Basecoat Hardener


I always use hardener in my basecoat. (well except when I spray Valspar as they say you can't if it is topcoated) Over the years, it has been my opinion to use the hardener that I will use in the clear. I have used a dedicated basecoat hardener like Diamont BCH2 in Diamont base. Last week the PPG rep stopped by and said I should be using a "primer" hardener in my basecoat....I'm sure this has probably been addressed here on the forum before but I don't recall seeing it. Maybe Barry could chime in with his opinion? What is the best option for catalyzing base?


Paint Fanatic
Staff member
Well maybe maybe not but why chance it?
If you look at the msds sheet on the BCH1 the iso main one is the "main one" used is all iso clears in this industry.
Now some primers may use an " aliphatic" iso and the "aliphatic" is key.

I go with safe as can't second guess what other company's are making so for years I have said "Any automotive clear-coat activator at 1 oz per mixed quart of base.