For what it's worth the biggest rocket I've seen that was glassed was an "Ultimate Endevour", at 6" diameter by 108" long, that was built by a friend of mine. It had two wraps of 6oz. fiberglass, no veil, and finished quite nicely.
As for attaching the fins he used his standard method of glassing the inside of the fin can. To do this you cut the fin slots **only** the length of the fin, not completely to the end of the tube. You then glue the forward centering ring to the MMT and glue the assembly into the rocket with the rear centering ring being left loose upon the MMT. The rear centering ring is only used to center the MMT in the airframe until the epoxy on the forward ring sets up.
Once the forward ring and MMT is glued in place you insert the fins through the slots in the airframe and glue the root edge of the fins to the MMT. Now cut a piece of fiberglass cloth as long as the length of the fin root and as wide as the sum of the distance between the MMT and the airframe and the distance between the fins measured along either the inside of the airframe or the outside of the MMT, depending on which joints you are reinforcing. You need to do both, one at a time of course.
Soak the fiberglass reinforcement in a good epoxy like "West Systems". Now it gets a little tricky. You take the well wetted fiberglass cloth and roll it up around a small dowell sized to reach to the front centering ring and still leave enough sticking out of the fincan to hold. Touch the cloth to one of the fins about 1/2 of the way from the MMT to the airframe and slowly unrap the cloth from the dowel forcing the cloth into contact with first the fin, then the MMT or airframe, and finally the other fin. When done the fiberglass cloth should look like a a square bracket "[" with the short legs going up the sides of the fins and the long leg laying along the MMT or the airframe. Repeat this for both the MMT to fin and airframe to fin joints for each of the pockets formed by the fins. This will completely glass the inside of the fin can and create a set of tremendously strong fin joint reinforcements.
Ken Holloway
