Ul or ULS glass

[Labasy]

Just wondering when it comes to glass what does everyone use, do you use the UL or the ULS?

Cheers

Glen

[Gringa Bows]

ULS most of the time

[woodie]

I'll ask, what is the difference between the two?
woodie

[Flatliner]

I only use UL glass, I have been told by Bingham's that the scrim in the ULS is mainly for lateral strength during construction, once its glued up in a bow it makes very little difference.

I'll ask, what is the difference between the two?
woodie

The difference is the UL glass only has fibres running in one direction (along the length of the strip) and the ULS has fibres running in both directions.

Cheers, Rob.

[woodie]

I see thank you for that.
Learn something new every day.
woodie

[bigbob]

because HH style longbows are narrow and deep there is little lateral movements from bending forces so UL Glass which has the scrim in one direction is safe to use but the wide thin limbs of a recurve require as much inherent strength as can be obtained due to the increased potential for twisting forces ,hence the unidirectional scrim comes into play. In short i ofetn use UL for longbows, and only ULS for recurves.

[Labasy]

Thanks Fella's

I knew what the difference was between the two but i wasn't sure which to use for what.

Cheers

Glen

[rodlonq]

I will only use ULS, it is not worth the risk to save few pennies.

[bigbob]

I will only use ULS, it is not worth the risk to save few pennies.

Me 3 Rod, especially for 'curves but do use Ul for longbows sometimes as the depth versus width ratio is much better.

[rodlonq]

Bob, I use ULS for longbows as well. Just in case there is a longitudinal weakness in the lamination, the scrim will keep it together. I have often wondered if the joints in the vertical bamboo are trustworthy, but discount any problem due to the stack being laminated and the joints are unlikely to line up as well as the scrim is doing it's intended job.

As a side note, there is a phenomenon called shear flow that shows not all shear stress in a beam is in the same direction as the applied force. Have a look at the diagrams at this website http://abe-research.illinois.edu/facult ... flow2a.htm and http://abe-research.illinois.edu/facult ... rflowa.htm for a brief explanation. A composite bow is very similar to an I beam in its stiffness characteristics.

Cheers... Rod