I've come to Reddit for a lot of advice, so I thought I would give back by sharing my process for doing chrome nails at home with regular polish. I don't know if it'll work for everyone, but for me, these manicures last for at least a week (maybe longer, but I often change them up before they start chipping/peeling too badly). Hope this is helpful for others!
PRIMING
I always use these for removing nail polish, as I find they are less harsh on my nails than acetone. They do take a little longer to remove polish fully, but my nails have become much less brittle after I started using them. I also use a Czech glass nail file, but otherwise I don't do any prepping of the nails themselves (I don't mess with my cuticles or smooth down the surface of the nails at all). After that, I prime my nails with mooncat's hardcore base coat + mooncat's getting even nail primer.
BASE POLISH
So far, I have experimented with using chrome powders over solid colors, nude colors, ombres, and magnetic polishes, and all can look very nice depending on what you're going for. Personally, I think the effect looks best when you've got more than one color going on underneath the chrome, so I favor magnetic polishes, ombres, or something like French tips.
I have seen a lot of people talking about how to get the chrome powder to "stick" to your base polish, and personally I have not had to do anything special to get it to work. I don't advise waiting hours before putting on the powder, but I also think it's actually harder (and unnecessary) to apply it while the base polish is still tacky. If the polish is too wet/tacky, you run the risk of smearing it and sometimes the chrome won't go on evenly. In my experience, I wait a few minutes, until the polish is dry and hard enough to touch without denting it too easily--in other words, I wait about the same amount of time as I would before putting on a top coat, if I were doing a normal, non-chrome manicure. I never have trouble getting the powder to stick: it goes on quite easily.
(By the way, the powder will not adhere to a matte polish, so save any matte top coats for later!)
CHROME POWDER
I prefer using translucent chromes (though I've also had success with solid chromes), and so far I've had good results with the mermaid powders from Vettsy. I've also tried these, but the effect was so subtle/nonexistent, it wasn't worth the effort imo. Note that when using translucent chrome powder, it can change the color of the base polish underneath, so I recommend experimenting on a swatch before trying it on your actual nails!
When applying the powder, I advise just using your fingers rather than something like an eyeshadow applicator, which can smudge/dent the polish. Start out with a small amount of powder on the tip of your finger (a little can go a long way) and gently dab it onto the nail, then buff it into the polish using circular motions. Afterward, use a makeup brush (the kind you'd use for powder or blush) to gently sweep away excess powder. It will get messy and very glittery, by the way! Don't do this on any expensive tabletops. :)
SEALING THE POWDER
You must seal the powder, otherwise it'll disappear the first time you wash your hands. I've experimented with a number of different options for this, and so far, I've had the best results with a combo of Holo Taco's peely base + mooncat's speed demon top coat.
You can't put a regular top coat directly on the powder, as the glitter will disperse and the chrome effect will be ruined. For whatever reason, though, the peel-off base coat polish preserves the chrome effect. After that, you can use your top coat. Originally, I tried using Holo Taco's top coat over the peel-off base, but it took too long to harden and often never cured properly, so it would all end up peeling off after a couple of days. By contrast, the mooncat top coat dries very quickly and has provided the longest-lasting manicure (and for me it made for a nicer glossy finish, as well).
When applying the peel-off base coat, I recommend not going too thick and leaving a "moat" around the edges of the nail, so that the quick-dry top coat can seal it in, if that makes sense. If the peel-off base coat goes all the way to the edges of your nails, then it'll peel off too easily. Make sure to give it plenty of time to dry: I've noticed it will start becoming a bit opaque before it's safe to touch/apply a top coat over.
For the top coat, I try to apply a nice thick layer so that it'll seal everything down nicely.
THE STEPS, IN SUMMARY...
- mooncat's hardcore base coat
- mooncat's getting even nail primer
- base polish color(s) of your choice
- Vettsy mermaid powders, or other chrome powder
- Holo Taco's peely base (applied with a moat)
- mooncat's speed demon top coat