Coppercoat – The Complete Process

[Elessar]

Re: Epoxy coatings (either before CC or normal A/F)

Thanks a bunch, Elessar! :encouragement:

Just a couple of last (hopefully... ) questions...

1) I googled a bit in the meantime for 3M epoxy & Coppercoat to find the exact 3M resin type, and I found several references to GP120, but apparently that's mostly meant for steel hulls.
Is there anything else which is better suited for GRP?

2) What would you suggest as a filler for minor repairs, before the 2 epoxy coats?

TIA!

yep I'm pretty sure that's the one they use.

I used to use a bit of the epoxy itself mixed with something like west system 409 microspheres in it because it's easy to sand. If its a corner or something use something harder like colloidal silica.

Once you've done the first coat it will often show imperfections you've missed, you can fill between coats too it will all bond together. (can't sand between coats though it won't be hard enough)

 

[MapisM]

Re: Epoxy coatings (either before CC or normal A/F)

Good to know, thanks again.
I'm just a bit puzzled by the "easy to sand" reason for using as a filler the same 3M stuff (GP120) with microspheres.
Do you mean that after using that as a filler, it's better to let it cure completely (i.e. for much more than just one day, I suppose), then sand it before going ahead with the two coats of pure epoxy (followed by CC) one day after the other?

I mean, it seems to me a sort of catch 22:
if you don't let it cure completely, you can't sand it.
But if you let it cure, you must sand it before the following coats...

 

[oldgit]

All revealed ?

All to be revealed this weekend, boat on blocks.

Coppercoat merely needing a few mins pressure wash off and a gentle abrade ..
or
or has the Coppercoat been overcoated at some point and hence a grotty morning recoating with evil standard A/F in prospect ...

Still, joy of joys, no anxious peering to see what has exactly gone wrong with any outdrives on this boat.

 

[Elessar]

Re: Epoxy coatings (either before CC or normal A/F)

Good to know, thanks again.
I'm just a bit puzzled by the "easy to sand" reason for using as a filler the same 3M stuff (GP120) with microspheres.
Do you mean that after using that as a filler, it's better to let it cure completely (i.e. for much more than just one day, I suppose), then sand it before going ahead with the two coats of pure epoxy (followed by CC) one day after the other?

I mean, it seems to me a sort of catch 22:
if you don't let it cure completely, you can't sand it.
But if you let it cure, you must sand it before the following coats...

yeah if doing it before the first coat, let it cure and you can sand it. In warm weather it may be ok same day. If it clogs your sandpaper use a hairdrier on it until it doesn't, epoxy curing is temperature related. Pros use a heat gun but you have to keep it moving fast and be very careful. All depends on the damage, pinholes you'll get right without sanding probably. A bigger thing or a corner and you'll want to shape it.

 

[MapisM]

Re: Epoxy coatings (either before CC or normal A/F)

All understood, thanks again.
Coming to think of it (and having in mind the very minor repairs required), I would think that a skilled operator with a putty knife should be able to make a job smooth enough to not require any sanding at all.
Time will tell, that'll be a spring job, before relaunching...