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Main Boards => The Bowyer's Bench => Topic started by: defiant on April 01, 2009, 11:14:00 AM
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Hi guys,I have a question about glass size and poundage.I made bows using .040 and .050 glass along with different lam thickness with same forms and don't know if there is any advantages or disavantages to it other than record keeping and added strength from thicker glass.Can anyone comment on this,thanks Frank.
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Sorry, I should of stated the bows would be of the same poundage after using .040 or .050.
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Well I'm sure there's better folks here to answer your question than me but here's my stab. Most consider fiberglass heavier in physical weight than wood so the thicker it is to reach your draw weight the heavier your limb is. The lighter your limb is in physical wieght the better for preformance, imagine swinging a four by four post or a two by four stud around.
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LC thanks for your intake on my question.I think you are right about performance and limb weight.What I should do is make two identical bows using .040 and .050 with a light wood like walnut or sassafras to reach the same poundage and see if one will out perform the other.In the pass I have built bows using both glass sizes but never considered if there would be advantages.I will try this in the near future and post any findings.Thanks Frank
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Well like you I've never done two identical bows with just different thickness fiberglass for comparisions so I just take others advice and hope they are right. Sometimes that's a good thing and sometimes it's not so good. I'm just glad alot of the great inventions in this world wasn't relying on me! lol It's good to think outside the box but sad thing is it can get expensive too! Let me know what you findings are!
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Well here's my thoughts, and I'm by no means a 1/4 as smart as some of the people on here.
They say that the fiberglass carries something like 87-88% of the work in a bow and the poundage increase as the distance between the pieces of glass increases.
Since fiberglass is heavier than wood, I would say then to use as little glass as possible because you can increase or decrease the poundage by using more wood (wood is lighter than the glass, remember) which would mean faster limbs.
That's just what I think, but there are better, smarter people than me.
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I ground some glass to .020" for a guy making a performance bow. As stated ,the lighter limb in 2 of the same design will be faster.
To build 2 identical bows of the same weight with diff thickness glass will be tough,because glass is stiffer than wood for thickness.
So you will have to really sharpen your stack figuring pencil to get 2 the same width and same #s without making several attempts.
JMHO, Kenny