Repairing a contaminated USL Finish

[Tim Malyszko]

Last night, I was spray finishing some barrister bookcases I built using Target USL Gloss. The finish looks great, but there was obviously some sort of contaminate either in the air or in the gun because when I touch it (especially the horizontal surfaces), it feels very rough.

On other finishes, I would just use 0000 steel wool or 400 - 600 grit sandpaper to remove the roughness, thoroughly clean the surface and apply another coat. I haven't however, had to 'fix' a spray USL finish yet, so do you have any recommendations?

Thanks in advance.

[Jim Becker]

You can sand USL with a non-stearate abrasive paper. Use a sanding block for the flat surfaces to level things. If you feel that the surface may be contaminated, consider spraying a coat of de-waxed shellac as a barrier coat before shooting more USL with a thoroughly cleaned gun. (Use lacquer thinner and do it outside) You may want to spray some test coats on scrap to be sure that the finish, itself, isn't contaminated.

[Joe Chritz]

It could be like the top for the hamper I just finished. I turned on the exhaust fan (which normally has insulation in front of it) without moving the insulation and got a metric truck load of crud on the finish.

I always scuff sand to remove nibs and just a bit extra took care of it all. Next coat went on like normal.

For sanding finishes I really like a sanding sponge. Usually 320 grit 3M sandblaster version from the green borg.

Because of the burn in properties of USL you really have to work to mess it up beyond repair.

Jim is correct in that if the contaminates are anything but normal dust you should use a barrier coat.

Joe

[Tim Malyszko]

Thanks for the replies. I'm fairly certain the contaminates are just dust as my spray booth resides in the same room as the boxes we store our Christmas stuff in. I was moving stuff around getting to the boxes just before spraying and I'm pretty sure I knocked up some dust, which eventually settled onto the finish.

[Tim Malyszko]

Just to update...

I lightly hand sanded the bookcases with 600 grit paper, cleaned the bookcase and shot 1 coat of USL. This morning, I checked them and they were smooth as glass. Now I just need to finish the glass doors and I can check this project off the list.

Thanks for the help.