Here's one of 200-something listings on Amazon. 8 ounces of hardener will treat at least half a gallon of paint. I used to use a pint per gallon of unreduced paint back when I managed a body shop. It's listed for acrylic enamel, but it also works on the older style alkyd enamel. Once it's mixed, leftover paint must be used- - - -not stored, so only treat the amount you intend to spray
https://www.tractorsupply.com/tsc/product/majic-catalyst-hardener-clear-half-1-2-pint
