Roman \"varnish\"

[John Conyard]

I've just finished a major paint job on a Roman "parade" shield. I want to protect the work, but have no wish to use a layer of thin oiled rawhide.

A varnish is the simple answer. But what would it be made of? I can only get as far as egg white which would give a gloss finish and taste good with strawberries. Caballo is experimenting with egg whites at the moment.

Any thoughts?

Can somebody move this post to the right section? The computor sent it here, not me!

[Medicus matt]

Aetius Amidenus writing in the late 5th C apparently describes using linseed oil (presumably thickened by heat) to preserve encaustic paintings; not seen the actual text myself though.
Earliest proper process I've got is from the Mappae Clavicula (oldest extant manuscript being early 9th C) which gives the following:-

How to treat a painting so that it cannot be destroyed by water.
Coat a painting in the sun with the oil called castor oil, and it is fixed so tightly that it can never be destroyed.

[M. Demetrius]

Moved.

[Magnus]

Linseed oil when left long enough leaves a nice protective coating...I am finding the trick is to apply it in such a way that it leaves a smooth finish. It may be worth experimenting with thinning it out with turpentine, or applying it with different types of brushes.

I have coated my shield boss in it, and the dome part turned out well, but the flat part has a lot of irregularities to it.

[M. Demetrius]

How well is that working so far for water resistance on the metal, Magnus?

[Magnus]

I'm not sure...haven't had it out of the house yet...BUT I did do the spear tip on my vexillum pole (the II AVG one that was at Lafe) a year or so ago, and it's been fine since...no rust.

I'm going to figure that as long as the finish doesn't get chipped or rather, rubbed off it's ok.

[John Conyard]

Thank you gentlemen.

I can readily understand the properties of any oil in protecting iron and steel against oxidisation. Thickening it could help it to "dry" making a varnish. But I do not want to run the risk of an oily shield. But I am all in favour of oil based Roman paints. I fear when using egg white my paint has always chipped. But I do feel egg white would dry, be relatively waterproof, and give a nice satin sheen.

This comes straight from Wiki.

"Early varnishes were developed by mixing resin, like pine sap, with a solvent and applying them with a brush to get the golden and hardened effect we see in today's varnishes.[1] The ancient Egyptians were acquainted with the art of varnishing, but its origin appears to be far east of there in India, China and Japan, where the practice of lacquer work, a species of varnish application, was known at a very early date. It has been claimed that Japan was acquainted with the art of lacquering by 500 or 600 B.C.E., but the majority of authorities place its first usage there to the 3rd century of our era, as an art acquired from their neighbors the Koreans. The natives of China and India probably knew the art much earlier than the Japanese. Varnish and lacquer work are, however, generally treated in the arts as separate and distinct.
[edit] Etymology

The word "varnish" comes from Latin vernix meaning odorous resin, the etymology of which comes from the Greek Berenice, the ancient name of modern Benghazi in Libya, where the first varnishes were used and where resins from the trees of now-vanished forests were sold. Berenice comes from the Greek words phero (to bring) + nike (victory).
[edit] Components of classic varnish
[edit] Drying oil

There are many different types of drying oil, including linseed oil, tung oil, and walnut oil. These contain high levels of polyunsaturated fatty acids.
[edit] Resin

Resins that are used in varnishes include amber, kauri gum, dammar, copal, rosin (pine resin), sandarac, balsam, elemi, and others. In the 1900s in Canada, resins from local trees were used to finish pianos. As a result these now antique pianos are considered difficult to refinish. However, shellac can be used over the existing resins provided sufficient time is allowed for thin coats to cure. Thus the original finish can be returned to its original lustre while preserving the colour and age related crackle.
[edit] Turpentine or solvent

Traditionally, natural (organic) turpentine was used as the thinner or solvent, but has been replaced by several mineral based turpentine substitutes such as white spirit or "paint thinner", also known as "mineral spirit". "

[Alanus]

Good morning gentlemen,

In my restoration work I always avoid anything containing mineral spirits or turpentine, because it's too "new." This goes for coach varnish, spar varnish, and tung oil finishes. For wood, ancient westerners used boiled flaxseed oil-- linseed-- vigorously rubbing it in, then letting it dry, adding successive coats until the wood was protected from the elements. I think ancient Gallic carriages carried this finish, but it doesn't work on metal.

The Ancient Chinese developed rather amazing finishes, including chromium-plated swords (a very thin coating) and what we now call "gun bluing." Their wooden products are often called "lacquer-ware." That's what interested me because it predates varnish. Unfortunately, what we know today as "lacquer" is a synthetic product. I don't know what it's made from and don't care.:roll:

I'm reasonably sure that ancient eastern lacquer now sells under the western term "shellac." It very old and an alcohol-based product. When you examine Chinese lacquer-ware you can still see a yellowish or golden tint. This equates with plain "orange shellac." Clear shellac is also sold, and that's what I use in restorations. It's ancient, water-proof, fast-drying, reasonably hard as a coating, and works on both metal and wood.:grin:

It's not ultra-violet ray proof! But, then again, neither are we.:wink:

[Magnus]

Yeah, i was seeing how the linseed would work on a large metallic surface. I must admit, it looks like crap lol. I think ill take it off soon. I may try melting a thin coat of beeswax next.

[Alanus]

Bee's wax might work as a "temporary fix" but on metal it will scratch off easily with any usage.

[M. Demetrius]

Wax, bees' or paraffin, will penetrate the surface grain of iron if it's heated, but then you have the trouble of discoloration from heat if you go just a little long in the fire. No easy solution there.