Making some picnic tables, that will sit in an open sided pavilion. Recommend painting or stain/sealing? Since they will not be out in direct weather, am considering non pressure treated wood.
Stain or seal paint will not hold up. I have, milled, built and sold many picnic tables. I just burned one this year that was 13yrs old, it was not treated lumber and was left out in our ever so changing weather yr after yr.
What kind of lumber are you using, is it rough cut, plained, store bought, what type{example; pine hemlock maple locust???}
you might consider a stain/sealer like Penofin. When it's time to reapply, just spray and wipe down...no sanding or stripping needed. They have stain formulated for pressure treated wood to work with the green tint.
NH TN 55, Kubota B2320 & RTV 900, Bad Boy Outlaw ZTR
Depending upon the type of wood, you may have "bleed-through" problems with knots if the wood isn't clear and you decide to paint. Eastern red cedar and pine are examples.
I've had success with Cabot's Problem Solver Primer (oil-based) in this regard. I've read about using wood glue to seal the knots, but haven't tried it yet.
We used to paint or stain picnic tables, I gave up due to the work and my inability to find a quality product that lasted. I currently have a sprice one that is 15 years old that has never been treated. It's just about done now I will admit though.
This year I painted a bunch of wooden chairs bright primary colors (Muskoka or Adirondack style chairs) with liquid plastic. So far it's been holding up mint, so hopefully it was a good choice.