By the way where did you find the Marissa K33 needles, what are they make of, and what airbrush are they originally for ? Do they come in different shaft stock diameters ? Oh and how is it polished to match the nozzle, do they come as a matched needle/nozzle set. or are you polishing them to match ?
I know I ask a lot of questions, but that's how we learn, grow and make our airbrushes and work better.
Thank you for the info in advance.
Spritz
The K33 needle is an aftermarket replacement needle for the Iwata Custom Micron. They are still made, and available here:
https://www.foxystudio.com/product/marissa-k33-0-18mm-fluid-needle/
They're polished to a higher degree than a stock needle, and have a special surface treatment that's supposed to make the polished surface more scratch resistant and hydrophobic. The idea is they're more tip-dry resistant than a stock needle (including a re-polished one). I have one, and can confirm that it can spray longer than a stock needle before you need to wipe the tip. They're not immune to tip dry, but you can go almost twice the time between wipes.
They're polished to match the nozzle in the sense that they have the same taper pitch as the original Micron needle, and thus the stock Micron nozzle. They aren't polished to match the texture of the nozzle, or matched to a specific
individual nozzle anything like that.
I polished the stock needles for both my Eclipse and my SOTAR, and lapped the nozzles as well. I just used a basic polishing paste compound (
Flitz). For the needles, I chucked them in my Dremmel and used a paper towel greased with Flitz. I don't recommend doing it this way unless you've got a hands-free bench mount of some sort for the Dremmel (I have the drill press attachment), and a foot pedal switch. You want to make sure you're holding the needle gently but firmly throughout so it doesn't wobble away from the spin axis and bend. Yo can do it by hand though no problem, a power tool just makes it go faster.
To lap them, I take the nozzle off the brush, push the needle a bit forward, apply a little polishing compound to the tip, then drop the nozzle over it and screw or clamp it down with the nozzle cap so it's all seated properly in the same position as during normal operation. Twist the needle back and forth like 50 times to lap. Take the nozzle back off, and remove the needle
through the front, not the back (so as to avoid dragging polishing compound through the brush body, packing, etc.). Clean the needle and nozzle thoroughly with a grease-cutting solvent. Soak the nozzle, and blow it out well. Basically the same sort of cleaning you'd do going from solvent-based to water-based paint.
Unless you actually damage the nozzle or needle, IMO you should only need to polish them once in their entire operational lifetime.
