Shelf life of shellac flakes?

richard newman · Dec 28, 2014

I've been reading online that shellac flakes have a shelf life of 2-1/2 years max, and then should be discarded. I've always thought that if the shellac dissolved and then dried hard enuf to sand it was ok. And I know I've used some stuff that was WAY older than 2 years.

What's the story here? Are the final properties of the finish compromised, even if the shellac seems to dry just fine? Should I dump my older stuff and replace it every 2 years?

DMF_TomB · Dec 29, 2014

shellac

richard newman said:
I've been reading online that shellac flakes have a shelf life of 2-1/2 years max, and then should be discarded. I've always thought that if the shellac dissolved and then dried hard enuf to sand it was ok. And I know I've used some stuff that was WAY older than 2 years.

What's the story here? Are the final properties of the finish compromised, even if the shellac seems to dry just fine? Should I dump my older stuff and replace it every 2 years?

.
i do not know life of flakes. i do know when i used white shellac as a paint with nothing
else after a few years in the sun and being outside it starts to peel off.
.
my guess is long ago thats all they had, nowadays i find a latex porch paint or paint
made for being outdoors and walked on is much tougher stuff
.
some use melted shellac flakes as a type of hot melt glue used to hold parts to a
lathe faceplate and when done pried off, heated to release, or alcohol to release.
so i would not throw the flakes away. maybe melt in a old coffee mug and microwave

stephen thomas · Dec 29, 2014

Richard-

I'd be glad to hear a finish technologies chemist chime in and describe whether shellac that still dissolves easily and sets fast, can nonetheless be degraded "somehow" or not.

Absent that, I do as you do and still use it.
I have stuff at least 5 yrs old, and maybe some 10 yrs old that still dissolves easily and works well.

My experience has been more that some batches or sources last longer than others in flake form. For instance, if the product spend a lot of time heated/hot storage or several cycles of same during the shipping process from India to dealer, to me, it will in all likely hood go "bad" more rapidly than something that went straight to Germany under the best controls, was shipped here the same way, and stored and shipped to me by a conscientious distributor. The example is just that, an example. I can't ever actually verify how the stuff got to me. But some has gone to where in alcohol it is goopy and virtually insoluble in maybe 2 yrs or less, and some is till "good" 10 yrs later.

I keep some lesser grades around for historic type color matches, but essentially only use dewaxed blondes for new work.

(there, that comment will probably derail this august discussion)

Not much help other than a "me too" and a bump.

smt

specfab · Dec 29, 2014

From Shellac (dot) net, some stimulating reading; I particularly like the use of "shiny and eye-catching" in various applications.

"Who uses it?

The largest uses for shellac are for the food, drug, and cosmetics industries. Fruits and vegetables in the produce aisle of your favorite grocery store are coated with shellac and wax to make them shiny and eye-catching. In the world of cosmetics, women (and men) use shellac-based hair-spray to make themselves appear shiny and more eye-catching. Many vitamins, pills and food supplements are coated with shellac to make them slide easily down your throat, into your tummy. Of course the most important use of shellac, in my not-so-humble opinion is as a woodworking finish, where you can make your projects shiny and eye-catching."

And on a lighter note, I prefer my blondes waxed. ;-)

Peter from Holland · Dec 29, 2014

Who says so ?
Distributor ?
He has a intrest that is not the same as that of the user
So I would take that with a grain of salt

Peter from Holland

richard newman · Dec 29, 2014

Peter, I've always had the same suspicions, thus the post. But the downside of being wrong can be so costly…

In the this case I'm using the shellac as a sealer coat on ebony and snakewood under nitrocellulose lacquer. Maybe that's even a less critical application than a complete shellac finish, but I'd hate to have my lacquer peel or flake off in the future. Seems like buying fresh stock might be reasonable insurance, or at least help me sleep well.

Greenwud · Jan 2, 2015

Have never had a problem, not with de waxed (inherited) flakes at 20+ years old or button lac at 10 years old. I usually add about 10% lacquer thinner to reduce blooming; this likely has an effect on otherwise insoluble material.
IME it does change in solution and will eventually deteriorate until it dries to a gummy film.

stephen thomas · Jan 2, 2015

I usually add about 10% lacquer thinner to reduce blooming

say more.

(what is blooming in this case?)

smt

sealark37 · Jan 2, 2015

When we cleaned out my Grandfather's shop (he had been gone for 15 years) in 1982, I found a can of shellac flakes. I only use a little every few years, but it still looks and works like new. The old boy was an old-school finish carpenter who wore a wool, three-piece suit and long sleeved shirt to work every day in Augusta, Georgia. He owned a Skilsaw, but preferred his hand saw. He could sharpen a hand plane or a chisel to scary sharp in a little bit. I never knew he was a drunk until I saw him sober when I was in my teens. Things have changed. Regards, Clark

Greenwud · Jan 2, 2015

stephen thomas said:
say more.

(what is blooming in this case?)

smt

"Blooming" is where the shellac develops a milky bloom as it dries. It seems to be something to do with humidity.

stephen thomas · Jan 2, 2015

Aha!
I thought it might be blushing (as often referred in USA). But best to ask.

Thanks!
smt

Greenwud · Jan 2, 2015

stephen thomas said:
Aha!
I thought it might be blushing (as often referred in USA). But best to ask.

Thanks!
smt

Don't it go pink if it's blushing?

mnl · Jan 30, 2015

All of mine is at least five years old, probably more like ten. When I do get a new container I weigh it out into small zip bags and put those back in the sealed container. I dissolve it with as dry ethanol as I can get. Generally the 200 proof grade, probably about 198 after the bottle has been opened a couple of times. By gas chromatograph it always seemed to be about 0.5% to 1% water. Never had a problem and seems to store pretty well.

gwilson · Jan 31, 2015

Dry flakes actually DO NOT have an unlimited life. It will get to the point that it will not dissolve in alcohol. They had that happen in the furniture conservation lab in Williamsburg,where I was the toolmaker. I store mine in bottles. Hopefully that will help. I don't know the chemical reasons why old flakes will not dissolve. But,I keep mine away from air,at least.

Blooming is the trapping of microscopic air bubbles when humidity is sufficiently high. The finish looks white and cloudy. The drying of lacquer or shellac is rapid,and serves as a refrigerant effect. The extra cooling causes the humid air to condense within the shellac or lacquer. I have had that happen. And,the blooming NEVER goes away. The only thing you can do is strip the finish and re do on a less humid day.

DMF_TomB · Jan 31, 2015

gwilson said:
Dry flakes actually DO NOT have an unlimited life. It will get to the point that it will not dissolve in alcohol. They had that happen in the furniture conservation lab in Williamsburg,where I was the toolmaker. I store mine in bottles. Hopefully that will help. I don't know the chemical reasons why old flakes will not dissolve. But,I keep mine away from air,at least.

Blooming is the trapping of microscopic air bubbles when humidity is sufficiently high. The finish looks white and cloudy. The drying of lacquer or shellac is rapid,and serves as a refrigerant effect. The extra cooling causes the humid air to condense within the shellac or lacquer. I have had that happen. And,the blooming NEVER goes away. The only thing you can do is strip the finish and re do on a less humid day.

.
i know some organic compounds change when exposed to sunlight for long periods of time. thus why some chemicals are stored in brown bottles and not clear glass bottles.
.
shellac i have used outdoors breaks down and peels within a few years. my guess is it is the sunlight exposure

gwilson · Jan 31, 2015

Why is anyone using shellac as an OUTDOOR finish? Or am I misreading something? It is the worst finish to use for outdoor use. Or do you mean you just were outdoors when you applied it? I doubt a short exposure of a bottle of shellac to sunlight would have much consequence.

Jaden · Feb 3, 2015

Or are you talking about blonde shellac flakes...?

stephen thomas · Jun 28, 2015

Well I after years of success, I have found my stash of shellac flakes has developed a dreaded case of "mostly will not dissolve".

Tried a 1/2 lb of superblonde, and then a 1/4lb of blond, and both turn into more of a mass of jelly, than a finish.

So, has anyone ordered anything form Shellac Shack? Recently?
Their online advertised price is about 30% - 40% better than most.
Store seems current, but last newsletter is.....'07!
I'll call tomorrow & see if they are still operational; but wondered about customer reviews from any PM'rs.

Shellac Shack: Purchase Shellac Flakes

smt

billzweig · Jun 29, 2015

I have no experience with flakes, but I am using shellac "cakes". Some 30 years ago I bought a few pound of those (orange shellac cakes, about the size of a cookie but thinner) and still using them without a problem. I keep them in a metal jar. It is possible that the flakes, with much higher surface area, can deteriorate through oxidation or moisture. Maybe melting the shellac flakes and cooling the melt as thin sheets could restore it.

stephen thomas · Jun 29, 2015

Been using shellac for 3+ decades or so myself. About a 1/2 dozen years ago, some older stock was slow to dissolve and made a jelly mess that was heck to strain out. (Shellac is a really, really good sealer, including the pores in paint strainers.

) Some of this is probably still from that batch, gotten worse.

Buttons apparently will last longer than flakes, but AFAIK, buttons still have the wax in them, which I don't use. Also do not think the really light shades (Platina) come in buttons.

My understanding is that shellac gradually poymerizes with exposure to oxygen and heat. So futher heating would not be expected to reconstitute it; but I'd be glad to hear if anyone else experiments.

Today I called Malcolm at Shellac Shack, they are doing fine, ordered 3 lbs of platina & 1 of super blonde. Will report anything newsworthy as it evolves.

smt

Shelf life of shellac flakes?

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