I use gflex as well and have had to resort to similar "hardcore" methods to remove a scale. So I do like the product. I am "disturbed" by what Ed experienced. You don't request the time and effort of a company/business person to test your product and then fail to behave properly. To me that's very unprofessional and does "stink" of wanting an endorsement rather than a fair test.
To be fair, some of Ed's concerns are polar opposite from experiences others have had.
I would like to reiterate a few things:
I think BOTH west systems epoxies and acraglas are EXTREMELY reliable high quality epoxies that will meet or exceed performance expectations provided we do our due diligence with proper process and surface prep.
I talked with Brownells AND West Systems yesterday. BOTH were extremely friendly and helpful. BOTH clearly stated their shelf life. Acraglas lists in print over 5 years and the tech said 7-10 years. West systems lists 2 years for hardeners and 3 years for resins but said in reality its much longer than that, citing several anecdotal reports of 15 years.
NEITHER company was able to speculate on life of bond once cured due to a host of factors and BOTH claim they have never attempted to give any such hard numbers.
BOTH companies dismissed the idea of any epoxy being engineered to break down after a given time, rather insisting that once cured, it becomes inert so there is nothing to break down.
BOTH maintain that cured product is 100% waterPROOF for the life of the product. West systems is used extensively in boat building....makes total sense.
NEITHER line of products are high heat tolerant epoxies. Generally what's bad for one is bad for the other. Acraglas is not in a significantly higher heat tolerance category than west systems.
G-flex when warmed (as suggested in the instructions) becomes much more viscous and pours wonderfully.
I WOULD ENCOURAGE THAT NO ONE TAKE MY WORD OR ED'S WORD OR ANYONE ELSE'S WORD ON ANY OF THIS. If you have questions, call the companies yourself and get the answer right from source.