Airbrushing Newbie Here, I Have Many Questions

[dawn tapir]

Hey there! I'm just getting into the painting hobby, and I'm going to be purchasing a nice beginner setup for airbrushing after I pass my current courses in college (a nice little reward for myself for getting through some difficult assignments!) I have a looot of questions, as I'm not sure how to find the answers to exactly what I'm looking for online. I'll try to keep things as organized as possible!

What I plan on doing: I plan on using my airbrush to custom paint things that I use daily. My keyboard keycaps, my mouse, video game controller, microphone, boom arm, etc.. Basically, anything that isn't the color scheme I want it to be, I want to make it that way. White and gold is my favorite color combo, so I want to make my stuff white and gold, and airbrushing is the best way to get a nice gold finish from what I've seen.

1. I watched a video today, and the guy said that adding polyurethane mix additive to your paints makes them super durable. Is that a common thing, and should I be using that?

2. If I want to block off details, like, say I have a base coat of white, and I want to have gold only in specific spots and not on others, what is common to use for that? Tape? I have a few statues and models I'd like to paint, how would I go about protecting intricate details from getting paint on them? Would something like Play-Doh work? Putting it over the spots I don't want painted?

3. If I get a really bad finish on something, and want to remove the paint entirely and start over, what's best for doing that? Paint remover? Sanding? Something else?

Thank you so much in advance for any help!

[prisma fractal]

1/ While it's true that polyurethane makes things more durable, it's the 1st time I hear that someone add some PU medium to a paint. Could you link the video, I'm interested to see it.
What is common is to prime with a PU primer, and after minis are painted, to varnish them with a PU varnish.
2/ Silly putty is the best recommendation. Easy to apply and doesn't stick as much as play-doh or even bluetac. I had one case of one cheap silly putty leaving a residue on the surface. I bought a pot of a similar material created for paint masking and no issue at all.
3/ Isopropyl alcohol and a medium soft brush. Soak a few minutes, brush, repeat.

[abstract blade]

Mission Models does a polyurethane additive for their paints and recommends adding it but I've never seen anyone else do it. https://youtu.be/gSdIkzujDcA?t=264

If you're going to be spraying functional objects then lacquer or enamel paints would be far more durable, but the fumes are toxic. Enamels are popular with people who their own fishing lures for example.

[valid jay]

A lot of people here aren't painting functional items that get a lot of use, so idk if you'll get a lot of advice there

For masking, common options are masking tape, flexible masking tape, silly putty type stuff, and liquid masking fluid which is a liquid latex type thing.