Shellac and humidity

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Forum topic by swirt posted 10-14-2010 08:36 PM 2720 views 1 time favorited 9 replies Add to Favorites Watch
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2785 posts in 2998 days

10-14-2010 08:36 PM

Topic tags/keywords: finish shellac moisture

I just read an article in the most recent Fine Woodworking (Dec 2010 No 215) on “Why Finish Wood.” (p78) The article itself had very little of anything great in it, mainly a little bit of compare and contrast between oil, shellac and poly… nothing ground breaking. There was a table in there though that surprised me.
It was a table comparing how well a finish repelled moisture, not from contact, but humidity in the air. Waxes, oils, lacquer failed miserably. The surprising part for me was that Shellac and Oil-based polyurethane were almost identical in their performance.

It does help explain why the 6 panel pine doors on my bathrooms seem to hold up well and not get too bent out of shape with the humidity from the shower.

The same issue has a great though slightly disgusting article on the process of making shellac. Now every time I use shellac all I can picture is some guy holding the shellac blob in his mouth as he uses his feet, hands and mouth to stretch it out. Still one of my favorite finishes.

-- Galootish log blog,

9 replies so far

View mafe's profile


11730 posts in 3115 days

#1 posted 10-15-2010 02:01 AM

Thats quite interesting.
Thank you for sharing this.
I think I have to see that picture to really imagine that!
Best thoughts,

-- MAD F, the fanatical rhykenologist and vintage architect. Democraticwoodworking.

View swirt's profile


2785 posts in 2998 days

#2 posted 10-15-2010 05:12 AM

LOL Sorry, it was a table of numbers, not a table of wood. So no picture … unless you were talking about a picture of me in the shower…. that aint happening either.

I traced the data back to a 1985 study by US Forestry Products. The date hints at why waterbased poly is probably not listed in the comparison.

-- Galootish log blog,

View swirt's profile


2785 posts in 2998 days

#3 posted 10-15-2010 05:13 AM

Ohh the shellac photo…. now I get it. I’ll see if I can find one for you.

-- Galootish log blog,

View swirt's profile


2785 posts in 2998 days

#4 posted 10-15-2010 05:25 AM

The closest stretching photo I can find, (without lifting the one from the magazine) is on this page.
The guy in this photo is only using his hands and feet though and not his mouth… which is less disturbing for me LOL

-- Galootish log blog,

View Dark_Lightning's profile


3165 posts in 3135 days

#5 posted 10-15-2010 05:42 AM

Aww, swirt, look how skinny those people are! Buy their shellac so they can afford a McDonald’s nearby…that sells only chicken. J/K.

As far as shellac and oil-based paints go, it’s lucky for us in sunny Cal that the weather is nice enough to not destroy the exterior paint every year. Elsewhere, you can buy oil-based paint (?) and the finish lasts a lot longer.

Another added benefit to shellac is that fantastic drying time. I did some (free, of course) remodeling work for my mother many years ago, and one of the things needing refinishing was the hall closet by the front door…a real nice mahogany plywood. I put a new stain-grade fir frame around it and shellacked the whole thing. She had emphysema from smoking cigarettes, and couldn’t stand petroleum distillates. That shellac dried tout-suite with low odor- no sick mom, and a nice finish.

Public service message- don’t use tobacco, it cuts the lives of our loved ones short, and what lives they do have are diminished in quality.

-- Random Orbital Nailer

View richgreer's profile


4541 posts in 3101 days

#6 posted 10-15-2010 05:03 PM

That is interesting. I’ve never had much respect for shellac and I only use it in 2 situations – I need super fast drying time or I need something that is food safe.

Did you know that shellac is edible? The primary ingredient in time release medicine capsules is shellac.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

View tnwood's profile


259 posts in 3113 days

#7 posted 10-15-2010 08:35 PM

Shellac is a great finish but it is no longer used in time release medicines. Years ago it was used as a tablet coating but new polymers that can be more easily regulated for release characteristics are now the norm. There may be some small companies using it but I’m not sure I would want to take their pharmaceuticals.

View swirt's profile


2785 posts in 2998 days

#8 posted 10-15-2010 09:23 PM

I use shellac quite a bit as a mere hobby woodworker. I like it all. I like that it dries fast. I like that I can apply it in my basement shop and not have my wife tell me how bad the house stinks. I like that I can repair it as easy as I can put it on.

I’ve only recently learned that it is pretty UV resistant and just with this article learned about its resistance to humidity. So now I like it even more.

I’ve got a little experiment going that just started. I replaced two windows on the south end of my house. On the sill and trim in one of them I used amber shellac then covered it with two coats of wipe-on spar poly. On the other, I just used amber shellac. I’m looking forward to seeing how they each hold up.

-- Galootish log blog,

View ChuckV's profile


3124 posts in 3553 days

#9 posted 10-15-2010 09:47 PM

I am also a shellac fan. I learned about it from my Dad a long time ago when he used it all around the house. My Dad is now in his mid-nineties, so his shellacking (if that’s the right word) days are over. But, I love the connection with the past. I think that it is mostly the aroma that brings back all the memories.

-- “Big man, pig man, ha ha, charade you are.” ― R. Waters

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