About that Blush

[Rod Thompson]

After an epoxy surface has cured and any potential blush has been washed off does one have to wash again if any amount of time has passed before the next coat (paint or epoxy) is applied.  Intent is to apply the next coat soon after the wash but sometimes the best laid plans go aground.  I guess I'm asking if the amine blush continues to come to the surface over time.

[Greg Luckett]

From West Systems:

"Cured epoxy-Amine blush can appear as a wax-like film on cured epoxy surfaces. It is a by-product of the curing process and may be more noticeable in cool, moist conditions. Amine blush can clog sandpaper and inhibit subsequent bonding, but it can easily be removed. It's a good idea to assume it has formed on any cured epoxy surface.

To remove the blush, wash the surface with clean water (not solvent) and an abrasive pad, such as Scotch-brite 7447 General Purpose Hand Pads. Dry the surface with paper towels to remove the dissolved blush before it dries on the surface. Sand any remaining glossy areas with 80-grit sandpaper. Wet-sanding will also remove the amine blush. If a release fabric is applied over the surface of fresh epoxy, amine blush will be removed when the release fabric is peeled from the cured epoxy and no additional sanding is required.

Epoxy surfaces that have not fully cured may be bonded to or coated with epoxy without washing or sanding. Before applying coatings other than epoxy (paints, bottom paints, varnishes, gelcoats, etc.), allow epoxy surfaces to cure fully, then wash and sand."

I say better to wash again than take a chance.

[Rod Thompson]

Thanks for the clip Garry.  Makes sense to be cautious and wash down before the application regardless of what went on before.  As it turns out I did get directly to the next coats.

Weave is now filled.  Only issue is some pinholes in spots.  Not a gas thing.  The west system guide says it is a surface tension problem over abraded fiberglass or epoxy.  The fix is to force epoxy into them with a stiff spreader held at a low angle.  Ever dealt with that before?