BLO vs Shellac on longleaf pine

[John McDavitt]

I have a question about BLO versus Zinsser seal coat. I live in a craftsman bungalow built in 1924. All the woodwork in the house is long leaf pine. I am nearing the end of a total kitchen redo and am ready to finish the original windows. After experimenting and learning about finishing pine, I have decided to go with dewaxed garnet shellac topped with an oil-based poly, but I'm open to suggestions on that too. I have read that BLO really makes the grain pop, but in my experiments, the BLO came out more "flat" than the Zinsser seal coat. I simply rubbed in the BLO and left it alone for several days. Is there something I missed or did wrong? Under even the best case scenario, is there that big of a difference between BLO and Zinsser seal coat? I am willing to do whatever is best for the long term protection and beauty of the windows. I do live in Texas and summer is upon us so I do need to act fast, especially if I go with BLO. All my experiements were done on long leaf salvaged from the house. I have already learned so much from this forum and look forward to any responses. Any advice or suggestions are greatly appreciated. Thanks.

[glenn bradley]

The 'usual' BLO application is to wipe on (or flood depending on what you're after), leave for a bit (5 minutes to an hour[?]) and then wipe it off for all your worth. As to leave-on time, anything short of it starting to cure is probably OK but I don't know that you gain anything after about 15 minutes. On open grain woods that I flood, the piece will weep for days before I can move on.

As to the difference . . . they are different. BLO will darken more than the shellac. BLO doesn't have much shine by itself where as shellac does. I have used BLO to "pop" and the shellac to seal and gloss. I generally knock a bit of the gloss off with a gray syntho pad and then paste wax if I am after an A&C look.

As always, test, test, test on scrap.

[Prashun Patel]

On all but the biggest, flattest surfaces, I honestly can't tell the diff between BLO's grain pop and shellac's grain pop. Pine has a fairly prominent grain already, and will pop with the shellac.

Further, pine will drink a good amount of oil, which means if you don't wipe quick, you'll lengthen yr dry time vis-a-vis shellac, which can be topcoated in hours or quicker.

Next, BLO has very poor water protection qualities. It blackened roofing shingles in a neighboring town from me about 20 years ago. Granted, they used BLO as the topcoat, but I still wouldn't put it near water.

Shellac on the other hand makes a good vapor barrier under an appropriate topcoat. The color will be a little more predictable than BLO which'll shift (although yr oil based poly might shift color). Last, since it's faster drying it tends to seal blotchprone woods more evenly than oil, which can preferentially seep into absorbent areas, giving blotch. So, I'd bet you'll get a more even coloring with the shellac than BLO.

For future reference: BLO dries dull. You can notice the pop when you topcoat it. The pop is subtle on some things - like prominently grained woods, and striking on some - like curly wood.




Have you considered a spar alkyd varnish or a spar urethane instead of (interior) oil poly? It'll be softer which might be more appropriate for a window that'll be subject to some expansion and contraction with the seasons...)

[Neal Clayton]

I have a question about BLO versus Zinsser seal coat. I live in a craftsman bungalow built in 1924. All the woodwork in the house is long leaf pine. I am nearing the end of a total kitchen redo and am ready to finish the original windows. After experimenting and learning about finishing pine, I have decided to go with dewaxed garnet shellac topped with an oil-based poly, but I'm open to suggestions on that too. I have read that BLO really makes the grain pop, but in my experiments, the BLO came out more "flat" than the Zinsser seal coat. I simply rubbed in the BLO and left it alone for several days. Is there something I missed or did wrong? Under even the best case scenario, is there that big of a difference between BLO and Zinsser seal coat? I am willing to do whatever is best for the long term protection and beauty of the windows. I do live in Texas and summer is upon us so I do need to act fast, especially if I go with BLO. All my experiements were done on long leaf salvaged from the house. I have already learned so much from this forum and look forward to any responses. Any advice or suggestions are greatly appreciated. Thanks.

greetings fellow old house zealot ;).

i have a 1908 house, also entirely built of longleaf pine, also refinishing floors and trim and doors with garnet shellac.

several points...

as mentioned above that old wood, especially on the windows, will be quite thirsty, so you'll probably need a few coats of whatever sealer you choose. the seal coat of shellac will be easier than the oil seal coat. shellac sticks to itself better than it sticks to anything else, so it will make getting the garnet on there a bit easier, although there's nothing wrong with an oil first coat. you might try BLO/seal coat/garnet garnet garnet garnet/top coat. make sure you use enough seal coats. as i'm sure you've noticed if you go straight to that old thirsty wood with the garnet it will be blotchy, like a stain on un-sealed wood.

on those old windows, i use a varnish rather than the poly for the top coat if it's a single/double hung. reasons being...

on an old window you have pretty heavy abrasion where the window touches the jamb, theres no way of eliminating this, and no finish will last there. so the idea is to use a finish that can be recoated and repaired with minimal effort in the future. the poly will require sanding before a new coat will adhere, and unfortunately shawn, the spar varnish would require removal. many varnishes of course can be spot repaired and recoated without sanding. also poly looks too plasticy for my taste, but that's a personal preference i guess. i personally use waterlox for top coats (and they have a satin if you prefer), but there are many alternatives.

if you're painting the outside of the window too, an oil enamel is really the only way to go, nothing else will hold up to the abrasion against the jamb as well, nothing else will last as long, and nothing else will be as easily serviceable. this is again assuming that it's a single/double hung. a casement or fixed window wouldn't suffer as much from the abrasion, but i think serviceable finishes are still a wise idea due to the reasons mentioned above anyway.

in fact you might try these guys (http://www.solventfreepaint.com/) for your exterior paints. i haven't gotten around to trying it yet but i've talked to a few who have, and the properties of that stuff per the folks i've talked to that are using it are very similar to the old lead style paints, only they're using titanium dust in lieu of lead for it to be legal in the US. for windows and doors if that stuff works like old lead paint as advertised it should in theory be superior to any modern paint, but i haven't tried it yet so can't endorse/reject it yet. "maybe tomorrow when i get around to it" like everything else in this rickety old place ;).

[Chris Padilla]

If you really want to learn more about finishing: Bob Flexner's Understanding Wood Finishing is the definitive bible on learning the real truth behind finishing and finishes. Every woodworker should have this book.

Start at your local library to start but I'm sure you'll be buying your own very shortly after that....

[Howard Acheson]

>> I simply rubbed in the BLO and left it alone for several days. Is there something I missed or did wrong?

Let me start by saying that BLO will not produce a glossy sheen. Unless you apply a fairly large number of applications, BLO is absorbed into the wood. BLO is more a treatment than a finish and is rarely used as a stand-alone finish. Finishes that produce a sheen are ones that sit on top of the wood called film finishes. However, BLO will highlight the grain of the wood and when a film finish is apply on top of it, a sheen will result.

Basically, it's the amber color that causes the grain to be highlighted. The amber color can come from BLO, amber or garnet shellac, or an oil based varnish. All will highlight the grain. But each may produce a somewhat different amount of amber. That's the reason that a finisher should alway test out the complete finish process on scrap from the job. That way the final look will be apparent and there is time to correct it.