Trad Gang
Main Boards => The Bowyer's Bench => Topic started by: onetone on March 15, 2023, 05:23:44 PM
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This fiberglass is on the compression side of an extreme reflex bow. Have shot a couple thousand arrows thru the bow. I have not seen these kind of striations in belly glass before and I’m looking for opinions on this situation. Does this signal eventual failure? There are no cracks or fractures that I can feel with a fingernail.
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I've never seen anything like that. Almost looks like the resin popped out of the glass strands.
Both limbs look same?
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Is it smooth?
:dunno:
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Couldi it be in the finish?
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Is it smooth?
Yes it is smooth. I don’t feel any variation in the surface when I draw a fingernail across it.
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I've never seen anything like that. Almost looks like the resin popped out of the glass strands.
Both limbs look same?
Yes both limbs look the same.
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Looks like glass that is sanded both sides
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It’s Gordon’s glass sanded one side only - the glued side.
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It is black glass not clear over dark wood?
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Jeff, yes it is black glass … or was!
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🤔
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Have you sanded it down and cleared it yet?
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Jeff - sorry I don’t understand your question. Please explain
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Never mind if it's showing that before it's sanded and cleared. It'll still show it after it's been sanded and cleared.
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Is it like that all the way out, levers and riser?
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Mad Max. I was just thinking the same thing as it's showing it all the way out or just in the main big hard bending areas?
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Mark and Jeff - the effect is concentrated in the area of maximum compression. Runs an 1 1/4” past the end of the fade toward the riser and about 6 1/2” from the end of fade toward the limb tips (both limbs the same). Doesn’t look so extreme in the pic below when seen in scale and not so close up. Other pic shows the light reflected off the surface of the affected area. As you can see there are no stress caused cracks or imperfections visible on the surface of the glass.
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You may have pushed it to the limit.bmaybe try carbon. You are definitely trying to get to Boldly Go. A star trek saying. Lots of opposite direction bending 😲 JF
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It could be just the finish, what did you use?
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Shellac sealer and multiple coats of TruOil. I don’t think it is the finish but I have been wrong a couple of times. Just seems deeper to me.
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Shellac sealer and multiple coats of TruOil. I don’t think it is the finish but I have been wrong a couple of times. Just seems deeper to me.
Shellac with TruOil?..... I'm thinking that's the problem.... Try sanding it lightly with 220 until you get the finish off , and hit it with some polyurethane, or Helmsman spar varnish. I'll bet that it disappears. Kirk
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Shellac sealer and multiple coats of TruOil. I don’t think it is the finish but I have been wrong a couple of times. Just seems deeper to me.
Shellac with TruOil?..... I'm thinking that's the problem.... Try sanding it lightly with 220 until you get the finish off , and hit it with some polyurethane, or Helmsman spar varnish. I'll bet that it disappears. Kirk
X2 on the sand and refinish
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Show them the unbraced and fully drawn pictures that you posted on the other site. It may change some opinions.
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Ok will post some more pics. Didn’t before because these guys have seen them previously. Gents I appreciate all the thoughts and suggestions. I’ll keep shooting this bow to see how the experiment plays out. Also will make sure the defect is not just in the finish, which is TruOil on the glass w/ shellac used on the wood only to fill grain and seal before the finish.
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Shellac is great for a sanding sealer on wood, but doesn't work well on glass for some reason. i've never mixed those two before.
Only time i ever used tru oil on a bow was on snake skin limb finish because its soft and flexible. I could see using it on a wood bow too though... But.... The true oil is a high maintenance finish. It scratches easily, But it polishes out nicely with steel wool again. .002 cents
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"While nothing will stick to waxed (amber) shellac, the dewaxed stuff is practically a miracle finish. EVERYTHING (practically) sticks to dewaxed shellac, and it sticks to everything."
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Yes I make my own de-waxed shellac as I need it. Fills the grain, dries fast and is easy sanding.
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A bit late to this post, my apologies. Those white streaks indicate matrix (resin) failure. The white you see in the picture is basically glass fiber areas where the resin has disbonded from the fibers. While it sounds horrifying, you are most likely fine for quite a while (might not ever break honestly). You will see a full failure coming a long way off as it gets whiter and fibers start to lift. Just keep an eye out to see if it changes.
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EDB - thanks for that info! Rings true. I seem to recall your work involves using composites?
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Yes sir, aircraft composite manufacturing and repair
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:thumbsup: :thumbsup: I will continue shooting this bow to see how it holds up and will watch for further changes in the glass.
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Just monitor it every few shots for the next few months and compare it to the pictures after every session. No changes after a few hundred more arrows and you are probably relatively safe. I have a store-bought recurve with the same marks on it that I've been shooting for a long time.
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Damon Howatt Hunter 1991 I think
(https://i.imgur.com/91QnKNw.jpg)
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Mark - Wow, that’s a real gray hair! :thumbsup:
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Mark - Wow, that’s a real gray hair! :thumbsup:
I'm sure yours will get there too :tongue:
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:shaka:
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Well at least with black glass you can paint it and clear coat it …. It’s really sad when it happens to clear glass and it ruins the wood veneer look. Kirk