losing colors after waxing a heat-patina on steel

The colours are due to interference effects of the thin layer of oxides on the surface. The thickness of the layer is the same order as the wavelength of light (very VERY thin). Waxing - or clear-coating - increases the effective thickness of the layer (or perhaps changes the percentage of light-loss at the oxide-wax transition) and you loose the colours.

You may be able to get the colours back by removing the wax with solvent, but I'd guess that it won't work that well - you might rub or scratch through some of the underlying oxide layer. Be prepared to start again from beginning of your surface prep.

And no, I don't think you can protect it without loosing the colours.

On Tuesday, October 30, 2018 at 6:07:55 AM UTC-4, snipped-for-privacy@gmail.com wrote :

a city skyline silhouetted offset from a background, all comprising sheet m etal steel.

round after cleaning it with an angle grinder. The patina came out really n ice, with brilliant blues and magentas.

all the nice colors were lost and the foreground and background basically l ook the same. I saw one post online that said those colors cannot be clear- coated because the optic properties are lost, but it recommended waxing.

the original colors hiding beneath? Or will I have to repeat the heat? In e ither case, is there a good way to protect the metal without losing the col ors?

No experince, but here are some ideas anyway. The first thing I would try in using some paint thinner and paper towels to remove the Renaissance wax . Should be easy to do and one experiment beats 100 conjectures. Next I would make some test plates by heating some scrap pieces And try some diff erent waxes. Maybe floor wax and autobody wax.

The colors are from oxides. Blueing on guns is a oxide coating and rosists rusting to a degree. So maybe you do not need any additional .protection .

Dan

No experince, but here are some ideas anyway. The first thing I would try in using some paint thinner and paper towels to remove the Renaissance wax. Should be easy to do and one experiment beats 100 conjectures. Next I would make some test plates by heating some scrap pieces And try some different waxes. Maybe floor wax and autobody wax.

The colors are from oxides. Blueing on guns is a oxide coating and rosists rusting to a degree. So maybe you do not need any additional .protection.

Dan

========================= Good point. Ask a gunsmith about Color Case Hardening.

Thanks, all. I'll try some of these techniques this evening!

On Tuesday, October 30, 2018 at 5:07:55 AM UTC-5, snipped-for-privacy@gmail.com wrote :

a city skyline silhouetted offset from a background, all comprising sheet m etal steel.

round after cleaning it with an angle grinder. The patina came out really n ice, with brilliant blues and magentas.

all the nice colors were lost and the foreground and background basically l ook the same. I saw one post online that said those colors cannot be clear- coated because the optic properties are lost, but it recommended waxing.

the original colors hiding beneath? Or will I have to repeat the heat? In e ither case, is there a good way to protect the metal without losing the col ors?

My experience is that those heat-induced "temper" colors are too fragile and ephemeral to be relied upon in any practical application.

Years ago I made some nice belt buckles, mild steel inlaid with brass. Skipping over numerous details and difficulties, I was able to get really nice heat-induced blues on the polished and carefully cleaned steel, lovely contrast with the brass. But they didn't last. A droplet of water/moisture would remove the color. Coatings changed it. Wear removed it fairly quickly.

The blue tones created with various gun bluing techniques are different, darker, less exciting, but far more durable. Brownell's OxphoBlue(tm) is one I've used a lot but tends, with aging, to nearly black.

There is a bluing technique using molten potassium nitrate reputed to give a better/nicer color but I've never used it or seen the result. You might research that with gunsmiths or, perhaps, makers of fancy spurs in the US southwest.

FWIW,

To get a thicker coating with heat, the traditional method (used a lot on guns, 100 years ago) was to heat the steel in the presence of a cyanide-based case-hardening material.

Yes, it's potentially dangerous. And it works. If you use a powder, you get the mottled colors common on Stevens rifle and many shotgun receivers.

There are other ways to do it, but I've long since forgotten what they are. Maybe a search on "heat treatment colorizing" or something like that will bring it up