I've worked with patina processes here and there with other hobbies that I do, but typically, I'm adding patina to lead solder. I've never tried to force a patina on copper. I've usually let copper sort of develop it's own patina. Not this time. I have to give credit where it is due. I've been plugged into the Patina Mods Facebook group for months now. And I've watched a ton of folks do theirs through that group. So when it came time for me to do my own, I had a pretty good idea what techniques produced the various results. And I knew what I wanted to do with mine.
The process is pretty simple. Through a variety of chemicals, you are essentially forcing a chemical reaction with the metal. The patina is a coating on top of the metal surface made up of quite a few chemical compounds. The resulting color is dependent on the chemicals that you use.
In my case, I knew what I wanted. I found an example in the Facebook group. It happened to be one of the easiest methods and uses common household items. I started with my plain jane copper Nemesis clone.
This next part is very important. You really don't want to patina your threads. You can. And I've seen a bunch of folks do it. But you're going to end up having to use vinegar or some other acid to clean all that patina off and there is a strong possibility that you'll end up screwing up the patina on the parts you want to stay there. Using Vaseline on the threads is messy. But it works. It keeps those parts from getting exposed to the chemicals that cause the patina. The trick is that you want to use a ton of it. Really nice thick layer of Vaseline on those threads. And don't forget the threads on the inside.
Then I put a folded paper towel into the bowl and poured ammonia until the paper towel was fully saturated. Next up, I sprayed my tube with the ammonia, baking soda, and salt mixture until it was pretty wet. Then I poured table salt over the tube until I had a nice layer built up on one side. I rotated the tube on the wire and added more salt. I continued this until the whole tube was pretty crusted in salt.
Getting the salt to stick to the tube can be a bit tricky. It just takes trial and error. After a while, you'll get enough stuck to it to start doing its thing. How much salt is added will certainly change the end appearance quite a bit.
So I moved my tube and mess to the garage where it could sit all day while I was at work. The patina continued even out of the ammonia bath as the whole thing dried.
Many folks rinse their mods at this point in water or acetone, but I found the whole thing to be quite delicate and didn't want to risk it. So I didn't. I simply brushed off the salt, wiped off the vaseline, and started the sealing process.
The spray enamel that I chose to use is one that I bought at Auto Zone. It is an automotive spray enamel that is very hard, incredibly fast drying, and really doesn't run too badly. If you want the highest contrast and best gloss, make sure to get the gloss clear finish. This "Premium Automotive Formulation" really stands up well to getting bumped around. But you can use any sort of clear spray enamel that you want to.
Here is what the whole thing looks like with the top cap, bottom cap, and beauty ring in the center of the two body tubes. I couldn't be happier. I now have a mod that is one-of-a-kind. The acrylic enamel coating should be durable enough to last, but it's easy enough to add another coat or two later on if anything starts to wear or chip.