Finishing 'Sappy' pine?

Making a couple of replacement bed side rails. Want to etch names, etc in the sides. What I'm worried about is finishing it. Not a wood expert but I feel the wood is 'Southern Pine'. I've had the wood for at least 3 yrs stored in the attic over my shop, got it from a shop closing so I have no idea when it was cut. When I cut & planed it I noticed areas that looked 'sappy'. When I started sanding the first thing I saw was that the paper in my random orbit clogged quickly. I wiped the boards down with lacquer thinner hoping to remove whatever it was but when I went to the next finer grit the results were the same. 65% of the boards are clear/clean wihte pine but the rest has as reddish/pink tint which is where the 'sappy' grain appears.
I can sacrifice sandpaper to get to smothness desired but am worried that whatever I use to stain & finish it will not adhere. Looking for advice form experienced finishers. My thought is to spray with lacquer sealer first and go from there. Have attached a couple of pics.


Thx, Rick H

Pitch can be tough to get past. Lacquer thinner is what I would have recommended but I see you have already tried that. As you already know, cleaning the pitch (at least) from the surface is important but if you are going to stain make sure you use a jell stain. Jell stains are designed to stay on the surface and are not as susceptible to blotching due to differences in varying density of the wood.

I bought some old floor joist at an auction 4 or 5 years ago for concrete forms. After using them, I thought they would make a nice loft in my shop. So after belt sanding the last of the concrete from them and after installing them, fresh sap drained from some of them. Oh and I found a date on them, 1911

Personally, I would not use sappy boards at all. I would select new wood instead.

If you "insist" on using that, perhaps you could seal it with a coat or two of Zinnser SealCoat (it is 100% wax free shellac).

Quote:

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Originally Posted by mtylerfl

Personally, I would not use sappy boards at all. I would select new wood instead.

If you "insist" on using that, perhaps you could seal it with a coat or two of Zinnser SealCoat (it is 100% wax free shellac).

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Thx for the Zinnser info. I agree about dumping the boards,,,, but this is one of those things we often get ourselves into helping out
someone while trying to keep the $$$ down. Had the wood and did all the sizing + planing before the realization set in. I will go ahead
and do my final sanding and then try to seal it. Hopefully all the time spent in fitting the end hooks along with the rest of the shop time
won't be lost.
Thanks to all for the responses & sharing your expertise.
Rick H.