Hi guys,
Been skinning for quite a while but now I've stumbled onto something new. I was doing a pair of doorsills using 400 gsm cloth. I applied the first coat letting it go to a full cure and then applied the 2nd coat ( epoxy laminating resin + fast type hardner) with sanding cause I felt the first layer may have been too thin.

2nd coat went for a full cure and then I started wetsanding it ( 400 grid ) After getting it all even, I saw white marks all over the panels, nothing new but this time they remain visible :-( Wiped it down with acetone but even then I can still see them .. Do I need to sand down even more or did something go wrong here ? Please advise :-)

I would tend to agree, but the first layer was fully cured (24h), and I didn't sand it.

Ahhh .. there's the problem ...  You did not sand or "key" the first fully cured coat of epoxy...

While a very pure epoxy like the EC coating stuff, will bond very well to itself, even with no sanding or keying, this is not the case with most laminating epoxies.

What you probably had then was unbonded areas under the second coat ... only cure is to sand through it ..

Good luck with the new coatings,,,



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Never had a problem before doing it that way, but I always used West Systems before.. ah well, gonna take the advice and give every fully cured layer a good sand from now on thanks