Bullseye sanding sealer over shellac?

[Rick Lucrezi]

I love the look of amber shellac over pine. I have been using Zinsser Amber shellac everywhere in my house. Even the fir floor. So know I am on to the kitchen cabinets and I know shellac is a poor choice, but I was not able to get the same grain popping look with any other product to match. So I called Zinsser directly and wanted there take on what can go over their waxy shellac to protect it. They told me I could use the Bulls eye sanding sealer over the shellac and then apply most any finish over the Bulls eye. I tried this. Waited 2 hours, went to micro sand for a Lacquer top coat and it gummed up. I had to strip the whole piece. I know in the past we have covered shellac to death but any experience here would be greatly welcomed.

[Jim Becker]

You only need one thin layer of the SealCoat (which is dewaxed shellac). If it gummed up on you, then 1) it was probably applied too thick and not cured...shellac isn't like varnish and/or 2) you sanded too much. In my experience, you only need to knock of any nibs and I use 320 or 400 wet and dry for that...a few quick swipes and then I wipe it down with a dry, lint-free paper towel. The whole purpose of the SealCoat is to put a barrier layer over the waxy shellac so that other finish products will stick to the workpiece. (This is not necessary for non-poly varnish, however...it will stick just fine) Sanding it down defeats the purpose of applying it.

BTW, contrary to what some folks say, IMHO, shellac is an excellent finish and a lot more durable than many people make it out to be. It also has beautiful clarity.

[Prashun Patel]

How old were the two products u used? Zinsser shellac has a longer shelf life than shellac from flakes, but I have had old stuff that's gummed like yr saying.

I do know that many oil-based finishes will go right on top of the Bullseye no prob. You only need the Sealcoat (dewaxed) if yr going water or poly top coat - even then, many have applied oil poly over it with no prob. I haven't taken that chance.

[Howard Acheson]

If I understand you correctly, you are saying that you applied a shellac coat using Zinsser's amber shellac. Then you applied a coat of Zinsser's SealCoat dewaxed shellac. You waited two hours and then attempted to sand.

If the above is the case, there are two possible issues. One may be that the amber shellac was old and did not dry properly. Test it by applying a coat on some scrap wood. It should fully dry within an hour and be sandable within four hours providing the temperature is appropriate. The second issue can be that you applied the second coat before the first was fully hard. Dewaxed shellac is almost impervious to the tranmission of air so it can seal the undercoat enough that it will take a long time to cure. If it's not fully cured, is will keep the second coat soft for quite a while. Sand with 320 paper and if the sanding dust corns (forms little balls) let it dry longer.

Now, let me ask what you intend to apply over the shellac? Any oil based varnish or particularly poly varnish, will add quite a bit of yellow or amber to the amber from the shellac. I would strongly suggest now might want to do what you should have done originally. Using scrap wood or the inside of a cabinet door, test your whole finishing schedule to see how it will actually look and to identify any finishing problems. No tears.

[keith ouellette]

I'm by far no expert on this but I understand that the coats of shellac dissolve into one another even if one is regular shlac with wax and the sealer is dewaxed.

And i also think that even though lacquer doesn't dissolve shellac it does soften it till it all re- dries


This being the case wouldn't you need at least 2 coats of sealer to make sure that the lacquer didn't interact with the waxy shellac?

[Rick Lucrezi]

i think the comment about too thick may be the issue. i think that it had not cured up enough to sand. I only wanted to create a scratch for the lacquer to bond to. I re sprayed last night with shellac, and sprayed a thin coat of bullseye this afternoon. Will wait to sand till tonight and then try to apply the lacquer. Any recommendations on lacquer or a better finish?

[Jerome Hanby]

BTW, contrary to what some folks say, IMHO, shellac is an excellent finish and a lot more durable than many people make it out to be. It also has beautiful clarity.

This certainly isn't a scientific observation, but the finish that has built up on the stick I use to stir my Bullseye Shellac is incredible.

[Prashun Patel]

Keith-
I am also no expert, but from what I witness and understand, the SHELLAC will partially dissolve in the presence of alcohol from additional coats, but the wax will not do that as well. The net effect is that the amber shellac will lift and blend with the top coat to an extent, but they'll both 'cover' the wax over time.

[Frank Hill]

Once you use a wax shellac, it is difficult to get a good finish, another stain or another shellac on top of it because of the wax content. The wax is doing what it is supposed to do - protecting the surface and repelling whatever is being applied.

I am about ready to redo our kitchen. I haven't yet got past the finishing storyboard level yet with my wife. I will tell you what I'm doing. I went out and bought a bunch of dewaxed shellac flakes of different colors to experiment with.

Everything I use is dewaxed shellac. First I seal everything with a .5lb cut of super blonde shellac. This will stiffen the wood without raising the grain and you can get a nice finish sand with 150 or 180 grit. It all serves to even out subsequent stains or shellac colors. From there I work about 4 different boards at any one time. All 4 will have the same base color shellac mixed at about 1.5lb cut, 3-4 coats of lemon yellow, then I will lay down 3-4 coats of a different color garnet, ruby, and then orange. I will then take another set of boards lay down one of the other colors as a base and use the others as a top coat, etc, etc. It is a long tedious process but I will be using over 200bdf of red oak for the kitchen so this is a necessary project evil.

Shellac and kitchen applications are not necessarily good bedfellows. there are three things that can adversely affect shellac: alcohol, ammonia and liquid water. All very common in the kitchen. The first two will dissolve the shellac and the last will cause opaque spots after the water has dried. To get around this try a 1:1:1 mixture of varnish, BLO and mineral spirits/turpentine. This mix is thin enough to pad on with an old T-shirt and if you use spar varnish there is extra protection. The BLO in the mix does increase the drying time but gives a nice depth to the finish. Also the varnish can not be a wipe on becuase that has already been thinned which is what the mineral spirits is for in the mix.

I started out with Zinssers shellac also but quickly wanted more options and flexibility which is why I went to dewaxed flaxes and started mixing and customizing my own colors. The one thing I didn't like with Zinssers other than the wax is that it seems to be a very heavy 2lb cut or or light 3lb cut. I would rather apply multiple thinner cuts to get a deeper finish than one thick coat.

[Jim Becker]

Frank, de-waxed shellac, as well as non-poly oil based varnish will adhere to waxy shellac with no problem.

[Frank Hill]

Frank, de-waxed shellac, as well as non-poly oil based varnish will adhere to waxy shellac with no problem.


I was always taught, 'Once wax, never go back,' meaning if you were going to use a waxy shellac, use it as your top coat and stop there and then do a time consuming hand polish.

Since using dewaxed shellac flakes and custom mixing my own cuts and color combinations, I've been getting a lot better finishes. Unless you really need waxed for a specific use, I think dewaxed is the way to go, IMO.

[Prashun Patel]

The only reason I still use waxed sometimes is convenience. If not for bullseye, I wouldn't use it.

I've used it under Waterlox without adverse effect.

[Jim Becker]

I was always taught, 'Once wax, never go back,' meaning if you were going to use a waxy shellac, use it as your top coat and stop there and then do a time consuming hand polish.

Since using dewaxed shellac flakes and custom mixing my own cuts and color combinations, I've been getting a lot better finishes. Unless you really need waxed for a specific use, I think dewaxed is the way to go, IMO.

Frank, I only use de-waxed myself and agree it's a great way to simplify things, but you can, in fact, use de-waxed as a barrier coat over waxy shellac to insure adhesion with finishes that have issue with wax. You can also use non-poly varnish with no issue over waxy shellac as I mentioned in my previous reply. It's good to keep in mind that there are some shellac "colors" (generally the dark stuff) that remain unavailable de-waxed so it's good that a simple coat of de-waxed can provide that barrier layer when other products need to enter the finishing regimen.

[Scott Holmes]

I use de-waxed most of the time. Poly and water-borne finishes have problems with shellac that has not been de-waxed. Other varnishes are not affected by the wax.

De-waxed over shellac that still has wax will not make it OK for poly or water-borne finishes. The wax will migrate to the final coat of shellac.

Shellac Shack has a wide selection of de-waxed shellac in just about every color.

[Scott Holmes]

Frank,
Depending on the type of wood you are using...It sounds to me as if you are applying your shellac way too thick.

The perfect shellac finish is the TINNEST possible coat that is FLAWLESS.

You should not build shellac up like you do lacquer or varnish; it will alligator...

Look at old furniture that had shellac improperly (too thick) applied.