Recipe for Sanding Sealer? – Question of the Week
This week’s question comes from a viewer who writes: “I’ve really enjoyed your podcasts, they are all very informative. I recently found myself more exited about woodworking. Though I’ve had an interest since childhood, I never really had the resources, till now (my wife also supports my dream). Anyway, I was watching one of your podcasts and you mentioned a recipe for making your own sanding sealer. Would you mind repeating that on an e-mail, or even easier, remind me what episode I’ll find it. Thank you so much for the added inspiration, though I’m starting later in life than you (36, I know this is going to be a lifelong passion. Once again thanx Marc keep it up!!”
And this was my response:
“You just can’t underestimate the importance of spousal support in something like this. I know far too many people who have to work against the grain just to get a new tool. That doesn’t seem like much fun, lol.”
“As for a sanding sealer, I usually just use shellac. Typically a 1 lb cut. There are two ways to do this. I either buy pre-mixed shellac (Bullseye SealCoat), and dilute it from 2lb cut to 1lb cut. Or I simply but dry shellac flakes and mix my own using denatured alcohol. So its not a true sanding sealer by definition, but it accomplishes the same thing. Oh and just a word about true sanding sealers. In general, they contain material that can interfere with finish adhesion to a small extent. The stuff that makes it easy to sand is the same stuff that can weaken the bond of the finish to the surface. So in general, I stay away from commercial sanding sealers. Shellac on the other hand, provides a great base for just about any finish. Hope that helps.”
Danish Oil on top of Shellac? – Question of the Week
This week’s question comes from Eric in Canada who asks: “I know you like to use dewaxed shellac and transtint for a bit of colour, and finish it off with General Finishes. GF is extremely hard to find here in Canada. Dewaxed shellac and the transtint is pretty easy to get. I was wondering if I can use Danish oil on top of the shellac?”
And here was my response:
The only problem with Danish oil in this application is the fact that most Danish oil contains a high amount of oil. That oil will have difficulty curing on top of a pre-sealed surface (from the shellac). The General Finishes products are mostly varnish, if not all varnish (Arm-R-Seal). So what you are really looking for is a simple wipe-on varnish to put over top of the shellac. Minwax sells a decent one that is widely available. A few light coats should do the trick.
You might also consider using a different coloring agent. Even though I do occasionally use a dilute shellac/dye solution for coloring, its only for certain situations. In most cases, I do my staining with water-based dyes or gel stains. Neither of these really seals the surface and you should have no problem following up with a Danish oil if you use them. So really, the sky is the limit for your combinations of coloring agents and topcoats. But to directly answer your question, you want to avoid putting oil/varnish blends on top of sealed surfaces.
Spraying Oil Stains? – Question of the Week
This week’s question comes from Jorge who writes:
I’m finishing some maple kitchen doors. I have a Fuji Mini-Mite 3x to apply the finish. I first applied a 1.5 to 2 pound cut of shellac and now I’m spraying the oil based stain. The problem is that I get what I think is called orange peel. Basically I can see the stain dots in the doors. Definitely the stain is not applied uniformly. Here is what I’ve tried so far:
– Applied a thinner cut of shellac thinking perhaps the shellac was too thick. Initially I used a 2.5 to 3 pound cut.
– Sanded the shellac coat more aggressively using 220 grit.
– Adjusted the hell out of the gun. I adjusted the air pressure, fluid control, fan size and any combination of these three knobs with no success.
– I bought a #3 air cap thinking that the #4 was too big for the viscosity of the stain. No success here either.
– Thinned down the stain to 3 parts stain and 1 part solvent. This helped a little bit but still the result is not what it should be.
I’d appreciate any pointers you can give me because this thing is driving me crazy.
And this is my response:
Hey Jorge. Take a deep breath brother! I don’t think the problem is in the gun or your technique. Its in the materials. The shellac, even at 1.5-2lb cut, might be a little excessive in this case. Traditional oil-based stains rely on absorption into the wood to work properly. By sealing with 1.5-2 lb cut of shellac, you essentially created a barrier on the surface of the wood. So now the stain just pools, much like trying to use a marker on a glossy surface.
So here are a few recommendations. If you need to seal the wood first (which is not a bad idea for a blotch-prone wood like maple), just use a 1/2lb cut of dewaxed shellac. After it dries, sand it very lightly with 220 grit. This usually results in a surface that is only partially sealed and will still allow the some stain to absorb. So you can then spray on the oil stain, and wipe off the excess. Do not let it pool up. You may even skip the spray at this stage because all you really need to do is wipe the stain on. Now to be honest, I might even be a little hesitant to do this. I just don’t trust traditional oil stains over even partially-sealed surfaces. So for more predictable results, you may want to switch to a gel stain. The gel formulation does not rely so heavily on absorption and will give you a much better distribution and intensity of color, without any blotching. Once the stain dries, you can then apply the top coat.
Now going back to the shellac surface. Lets say you had that heavier coat on and you still wanted to add color. How would you do it? Well, you could always add some dye to the shellac itself. That’s a great way to bring some base color to the party. You could also add dye to lacquer (if lacquer is your top coat). I like to make very light dye mixtures (using both shellac and lacquer) that are mostly thinner and dye. But I like to add a little of the finish itself to the mix as that helps bind the dye to the surface. Basically, this is what is known as a “toner”. Hopefully that gives you enough to chew on. Good luck!
Shellac as a Sealer? – Question of the Week
This week’s question from from Ron in Chicago who writes:
I have a table top that I stained with oil based stain and I want to use Endro Precat Lacquer but the directions say that I have to use a pre-cat sealer. Can I use a 1LB cut shellac as a seal coat or do I have to buy the special pre-cat sealer?
And here is my response:
Hey Ron. It is nearly always a safer bet going with the sealer recommended by the manufacturer. But, that doesn’t mean you have to. It also doesn’t mean you will get bad results using shellac as a sealer. Shellac really is like a universal binder. I like to think of it as a “clean slate”. A nice light coat of dewaxed shellac is a suitable sealer coat for pretty much any finish. I have used shellac as a sealer for pre-cat lacquer many times with great results.
Just to be safe, it’s always a good idea when trying some new combination, to test adhesion. Get a sample board, give it the sealer coat, then try the enduro finish. Let it completely dry and test for adhesion. You can do a few things for this. Try scraping it off with your fingernail. Then try putting tape on the surface and see if the top layer comes up when you pull the tape off. If either happens, the finish did not adhere properly and the shellac isn’t a good option for that topcoat. I have yet to see that happen though. Good luck!
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