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View Full Version : natural copal and alkyd medium like copal


hblenkle
05-30-2002, 12:07 PM
can anyone tell me how ron garret's copal medium conpares to neo-meglip, which is an alkyd version of copal medium developed to be like turner's medium?

alva
05-30-2002, 12:14 PM
Good question, I'm interested in that as well...without knowing I'm GUESSING it behaves similarly to liquin, but someone who has used it AND is unbiased could give credible info here...alva

Titanium
05-30-2002, 02:44 PM
hblenkle and Alva,

first let me say that I do not think it wise to
use copal/ amber or alkyds in a painting.

That said as one who can make the stuff, understand
that you can make copal / amber colophony in oil to
be a fluid medium, a viscous medium, a dark coloured
medium and a light coloured medium.
You can make it dry very fast or very slowly.

It is matter of what you want to do with it.

Adding a solvent to any of the above mixes, will
also change the body of your oil paint.

Liquin is [ once again- chuckle ] a soybean alkyd,
solvent and a thickener.The drier is cobalt as far
as I know, which dries the top of the coat , but
the underneath will still need to " cure".

An alkyd oil resin dries at the speed of the oil that
is used in the manufacturing.
A linseed oil Alkyd dries at a linseed's speed.
Soybean has to be altered and helped to dry as it
is a semi - drying oil.

The better Alkyd oil resins are made with sunflower,
safflower or castor oil.

If you want to make your own - Neo- Meglip whatever,
buy some Alkyd GG from Kremer pigments or Sinopia.com
and try blends of a drying oil, stand oil , solvent and
the Alkyd GG.
You can also just us a drying oil to thin an Alkyd oil resin
no need for solvent.

For fast drying you will need a Drier also sold by the
companies named above.

Copal resin maybe more difficult to obtain, but James
Groves also makes Copal mediums if you want to do a
proper search/ test. He is also on-line.

Amber is easier to cook into a drying oil.

BUT both Copal and Amber require high temperatures to
crack.

Then there is the other commercial way to do it.
Read up on - Heaton - Outlines of Paint Technology-
in you library.

Know what you would like out of the various mediums.
Then test.
Good Luck.
Titanium

* These mediums will make your paint more glossy,
add on what looks like " Vermeer Type Highlights",
[ this is not to say Vermeer used the stuff ]
harder and if abused may lead to cracking and yellowing.

Use sparingly please, a little goes a long way.