Trad Gang
Main Boards => The Bowyer's Bench => Topic started by: breazyears on April 06, 2020, 07:37:58 PM
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Some time ago I purchased some bear paw glass. I faintly remember Kenny saying to build the bow 10lbs heavy or light. I cant remember???
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If it was a while back add 5 lb to the stack but in the last 6 months or so deduct about 7 . Hope it gets better at staying the same... :banghead:
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thanks Kenny
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Hahaha I’m dealing with the “light” glass. At least it’s streak free
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Just out of curiosity do you guys have a preference between Gordon's and Bear Paw? I have not had any complaints about Gordon's so far and glued up my first set of limbs with bear paw, the bear paw is very very clear but I wish I'd seen this thread before I ordered it.
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I use bp for all clear applications and Gordon's for colors. Somehow I have skated through and around the Gordon streaks but still........
I have two strips of Gordon's clear left. I'll use it soon and be done with it.
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All three glass bows I have built used clear glass and in my opinion BP has the upper hand. The first two made with Gordon's looked good with no streaking, but you always had that slight hint of the fiberglass weave when you looked closely. I finally read up on the difference between the two before starting my third bow and decided to order some BP. The name is spot on, it really was crystal clear when I pulled it off the form. Personally, I'll only use BP for clear applications from here on out.
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I just checked my newest set of limbs with BP glass and they are exactly 7lbs lighter than my Gordon's glass limbs with the exact same stack thickness. So Kenny was spot on. Wonder why it's that big of a difference??
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It is interesting and potentially useful. If the same thickness of glass is 7 lbs heavier, you might be able to reduce your stack (and limb weight) and speed up performance. That is kind of what carbon is about, you can use pretty thin lams to get the same weight as a thicker all glass bow...
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On a hill style where glass ratios can get weak maybe Gordon's on the belly and bp on the back.?
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I loved how clear the BP was and I'm sure it's a good product but I'm probably going to stick with Gordon's from now on.
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On a hill style where glass ratios can get weak maybe Gordon's on the belly and bp on the back.?
Glass ratios can get weak? What do you mean?
I use .050 On belly & .040 on back. BP has been fine so far. Shoots good just comes in a bit light vs Gordon’s.
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For example; hill style, stack .55, glass .090. Thats 16.3% glass.
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to me, coming in lighter at the same thickness. means there is less glass in there.
now what that means in the long run, with regards to longevity and performance :dunno:
but it will have some effect!
enough to worry about :dunno:
The pieces of Gordons that i have studied closely, and cut up and looked at the cross sections, the streak areas seem to be less than perfect saturated glass fibers.
which means they are right at their saturation limit of glass to resin ratio!
hence also the slightly more opaque quality of the Gordons vs BP.
Which to my experience, tells me that the BP , has a higher resin to glass ratio, which improves the clarity, but will also reduce the "spine" of the glass.
Remembering the tensile strength of this matrix comes from the glass, not the resin.
So a matrix with a higher glass ratio will always be better!
so, once again, is this significant enough to warrant concern, and how will it effect performance and longevity of a bow built with BP glass :dunno: :dunno:
the real test may be to approach one of those industrial testing agencies, a put sample pieces on one those cyclical flexion machines, that measure the repetitive flexion durability???!!??
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For example; hill style, stack .55, glass .090. Thats 16.3% glass.
I’ve built kids bows with .050 back and belly knowing they’d get dragged through the gravel roads at shoots. Kids bows for young women, women’s bows, and adult. I’ve never noticed any shootability feel or performance issues with Hill style ASL or a mild R/D. Before I started using different thicknesses I used all .050. I don’t think you’ll have a problem with glass to wood. I’ve also messed with thinner glass. I like .050 on belly all the time because I believe that’s where much of the performance comes from.
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Matt, I haven't taken the time to test this so maybe you can tell me: How much difference does .040 to .050 glass make with same total stack? TIA :thumbsup:
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I just got some glass from Kenny.So with all this talk thought would check it. I hung 11 5/8s over and clamped it right at that mark. Used the very same clamp on both pieces and was careful to get the clamp on the same. the stuff I just got shows weaker than what I already had on hand. The new stuff measured .040. the old stuff was .041 that would not matter in my thinking. Now I am sooo confused. My last bow did come in heavy tho.
Got no idea how much to change the stack ??
(https://i.imgur.com/PxZz6yK.jpg)
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I feel your pain Mike. Screwed up a set of limbs for a friend of mine so I'm eating what I have in them. 80ish bucks probably. Hoping to get a kids bow out of them right around 42lbs when they were supposed to be 50ish.
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Well crap, I’m just about to finish up my first roll of BP. So far I’m not really that impressed. I’ve had to cut off and trash a few sections because of streaks and have had several sets of limbs show some minor streaking.
I will say it’s “mostly “ clearer than Gordon’s but if they are having issues with consistency I may just go back to Gordon’s. Guess I’ll have to make that decision when the time comes.
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Exel composites of Finland makes glass also.
I believe Blacktail use their glass.
https://www.exelwebstore.com/composite-laminate.html
https://www.exelcomposites.com/Portals/154/documents/Brochures/Exel%20Archery%20Laminates_Datasheet%202017_web.pdf
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Buemaker, excel was supposed to come out with a total clear glass and has said so for years... never produced. Far as I know, blacktail has moved around in search of the best glass as has most of us.
The Bear paw glass is still clearer than gordons was.. haven't used any Gordon glass lately so can't say what it is like currently.
I will say that I haven't seen a clear piece of Bearpaw in several rolls.. again, it's still nice, but not clear.
It seems that no manufacturer can maintain the clarity. I'm afraid to purchase a batch of Gordons and be stuck with a 1000 plus pieces of streaky glass.
Kenny, I did a test between the .040 and .050 bearpaw glass and there was no difference whatsoever in draw weight using matching stack thickness. Now it was only done once and the the .040 and the .050 could have been from different batches meaning the .050 could have had a little less than normal spine and the .040 could have been a little stiffer. I go through a lot of rolls and don't mind missing weight occasionally. When I build a bow out of a new roll, I look at the most recent info and if it misses, I make adjustments. I'm then good through that roll.
Between selling glass and using it, I go through a couple rolls a month or so.
BigJim
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Thanks Jim!
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I guess I need to get a whole roll.
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We sell the rolls of BearPaw as well.
Thanks, BigJim