Scum line on Bottom Paint

Tug · Posted: Mon Oct 03, 2011 3:26 pm Post subject: Scum line on Bottom Paint

How do you remove the scum line on the boats' bottom paint. Once i tried just washing it off but that didn't work at all. Do you lightly sand the scum line off and than re-coat or just apply a new coat of bottom paint over the scum line. Thanks Tug

Sea Wolf · Posted: Mon Oct 03, 2011 3:34 pm Post subject: Re: Scum line on Bottom Paint

ferret30 · Posted: Mon Oct 03, 2011 3:50 pm Post subject:

Assuming it's just discoloration and not an actual build up, try a compound like 3m color restorer. I ordered Starbrite hull cleaner online for that purpose (oxalic acid), but while I waited for that to arrive I realized it came off easily with a light compound. Starbrite is nice since it doesn't require any abrasives, but it's harmful to bottom paint and galvanized trailers, so it requires masking, tarps, etc.

Tug · Posted: Mon Oct 03, 2011 5:14 pm Post subject:

Thanks for the information, will try that.Tug

thataway · Posted: Tue Oct 04, 2011 12:22 am Post subject:

Use the scotch pad--not the starbrite (oxalic acid) hull cleaner or 3 M color restorer (that is for gel coat--not bottom paint. A lot depends on what bottom paint you have used. Many copper based paints oxidize and there will be a very pronounced line. That may not come out as well as a scum line. Also bottom paints like Vivid clean up very well with the pad.

ferret30 · Posted: Tue Oct 04, 2011 1:41 am Post subject:

Oops, I thought we were talking about the scum line right above the bottom paint, not on the bottom paint itself. Sorry.