The Great Shellac Quandary of 2007!
This was left as a comment by Amalie over at "Oh Bungalow" I felt it required a post of its very own to answer.
"You've done some really beautiful things-- especially with shellac! That's why I thought I'd ask for your advice now that we've decided to shellac our antique heart pine floors. That's how they were originally finished, and beautiful warm amber tones-- from blonder to a deep red mahogany color. They were in need of a refinish, so we've sanded them and decided to go back to shellac. Goodwin Pine suggested using a 3lb cut of dark dewaxed shellac, thinned to a wash (wouldn't that be the same as, say, a 1lb cut?) and then using a water-based poly on top. We can only find regular amber shellac, premixed as a 3lb cut not dewaxed. Any suggestions on finding the flakes at a reasonable price? We also have no idea how much coverage you really get out of a gallon, or how many coats we ought to do...I guess that last one depends on seeing what we like as we go or if we get regular amber or garnet(which is better?). I just hate having to guess at ordering-- too much that's difficult to return or not enough that's gone halfway through-- or the wrong thing alotgether. It's the first time either of us has ever done much with shellac, so we're kind of in over our heads...Any advice you can give us would be really great!!! "
I remember being in the same predicament way back when we were ready to start finishing the woodwork. There were no blogs about using shellac back then so I read everything I could find and then ordered a bunch of seed lac and shellac flakes from shellac.net. I also bought a can of Zinsser Bullseye amber shellac from Home Depot or Lowes. I wrote this post a while back and a couple more around the same time describing the experimentation process. What I can tell you is this. Rub a little linseed oil or mineral spirits (paint thinner) on the sanded wood to see if it darkens. If it darkens then that is the color it will be with any kind of clear finish. Adding shellac whether it is lemon, amber or garnet won't really matter because the tone of the shellac is lost by the color of the wood. When I played with the lemon shellac and the dark seed lac I found that in the end there wasn't a huge difference in the finished wood. The differences were so subtle that it is lost in something as big as a floor where there are so many variations in the wood planks. It would make a bigger difference if applying it to new wood and possibly maple or oak. I think you will find that your old pine is going to turn an amber color right off. In the end I settled on only using the store bought clear or amber shellac because it was easier to acquire when I would run out. The mix and color was consistent and most importantly I didn't have to spend huge amounts of time filtering the bits out! If you add the price of 3 lbs. of shellac and a gallon of alcohol and figure it might give you a little more than a gallon of shellac the price is comparable or even less if you buy the pre-mixed stuff. I have gone through gallons of the stuff at our place, maybe a dozen or so.
Use a 2" brush and apply the shellac two or three board widths at a time along the length of the room keeping a wet leading edge to prevent lap marks.I think I averaged two or three quarts per floor. Our rooms are big though and I tended to thin to a two pound cut. You can mix amber with clear and end up with a paler tone. You can also alternate layers of clear and amber. It really won't make a noticeable difference since it is a floor after all and not an exquisite piece of furniture. You can darken shellac with aniline dye. You can tint clear shellac with a little turmeric for a golden yellow color. The wood will start to darken with more and more coats of amber shellac. This starts to be most noticeable after the third coat. I applied at least three coats and sometimes four. I lightly sanded with 220 grit sand paper after the first sealing coat and every two coats after that to get the rough bits and dust out. Since you plan to finish with a polyurethane then stop at three coats of shellac because the poly will give you the final smooth surface. I would apply two thin coats of polyurethane as the final finish. Unless you are going for a high gloss wet look, I suggest that you finish the floor with two coats of paste wax furniture polish applied with superfine steel wool and buffed with a rag. Your floors will be super slippery for a week or two but they will feel super smooth and sweeping them with a brush becomes so much easier! It's fun watching the pets slide across the floor too! So for ease of acquisition I would tell you to buy a gallon of clear shellac, two quarts of amber and a quart of polyurethane. That should do at least two average floors. You could have the floors done in two days because the three coats of shellac and a coat of poly could be applied in about 6 hours and your second coat of poly put on the next morning. Waxing is a little hard on the knees and fingers but worth it. It eliminates that plastic look that polyurethane gives.