If there were 2 bows , equal core stack but one with .040 glass and the other with.050 glass what would the performance be like between the two. Also if one had 2 bows equal draw weight but one with .040 glass and the other .050 glass, which would have the better performance given that the draw weight was not extreme for the size of glass.I do understand that at some point glass can overpower the core, and conversly in another example be thin enough to compromise the core . I hope this garble is understandable.

I'm not 100% sure, but I'd say with equal stack, the one with .050 glass would be a heavier draw weight and thus have greater cast.

Now the two bows of equal draw weight but different glass thickness, my guess is the one with 0.040 would have greater cast since the limbs would be lighter.

...just some guesses here and I'm sure one of the professional guys here have actually done this for an empirical comparison.

Thanks for your reply John. Looking for more input as well.

Bob...........

On my R/D longbows I have found with the design I use .040 on the back and .050 on the belly gives me better performance.

Thanks Jamesv. Belly would need more glass to allow for compressive forces I guess, but at another guess your R/D bows would follow a slightly different force draw graph to my straight laid H.H types.Do you have a rule of thumb % wise as to glass versus core stack. I vaguely remember something about 20% - 25% glass to core. would that be right. I have made 2 recent bows One has .040 glass front and back at 40# @ 28", the other has the same glass but is 56# @ 28". these are lamboo cored HH bows 68ntn and 16" risers. Is the heavier bow underglassed? I havent shot it much at this time.

20-25% Glass to core ratio is what you should be shooting for.

Thanks tenbrook. Good to know that ratio. gives me some specifics to work within.