keeps it from assuming ambient temperature, as does the release in shooting.

First:  There is no ambient temperature in a vacuum.

Second: Wind may 'blow off' heat if the temperature of the bow is greater than that of the wind, otherwise the heat will flow from the wind into the bow.  This is a basic law of thermodynamics.

Third: The hotboxes the ottomans used where heated with charcoal

Between these, the question about Ferenhite to Celsius, and some other basic blunders, I have to ask what claims to credibility you have.

Just shut up and stop trying. You have no idea what you're talking about.

[Tom Dulaney]

Can't say I've ever seen Tom D post anything of his own making.  It's always quotes from other sources or pics from online

That's usually what educated people do. They post material that was authored by experts rather than whatever they think they "know". It's called secondary research.

[PatM]

Can't say I've ever seen Tom D post anything of his own making.  It's always quotes from other sources or pics from online

That's usually what educated people do. They post material that was authored by experts rather than whatever they think they "know". It's called secondary research.

 Educated people know the C and F difference though.

[Tom Dulaney]

Yes JW that is a fact. Around 40 - 45 celcius was the temperature used. 105 - 115 f.
During construction of a hornbow when gluing the horn to the core the horn is heated to around 50 celcius. The horn at this point has many sizings coats of thin glue. The heat is to soften the horn so it follows the cores shape perfectly and with less ressitance. Also during tillering the bow can be heated to 50 degrees for correction of twists. Relatively high heat is the primary tool for correcting twists etc on hornbows.....funny how they don't all fall apart

The original Ottoman hornbowyers never used those stupid lightbulb boxes, for the obvious reason that lightbulbs and accurate thermometers didn't exist in Turkey until the 20th century, when the art was dead. They are a toy of 21st century morons who call whatever is is they do "Turkish archery". Nobody stores a bow at +105 degress farenheit.

Again you have picked some ill explained section from the internet and that is your 'proof'......
Seriously you know nothing about this stuff and your responses prove it. I for one am not going to waste my time with a troll like you. I have been making these bows for quite a few years now.  I KNOW what i'm saying is correct through direct, first hand experience. No cut and pasted quote is going to alter what I KNOW to be the truth. I could go through that section of text and explain what is going on with it but this is the last response you will get from me.wl6

Says the guy who actually believes hotboxes are a part of authentic Ottoman archery.

[Tom Dulaney]

Can't say I've ever seen Tom D post anything of his own making.  It's always quotes from other sources or pics from online

That's usually what educated people do. They post material that was authored by experts rather than whatever they think they "know". It's called secondary research.

 Educated people know the C and F difference though.

Ok, please show me where I have erred.

[PatM]

Can't say I've ever seen Tom D post anything of his own making.  It's always quotes from other sources or pics from online

That's usually what educated people do. They post material that was authored by experts rather than whatever they think they "know". It's called secondary research.

 Educated people know the C and F difference though.

Ok, please show me where I have erred.

 When you used  the  60C  quote to show "low" heat being used to bend the Scythian replica.  Then replaced it with F.