I think George has a good point here. A factor of 4 seems to be a lot to me. The only scarf joint I have ever had fail was the first one I did; I used saran wrap between layers and it got into the joint. After that I did several peices of scrap and broke them open to be sure I was comfortable with my work. Nothing scientific about it, but as I recall some broke easier than others... One in particular had not had enough epoxy in it. I now precoat, and assemble "green".

What was that book on composites? I have argued before that test panel data is way better than no data at all. I really would like to see George, Nick, maybe Jay, and Chris K submit panels of different layups to a lab for testing. Off the cuff, my bet goes to George. He has obviously done more research...

Not that that makes any others bad, mind you. The goal here should be to develop "standard" techniques with a known range of results (better than a factor of 4...). Aircraft builders do specify how thier material is to be tested.

> I read a lot of posts on this issue, but I never see one item come out of
> it that seems to me to be obvious.

> Do S & G kayak builders have joints fail on finished boats? We can
> argue all day about strength and joints and the like, but if the don't
> fail in the field why the fuss? If they do fail in the field, then we
> might have an issue.

> What do some of you users have to say about this?