Ask the Expert Question-and-Answer Archive

by Ron Joseph

October, 2004

Paint Peeling Off Concrete

Q. We use a satin (40% shine) NC clear to finish on solid red oak table tops, but gloss obtained after drying for 3 days, are not consistent. Even on a same piece of table top, the shine obtained after curing can vary from 12% - 32%. Is this a normal feature when finishing over solid oak? We apply a glaze and sealer before putting on the topcoat.

I'm assuming that when you say N/C clear, that your referring to a clear nitrocellulose lacquer.

It is not unusual to see a gloss drift after three days of drying, (depending upon the formulation, and solids content) however the variance should not be as great as you describe.

It sounds to me as if the glaze maybe the culprit. The amount of glaze that is left on the surface will have an effect on the overall gloss. If you create uneven film thicknesses over the surface of the table top, these inconsistencies will show up in the topcoat as a difference in appearance and sheen.

The glaze is higher in solids content than a stain, and will create a higher build when applied and allowed to remain heavily. The gloss will appear higher in these areas where the glaze remains heaviest. If the glaze is not allowed to dry and is over coated too soon this may also have an effect on the appearance.

In order to maintain the current appearance and color scheme, you may consider the application of an additional coat or two of sanding sealer.

By building up consecutive coats of sanding sealer and locking in the glaze, this will allow you to flat sand the surface of the tables to a more even and consistent profile. After the application of the top coat lacquer you should notice a more consistent and even gloss.

Regards,

Jim Burke