go Sam and Nick!

Posted by LeeG on Jun 28, 2005

that's great. Carbon is weird stuff. It's surprising to see that a glass/ply/carbon layup failed at a lower load than glass/ply/glass of a similar weight but it's close to what I saw with the test panels. So much stress would get dumped at the edge of the carbon and ply that the woods ability to transition slowly in a failure was wasted next to the carbon which concentrated the stress in one area. The result would be ply totally delaminated next to unbroken carbon,,or carbon/wood totally fractured with a razor sharp edge. In a sense it was pre-disposed to fail where there wasn't any carbon to a more noticable degree than glass/wood transitions.

I bent a test panel that had 4oz s-glass on both sides to a C-shape without it fracturing through. 4oz e-glass would fracture completely, 6oz e-glass would bend less before fracture but also fracture completely. I'm surprised that the fine weave s-glass did poorly compared to the 5oz fine weave e-glass. I would want to see another test with another batch of cloth before drawing conclusions. I have heard varying opinions on age/storage affecting s-glass.

Note to folks thinking of using fine weave 5 oz E-glass,,I've read more than one person who had a hard time wetting it out which is NOT something you'd want to experiment with on a cold building day. The 3.25oz isn't hard to wet out although it takes more care than regular weave e-glass. There's a reason why 6oz e-glass is ubiquitous,,it's easy to wet-out, it's thick enough for repeated bumps and abrasion, it's tough and cheap. For ultimate weight/strength lay-ups I'd look to 3.25oz fine weave e-glass and 4oz s-glass LONG before thinking of spending money on carbon.

In Response to: Re: continued by J.Schott on Jun 27, 2005