Generally speaking...no offense to anyone that uses the stuff. People that use Marine Tex often don't take the extra time to study up on how to properly repair their damaged boat. MT is blobbed on like bondo, and it's expected to become a solid repair. Then down the line, after the hull has flexed for years and years, the MT still seems like it's hanging on, when actually it has cracked away from the hull half way around, allowing water to seep into the foam core. I have seen probably a hundred boats with leaky MT 'repaired' keel areas.
Hobie hulls flex. MT is as hard as a rock, therefore it cant make a solid, lasting bond. Eventually it will fail. It's so hard, in fact, that you can break out a tap and cut threads into it. A useful trait for other things, not so good for flexing Hobie hulls.
I'm on a crusade in three areas of 'The Hobie Way of Life'.
1) Why the heck can't trailer hitches all be 2"? I'm fixing that one trailer at a time!
2) I want to stop people from overspending for unnecessary materials for repairs. That means no epoxy when you're laminating glass. Read elsewhere in these forums for the reasons. I'm not getting into it now.
and... 3) (This one is kind of selfish.) I want every fiberglass guy down the road 20 years to not suffer the way I did on a bulk daggerboard repair job a couple of years ago. I had 12 H18 DBs here at the shop, and every one of them had MT on them. I underestimated the invoiced labor time by days, not hours, and had ended up grinding for 2 extra days. After I prepped and repaired the damage, I faired them and shot them all with about 10 coats of gelcoat, hot-coating the whole way. Unbeknown to me while I was spraying, the small scratches that still had MT in them were making the gelcoat not cure properly. I had to strip the uncured areas, grind them out and re shoot. Since the gel had PVA on it, I had to resand the entire board to make sure that the new coat of gel stuck. Took 4 extra days.
I should've read the MT website a little more carefully:
Quote:
How to apply gelcoat over epoxies (Marine Tex):
-Applying polyester resin (like gelcoat) over epoxy is very tricky and must be done extremely carefully. The smaller the repair, the easier it is to coat epoxy with gelcoat. The larger the area, the polyester will be more difficult to work with and more likely to malfunction (not cure).
Just thicken some gel, catalyze, fill the scratches, cure, fair, buff. It's just as easy.