Plastic Sealant

I am searching for a plastic sealant that will seal plastic onto plastic. I paint flowers and designs onto plastic cake plates, etc. I need to seal over the plastic so it won't wash off. Can you help me?

You could use a clear spray paint, lacquer or whatever. It sounds like you need to protect the painting from the cutting knife. If this is the case try using floor polyurethane, epoxy or casting resin. The last two require you to mix two chemicals together (two part) for the epoxy I'm referring to a container not a little glue bottle. Hardware stores or boat stores should have what your looking for. Epoxy is the best and most $$ the Poly is probably the easiest. Any of the cured plastics are food safe