Should I use oil based or latex paint for untreated pine exposed to the elements?

I'm building stake sides for a utility trailer out of pine 2x4's and 1x4's, and would like them to last as long as possible.Should I use oil based or latex paint for untreated pine exposed to the elements?
An oil-based (alkyd) primer. 2 or 3 coats.


The solvent, paint thinner, will penetrate the wood fibers and make a good bond for the top coat.





Top coat can be either oil or latex.





If you used a latex primer, the water will be absorbed by the wood, but the latex will dry and shrink kind of like a latex balloon.





Someone advised for primers - match the primer to the material.





Soft woods like pine have an oily pitch (turpentine is extracted from some the resins of pine trees), so use an oil-based solvent.





For sheetrock, which have a paper coating, use a latex primer.Should I use oil based or latex paint for untreated pine exposed to the elements?
I think you should use oil based paint.
Prime with oil based and finish coat with water bases.
Latex paint lasts longer because it can expand and contract with temperature changes. Sears, for instance, sells outdoor latex paint with a lifetime guarantee. I used their outdoor latex paint with a 15 year guarantee, which was the best they had at the time, and it didn't start to peel off for 13 years. Of course I didn't save my receipts for 13 years.





If you use oil based paint, use natural bristles. Don't use natural bristles for latex. It's water-based and natural bristles absorb water and get limp and soggy.
Oil base is much more durable, will out lat latex. I would recommend the oil.
Definitely oil-based, perhaps over a coat of primer for extra durability.