I need some input

[kennym]

Seems I and some others have had some bows come in heavy with  Bearpaw clear glass. Has any bodies results changed?

I’ve been telling folks to add 5 if using but now I’m coming in 10 heavy , more than once !!

[monterey]

I thought it was that they could come in light??

My only comparison would be two identical bows about 1 1/2 years ago.  One gordons colored glass and one BP clear.  Identical stack thicknesses and the BP was about 4# lighter with both bows in the 40's.

Hope to hear more about this.

[kennym]

Yes, I was coming in light, but now heavy, maybe its something I did , but trying to figure it out.

[monterey]

Was the glass off a new ring?

[kennym]

Yep, two different ones came in heavy...

[Flem]

As a dealer, can you contact them directly and find out if they changed their manufacturing process?
It would be interesting to know if and what they might have done.

[kennym]

I have an email to my supplier but prob won't get an answer til next week, especially if he needs to talk to the factory.

[Flem]

I was just now looking at the Bearpaw website. The glass to resin ratio has not changed, unless they have not updated the info. But it does say that they changed the thickness from 1.2mm to 1.29mm.

[kennym]

Still checks at .040 on the dot

[Robertfishes]

Kenny, maybe you can do a flex test using the same hanging weight each batch? keep a log book just like your build book and maybe you can get closer??

[Flem]

Thats interesting. Sound like their QC need a revamp. 1.2mm=.047 and 1.29mm=.050.
Either one is way off from what you have in hand Kenny

[kennym]

I’ve done some redneck flex testing against Gordon’s Robert, but I don’t have any of the older BP on hand .

Flem , that is the thicker roll which checks at .050” but I don’t use much of it on my bows ...

[Shredd]

Just a wild shot but you could try weighing 2 pcs of glass...  Glass is heavier than resin... Could show if one has more or less glass in it...

[bigbob2]

All mine with BP mostly came in light,

[kennym]

Good idea Shredd, I will do that.

Bob mine were too until they weren't .

I'd seen some stuff about the bows coming in heavy but hadn't had anything but light til now.

I'm checking all my math and going back to notes from known bow weights I've built now.

[kennym]

The redneck flex test, 12” out from bench, clamped flat on bench with a board, both clamps same weight, both glass same dimensions, bp is the closer one and somewhat stiffer.

[Shredd]

Two other things could change stiffness...  The glass could have been under more tension when they produced it or the resin could be different...  There could be a list of other things also such as cure time and cure temperature whether the machine operator was out on a binge the night before...

[kennym]

Right on Rich, I have a spine checker made to check against Gordons as that is what I made my stack charts from. 

Sure nuff, the .040 is roughly 5 lb stiffer than Gordons where it used to be about 5 lb lighter.

The .050 checked exactly same as Gordons , and the Gordons is all real consistent between clear and color glass.

[Flem]

Did you ever weigh some samples Kenny? Like Rich pointed out, glass is heavier than epoxy, like twice as heavy.

[kennym]

I didn't yet, I was so much interested in spine I forgot, but that may go right along with the spine issue.