Edison Screws

[victorthesixth]

What was the chemical formula to blacken the screws? Thanks!!

[tomb]

I use gun bluing . I get a small clean bottle and pour a little gun bluing in it, then soak the screws in it till they are the darkness I want. It works well for me. It will also do brass screws. Tom

[VanEpsFan1914]

Hey,

The old hardware isn't blackened per se, but rather blued: you need a blowtorch, a pair of needlenose pliers, and a coffee can full of used motor oil.

Get the torch, heat the screws red hot, and quench them in the oil. There will be a lot of smoke, there might be a little fire, but this is what it takes. When you pull them out, wipe them with a soft cloth to dry and polish the new finish. They will look wonderful.

This finish is not waterproof, and, like a gun-barrel, should be oiled every now and then like your phonograph itself. Practice on a few old screws first, and don't use galvanized ones unless you burn the coating off in the torch. Practice will show what color the steel must be before it is quenched.

Good luck on your Edison project! Those look great restored.

VanEpsFan

[JerryVan]

I do almost exactly as VanEps describes, with the exception of not getting the screw red hot. I start with a cleaned up screw, with burrs removed, and heat only until I see the color turn blue. I then dip in oil. Fast and easy and looks good too.

[Phono48]

I do the same, but on the first attempt, stupidly used a plastic tub to hold the oil. The red hot screw immediately sank to the bottom, with the result that can be imagined. Amazing how much mess a cupful of engine oil can make!!

[PeterF]

Ha! Sprayed a bit of coffee on my keyboard when I read that just now. Glad I wasn't drinking a cuppa motor oil.

[victorthesixth]

Thanks everyone

V6

[Dave D]

I do the same as Jerry Van. When you get the desired color, slowly remove the screw from the flame.
Dave D

[startgroove]

There is a product called Novacan, which is available at lead glass supply stores. It is used to turn the caming or lead on a stained glass piece to a dark color. It works well on most metals (except for nickel and chrome), by chemically oxidizing the metal. I rarely use it full strength, mostly I use it in diluted amounts, by adding 30%, 50% or 70% water, to slow down the reaction, so there is better control over how dark the color becomes. It works faster on iron, brass, copper and aluminum. Immersing in the solution for a period of time causes the reaction. The longer the immersion time, the darker the shade. The product is available in different colors, such as brown and black (and maybe others).

I've successfully colored iron screws with this process. Depending on what the alloy is, and which color of Novacan used, the color comes out deep purple, brown or grey/black. I usually polish the screw heads first, either with a buffer or a wire wheel. Then clean the parts with detergent water, and then treat. Once it dries, it is hard to wear off. The finish is a flat color, with no sheen. To add sheen (semi-gloss) I will rub on a light coat of Watco oil (that takes about a week to fully dry).

I've also used it to color the escutcheons on early radios. A highly diluted solution will cause a milder reaction, allowing the color change to happen slowly, so you get good control of the shade. The color change stops when the part is removed from the solution and rinsed in tap water. That is how an even light brown color can be imparted to a brass escutcheon.

Novacan is a chemical which will stain counters, floor material, clothing, hands and other household objects, so be careful not to spill or splatter it. It does not seem to color, or attack, plastic or glass containers.

Cheers, Russie