Ok, so I restore vintage Italian scooters, and am currently prepping a bike for paint. Several years ago, I had a color match done at my local Sherwin Williams Automotive paint shop. The system was Acrylyd HS 3.5 Urethane Single stage. I am using the remainder of the paint I had mixed several years ago, the problem is that I need to purchase the hardner (AH 390) for this Acrylyd system, but the paint line is no longer being produced.

I need to find out if anyone knows of an alternative hardner and reducer that I can use in this paint. Can I just use another single stage acrylic urethane hardner, along with a urethane reducer? Please help! Thanks in advance.

Guido