How can I reduce drying time for alkyd paint?

Question

Watching paint dry is a metaphor, but it is really true. It seems to take a long time for it to dry, especially in a humid climate.

I am trying to paint a piece of wood and I have literally been working on this for 3 days and I have just finished the primer, now I am facing at least two more days for the paint. Is there any way to hasten this process?

What happens is I apply the first layer of primer, it takes about day for it to dry. I then sand it, which causes bare spots, then I paint another layer of primer. I wait another day for it to dry. Then sand again, some more smaller bare spots. Paint another layer of primer. Wait another day. Sand again. Block is ok and ready for painting.

I tried putting the block in a microwave oven for 30 seconds. The block got hot, but it did not really dry. The paint was still tacky.

Is there any way to speed up the process?

BTW I am talking about alkyd paints, not latex.

Answer 1

For oil-based paint, what you are looking for can be called a hardener, accelerator, catalyst, drier, and I'm sure other things.

Paint (coatings) chemistry is complicated. With oil based paint, I find a more helpful mental model of the "drying" process is less the liquid drying/evaporating away, and more of a chemical reaction happening to make a polymer (plastic if you would).

Japan drier is an old-timey product, readily available in your regular hardware store that is supposed to be used for this. Getting back to the "paint chemistry is complicated part," it is strictly best to use a product recommended by the paint manufacturer as compatible.

Valspar and Majic both sell hardeners that speed drying time, intended to work with tractor/implement paint, which are pretty basic oil-based paints. EX: Valspar 4625 Enamel Hardener

You mentioned you are working with wood. For primer I would suggest you check out something like BIN from Zinsser, I think Kilz has a similar product. I think they are generally shellac based (in which case solvent evaporation is the main process), are intended to be fast drying, and to work with a variety of top coats including oil-based. Usually used for cover up jobs in things like rentals.

Anecdotally, I've thinned run-of-the-mill oil paint (Rustoleum) with acetone, and it did get to the hard state much faster. Rustoleum recommends a very low amount of acetone be mixed in. I used more than the recommended amount, because I just needed some temporary surface rust protection, but wouldn't want to make claims about the long term durability.