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Dewaxed shellac

fishnskibum's picture

Dewaxed shellac (post #107453)

I've been meaning to ask this question for some time now. Can somebody pleas tell me what dewaxed shellac is? I know, I know, it's shellac from which the wax has been removed. But what are the characteristics of both kinds, and when does one use one instead of the other, and why.


I've also read that you can dewax your own shellac. If true, how is this done.


Also what does #1 cut or #2 cut mean? Would that be one pound (or two) of flakes to a gallon of alcohol?


Thanks in advance.


 


Chris

Rich14's picture

(post #107453, reply #1 of 16)

Chris,

A wax is a normal constituent of shellac as it is prepared from the droppings of the lac bug. There is quite a bit of it in the deeply colored shellac varieties. As shellac is further refined into the paler shades, a lot of the wax is removed as a consequence of the refining and almost all of it gets removed in the ultra blonde varieties which are bleached.

The wax does not mix with alcohol and a quantity of waxed shellac is not clear in the container. Clouds of wax swirl up every time it is stirred or mixed.

If shellac is being used as the only final finish, there is no need to remove the wax. Additional coats of shellac adhere to each dry under coat. But if certain other finishes are to be used, the shellac should be dewaxed. Polyurethane varnishes and many lacquers won't adhere well to waxed shellac, although standard varnish will.

Some people recommend decanting the top, clear shellac off a mixture of waxed shellac after it has been left for the wax to settle to the bottom. This is very hard to do, as the wax very easily swirls up into the clear shellac as one tries to pour off the upper layer.

Another way is to filter the shellac through open mesh paint strainers, then a coffee filter. This will remove most of it, but it's tedious and you have to use a lot of paint strainers as the mesh gets clogged quickly.

A method that will remove 99.9% of the wax in one operation is to fill a plastic squeeze bottle 3/4 full with waxed shellac, 1/4 mineral spirits. Put the tip on the plastic spout and shake vigorously, homogenizing the alcohol/mineral spirits mixture which will become milky white. Turn the bottle upside down with the tip pointing down and let it settle overnight. The clear shellac will be on the bottom, the wax will be in the oil layer on top. Remove the tip and gently squeeze out the alcohol layer until the white oil layer just starts to enter the downward pointing tip and stop. Voila - perfectly clear, dewaxed shellac.

Your formula for mixing is correct. A 1# cut contains 1 lb of shellac flakes disolved in a gallon of alcohol. Other cuts are proportionate.

Rich


Edited 5/26/2005 2:21 am ET by Rich14

forestgirl's picture

(post #107453, reply #5 of 16)

Wow, great explanation.  Thanks for the "squeeze bottle technique" for dewaxing.

forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Another proud member of the  "I Rocked With ToolDoc Club" .... :>) 

forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 

Rich14's picture

(post #107453, reply #6 of 16)

forestgirl,

You're welcome. The wax layer is interesting also. Squeeze it out and let the solvent evaporate for a few days (or weeks). I've never had the wax get very hard. It just remains a soft, pale substance. I don't know if it's good for much, other than as its natural self when it's still in the shellac and helps as a lubricant when French Polishing!

Rich

forestgirl's picture

(post #107453, reply #9 of 16)

"I don't know if it's good for much..."  Maybe it could be turned into some kind of beauty product for women (or men!) who go for such things.  Might be the next big thing, ya never know!

forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Another proud member of the  "I Rocked With ToolDoc Club" .... :>) 

forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 

nikkiwood's picture

(post #107453, reply #10 of 16)

I have heard that shellac wax is (or at least used to be) one of the main ingredients for paste-style shoe polish.

********************************************************
"I tend to live in the past because most of my life is there."
-- Herb Caen (1916-1997)

******************************************************** "It is what we learn after we think we know it all, that counts." John Wooden 1910-
forestgirl's picture

(post #107453, reply #12 of 16)

Shoe polish?  What's that?? <g> doesn't work on my Avia's or my sandles, which I'm finally, finally getting to wear this week!

forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Another proud member of the  "I Rocked With ToolDoc Club" .... :>) 

forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 

douglas2cats's picture

(post #107453, reply #2 of 16)

The dewaxed varieties are what you want to use when you're using shellac as some sort of barrier coat between other types of finishes. Many other finishes will bond to the dewaxed shellac, but not to shellac with wax in it. If you're after a shellac only finish, there's no need to go through the hassle or extra cost of getting the dewaxed type. You can buy dewaxed flakes. Or mix a batch and wait til the wax settles out then pour off the top layer into a separate container.


Your right on the 'cut' math. HH's library site has a pretty clear FAQ.


http://www.tools-for-woodworking.com/mixingshellac.pdf


Waddaya mean it wont fit through the door?

If you build it he will come.

fishnskibum's picture

(post #107453, reply #3 of 16)

Thanks to both.


This forum is a great source of info.


 


Chris

nikkiwood's picture

(post #107453, reply #4 of 16)

If you don't want to dewax your own shellac, you can buy Seal Coat (Zinsser), which is a 2 lb cut they have dewaxed for you.

Another alternative is to buy "Super Blond" shellac flakes, and mix with alcohol.

Dewaxed shellac is especially useful for two purposes:

1) Water based finishes will raise the wood grain, which you can avoid entirely by first sealing the surface the the dewaxed shellac.

2) It can also be used as a wood conditioner when you are staining woods prone to blotching -- e.g. cherry, birch, maple, and pine.

Dewaxed shellac is one of the most useful items you can have in your finishing arsenal.

********************************************************
"I tend to live in the past because most of my life is there."
-- Herb Caen (1916-1997)

******************************************************** "It is what we learn after we think we know it all, that counts." John Wooden 1910-
Rich14's picture

(post #107453, reply #7 of 16)

nikkiwood,

Alcohol also raises wood grain. Not as much as water, but the effect is not trivial and a thin wash of shellac will leave both raised grain and shellac nibs which must be knocked down with sanding before the next finishing step.

Rich

nikkiwood's picture

(post #107453, reply #11 of 16)

Of course you're right about alcohol raising the grain, but this is also at least somewhat misleading. With even a 1 lb cut of shellac, I would argue that the grain raising effect is negligible, and easily rectified by a quick, light sanding -- resulting in a glass smooth surface.

Grain raising with any waterbased product is dramatic and pronounced, and difficult to smooth out. You can diminish this effect somewhat by pre-wetting the wood surface with plain water and sanding off the nibs. But it is way easier, with a better result, if you seal with dewaxed shellac first, sand, then move on to you water based product.

********************************************************
"I tend to live in the past because most of my life is there."
-- Herb Caen (1916-1997)

******************************************************** "It is what we learn after we think we know it all, that counts." John Wooden 1910-
JP's picture

(post #107453, reply #8 of 16)

Chris,
You may find also that waxy shellac will rub out a little easier than dewaxed. I dewax my own with the method described previously as well and I swear that the waxy garnet and seedlac that I use rubs out better than the stuff I dewaxed. Waxy shellac tends to leave a little more residue on the steel wool and less drag on the pad when rubbing out.

Maybe I'm crazy but it just seems to be that way for me.

J.P.

HowardAcheson's picture

(post #107453, reply #13 of 16)

Here is something that may be helpful. It is from Michael Drendner in responce to a question on another forum.

QUOTE

Subject: natural vs. dewaxed -- pros and cons
Posted By: Michael Dresdner <janeandmichael@msn.com>;
Date: Sunday, 16 February 2003, at 11:59 a.m.
In Response To: please clarify wax vs dewax issue (bill tindall)

First, to clarify, neither natural nor dewaxed shellac is "better" -- one or the other is simply more or less appropriate for the job at hand. But there are differences, and you need to know them to make an educated decision when to use one or the other.

In its natural state, shellac contains about 5% wax. Shellac is the protective shell that the lac bug (laccifer lacca) creates for itself during its larva stage. It is believed that the wax is created as breathing tubes. In any case, shellac wax is the second hardest wax we know of (just behind carnuba, a plant wax) and it is widely used in both wood and car polishes.

Only modern finishes have a problem going over natural shellac -- and in fact, only a few modern finishes (polyurethane, conversion, and waterbased) at that. However, many of us do use modern finishes (myself included -- I also use both modern power tools and traditional hand tools side by side). If you don't use modern finishes, it may not be an issue. But if you do, and you plan to use shellac as a sealer coat -- something it is ideal for -- then you must use dewaxed shellac under them.

The other characteristics: pros and cons

Natural shellac (with wax) is easier to sand, though not that much, and it is definitely less glossy -- something many people prefer. Some folks feel the wax adds lubricity for both French polishing and lathe work, though personally I have not seen much difference.

Dewaxed shellac is better for sealing under modern finishes, and has more clarity. (The wax makes the shellac slightly cloudy.) Again, this shows up on thick shellac finishes, but is not very apparent on thin ones. There is some evidence that dewaxed shellac has slightly better resistance to water spotting, but again, if this is the case, it is a rather subtle difference. Technically, dewaxed shellac is harder, but once again, the difference is something you could prove in the lab but would not notice on fine furniture.

As for shelf life, there is no evidence that the shellac either prolongs or shortens shelf life. It seems to have no effect on it whatsoever. For the record, the patented process used to create SealCoat has nothing to do with the wax, and can create long shelf life shellac with or without the wax in it.

END QUOTE

Howie.........
Howie.........
nikkiwood's picture

(post #107453, reply #14 of 16)

<<"As for shelf life, there is no evidence that the shellac either prolongs or shortens shelf life. It seems to have no effect on it whatsoever. For the record, the patented process used to create SealCoat has nothing to do with the wax, and can create long shelf life shellac with or without the wax in it.">>

Anybody else confused by this last statement?

********************************************************
"I tend to live in the past because most of my life is there."
-- Herb Caen (1916-1997)

******************************************************** "It is what we learn after we think we know it all, that counts." John Wooden 1910-
HowardAcheson's picture

(post #107453, reply #15 of 16)

I assume Michael meant "wax" rather than "shellac". In other words:

"As for shelf life, there is no evidence that the wax either prolongs or shortens shelf life."

Howie.........
Howie.........
forestgirl's picture

(post #107453, reply #16 of 16)

Howie, thanks very much for posting that explanation here.  I find Dresdner's explanations thorough and well-written.  We'll forgive him the wax/shellac confusion, LOL!

forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Another proud member of the  "I Rocked With ToolDoc Club" .... :>) 

forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)