Sandarac Shelf Life??
Guitarmakermark
Have decided to experiment with adding Sandarac resin to my shellac,
to test out as a guitar finish. Have been having great success with
padding on shellac, and having reached the point, thru repeated
practice, have arrived at the point where shellac padded on is my
first choice for finishing my hand-made instruments.
The trouble is, this Sandarac does not seem to want to readily
dissolve in the (denatured) alcohol in which I dissolve my shellac.
Two questions:
1. Does Sandarac have a shelf-life, after which it will not easily
dissolve (if at all) in alcohol, and,
2. Does anyone here have experience with Sandarac and would perhaps be
willing to offer some suggestions regarding how best to dissolve this
resin into alcohol?
Thanks!
Mark
David Hajicek
Kremer Pigments claims Sandarac is soluble in pure ethyl alcohol. They make
no caution about shelf life. I've never used it. Give it more time or try
some heat (carefully). Turpentine may also dissolve it, and then it could
be added to the shellac.
Is this supposed to make the shellac harder?
Dave Hajicek
"Guitarmakermark" <Guitarm...@Yahoo.com> wrote in message
news:62501b1b-a2fd-4962...@12g2000pri.googlegroups.com...
Guitarmakermark
Nice to hear from you!
Sandarac supposedly will make the dried film a bit glossier and more
flexible, perhaps making the shellac/sandarac mixture a bit more
musical sounding than shellac alone.
I'm going to dunk the bottle in my glue pot to help dissolve the
sandarac. I don't want to introduce turpentine into the mix, but I'm
thinking it might have been better to dissolve the two resins
separately, then mix them together.
Thanks for the data from Kremer.......how have things been for you??
Mark
David Hajicek
"Guitarmakermark" <Guitarm...@Yahoo.com> wrote in message
Hi Mark.
I know what you mean. The shellac can be a bit bright sounding for a while.
But that goes away (in my experience, anyway) after a bit of playing.
I'm kind of slow on the music/guitar making scene. I'm still working full
time at my day job and my back has been giving me a lot of problems. So I
just crash when I come home. Hopefully the doctors will come up with
something that works long term so I can be more active in the guitar making.
I have lots of projects I want to do.
Wish me luck.
Regards,
Dave
Guitarmakermark
I hear you loud and clear, regarding back pain issues!
I crashed my bicycle at 16 mph about four weeks ago, twisting my knee
and giving the right side of my body a significant road-rash, not to
mention banging up the right side of my ribcage and abdomen pretty
badly.
So, these days, I'm hobbling about like an 85-year-old rather than my
rightfully earned 57 years....very slow to get work done in my
workshop! Nonetheless, it's getting better, a little bit each day.
Courage, my friend, your back pain will get better, too, I promise!
In the meantime, I'm going to separately dissolve some sandarac and
shellac, to try to find out which of those was slow to fully
dissolve. I read elsewhere too, that one can filter the liquid to
remove the undissolved resin portion, and still have a usable spirit
varnish.
Take care, David.
Mark
A.J.Lucas
I'd be interested to hear how you get on. I use French polish (the
only finish named after two nationalities (three if you count
Finnish!)) and have thought about adding gums to make it harder. At
the moment I'm polishing with walnut oil as the lubricant, which is
supposed to dry in the finish to make it harder.
Adrian
www.lucasguitars.co.uk
David Hajicek
"A.J.Lucas" <ajl...@ntlworld.com> wrote in message
news:a2d6a53f-5ccd-43dc...@37g2000yqm.googlegroups.com...
Adrian
www.lucasguitars.co.uk
__________
Adrian:
Walnut Oil is a good choice. You can use the extra on your salad.
The Walnut oil one normally buys at the supermarket has an anti-oxidizer
added so it doesn't spoil too quickly (It may not harden either). A
health-food store may have some without the additive. So maybe keep it in
the fridge when it is not needed? How has this been working?
Dave Hajicek
Jim McGill
>
> I'd be interested to hear how you get on. I use French polish (the
> only finish named after two nationalities (three if you count
> Finnish!)) and have thought about adding gums to make it harder. At
> the moment I'm polishing with walnut oil as the lubricant, which is
> supposed to dry in the finish to make it harder.
>
> Adrian
> www.lucasguitars.co.uk
> __________
> Adrian:
>
> Walnut Oil is a good choice. You can use the extra on your salad.
>
> The Walnut oil one normally buys at the supermarket has an anti-oxidizer
> added so it doesn't spoil too quickly (It may not harden either). A
> health-food store may have some without the additive. So maybe keep it in
> the fridge when it is not needed? How has this been working?
>
> Dave Hajicek
>
>
use almond oil (which will also polymerize - it's the oil of choice for
woodwinds).
Guitarmakermark
It was not the Sandarac, after all, which was not dissolving in the
alcohol.....it was the blonde shellac flakes which failed to dissolve.
I proved this out by dissolving some sandarac and some of the blonde
shellac in separate bottles; the sandarac dissolved like chocolate
syrup in hot milk!
I made up a mixture of 4 parts (fresh) orange shellac and one part
sandarac....made a beautiful polish which pads on really nicely. We
shall see, after the finish has dried, how it compares to pure
shellac.
Regarding the walnut oil, I have been getting really nice results in
my padded shellac finishing using no oil or other lubricant at all. I
have read, I don't recall where, that oil in shellac tends to degrade
the quality of the dried film. Nonetheless, I am curious as to how a
bit of walnut oil would affect the padding shellac finish, so,
probably I will experiment with it some time in the future.
For now, thanks to all who posted in reply to my original queries.
Peace,
Mark
Dwain
Mark, I dissolve shellac flakes more easily by putting them in a
coffee grinder! Grind until you get dust, then pour into the alcohol
while stirring vigorously. I use 1 oz (wt) shellac to 1 cup alcohol
for a 1-lb cut for brush work, and at this mixture, starting with
powdered flakes really speeds up the disolving process. Make sure you
stir vigorously enough so the flakes don't form a sediment on the
bottom while you're adding. By next day, I find it enough dissolve to
be fit for use. Within two days its all dissolved.
Dwain Wilder
Bear Meadow Appalachian Dulcimers
David Hajicek
"Guitarmakermark" <Guitarm...@Yahoo.com> wrote in message
If you are happy with the results you are getting now, I would hesitate to
add oil. It does make it easier to pad on, but then you have to spirit off
the excess and it can slow the hardening time by quite a bit. Like you, I
don't use oil. I use mineral spirits if I need lubrication and that does
not get amalgamated into the shellac.
Supposedly (though I cannot confirm this), the oil will eventually make the
shellac harder and less likely to be affected by alcohol or other solvents.
My personal opinion is that it was a way for ancient makers to get an
acceptably smooth finish without having to sand and polish (which would have
been hard for them to do, if they could).
Dave Hajicek.
Father Haskell
wrote:
> "Guitarmakermark" <Guitarmakerm...@Yahoo.com> wrote in message
Mineral oil. Flexner said naptha is better for spiriting off
than alcohol, because it won't dissolve the shellac.
> Supposedly (though I cannot confirm this), the oil will eventually make the
> shellac harder and less likely to be affected by alcohol or other solvents.
> My personal opinion is that it was a way for ancient makers to get an
> acceptably smooth finish without having to sand and polish (which would have
> been hard for them to do, if they could).
Keeps the rag from sticking. Pumice brings up the gloss.
David Hajicek
"Father Haskell" <father...@yahoo.com> wrote in message
news:1573689b-cd16-42ea...@33g2000vbe.googlegroups.com...
On Dec 13 2009, 11:49 pm, "David Hajicek" <haji...@skypoint.com>
wrote:
> "Guitarmakermark" <Guitarmakerm...@Yahoo.com> wrote in message
>
> news:1b1d3da1-3cd7-4636...@y32g2000prd.googlegroups.com...
>
>
> > Follow-Up on my earlier post regarding Sandarac...
>
> > It was not the Sandarac, after all, which was not dissolving in the
> > alcohol.....it was the blonde shellac flakes which failed to dissolve.
> add oil. It does make it easier to pad on, but then you have to spirit off
> the excess and it can slow the hardening time by quite a bit. Like you, I
> don't use oil. I use mineral spirits if I need lubrication and that does
> not get amalgamated into the shellac.
Mineral oil. Flexner said naptha is better for spiriting off
than alcohol, because it won't dissolve the shellac.
> Supposedly (though I cannot confirm this), the oil will eventually make
> the
> shellac harder and less likely to be affected by alcohol or other
> solvents.
> My personal opinion is that it was a way for ancient makers to get an
> acceptably smooth finish without having to sand and polish (which would
> have
> been hard for them to do, if they could).
Keeps the rag from sticking. Pumice brings up the gloss.
=========
In my case, the Mineral Spirits (not oil), basically oderless paint thinner,
is used as a lubricant instead of oil, to keep the pad from sticking. Some
people use Kerosene, which works better (thicker), but I don't like the
smell. I would be afraid of using mineral oil as any that gets entrained
would never harden. Only a hardening oil should be used.
One could try to use mineral spirits to spirit off some Walnut oil or such,
it would be easier to use than alcohol. I just don't know how effective it
would be.
I didn't think pumice was used except in the initial pore fill steps. The
intention in the final steps (if you use oil) is to burnish the slightly
soft finish to a fine gloss. Of course, this will have to harden for maybe
a few weeks to keep the surface from picking up impressions as it stays soft
until the hardening oil can harden.
If you do not use incorporated oil, then you need to sand and polish the
shellac as with lacquer. I suppose pumice could be used instead, but it
would have to be a very fine grade to keep from introducing scratches. I
find automotive polish containing carnauba wax does a pretty good job with
minimum effort. Just don't heat the surface when you buff or the grain will
telegraph through. But maybe you want that on a Classical.
Dave Hajicek