I've just about finished my first "A Pack" of West System epoxy, and since my Dad was passing by the shop, that's only open when I'm at work, I asked him to pick up more of the same. He came back with a pack of SP.
I presume this is pretty similar, but is it identical? I've got used to the handling characteristics of the West stuff now. I'll also want to swap the measuring pumps over from the old containers to the new - will they a) fit the thread and b) avoid any undesirable reactions as the new product meets the old in the pump?
"Pete Verdon" wrote in message news:hl1r25$u1l$ snipped-for-privacy@news.eternal-september.org...
I suspect measuring dispensers will not be compatible between competing manufacturers. The product might be similar or identical. However, West's headline banner would put me off their products for ever: Perfect Epoxy for an imperfect world. YMMV
TBH I prefer SP to West. I tend to use the low viscosity, long cure SP products because I'm working with plywood and flow coating it. I've not found any West product that equals SP for penetration of wood. There are items that I have made in WBP coated with SP epoxy and finished with International Crystal varnish that look like new ten years after I made them, and after ten years of exposure in a marine environment.
I doubt if you'll notice much difference in handling characteristics between the two.
What's "SP" - a different brand? If so, then it's not a good idea to use one brand of resin with another brand of hardener. Even if the "part A" was formulated using the same type of base commodity resin, the maker may add different reactive diluents etc to adjust viscosity,or they may use a completely different resin type, and that changes the ratio for mixing. And talking of mixing, then these two pack epoxies rely on correct stoichiometric ratio to achieve maximum mechanical properties when cured
- the correct ratio is very important. Too much resin, and the epoxy cures too soft/flexible. Too much hardener, then although the resin seems to cure hard and a little faster than usual, there's unreacted amine/amide left in the otherwise cured resin. That draws in water, so in any case but especially below the waterline, it eventually goes cheesy or causes other major problems. So if you bought matching packs of West System, and find out that you've run out of one component before the other, then you need to ask yourself why that might be.
If the "SP" is a different brand of resin, take it back and exchange it for the right stuff.
We built our YM "Wild Duck" with SP systems epoxies of various types. We had no problems at all either with the coating or the gluing properties, and we are now approaching 25 years on.
I've done a few repairs with West systems simply because it's easier to find locally. Seems very similar.
Some points. It's worth finding a decent supplier and finding what materials are available. We had to order some of the fillers and "diluted" paint type products for some uses. At that stage SP systems were extremely helpful. When I had the chance recently to buy a small pack of SP, I bought that in preference to West.
I don't know about the dispensing systems. I always used syringes. I assume the OP was referring to using the same dispenser for west vs SP hardener and West vs SP resin. I have re-used syringes between brands like this, and it doesn't seem to matter, but I would change to new dispensers for anything important.
I've used both on my plywood dinghy for repairs and found very little difference between them other than colour, the Wests tends to be clear and the SP is a little yellow. They both do a similar job in terms of wetting out the wood . I've never used dispensers so can't answer that question. I go by eye and it's always worked for me.
I've also coated my hull prior to putting Flag Copperquick* on it and used both Wests and SP and once again so no difference at all in terms of adhesion or coverage - the only difference being colour.
*Under no circumstances consider using Flag Copperquick. You end up with a wonderfully burnished hull that turns slowly green and is very attractive to both barnacles and the weed that grows on barnacles that looks like blond pubic hair. I contacted Flag and they agreed that it doesn't work and suggested I should be using their premium abrading anti fouling.
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