I would not be surprised if the resin they are using is actually vinylester not polyester. They are very similar, but vinylester is much better than polyester. The epoxy they used was probably designed to be autoclaved - baked under pressure. This is a different epoxy than what we use.

vinylester may have applications for home-built, wood cored boats, but it is still not as good an adhesive as epoxy, so the bond to wood would not be as strong. It also smells just as bad as polyester and has all the safety concerns of polyester. While epoxy isn't exactly "safe" to use, the vapors are not as immediately harmful.

Some builders have experimented with post-curing epoxy by putting their boat in a hot space. This is said to increase the strength in some way, but it is not really the same thing as the pressurized, baked, cure of an autoclaved epoxy.

There is lots of room for experimenting with new resins and specialized manufacturing techniques in home-built boats. Any of the techniques used by professional builders could be applied to home-built boats. The thing about these techniques is they often require special equipment, or special skills. Epoxy on wood, is fairly straight forward, doesn't require too much skill or special equipment and works very well with a minimum of fuss. It is worth trying some of the materials and techniques used by commercial manufacturers, but realize you will end up having to experiment, and with experiments comes the risk of failure.

: I know of 2 European top racing kayak manufacturers, who are using less and
: less epoxy. They go for the newer polyesters that apparently are as good
: as epoxy. Also they are MUCH cheaper. Second thing is, WHEN they still use
: epoxy on a boat, they will ALLWAYS vaccuum bag it, and bake it (to some
: 70° Celcius) which will make it much more stronger and stiffer. Those 2
: professional boatbuilders (located in Portugal) will NEVER apply epoxy on
: a kayak without the procedure described above.

: Now, I can only speak for myself: I'm just an amateur in boatbuilding. But I
: would like to know if these techniques are of any use for us. And IF, I'd
: like some ideas have about how to enhance the final result.

: 1) I wouldn't risk to damage a stripped hull, just for trying polyester, but
: if they use it with succes, why shouldn't we use it on the strippers then.
: Has anyone tried it ?

: 2) I've read a small post in the past about vaccuum bagging a real small part
: of the hull (1 Ft by 1 Ft approx.). I think it should be possible for us
: to vaccuum bag the entire outer or inner hull.

: 3) I won't ask for ideas how to bake an epoxied hull.