Best way to finish a big (6'x4') piece of raw pine for outdoor use

[Eddy K.]

Hi,

I cut down a big Monterrey pine last year, and I'm trying to turn one of the larger pieces into an outdoor table.  I left the bottom-most section of the tree as a single piece (about 6' tall) and cut it down the middle.  It's about 4' diameter.  So, I'm left with a flat surface that's about 6'x4'.  The original cut was with a chainsaw.  Then I switched to a planer.  I'll finish off with a sander.

What are recommendations to finish this piece so that I can leave it outside (in the sun)?  I've been reading various online articles, and this is what I've gathered so far:

  - shellac all around the piece (for the smooth top as well as unfinished bottom).  The shellac seems best for pieces that are still releasing sap.

  - polyurethane (3-4 layers) for the top (finished) side.

  - CPES (clear penetrating epoxy sealer) for the bottom (unfinished) part of the piece.  This is the part of the wood which originally was covered with bark.  I have cut off a section of the bottom so that that piece can sit flat on the ground.

Does anyone have any better suggestions to treat this piece?

Thanks,

Eddy K.

 

[wtnhighlander]

Pine is not particularly resistant to weather or insects. I would recommend keeping it off the ground, using a metal, stone, or concrete base structure. Also, you have a thick piece of 'green' timber, which will dry unevenly if left exposed, and very likely crack. In my limited experience, softwoods do better than hardwoods in this situation, but still. I would suggest keeping it out of direct sun, and rain if possible. And I would say to use something like Thompson's or similar deck sealer, which doesn't form a hard film but will aid in repelling water. Shellac, poly, and epoxy film finishes will crack and peel away as the wood dries and shrinks.

[Eddy K.]

Thanks wtnhighlander!

I appreciate the advice.  Given that I don't have much more that I can do with this piece, and I've already spent a few hours smoothing out the top side, I'm inclined to keep going with the project.  I got your point about film finishes.  I had read that elsewhere and thought that 18 months of "curing" in the sunlight might be enough.  It has cracked a bit but no warping so far.

Anyway, based on your advice, I'll go with a sealer like: https://www.penofin.com/wood-stains/ultra-premium-red-label-wood-stain

and just seal the heck out of it (especially the two ends).  I'll also try to raise it on some sort of a metal structure to give it better stability and so it doesn't sit in any prolonged water.  If I can get ~10 years out of the piece, I'll be happy.

Thanks again.

[wtnhighlander]

If you can keep it from sitting on the ground, you might have a chance. If the insects and/or fungi ever get started, pine turns into sponge very quickly.