I had no idea what to use, but after a bit of checking I found that I could use acrylics if I sealed it properly with an outdoor varnish. He was told he may have to put on a new coat occasionally if it started looking worn. The pieces would be protected by a roof so they would get little exposure to the elements.
He was thrilled, and as far as I know he has had no problems, that was about 15 years ago.


