Shellac or varnish?

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An old topic, but I am *newly* confused. I installed new doors and trim, coated with 3 coats of shellac. After just two or three years the bathroom doors and trim are showing major signs of apparent water damages, with the finish roughening and lifting, especially around the upper portions of the doors where the shower steam condenses on the doors and trim.
Here's the question. Recently I read that shellac is actually MORE waterproof than varnish, and I have read of at least two double- planked boats in WoodenBoat magazine that have shellac between the layers of planking because it is believed to be more waterproof.
So what gives? I need to refinish the doors and trim as soon as the weather improves enough to open the windows, but varnish or shellac? Of course, I prefer shellac, as it is less toxic and dries much faster, but if varnish is the solution, then I need to use that.
Any ideas and explanations?
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You will find that shellac is not a good waterproofing agent. Perhaps what you read about boat guy using it was their use of it as primer.
To be able to say that it has held up well in a hot steamy bathroom is a good testament to your application.
You can settle this for yourself; put some shellac on a board, then put some varnish on another area. Put a wet glass on each area and see which one shows signs of moisture penetration.
Shellac is an excellent choice of wood primer to me. But for a finish application in a wet environment I wouldn't use it for a finish coat. I would look at some of the better water (or solvent) based polyurethanes. There are a lot of them out there. Maybe you can con Lew into commenting on this subject, as he is a boat guy.
I personally don't like spar varnishes, etc., as they dry too soft for stationary applications, are not highly abrasion resistant, and since most are based on old oil formulas they yellow badly. Some of the newer polyurethanes dry very hard, stay pretty clear, and are easy to apply with gun, pad, or brush.
Make sure whatever you choose to apply, you sand/clean the surfaces thoroughly as the wet, soapy steam and condensate can murder your finish.
As for fear of poisons, this discussion rears its head frequently in woodturning. The answer is always the same, and that is that almost all finishes (certainly those we buy without a license!) are food safe when dried. As a matter of fact, this was just brought up again on the spinning side of the wood fence:
http://tinyurl.com/2d3a9z
Good luck!
Robert
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wrote:

And that, my friends, is the most confusing sentence I've ever read....
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You should read more of my posts. I can be more confusing that than that... and have! My brain often works a lot faster than my typing, so it wanders away while my fingers are still working.
I have I have a tendency to try to answer a question as quickly as possible if I think I can be of some help. I don't always worry about punctuation, grammar, correct pronoun references, etc. I leave that to others here that have the time and patience to turn in a professional quality dissertation. All I want to do is to disseminate information, or in some cases, just my own opinion based on my experience.
But if you were confused (and of course actually interested in the subject), tell me where I threw you off and I will be glad to elucidate.
Robert
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I understood it to mean that what the poster read (past tense) about "the boat guy" (apparently someone who works with boats) was that the the boat guy was using shellac as a primer. Therefore, the OP concluded that shellac was good for use on wood exposed to water (or condensation). However, Robert suggested that the OP might have been misled because the "boat guy" was only using shellac as a primer; which is to infer that, after using shellac as a primer, the "boat guy" used some other coating for water protection. But, unless the "boat guy" responds, we might never really know for sure. Let's see if I'm right. Robert?
Max
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SNIP

Dead spot on. Like you were reading my mind.
That's kind of scary.... ;^)
Robert
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Jeff wrote:

You obviously are not that well read....To be a properly "confusing sentence" a statement must not communicate its intended point....sadly I've read enough posts to perfectly understand his intended purpose. Not to worry with enough time, diligence and patience you too may achieve such heights of understanding. Rod
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On Mon, 10 Mar 2008 18:05:02 -0700, snipped-for-privacy@aol.com wrote:

Dewaxed shellac slows down moisture vapor exchange, and thus wood movement, better than any other finish with the possible exception of epoxy.

I put several coats of dewaxed shellac on a piece of jatoba. I then set glasses of water, both tap temperature and iced on it and left them overnight. No water marking. Then I just sprinkled it and left large drops of water on the surface. Still no marking.
It's the WAX that causes the water marks.
That said, I'd use poly on horizontal surfaces in a bathroom just to be extra cautious.
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I don't know, but I would be willing to learn if you could point me in the direction of that information. I thought the post catalyzed 2 K urethanes with flex additives would be better than shellac, especially for finishing wood products. No?
Got my interest up, there. Love to see some empirical data if it is easy to get to, or just post a quick link.

That is absolutely true if you have the right shellac. The clear blonde, dewaxed stuff that O'Deen used to sell was supposed to be able to deflect bullets after being mixed nd properly applied. As hard as a good poly, and almost as water proof. But you had to roll your own when using it as this was not over the counter stuff.
Reading between the lines you can easily see that it is that blend the OP was talking about as it is put >between< the planks on a double planked deck. This is because shellac (no matter what amount of additives are) is not very UV resistant. If he had used the super blond dewaxed brewed mix on his doors he probably wouldn't be having any problems now.
I made an assumption (perhaps incorrectly) that the OP used off the shelf shellac which is probably a Zinsser (or similar) product, and that was the source of the problem. If it was marked as their "sanding sealer", it would be dewaxed, but probably not recognized as a viable finish coat material by most.
I assumed that he probably used the other Zinsser (or similar) products off the shelf, as he is probably not a full time finisher, because no full time finisher I know would mix dewaxed shellac just to use in a bathroom. No full time finisher I know would use shellac in a bathroom to begin with, even with the proper material and mix.
If I was wrong, I hope he pipes in.

Me, too. I'd also put poly on all the vertical surfaces as well like the doors and trims where he mentioned he was having his problems. Wouldn't give it a second thought.
Robert
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On Mon, 10 Mar 2008 21:28:51 -0700, snipped-for-privacy@aol.com wrote:

Flexner's book calls it "excellent." McNamara:
http://www.woodworking.org/WC/GArchive99/9_19mcnamara2A.html
calls it "best possible" and Jewitt:
http://www.assoc-restorers.com/r-articles/shellac.html
references a USFPL study that rates it above poly,varnish, and lacquer, but I couldn't find that study on their website.
Best I could do = hope it helps.
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Larry Blanchard wrote:

Try:
http://www.fpl.fs.fed.us/documnts/techline/protecting-wood-from-humidity.pdf
--
Jack Novak
Buffalo, NY - USA
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Nova wrote:

The gory details for that one are at http://www.fpl.fs.fed.us/documnts/fplrp/fplrp462.pdf .
I don't see anything there to support the contention that shellac will be superior to a marine-grade 2K polyurethane.
--
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--John
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I honestly doubt that you ever will see anything like that, anywhere. Shellac has its applications to be sure, but it has it limitations as well.
Robert
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I think it is important to study the source as well as its age. While that information was probably valid in its day, it is over 20 years old!
The quantum leap forward in polymer resin formulations has been nothing less than astonishing. Garden variety finishes that are sold at the big box stores are often (if not always) superior in performance than the finishes we used to buy as "pros".
I would certainly take that study for what it was worth in its day as a historical document, not as a fact sheet relevant to today's finishing protocols.
Robert
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First, thanks for the links. But Larry - I think the sources you posted did more to harm your premise than to support it.

It does indeed. But it goes on to say: *********************** Shellac Although shellac provides the best possible moisture vapor barrier, it does not resist long term liquid water at all. ***********************
Direct language from your source, which you can see differentiates between a moisture barrier and a water barrier. Granted that his article is meant to be an overview and not deal in specific types of shellac, but in generalities it supports your statement as a vapor barrier, but refutes your further thoughts on actual water proofing.

And also from Jewitt's link under disadvantages:
********************************** 2. Forms white rings on contact with water. This is more of a problem with shellacsthat have wax and old shellac surfaces. *********************************
I agree with your statement that it is the plain "waxy" shellac that causes most of the problem, but again, I am thinking that the OP (who has probably long lost interest in this) is using off the shelf stuff which has chemical binders added to it to make it last longer, be more water resitant and to keep the shelf life up and is not dewaxed.

I always like new information. I think the important thing to remember here is that the information links you posted were taken in generalties, not in specifics.
At one time there was a denizen of this group (Paddy O'Deen - aka Patricio Olguin) ) that was a supplier and cheerleader for shellac. He was able to supply some kind of white shellac that was hard as nails and pretty damn water resistant. I would have to think that is what the boat guy in OPs post is referring to, not the Borg stuff.
Robert
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Just for clarity sake - shellac *is* a type of varnish. Quoting from woodweb:
"Non-convertible coatings do not go through a change when they dry and can be re-dissolved by their original solvent. Shellac, cellulose and thermoplastic acrylic are such materials.
Convertible coatings go through a chemical change (get converted) and are no longer soluble in their original solvent.
Within this, there are a number of different types of curing systems. There are the air-drying or oxidative resins such as alkyd and urethane oils that use oxygen from the air. This is a slow process that can be sped up by the addition of metallic soaps (driers)..."
wrote:

Back when I was selling a metric ton of shellac per month, one of my most loyal and interesting clients were those making wooden whitewater canoes. They would buy only the finest Kusmi buttonlac (somewhat of a contradiction in terms, as buttonlac is minimally processed, and contains wax, bug parts, bush parts, etc.) to apply to the outsides of the hull. They did this for three reasons:
1. Shellac is the only thing that will slide over rocks. 2. It was resistant to water (cold). 3. It was durable, and yet easily renewable.
It was the *only* stuff they would buy. Buttonlac is processed by heat (wrapped in burlap and then heated over a fire until molten), not solvent, and so it is polymerized. Advanced users would either separate it in a centrifuge (in solution), or double-wrap a wad of buttonlac in some commercial filters, submerge in alcohol, and then wait a few weeks for the precious finish to seep out.

That would be me. All the stuff I sold was filtered, not bleached, and thus the ability to retain most of the water resistance properties it originally had.
Someone else mentioned that shellac isn't flexible. I've had the opposite experience. One of my favorite parlor tricks was to take a client's business card (at the beginning of lunch, say), dip it into a handy jar of orange shellac, and then at the end of lunch, bend the card into a circle without the then-dry finish cracking. It loses flexibility after perhaps 100 years or so... don't we all?
Paddyo
p.s. There are a few people that are distributing the same product I used to. shellacshack.com is one of them. I did receive some free samples from the guy when he was looking for verification of his product, but other than that, no affiliation. It ain't as cheap as I used to sell it, but a durned sight cheaper than most I'd say.
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snipped-for-privacy@gmail.com wrote:

Dewaxed shellac is very good at resisting water, but it's not particularly durable/abrasion resistant compared to varnish.
You might consider one of the waterborne varnishes...less stink and dries faster.
Chris
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snipped-for-privacy@gmail.com wrote:

Provided that the shellac you used was dewaxed...
Shellac has good water resistance but is soluble in alcohol, aqueous solutions of alkali, organic acids and ketones. Although shellac is insoluble in water it can be dissolved by alkaline solutions such as sodium carbonate, borax, and ammonia.
I would suspect products used to clean the bathroom, especially aerosol and spray cleaners as the cause of the problem.
source: http://www.ams.usda.gov/nop/NationalList/TAPReviews/shellac.pdf
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Jack Novak
Buffalo, NY - USA
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Funny thing you should mention.
I just got my latest copy of WOOD magazine and what should appear but the following:
Few finishes survive frequent contact with water.
Kitchen cabinets must survive grease and moisture in air and frequent skin contact around knobs and pulls, and occasional heat.
If you have spray equipment, use a 2-part polyurethane, a pre-catalyzed lacquer, or a post-catalyzed lacquer. Otherwise, brush on an oil-based polyurethane thinned about 10 percent with mineral spirits. Apply at least 3 coats. If you are covering an existing finish, thoroughly clean and scuff it first for a good bond.
I know this applies to kitchens, but it should work for bathrooms as well. Hope this helps.
P D Q
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On Tue, 11 Mar 2008 15:08:01 -0500, PDQ wrote:

<snip>
If I had a nickel for every time I've spotted wrong advice in a ww magazine ...
The article you reference may or may not be correct, but if the author isn't one of the well known ww gurus, take it with a grain of salt. And even then, try it for yourself.
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