Shellac questions (sorta long)

[Dan Bundy]

I'm building an armoire out of cherry. I was planning on finishing at least the inside with shellac (because of the low odor), then covering with something else, also low odor (water-based poly?). I was testing some shellac sealer (Bulls Eye, I think, 3lb cut) on a scrap of cherry here at work to see if/how much the color changed. Liked the color. HOWEVER, the directions on the can said NOT to put poly over it (didn't say regular or water, just no polyurethane over it). I thought shellac worked under everything.

So finally to the questions:

* Can I put water-based poly over shellac?

* If not, what's a good low/no odor protector I can put over it?

* Or, what's a good low/no odor protective finish I can use instead of shellac & topcoat? I'd use plain water poly, but it doesn't darken the wood, like I would like it to.

I'm not to worried about protecting the insides of the drawers, but the divider shelves the drawers ride on, and the part where the TV, VCR, etc., live probably need something tougher than just the shellac. Don't they?

Thanks. DB

[Jeff Sudmeier]

I am just thinking out loud here, because I just posted my own shellac questions. First I would say that you can just use the Shellac on the inside of the armoire using the instructions for shellac. When you are done you can put a coat or two of wax on to get the shine that you want.

Water based poly to me would still have too much ordor for an armiore. I built a blanket chest about 5 years ago and used water based poly throughout. They thing STILL smells like poly sometimes

Good luck, the finishing experts will be along shortly to help more than I can

[Teresa Jones]

Dan,

I suspect the caution on the can regarding the poly is related to the fact that the shellac you are using is NOT dewaxed. If you use dewaxed shellac it should be OK.

Having said that, I would not put anything but shellac on the inside.

TJ

[Jeffrey Schronce]

Your sanding sealer is 3# cut? I would think it would be more like 1 - 2 # cut if it is the pre-mixed Zinsser Bulls Eye Sanding Sealer. 3# is way to thick for a sanding sealer, IMHO.

Note that Zinsser Bulls Eye Sanding Sealer is typically dewaxed. Check the label of the can as it will advise if it is dewaxed.

As noted, Poly over dewaxed shellac is no problem from a finish perspective, however you are still going to have the poly oder to deal with. Again as noted, I would apply a few coats of 2# shellac. Amber shellac gives Cherry a great look in my opinion. I belive you would be fine using shellac alone as it is incrediably durable, except for certain things like solvents.

[Steve Schoene]

For a pre-mixed dewaxed shellac you want the Zinsser SealCoat. However, I can't think of any particular reason why you would need another material over the shellac on the inside of an armoir. Plenty durable.

For that matter, I would use shellac as the complete finish for the outside as well since the mostly vertical surfaces don't have much potential to be damaged by chemicals.

[Jerry Olexa]

The undercoat for poly and most varnishes must be dewaxed shellac or it will not adheree. I agree shellac only for interior drawers. Also try some BLO before you shellac and topcoat. Brings out the grain nicely esp on Cherry...

[John Kain]

The undercoat for poly and most varnishes must be dewaxed shellac or it will not adheree. I agree shellac only for interior drawers. Also try some BLO before you shellac and topcoat. Brings out the grain nicely esp on Cherry...

Jerry, I'm not trying to be a joker here but:

Have you ever had a waxed shellac not accept poly? From personal experience, I have yet to have any problems with using Zinsser Shellac covered by OB poly. Maybe I've gotten lucky.

Now truthfully, I don't use waxed shellac anymore. But I agree with what Steve said, especially with Zinsser (waxed shellac). Just a couple coats of the Shellac should be OK for what you need it for. You can add thin coats for shine as needed. The wax will only help you.

[Howard Acheson]

John, there is no question that oil based poly varnish and waterborne finishes do not adhere well to shellac containing its natural wax.

There is a standard test for finish adherence that consists of applying a finish, letting it fully dry until it is cured and then crosshatching it in 1/10" squares using an exacto knive. You then apply a Scotch type tape to the scrored surface. After pressing it down firmly you remove the tape and then count the number of squares of finish removed. Anything more than 5 out of a 100 is considered OK but most would want no more than two. If you try the test with a wax containing shellac, you will find about 50% of the squares will be removed.

Now,this is not to say that, in some applications, you can get away with the reduced adhesion. Given that poly is generally used for surfaces that will get some abuse, you would want to shoot for a finish that had maximum adhesion.

It's easy enough to use a dewaxed shellac or to use a non-poly oil based finish. If a waterborne finish is desired, then the use of a dewaxed shellac is the only alternative.

[John Kain]

John, there is no question that oil based poly varnish and waterborne finishes do not adhere well to shellac containing its natural wax.

There is a standard test for finish adherence that consists of applying a finish, letting it fully dry until it is cured and then crosshatching it in 1/10" squares using an exacto knive. You then apply a Scotch type tape to the scrored surface. After pressing it down firmly you remove the tape and then count the number of squares of finish removed. Anything more than 5 out of a 100 is considered OK but most would want no more than two. If you try the test with a wax containing shellac, you will find about 50% of the squares will be removed.

Now,this is not to say that, in some applications, you can get away with the reduced adhesion. Given that poly is generally used for surfaces that will get some abuse, you would want to shoot for a finish that had maximum adhesion.

It's easy enough to use a dewaxed shellac or to use a non-poly oil based finish. If a waterborne finish is desired, then the use of a dewaxed shellac is the only alternative.

Fair enough. Just from experience, I have never had any of my projects that have had poly finish problems after applying after waxed shellac. I have 2 kids who really abuse their "furniture" made by Dad with no problems. Real world situation, I guess.

I don't want to piss anyone off either way here. But I've never had any furniture problems with waxed shellac under Oil Based Poly.

[Bob Swenson]

To dewax shellac put it in a jar and let it sit until the wax settles to the bottom. Before using it decant the top to an other jar.
Bob

[Steven Wilson]

* Can I put water-based poly over shellac?
Yes, as long as it's dewaxed shellac. The one in the can isn't

* If not, what's a good low/no odor protector I can put over it?
Just use shellac by itself. You don't need a top coat (on the inside)

* Or, what's a good low/no odor protective finish I can use instead of shellac & topcoat? I'd use plain water poly, but it doesn't darken the wood, like I would like it to.

lacquer

*I'm not to worried about protecting the insides of the drawers, but the divider shelves the drawers ride on, and the part where the TV, VCR, etc., live probably need something tougher than just the shellac. Don't they?

No


Shellac is a fine finish for bookcases, armoirs, tables and such. If you use dewaxed shellac then you can top coat it with whatever you want. I personally like to use a mixture of BLO:Tung:Turps in the ratio 1:1:2 applied lightly to pop the grain, then apply a few coats of kusmi shellac with some brown or red-brown transtint dye added, then followed with lemmon shellac until I get the build I like. For drawers (like a chest of drawers) I like to use blonde shellac until it just starts to build. If you want to use poly you could apply some BLO to pop the grain and then seal it with a dewaxed shellac. A good lemon to orange/red dewaxed shellac (I don't know if there is a dewaxed Kusmi) applied to get the color you want and then coat with poly. IMNO you don't need to but if you must go ahead.

What ever you decide, try your entire finishing schedule on scrap first.

[Tim Devery]

I am a pro floor refinisher, and putting any poly over regular shellac is not going to adhere properly.
In my profession we use Zinnser SEALCOAT only.
Waterbase or regular oil poly can go over it in one hour.
I never sand out the sealcoat, put it down as thin as you can to prevent grain raise. Then abraid your next coats.
waterbase would be perfect for your job.
Hope this helps.

I must add I am not as good as 99% of the folks here when it comes to furniture. This is just what I would do, good luck

[Rob Blaustein]

* Can I put water-based poly over shellac?
Yes, as long as it's dewaxed shellac. The one in the can isn't

Actually Zinsser Sealcoat is a 2lb cut of dewaxed shellac and it comes in a can.

On the advice of Howie and others I've been finishing the inside of a vanity using waterbased poly (over dewaxed shellac) rather than an oil-containing varnish to avoid the possibility of the oil odors leaching out--something you might consider given that you are building an armoire. Though you might not need anything over the shellac if you use several coats.

[Steven Wilson]

Actually Zinsser Sealcoat is a 2lb cut of dewaxed shellac and it comes in a can.

Yes, and it is not available most places. If you find shellac in a can at your local store it's most likely NOT Sealcoat but the regular Zinsser product and that has wax.

[Jerry Olexa]

Menards carries Sealcoat (unwaxed)