Is nickel plating the same as chrome?
I'll throw in what I think I know.
First, this may or may not be totally true, but I'm sure at least some of it is correct. I looked into having things chromed a few years back for some parts I machined that needed chrome plating.
Also, used to repair/restore wind instruments and had several things plated with various platings back in the day.
Regarding chrome, what I understand is:
The chemicals required are apparently very toxic or regulated or whatever, so many local shops that used to do it couldn't keep up with the government requirements (here in the USA anyway) and there are many fewer shops doing it now than there used to be a few decades ago. If that is true, home-done chrome may take more to do than the average guy may want to get into. However, there is usually a local auto bumper shop which will take in small chroming jobs for a pretty reasonable cost. You'd just want to do your own prep (polish to a mirror finish) so you don't have to pay them to do it. That's the time-consuming part anyway.
Chrome plating is two steps. It gets nickel plated first, then chrome over that. Maybe pinball parts can be nickel plated at home, then just pay the outside shop to apply chrome only. Two advantages here might be that you can see exactly how well you did your polishing and re-do missed pits and such, plate again and have it chromed only once you're completely satisfied. The other is that you may save some money since the shop wouldn't need to nickel plate first.
Another factoid is that the shape of the part can affect how well it will chrome plate. Nickel doesn't seem to have this problem, but apparently due to current flow in the process, inside corners cause some kind of electro-magnetic interference and it won't take the plating. Thus the inside corners will show the nickel plating underneath and blend out to the chrome about an inch or so away from the corner. The nickel looks yellow-ish right next to the chrome so it's fairly obvious at the blend if you're looking. Luckily for pinball parts, the inside corners tend to be the hidden part and will still look fine. However, this does likely preclude the worthiness of chrome plating parts such as what was pictured earlier - many areas of a part with all those right angles would be only partially chromed (of course the nickel would be fully plated underneath though). There may or may not be techniques and ways around this, but the average bumper shop will probably not want to deal with it. Besides, nickel looks pretty darn good too, so personally I'd just stick with that for parts that don't get seen and/or handled. Legs, lock bars, side rails and various external hardware (bolts, etc.) are good candidates for chroming.
The main thing to know has already been mentioned. Your part will look pretty much exactly the same coming out as it does going in other than the surface color. So it needs to be as mirror-smooth as you want it and can make it before plating. Buffing is a little dirty, but it's kind of fun & easy and a very handy skill to have. For steel, you'll want just the more aggressive buffing compounds (emory & tripoly for example). The finer compounds (rouges) like you'd use on brass or aluminum won't touch steel so they are just a waste of time. And of course the buffing is a waste of time unless you smooth out any pits, deep scratches, etc. first with a belt sander or whatever, using progressively finer grades as you go. Just like finishing wood, except (here's a tip) alternate directons between grades so you can more easily see that you've smoothed out the lines created by the previous (courser) grade. After proper sanding, you'll be amazed by how easy it is to buff steel so it shines like a saxophone.
Pretty neat Beaky. That looks great and takes things perfectly just a little-too-far. Good on you for pushing the envelope.
