Pine sap??

Cabot's

Mark Mandell - Gone Round In New Jersey

"Problem Solver Primer"

Took care of tannin and sap bleeds on pressure-treated SYP and eastern white cedar.

Re: Pine sap??

paul in AZ

a varnish based primer such as Bin. Or just varnish as a sealer.

Isn't BIN shellac based?

my bad.  it is shellac based

paul in AZ

Oops. My head was elsewhere when I wrote that.

Bin makes several including a white shellac based primer.

Re: my bad.  it is shellac based

Tom Norton

I thought about Bin or just shellac but was sure about using it in an exterior application even with an exterior paint.

Re: my bad.  it is shellac based

Keith Newton

Other than the water base latex, if I recall, one of the main problems with most of the other finishes, is that the solvents will also dissolve the pitch, except the alcohol. I would imagine that epoxy might be a good option, except I'm not sure how good the adhesion would be.

Not knowing what grade of pine you started with, but some of the lower grades at the lumber yards are only dried down to about 20% MC, which may or may not have been in a kiln. It's been a while since I read something about this, but there are a number of compounds in this rich-pine that liquify at different temperatures. Some will flash off at a low temp, while others have to get on up there. If your shutters are painted dark, and out in the full afternoon Sun, that temperature can get quite high, so it just melts.

Re: my bad.  it is shellac based

Tom Norton

They do get the West sun and they are painted dark green. I might try the epoxy idea.