On Sun, 23 Oct 2016 14:35:37 -0700, Larry Jaques
wrote:

On Sun, 23 Oct 2016 11:04:05 -0700 (PDT), robobass
wrote:

I make an unusual product (www.basscapos.com) which must be polished to jewelry standards, but includes a 5/16-24 threaded brass stud which is soldered to a brass bar. Torch soldering naturally produces firescale, which is hard to remove from the threads. There is a very effective product to combat this called Cupronil. You first preheat the work to maybe 600°f and then spray it on. It leaves a coating which protects the part. Works wonderfully. Problem is, I am going through it like mad. I have tried a bunch of different pump spray bottles, but none give me a nice focused spray pattern so that I don't waste the bulk of it. It wouldn't be such a problem if I could buy it in my country (Germany), but I can't. I suppose I should invest in an airbrush. I have a compressor, but I like the simplicity of a spray bottle, and the airbrush would still involve some experimentation to get it right. Can anyone think of an application where a precise pump spray bottle is used and easily
available? Cupronil seems to be similar in viscosity to water, but it is enough different that a bottle which gives a perfect spray pattern with water isn't very good with Cupronil.

Thanks!

Yeah, most atomizers are designed for thin liquids.

Setting up an auto injector would be far too complicated and
expensive. Spin the stud in the holder while pulsing the injector
full of Cupronil.

Perhaps something like a misting head would work with a higher
pressure pump. I'm guessing the Cupronil is slightly more viscous
than water, but depending on pressure, some pretty thick stuff will
still turn into a mist. Solder (or thread?) a brass misting head onto
a pump oiler and see what it produces. I've never pressure tested a
pump oilcan, but they can squirt out 140 gear lube pretty easily, so I
think they can put out some pressure. A 5/16" stud shouldn't take
much liquid, and a misting head should focus it pretty finely, given
the proper PSI.
Apply the cupronil with a small artist's brush and an ounce of the
stuff will last a LONG time!!!!