Originally Posted by
HarryC
A few years ago when i got my first tube of Hysol I did a little test of it in compariosn to Devcon 30 minute epoxy. Using each glue I stuck a piece of 1/4" balsa end on to a piece of epoxy glass board, and left them for a couple of days. I then pushed the top end of the balsa stick to see how much effort it would take to either break the wood or the glue joint. The devcon joint snapped cleanly away from the board with just a little force taking a perfect imprint of it and leaving no devcon at all on the board. It had barely stuck at all The Hysol required a lot more effort and tore very thin bits of the board surface with it. Therefore in my experience Hysol sticks to fibreglass much better than normal epoxy, it isn't simply epoxy with thickeners.
Does not surprise me one bit, that's what I would expect.
Hysol is just a brand name - but of a line of well formulated adhesive systems from a competent commercial manufacturer. Chosen correctly for the application I would expect them to consistently meet or exceed the properties of anyone's System X, 30-minute wonder bond, or other general purpose retail systems.
There are different base epoxy resins, reactive and non-reactive diluents, coupling agents, rubber modifiers (tougheners), wetting agents, bla bla,
plus the the thing that you never see in these types of forum discussion is the fact that there are choices in curative chemistry (not just reaction time) - it takes two to tango in a two part system. A lot of your retail grade xx-minute epoxies are simple resin downpacks with a blend or neat downpacked curative. I don't suggest this is a universal truth but it applies in many cases. And this is why, although those systems will work for almost anybody and have decent properties, they are nowhere optimum for many uses. The truth rears its head in situations that truly challenge the material properties. I'd say the vast majority of epoxy bonds that ever fail in modeldom are due to misapplication or inadequate surface prep.