How do I know what body filler is safe to use with the primer/top coat I am going to use/ In this case it would be single stage urethane top base. And I am assuming that depending on the body filler type, would determine what type of primer and top coat to use?
Thanks in advance.

Read the tech/spec sheets for your products.

But pretty much any of the good fillers can be top coated with the current paint systems.

Use a sealer or epoxy over your filler and you are usually good to go.

What is your project? Experience? Tools? Expectations? - Photos help

Do your research first, including pinging this board's experts - they have years and years of knowledge that they share - a little research will help save lots of money/time.

Don't worry about asking a dumb question, but do read first. I have already asked most of the dumb questions over the last two years and they haven't kicked me off this board (yet!)

He gets one more day
Jay D.