Does anyone have recommendations for what to do if my underglaze has little pinholes? I'm applying to leather hard greenware, and watering down my Amaco Velvet underglaze about 1:3 (water:underglaze).

Is this after bisqueing? If it's after bisque and you have not fired to your final time yet, I would sand down with 100 grit sandpaper and then 200. If you have not fired at all, I would use a 400 grit sandpaper or those Scotch green scrubber things, then reapply another coat.

On occasion, I have had the same situation with Speedball underglaze. Mostly when the area I am covering is textured. Try rubbing your finger over the dry underglaze. If it’s powdery enough it will pick up the underglaze and spread it around a bit allowing you to try to kinda pack the underglaze into those shy areas. I don’t know if the velvet underglaze will work the same way….you’ll have to let us know.