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?
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
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:
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
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
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
Let's see if I'm right.
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
On Mon, 10 Mar 2008 18:05:02 -0700, email@example.com wrote:
Dewaxed shellac slows down moisture vapor exchange, and thus wood
movement, better than any other finish with the possible exception of
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
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.
On Mon, 10 Mar 2008 21:28:51 -0700, firstname.lastname@example.org wrote:
Flexner's book calls it "excellent." McNamara:
calls it "best possible" and Jewitt:
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.
The gory details for that one are at
I don't see anything there to support the contention that shellac will
be superior to a marine-grade 2K polyurethane.
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
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
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:
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.
Just for clarity sake - shellac *is* a type of varnish. Quoting from
"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)..."
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?
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.
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
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.
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
If I had a nickel for every time I've spotted wrong advice in a ww
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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