What the title says.
I was interested in using commercial grade alkyd oil primers to prime my own canvases,
the only thing I could find were generic warnings from artists who were not chemists to “use only art grade materials!!”
…and that’s fine if that’s the answer! 🙂 it’s more the principle than the $. if utrecht oil primer @$60/gal >> zinsser oil-based primer @$15, I just like to know specifically what makes it so.
I just need to know WHY. because some times, there IS no difference. a $15, 50# bag of whiting powder from the clay supply store is the same as a $15, 4# bag of “ground marble” from an overpriced paint brand. and some times, there really is a seriousdifference after all, and, I want to educate myself.
but just using google I’m finding very little. and paint brands like to keep their formulas proprietary, as well.
what’s the difference between a urethane alkyd and a silicone alkyd?
…and “alkali-refined linseed oil”?
are all three alkyd categories cross-compatible (will stick to each other)?
is there a chemical relationship between a urethane alkyd and a polyurethane varnish?
alkyds are 100% compatible with traditional oil paints, or no?
enamel gets used like a marketing term all over the place for all kinds of totally different products… does it have a specific technical meaning?
“titanium white oil paint” versus “oil primer” vs an oil-based gesso (I guess acrylic gesso is more common)
is the difference between paint, primer, and gesso, the amount of whiting powder and pigment filler versus the amount of binder? primers have more filler to be thicker and more opaque, is it just that simple or there’s more to it?
I’m sorry there’s so many questions. these are things I’ve wondered for YEARS and never found clear answers to.
I even have the artists’ pigments books which are fascinating. i loved making the pigment connections when I got into both car autobody+paint and pottery glazes.
the fellow at NAPA auto paint was explaining that toyota’s gold paint from 2000 bleaches in hawaii’s equatorial sun to a silver– it has quinacridone red, which is a mostly permanent organic pigment but apparently 20 yrs of direct UV exposure, will break it down).
But I never really learned about binders!
I figure the conservationist folk here would know better than anyone!
I’m a smart dude and I’d be happy to read through some literature if you can point me in the right direction, to something that’s just laymen enough for me to understand it while also technical enough to correctly describe the chemistries of these different alkyd binders
(I have some collegechemistry background, doesn’t have to be totally dumbed down; but perhaps not so technical that I need a masters in petroleum engineering and matsci!).
thank you again for the help,
Bernie
There are a lot of different materials listed in this inquiry so I am going to start by distinguishing between traditional artist’s oil primers and architectural primers. Utrecht Oil Priming White, which the OP mentions, is not an alkyd-based primer. The binder for this product is a combination of alkali-refined linseed and safflower oils, not alkyd. Alkali-refinement is totally unrelated to alkyd, despite the similar sounding terms. Alkyd is a resin synthesized from vegetable oils which produces a tough, fast-drying film. Alkali refinement is a process of “washing” away free fatty acids, mucilage and other components of expeller-pressed oil. (Expeller pressing extracts more oil from flaxseed than cold pressing, but it also releases additional material that would make the oil less usable and prone to spoilage if not removed through refinement.) So, a paint that has alkali-refined oil as a binder has a vegetable oil binder, and the product is a traditional oil paint. Oil-priming white has a very high proportion of solids (white and inert pigments) and is not brushable from the container like a house paint-type primer.
Silicone alkyds are a type of solvent-reducible paint that has superior weather resistance to older types of alkyds. Urethane alkyds are a hybrid product that facilitates water cleanup instead of hydrocarbon solvents. I am not knowledgeable as to whether these types have any application in permanent painting, but architectural paints are not generally formulated for durability into the antique age as we expect (or hope) paintings will achieve. This isn’t a defect- it’s expected that buildings will be repainted every couple of decades at least, so house paint can have components that aren’t normally used in artists’ paints, if the ingredient imparts a desirable performance or appearance and does not need to last “for the ages”.
“Enamel” is a generic term describing the shiny, hard, level finish associated with this type of paint, and the typical applications, like vehicle exteriors. Most enamels are now alkyd or acrylic-based, but in the past, natural resins were used instead. “Coach enamel” was once made from Congo copal or other natural resins, heated and mixed with dangerously hot oil.
The last part of my response deals with the question about bulk commodity ingredients like whiting or “marbledust”, whether there is a difference between brands/sources, and whether the difference in price reflects a significant physical difference in the product. This is a broad question which is not going to have a single answer for every product. I can confirm, however, calcium carbonate sold for artists as a consumer packaged product has been recalled if found to contain asbestiform particles. I assume that there are some industries where this is not restricted, so that is one commodity I am confident in saying that artists are getting a higher grade compared to industrial or bulk supplies.
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