Zinsser shellac advice wanted

[Derek Cohen]

I am building kitchen doors and drawer fronts from US Hard Maple. The aim is to keep to wood light in colour - so the plan is to use a blond shellac.

Rather than use the local Ubeaut white shellac, which requires thinning with alcohol, I am considering using Zinsser out of the can.

Zinsser comes in two forms, the waxed Bulls Eye Shellac, and the dewaxed Seal Coat. Only the Bulls Eye is available in Australia.

What is the difference between these two if the wood is not to be stained/dyed and no other finish is to be applied? As I understand, the de-waxed shellac is the choice when another finish is used against it. Is this correct?

Are there advantages/disadvantages of using the waxed version?

Regards from Perth

Derek

[Patrick Chase]

I am building kitchen doors and drawer fronts from US Hard Maple. The aim is to keep to wood light in colour - so the plan is to use a blond shellac.

Rather than use the local Ubeaut white shellac, which requires thinning with alcohol, I am considering using Zinsser out of the can.

Zinsser comes in two forms, the waxed Bulls Eye Shellac, and the dewaxed Seal Coat. Only the Bulls Eye is available in Australia.

What is the difference between these two if the wood is not to be stained/dyed and no other finish is to be applied? As I understand, the de-waxed shellac is the choice when another finish is used against it. Is this correct?

Are there advantages/disadvantages of using the waxed version?(esp water-based)

Regards from Perth

Derek

The SealCoat version is dewaxed, while BullsEye isn't IIRC. There is no practical difference between waxed and dewaxed if you aren't putting anything else over it. As you say dewaxed works better as a base layer with certain finishes, especially water-based ones.

Why don't you want to use flakes though? Dilution is pretty simple if you have a scale, there's a wide range available, and they last a *lot* longer even than Zinnser (which is chemically stabilized and lasts longer than most mixed shellacs). I particularly like the Brooklyn Tool and Craft dewaxed shellacs that Joel and LV both carry. They're on the expensive side, but they're of high quality and purity with no bark particles etc.

A few random notes:

• The Zinnser shellacs are 2 lb (SealCoat) or 3 lb (BullsEye) cuts, which are on the heavy side, so you might not want to use them "out of the can" unless your technique is both fast and flawless or you fancy sanding out brush marks. A lot of books recommend 1 lb for starting out, I personally use mostly 1.5 lb and sometimes 2 lb these days (though I always prepare 3 lb cuts and then dilute for each use). Note that when you dilute the Zinnser stuff with denatured alcohol you'll undo their chemical stabilization, so only dilute what you need
• The wax in shellac settles out over a few days, so you can (mostly) dewax shellac by letting it sit in a tall container and pouring off the clear part. It won't be as pure as properly dewaxed shellacs like the BT&C stuff, but it'll be good enough.
• The reason people advocate shellac as a base layer is because it's compatible with most other finishes, and does a good job of blocking things like silicone and resin.

[Joel Thomas Runyan]

I believe dewaxing is strictly to ensure compatibility with ensuing topcoats; iirc, all the instructions I've ever read for Sealcoat are about priming/sealing, no mention of its finishing properties... which are great. I've heard regular (unwaxed) shellac rubs out easier, but have no experience with it. I think the primary consideration for using Zinsser out of the can is that the cut for both Bullseye and Sealcoat can be too heavy for application on anything sizable or multi-faceted... so you might have to thin it anway.

[Phil Mueller]

Not much that hasn't already been said here, but to say that I use out of the can all the time. I do cut it 50/50 with DNA (just because I'm more confident wiping on lots of thinner coats). I have found it to provide a great finish that polishes out well.

[Frederick Skelly]

Derek,
I don't know how much stock you put in Bob Flexner, but I've found his advice to be good for what I build. According to Flexner, "The wax slightly reduces the transparency of the shellac on the wood. It also makes the shellac less water resistant, and it prevents good bonding...."

However, he also says "Shellac is not especially durable. It scratches relatively easily, and heat, solvents, acids and alkalis cause damage fairly easily." Though he follows that with "Even though shellac can be damaged more easily than other film finishes, it's still durable enough for use on most wooden household objects." (All of this is from his Understanding Wood Finishes book, chapter 9.)

I recall reading somewhere that dewaxed shellac gets a little harder and therefore is a little more durable, than waxed shellac. But I can't find a reference to support that right now.

I looked for an explanation of why there is wax in shellac, and he says "Most shellac still contains its natural wax." This implies to me that it's just there - it wasn't put there to serve a function. But maybe George or one of our other Professionals can better speak to that.

I use Sealcoat on a lot of small light wood projects and it works very well. I've also done as Patrick (and Flexner) suggest and let the wax settle out, then pour off the dewaxed portion. That was just fine too.

You always help me, so I hope a little of this will help inform your decision.

Best regards,
Fred

[Patrick Chase]

I looked for an explanation of why there is wax in shellac, and he says "Most shellac still contains its natural wax." This implies to me that it's just there - it wasn't put there to serve a function. But maybe George or one of our other Professionals can better speak to that.

That's right, the wax is part of the Lac beetle's secretion.

[Patrick Chase]

Derek,
I don't know how much stock you put in Bob Flexner, but I've found his advice to be good for what I build. According to Flexner, "The wax slightly reduces the transparency of the shellac on the wood. It also makes the shellac less water resistant, and it prevents good bonding...."

The "..." part of that sentence is fairly important and relevant. It continues: "[the wax] prevents good bonding when reactive and coalescing finishes (varnish, two-part finishes, and water base) are applied over shellac".

To be honest I'd forgotten until just now that the wax was a problem for oil-based varnishes. I mostly use dewaxed anyway.

FWIW Flexner recommends 1-1.5 lb cuts for people starting out with shellac. I personally find ultra-thin shellac to be a bit tedious so I use 1.5-2 lb.

[Prashun Patel]

Bullseye and Sealcoat are approximately the same color of blonde. Both will make the maple appear slightly golden. If you want it strictly white you would do better with the "platina" flakes or to use a lacquer or a water based top coat.


I use sealcoat under water based final she's precisely because it gives a little color and life.

[Patrick Chase]

Bullseye and Sealcoat are approximately the same color of blonde. Both will make the maple appear slightly golden. If you want it strictly white you would do better with the "platina" flakes or to use a lacquer or a water based top coat.

BullsEye comes in a "clear" and "amber". The "clear" is indeed the same color as SealCoat, a bit darker than BT&C super-blonde (and darker still than "platina"). The "amber" is roughly in line with others makers' amber shellacs.

[Brian Holcombe]

Derek, if you need a visual reference, most if not all of the frames on my blog are hard maple finished in super blonde. I mix flakes with DNA.

If the Zinsser stuff is darker than this I think you will want to use platina to get a very clear appearance. I like the result of super blonde, but it does darken the wood slightly.

[Dave Cav]

I've used lots of shellac, mostly for boxes, small projects and shop/utility cabinets. I think it would be about my last choice for kitchen cabinets due to it's relative lack of durability and lack of solvent resistance.

OK, actually straight BLO would probably be my last choice for kitchen cabinets....

You can get some pretty good "water clear" water based finishes these days. They don't change the color of the wood and would be more durable than shellac. They don't pop the grain, though, so you would need a light undercut of BLO or dewaxed shellac.

And I can also recommend Flexner's book. I wish he would write another one strictly on WB finishes.

[glenn bradley]

Prashun hit on my feelings about coloration. While Seal Coat is pretty clear, if you want very clear I find that Minwax Polycrylic (water based) stays remarkably clear over time. It is recommended as a brush-on finish but, I have padded it like shellac (multiple thin coats) without issue. I'm not sure about availability but, Wal Mart carries it and they're everywhere ;-)

[Prashun Patel]

Bullseye and Sealcoat are approximately the same color of blonde. Both will make the maple appear slightly golden. If you want it strictly white you would do better with the "platina" flakes or to use a lacquer or a water based top coat.


I use sealcoat under water based final she's precisely because it gives a little color and life.

[Patrick Chase]

Prashun hit on my feelings about coloration. While Seal Coat is pretty clear, if you want very clear I find that Minwax Polycrylic (water based) stays remarkably clear over time. It is recommended as a brush-on finish but, I have padded it like shellac (multiple thin coats) without issue. I'm not sure about availability but, Wal Mart carries it and they're everywhere ;-)

I actually shot that stuff out of a (traditional neanderthal) HVLP gun once for kicks. It worked OK, though IIRC I had to use a small orifice and relatively high pressure to get good atomization as it's definitely on the thick side.

[Derek Cohen]

Prashun hit on my feelings about coloration. While Seal Coat is pretty clear, if you want very clear I find that Minwax Polycrylic (water based) stays remarkably clear over time. It is recommended as a brush-on finish but, I have padded it like shellac (multiple thin coats) without issue. I'm not sure about availability but, Wal Mart carries it and they're everywhere ;-)

Thanks all. The reason for considering blond shellac was my understanding that it does not add to the colour of the Maple. It is obviously not as durable as I thought. Zinsser Seal Coat is also not available in Oz, so that puts it to bed.

Tell me about Minwax Polycrylic. This sounds interesting. I do not have spray equipment and would wipe it on.

Is your experience that it remains clear? And what is the preferred method of application? How durable is it?

It is also available in spray cans. Any comments on this?

Regards from Perth

Derek