FR wrote:
He said.........

I am using West system epoxy. The material is about 6 mos. old. I am
bonding over fairing putty that was used to level the surface prior to
putting the fiberglass down. It was a clean and course surface. The part
I don't get is that it didn't even stick to itself. I did some repair
work using this epoxy and DB1808 and it is solid as a rock.



You have discovered that the 6 oz finely woven fiber glass that is commonly
sold by "fiberglass supply houses" is terrible when it comes to adhesion
properties. I have found this to be true regardless of the resin type
Epoxy, Vinylester or Polyester.

I think it is attributable to the tightly packed and twisted tows used to
make the material. It does not allow for good saturation.

Next time use a DB1208 and you will get the same results as the DB1808 and
save a bit of weight. The glass mat sewn to the double bias strands offer
good saturation and great adhesion and a superior water proofing layer.

I know of very few "pros" who use this stuff in fiberglass work but for
some reason it seems very popular with do it yourselfers.

In 28 years of fiberglass boat building with five different companies I have
never used this product in a commercially built boat.

My advice is to stay away from it unless your are building model boats.

That's interesting, as I know literally hundreds of people that have
covered wood (S&G or strip) kayaks and canoes with 6 oz. fabric and
epoxy of various brands with zero problems. I've used it in multilayer
kayak repairs with zero problems. I suspect that there's more to this story.