Layer of Biax?

[mtnrat]

Just finished bedding, filleting and glassing in my stringers. I have read in a few threads that when using 6" biaxial tape and epoxy I only need to apply the one layer of tape to glass in the stringers? I have read with using epoxy that it is very strong. I am using systems three silvertip epoxy. Do I need to use more layers as when using polyester resin or am I good to go?

The first pic shows before wetting out.
The second shows after wetting out.

[kengrome]

Biax comes in different weights and different fiber orientation patterns so it will help if you tell us the specifications of the biax you're using. The number of layers you use will depend upon which product you're using, how you're using it, and what your goals are ...

If your goal is to bond two components together where they meet along a linear or curvilinear joint it is best to use +45/-45 biax tape because all the fibers will cross over the joint -- and you want as many fibers as possible to cross the joint in this application.

On the other hand, if you are trying to strengthen a structural member longitudinally it is best to use 0/90 biax since typically 90% of its fibers are oriented lengthwise and only 10% are oriented sideways -- and it is the fibers running the same direction as your structural member that will strengthen it most.

Installing stringers usually means you want to accomplish both of these goals, so naturally it is "best" to use both types of biax, each one for its specific characteristics, although I'm not convinced that most shops will bother.

[mtnrat]

Thanks for the reply I am using 45/-45 12oz 6" biax tape. I already decided to tab in another layer but dropping it about 1.5cm down from the first layer so it spreads out on the hull a little further. Just finished up.