I want to paint my spindles on my stairs white,I already have 2 coats Clear Acrylic-Urethane Satin,thanks?

With this being an acrylic urethane you can get a product called ';Wil-bond'; it's a liquid deglosser, wipe down areas to be painted and paint, no sanding required. You must read the directions though for use because you only want to prep (wipe down) what you can paint in 30 minutes, how it works is it will soften that urethane for that long, once it starts to harden again it will take the paint and harden that with it so you get a good bond, saves the mess and hassle of sanding, any deglosser , liquid sand will due but I've been using the Wil-bond for over 35 yrs and find it to be the best, good luck Les the painter