I'm trying that right now. We made our own "copper coat" and launched last September. It hasn't been long enough to say much, but we had barnacles
all over the "control" area, on the sterns, and so far nothing on the hulls, which have been covered in our copper concoction. Mind you, we're in Halifax Nova Scotia
, so we haven't even had a summer yet. There is some slime, which I understand is normal for Copperbot too.
Though, as I said, the "control" area was quite infested, so I'm hopeful. I'll not share our formula, or our methods, until we know it works. Then I'll be happy to share.
It was quite labour intensive to do. It was polished like a new copper penny, for about 2 days, when it turned brown, like an older penny. It has never turned green though, which is interesting.
I'll not argue the fact that it's expensive. It cost us about $1000 US in copper alone, not counting the "special" resin, which is not water based.
However, I'm just that kind of guy who has to try it, when folks tell me it can't be done. If someone else has done it, I'm pretty sure the rest of us can too. If it works, it will cost us about half of what Copperbot would have. If it doesn't, I'll be giving Copperbot a try.
Cheers, and good luck.