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Bertram31.com General Bulletin Board
Re: Epoxy *LINK* *PIC*
Posted By: Capt Partick McCrary In Response To: Epoxy (Harry)
Date: Tuesday, 21 March 2006, at 9:53 a.m.
Harry,
Gougeon/West is undoubtedly a fine epoxy but you're paying a premium for the name and their marketing costs... There are numerous other epoxy systems that don't carry such baggage. MAS, System 3, & Smith to name a few other brand names.
The biggest savings will usually be had by using a generic epoxy.
The key factor in selecting an epoxy is to make sure that the resin is labeled 100% solids. "Cheap" epoxies are often cut with other fillers or chemicals to expand the volume & make more profit for the seller.
There are only a couple of US chemical companies that make epoxy resin & every US brand of epoxy comes from them. Hardners are produced to meet the specific demands of the epoxy suppliers, (MAS, System 3, & Smith, etc). These demands will also dictate the mixing ratio of resin to hardener. The lower the ratio, the more forgiving the mix will be.
West's 5:1 ratio yields a higher grade mix by diluting the resin less than a 1:1 ratio, but makes mixing very critical. Too much of either the epoxy or hardener can cause an incomplete cure.
I prefer a 2:1 ratio which is easily mixed by eye, (no pumps required), and also allows me a wider latitude to purposely mix off ratio if I want a harder, more brittle cure or a softer, more flexible cure.
Beyond 100% solids, the other factor in selection is what your intended use is. Layup resins, while still 100% solids, are thinner to better wet out fiberglass cloth. Bonding/laminating resins are thicker & won't soak into a substrate as readily.
Check with your local fiberglass shop, if you have one, to see if they offer their own "House Brand", (generic). If you don't have access to a local supplier, there are numerous sources online. I use two suppliers in West Palm Beach, FL and only use their generic brands with never a failure due to the product in over 18 years...
The one with the best online ordering is Shop Man/US Composites linked below. For fiberglass layups use their 635 Thin resin, (2:1). For bonding/lamination, (gluing two pieces of wood together), use their 150 thick resin, (1:1, 2:1, 3:1, or 4:1).
Cost comparison of US Composites prices between West & generic:
1.25 gal kit of West $93.10 ($0.59 per oz)
1.5 gal kit of 635 2:1 $90.45 ($0.47 per oz)
Savings of generic over West: 19%Br,
Patrick
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