Builders' Forum Archives
Re: 6 oz or 9 oz for fill
Posted by LeeG on Mar 17, 2006
no prob,,If I recall correctly the A.Hawk has only fillets in the cockpit and no glass,,some builders have used only 6oz cloth on the inside over small fillets.
Quite a change from the early CapeCharles/Patuxents that instructed one to lay down TWO layers of 3" 9oz tape and NO cockpit cloth.
When I built a Patuxent 17 I took the instructions literally,,when it said exterior tape on the chines was optional "for rough use" I put it on. Between the two layers of tape on the inside, cloth on the outside and tape on the outside,,it was one heavy boat. But with no cloth in the cockpit it still developed waterstaining cracks even with all that armor on the chines.
This is a roundabout way of saying that with 6oz on the outside, and the thick fillets with tape over them I doubt there's any problem. Now if you made the fillets 2" wide and put on 1 1/2" tape the weight of the tape would be irrelevant.
I bet you could put on 1 1/2" 6oz tape over 1/2" fillets and it would be strong enough. If in doubt make some test joints and smash them. You'll find that the failure won't be in the joint but at the edge of heavy reinforment next to no reinforment.
For example I made two chine test joints, both with medium width 3/4" fillets, one joint made with glassed panels and 4oz 2" cloth strips over the fillet, one made with unglassed panels and 4oz cloth over the fillets.
The wood failed when the panels were stepped on. On the unglassed panels it was at the edge of the cloth reinforcement over the fillet, with the glassed panels it was over a larger area but it took more to break the wood. In both cases the actual fillet never broke.
In Response to: 6 oz or 9 oz for fillets by Ted on Mar 16, 2006