Shellac composition

I don't know about the dewaxed or not, but I use the premixed Bull's
Eye shellac available from home depot. It is already mixed in a
factory, so they can do it much more accurately than I could ever. It
is dewaxed, and can be thinned with alcohol if necessary. It may be
hard to find in Mexico, but I bet that you can get it by mail. My
guess that the hardware store shellac might have used to be passable,
but it has probably sat there much beyond its shelf life, which is
usually only about 6 months.

"AAvK" <[email protected]> wrote in message
news:JGA8e.29236$A31.28554@fed1read03...
>
> I think the right alcohol is "anhydrous" ... means there is no h2o in it.
> Sold and explained by Hock tools.

Yes and no. Truth to tell, the stuff they put in to get the last 5% water
out is about the worst (for you) part of the mix. Why 5%? Look up
azeotrope.

Then there's that other truth, that open jars and jars with a lot of air
allow the alcohol to gain atmospheric water. It's not a big deal up to
perhaps 10%.

>
> What is the problem with waxed shellac anyway? Why the preferences
> for the dewaxed variety?

As others have mentioned - it behaves like wax in its rejection of finishes
and traps water underneath to give a brighter "blush" ring. Not to mention,
there are probably some other non-polar organics extracted along with the
wax, though they may have helped, rather than hindered by being there.

> I assume you aren't buying dewaxed shellac, and if that is the case,
> then the wax will always be suspended in the mixture and if it sits for
> a few days, it will settle to the bottom of the jar. My guess is you
> are seeing mostly wax falling out of the solution. Also bear in mind
> that since shellac is a natural product produced by insects, it will
> have impurities in it and you are supposed to strain it before using it.
> What you are seeing sounds normal to me and if you separate the clear
> solution from the precipitate on the bottom, you will have made your own
> dewaxed shellac. Also beware of the quality of your alcohol as well as
> the shellac. If the alcohol has much water in it, it won't dissolve the
> shellac very well. Alcohol would be a good thing to buy from a chemical
> supply house, because the quality should be very high. Keep your
> alcohol closed tightly at all times, because it will draw moisture from
> the air. If you can find Zinsser Seal Coat in Mexico, it is a dewaxed
> shellac already made for you in a 2 pound cut. It is very common in the
> US.


I think the right alcohol is "anhydrous" ... means there is no h2o in it.
Sold and explained by Hock tools.

What is the problem with waxed shellac anyway? Why the preferences
for the dewaxed variety?

--
Alex - newbie_neander in woodworking
cravdraa_at-yahoo_dot-com
not my site: http://www.e-sword.net/

Zinsser says their spray can is also dewaxed as wax plugs the nozzle.
www.homeateadfinishing.com has the history of shellac as an article that
makes an interesting read albeit fairly long.


"Hax Planx" <[email protected]> wrote in message
news:[email protected]...
> woodworker88 says...
>
> > I don't know about the dewaxed or not, but I use the premixed Bull's
> > Eye shellac available from home depot. It is already mixed in a
> > factory, so they can do it much more accurately than I could ever. It
> > is dewaxed, and can be thinned with alcohol if necessary. It may be
> > hard to find in Mexico, but I bet that you can get it by mail. My
> > guess that the hardware store shellac might have used to be passable,
> > but it has probably sat there much beyond its shelf life, which is
> > usually only about 6 months.
>
> Only the Bullseye Seal Coat is dewaxed, but it is found in more stores
> than the regular shellac, because it isn't advertised as being shellac.
> The hoi polloi wouldn't buy it if they didn't think it was a new and
> mysterious concoction. It's a good bargain at about $8 a quart for a 2#
> cut from a discount box store. The regular Bullseye blonde and orange
> shellac is definitely NOT dewaxed.

woodworker88 says...

> I don't know about the dewaxed or not, but I use the premixed Bull's
> Eye shellac available from home depot. It is already mixed in a
> factory, so they can do it much more accurately than I could ever. It
> is dewaxed, and can be thinned with alcohol if necessary. It may be
> hard to find in Mexico, but I bet that you can get it by mail. My
> guess that the hardware store shellac might have used to be passable,
> but it has probably sat there much beyond its shelf life, which is
> usually only about 6 months.

Only the Bullseye Seal Coat is dewaxed, but it is found in more stores
than the regular shellac, because it isn't advertised as being shellac.
The hoi polloi wouldn't buy it if they didn't think it was a new and
mysterious concoction. It's a good bargain at about $8 a quart for a 2#
cut from a discount box store. The regular Bullseye blonde and orange
shellac is definitely NOT dewaxed.

[email protected] says...
> Hello all.
> Does anyone have information about dewaxed shellac composition.
> I usualy bought shellac from a hardware store and I am not sure that
> its the best shellac to use on finishing, hardware store could not
> provide me any specifications.
> So while looking at chemistry supplies providers if found this shellac
> **************************
> Alcohol Insoluble 0.72%
> Color Lovibond 12
> Acid Value 65
> Fusion Range 73°C
> Iodine Value 14.5
> Humidity 1.33% in Alcohol
> Wax 3.42%
> Ashes 0.145%
> Rosins NIL
> Colofonía NIL
> ****************************
> It says 3.42% wax, I wonder if dewaxed means 100% wax free or not ?
>
> Also regarding shellac preparation, I use 15gr shellac + 120 gr alcohol
> for 1 pund cut and 30 gr shellac + 120 gr alcohol for 2 pound cut. So I
> tried this time to use hot water to heat up the flasks with shellac,
> stirr every now and then, for 2 days but shellac just wont dissolve, a
> large amount of flakes just wont dissolve totally and just sit there.
> In the beggining the solution is like a suspension but after a couple
> of days it cleared up and the undissolved matter kind of 'vulcanised',
> I mean that it formed nuggets and precipitated on the bottom. For one I
> am happy that the solution is nice and transparent but otoh I wish that
> all of it dissolved. I guess the shellac from hardware store I am
> buying is not top notch quality. I guess Id have to get some dewaxed
> from shellac.net, happens that I am in Mexico and its kind of hard to
> get something good quality with full specifications on it.
>
>
>
> Konstantin.


I assume you aren't buying dewaxed shellac, and if that is the case,
then the wax will always be suspended in the mixture and if it sits for
a few days, it will settle to the bottom of the jar. My guess is you
are seeing mostly wax falling out of the solution. Also bear in mind
that since shellac is a natural product produced by insects, it will
have impurities in it and you are supposed to strain it before using it.
What you are seeing sounds normal to me and if you separate the clear
solution from the precipitate on the bottom, you will have made your own
dewaxed shellac. Also beware of the quality of your alcohol as well as
the shellac. If the alcohol has much water in it, it won't dissolve the
shellac very well. Alcohol would be a good thing to buy from a chemical
supply house, because the quality should be very high. Keep your
alcohol closed tightly at all times, because it will draw moisture from
the air. If you can find Zinsser Seal Coat in Mexico, it is a dewaxed
shellac already made for you in a 2 pound cut. It is very common in the
US.

AAvK says...

> I think the right alcohol is "anhydrous" ... means there is no h2o in it.
> Sold and explained by Hock tools.
>
> What is the problem with waxed shellac anyway? Why the preferences
> for the dewaxed variety?

In addition to what Jack said, dewaxed shellac gives a clearer finish.
I'd be curious to hear if anybody knows a situation in which leaving the
wax in is preferable. Maybe there is, but AFAIK, the only disadvantage
of dewaxed is the cost, or time if we do it ourselves.

nospambob says...

> Zinsser says their spray can is also dewaxed as wax plugs the nozzle.
> www.homeateadfinishing.com has the history of shellac as an article that
> makes an interesting read albeit fairly long.

Forgot about that. But it's kind of expensive.

eliminate the typo and try:

www.homesteadfinishing.com

--
Learn from the mistakes of others. Trust me, you can’t live long enough to
make them all yourself. I’ve tried!!
"Hax Planx" <[email protected]> wrote in message
news:[email protected]...
> nospambob says...
>
> > Zinsser says their spray can is also dewaxed as wax plugs the nozzle.
> > www.homeateadfinishing.com has the history of shellac as an article that
> > makes an interesting read albeit fairly long.
>
> Forgot about that. But it's kind of expensive.

AAvK wrote:

>
> What is the problem with waxed shellac anyway? Why the preferences
> for the dewaxed variety?
>

If shellac is used as a barrier coat wax may cause adhesion problems
with the top coat.

Most of the problems people often associate with a shellac finish are
caused by the use of shellac containing wax. For instance, I've
experimented with shellac by taking a scrap piece of black walnut
finished with dewaxed shellac. I poured a puddle of water on the
finished piece, set a glass in the puddle and left it sit over night.
the water did not harm the finish and there was no white ring. Trying
the same thing with a scrap finished with shellac containing wax didn't
fare too well.

--
Jack Novak
Buffalo, NY - USA
[email protected]
(Remove -SPAM- to send email)

Konstantin:

Try http://www.woodfinishingsupplies.com/
click on Shellac link.
This site has about 2 hours of reading on shellac and the products they
sell.

As you said, you purchased shellac from your local hardware store, but since
not all shellac is created equal (natural product like wine, beer, etc) I
suggest you try another source. Several sites on web sell high quality
shellac, and with higher volume sales, products from these site may not have
been on store shelf for long time.

Phil