Speeding Up Acrylic Enamel Curing

Q. I was penny-wise and pound foolish and sprayed acrylic enamel a few days ago without hardener. I didn’t think I really needed the hardener since the acrylic dries in a few hours but I didn’t realize it doesn’t get hard until it cures, which can take a long time. The finish looks good but is still a little soft, but it is dry. I believe acrylic cures by absorbing oxygen from the air instead of curing through evaporation of the solvents. I’ve read a few things off the web and it’s not really obvious to me if I can speed up the cure time of the acrylic enamel.

Can I use a fan to help the paint absorb oxygen? Can I use heat to speed up the chemical reaction that occurs during the curing process? Can IR lamps speed the curing time of acrylic enamel better than simple heat? I’m getting a little desperate. Thanks for any advice you can share. C. F.

 

A. Since Painting Clinic is not the forum for discussing paint curing mechanisms we will not go completely into them. However, you are wrong about acrylics drying by reacting with oxygen in the air to form a crosslinked film. Therefore, the film will not cure if you use a fan to blow oxygen-laden air over it. Basically, without knowing its chemistry, I don’t know if heating the film will cure it. You can certainly try heating. I don’t know what you mean by simple heat, but I do know that IR lamps are used to heat and cure films. Again, without knowing the chemistry of the resin in your enamel, I can only say, in order to cure, it must need to react with the other component, the one you did not add.

This brings to mind an incident that occurred during the time when I was the paint consultant at Westinghouse Research Labs. There was a frantic phone call from a manufacturing engineer who said they painted the inside of some circuit breaker tanks the week before, with epoxy paint, and it was not dry. You guessed it, they did not mix in the hardener.