Painting - Painting old ceiling tiles

I have alot of old metal (tin?) ceiling tiles and have been experimenting with different painting techniques. First, I put on a base color, then a second color, then sand certain areas so the base color shows through. Does anyone know if I should do something else before the 2nd color, like an oil or wax-so the sanding doesn't immediately take off both coats?

Then I used a bit of burnt umber with a glaze to antique it a bit, then a matte finish-

any ideas???- I'm just flying by the seat of my pants, as usual!

Pat :)

Hi there,

One thing to try is use either an acrylic or alkyd oil under the last coat with a satin/eggshell sheen. When you sand through the first coat, the sheen of the under coat may provide you with adequate durability to withstand the sanding. If the bottom coat`s sheen is visible, lightly sand it with a very fine sand paper or block it (water sanding)

The key is your first coat.

Best Wishes

The Quick Reference Paint Recommendation Guide---The Pocket Painter

thanks so much-I'll try your ideas-
Pat