How to varnish/seal plastic planter
Didn't know where to post this so just trying here. Sorry if it's in the wrong place.
I primed some plastic planters with primer spray paint from the car section in Halfords. I then painted them with a couple of layers of copper acrylic paint.
What can I seal it with to ensure it's waterproof for outside use? I am not sure the acrylic paint won't wash off eventually if left like that. I have looked for varnish in the hardware shops - the varnish I found all said 'exterior' on it, so I thought it might be okay but they all seem to be for covering woodwork. Is there another varnish type I can use? I don't really want a spray, I want to put it on with a brush.
Thanks in advance.