I'm puzzled. I've always read that shellac has about a 6 month shelf life
and to toss the old stuff after that time. About 18 months ago I made up
some 2# cut of shellac from scratch. After I was done with it, I kept it in
a sealed plastic bottle.
Out of curiosity I took it out this weekend and used it straight from the
bottle on a small test project just to see what happens.
Nothing. It *appears* just fine. Dried quickly and firm. I was able to scuff
sand between coats. Tried brushing and padding - same thing - no problem.
Is there a hidden downside or did I just get lucky?
Not the most earth shattering issue of the day but a curiosity to me none
the less.
Thanx,
Vic
--
There are 10 kinds of people - those who understand binary and those who
don't
On 17 Jul, 20:11, "Vic Baron" <[email protected]> wrote:
> I'm puzzled. I've always read that shellac has about a 6 month shelf life
> and to toss the old stuff after that time. About 18 months ago I made up
> some 2# cut of shellac from scratch. After I was done with it, I kept it in
> a sealed plastic bottle.
>
> Out of curiosity I took it out this weekend and used it straight from the
> bottle on a small test project just to see what happens.
>
> Nothing. It *appears* just fine. Dried quickly and firm. I was able to scuff
> sand between coats. Tried brushing and padding - same thing - no problem.
>
> Is there a hidden downside or did I just get lucky?
>
> Not the most earth shattering issue of the day but a curiosity to me none
> the less.
>
> Thanx,
>
> Vic
>
> --
> There are 10 kinds of people - those who understand binary and those who
> don't
I've got a couple bottles of shellac that are at least 25 years old. I
don't often
use it, but whenever I do I have no trouble with its finish or
drying. These are quart
bottles; perhaps the larger volume/exposed surface ratio helps
preserve it?
> ... I've always read that shellac has about a 6 month shelf life and to toss the old stuff after that time. About 18 months ago I made up some 2# cut of shellac from scratch. After I was done with it, I kept it in a sealed plastic bottle.
>
> Out of curiosity I took it out this weekend and used it straight from the bottle on a small test project just to see what happens.
>
> Nothing. It *appears* just fine. Dried quickly and firm. ...
>
> Is there a hidden downside or did I just get lucky?
Keeping shellac a sealed bottle just keeps the alcohol from
evaporating. Shellac contains organics acids that will, over time,
react with alcohol to form esters. At that point the shellac won't dry
properly. Clearly, the rate of the reaction in your case was slow, but
about six months is the time it normally takes for esterification to
occur.
Joel
I have had goo dluck using shellac that is as old as 4 or 5 years.
I've never had shellac "go bad".
While I understand the chemistry involved with thetheoretical deterioration
of shellac, I've just never experienced it. I use steam distilled alcholohol
to make my shellac, almost always use dewaxed stuff, and store it in sealed
dark bottles at room temperature (my shop is usually fairly cool, and rarely
gets over about 70 degrees F)....
YMMV
-James (who also happens to be a scientist....)
"Vic Baron" <[email protected]> wrote in message
news:%[email protected]...
> I'm puzzled. I've always read that shellac has about a 6 month shelf life
> and to toss the old stuff after that time. About 18 months ago I made up
> some 2# cut of shellac from scratch. After I was done with it, I kept it
> in a sealed plastic bottle.
>
> Out of curiosity I took it out this weekend and used it straight from the
> bottle on a small test project just to see what happens.
>
> Nothing. It *appears* just fine. Dried quickly and firm. I was able to
> scuff sand between coats. Tried brushing and padding - same thing - no
> problem.
>
> Is there a hidden downside or did I just get lucky?
>
> Not the most earth shattering issue of the day but a curiosity to me none
> the less.
>
> Thanx,
>
> Vic
>
> --
> There are 10 kinds of people - those who understand binary and those who
> don't
Steve wrote:
> "Woodie" <[email protected]> wrote in message
> news:hZMfk.202663$TT4.186039@attbi_s22...
>> Artificially short shelf life predictions are published to ensure that new
>> product gets produced and sold. Just another reason to hate and fear
>> scientists.
>>
>
> That has NOTHING to do with scientists. It's the marketing folks who dream
> up that stuff.
>
Scientists are behind it. They always are. Evil, plotting, scary,
maniacal scientists.
On Jul 17, 9:10=A0pm, "[email protected]" <[email protected]> wrote:
> > ... I've always read that shellac has about a 6 month shelf life and to=
toss the old stuff after that time. About 18 months ago I made up some 2# =
cut of shellac from scratch. After I was done with it, I kept it in a seale=
d plastic bottle.
>
> > Out of curiosity I took it out this weekend and used it straight from t=
he bottle on a small test project just to see what happens.
>
> > Nothing. It *appears* just fine. Dried quickly and firm. ...
>
> > Is there a hidden downside or did I just get lucky?
>
> Keeping shellac a sealed bottle just keeps the alcohol from
> evaporating. Shellac contains organics acids that will, over time,
> react with alcohol to form esters. At that point the shellac won't dry
> properly. Clearly, the rate of the reaction in your case was slow, but
> about six months is the time it normally takes for esterification to
> occur.
>
> Joel
WRT the 6 month life, does the clock start at manufacture or at the
first time the factory can is opened?
Thanks,
Bill L.
"Woodie" <[email protected]> wrote in message
news:hZMfk.202663$TT4.186039@attbi_s22...
>
> Artificially short shelf life predictions are published to ensure that new
> product gets produced and sold. Just another reason to hate and fear
> scientists.
>
That has NOTHING to do with scientists. It's the marketing folks who dream
up that stuff.
--Steve in Roseville
Vic Baron wrote:
> I'm puzzled. I've always read that shellac has about a 6 month shelf
> life and to toss the old stuff after that time. About 18 months ago I
> made up some 2# cut of shellac from scratch. After I was done with it, I
> kept it in a sealed plastic bottle.
>
> Out of curiosity I took it out this weekend and used it straight from
> the bottle on a small test project just to see what happens.
>
> Nothing. It *appears* just fine. Dried quickly and firm. I was able to
> scuff sand between coats. Tried brushing and padding - same thing - no
> problem.
>
> Is there a hidden downside or did I just get lucky?
>
> Not the most earth shattering issue of the day but a curiosity to me
> none the less.
Artificially short shelf life predictions are published to ensure that
new product gets produced and sold. Just another reason to hate and fear
scientists.
I guess it time for me to let out one of my maniacal cackles! You'll have
to imagine it, because I don't know how to spell it.
--Steve, whose job title was once "Research Scientist"
"Woodie" <[email protected]> wrote in message
news:Q4Tfk.203470$TT4.92133@attbi_s22...
> Steve wrote:
>> "Woodie" <[email protected]> wrote in message
>> news:hZMfk.202663$TT4.186039@attbi_s22...
>>> Artificially short shelf life predictions are published to ensure that
>>> new product gets produced and sold. Just another reason to hate and fear
>>> scientists.
>>>
>>
>> That has NOTHING to do with scientists. It's the marketing folks who
>> dream up that stuff.
>>
>
> Scientists are behind it. They always are. Evil, plotting, scary, maniacal
> scientists.
On Mon, 21 Jul 2008 08:25:18 -0700, Bill Leonhardt wrote:
> WRT the 6 month life, does the clock start at manufacture or at the
> first time the factory can is opened?
At date of manufacture. But Zinsser puts some sort of preservative in
their shellac that they claim keeps it usable for 3 years. I get nervous
after two and toss it.
BTW, use the Sealcoat, not the stuff with wax in it. Sealcoat is marketed
as sealer, but it's just a two pound cut of dewaxed shellac.
I've been told that the preservative keeps the shellac from ever drying
quite as hard as the non-preserved stuff, but I can't tell any difference.
If that possibility bothers you, mix your own from dewaxed flakes.