How do I tell the difference between aluminum and stainless

[77mustang]

Hello, I'm new here. I tried a search before posting, but I did'nt find anything.
I will be polishing all trim work on my car, but will be starting with the trim around the windows. On my 77 Mustang II.
How do I tell if it is aluminum trim or stainless steel trim? From what I have learned so far from searching this forum, there is different polishes and methods to polishing either aluminum or stainless, is that right?
Thank you for any help.

[clockman]

try using a magnet. if i am not mistaken it should stick to stainless and not aluminum

there is non magentic stainless out there
but here is what you can do :
wet sand with 600 - up to - 2000
buff with white on a losse cotton.. if i get a chance today i will tear a part off the junker in the back and polish it up..

wait better yet
green on sprial
white on loose

than should give you a shine that you want

[chiliuno]

stainless is not magnetic to my knowledge. you can tell by shooting a tig torch at it on dcep- if you get a nice pool, it's stainless. if it just looks nasty and spatters, it's aluminum.
another way to test it to try and drill a hole in it or mill it or just scratch it. aluminum is soft, stainless is relentless in hardness.

[77mustang]

customandsound: Ok I am working on a trim piece, started with a small section about 1 foot long.
I did what you said with the wet sanding.
I don't have all the green on loose or white on spiral stuff. I am using Mothers aluminum and metal polish, with clean, white 100% cotton t-shirts. Starting with a clean section everytime.
I'm doing something wrong!!
I wet sanded about 3 min. each with each grade of sandpaper. Remember the section I'm working on is only about a foot long. Do I need to sand for a longer time with each grade?
I then took the piece inside and started polishing. I have polished in that one spot for 4 hours. It's got a shine to it, but not good enough, I want it to look like a mirror when it's done.
And heres what blows my mind. After all the wet sanding, after 4 hours of polishing. I start with a clean section of rag everytime, as soon as I start to rub, the rag instantly turns black, dark black, everytime.
What am I doing wrong, please help. I could be 65 by the time I get this stuff polished.

can you email me your phone # or call me
customandsound@yahoo.com
my phone # is on my webpage www.customandsound.com

[offroadbum]

the trim is stainless,as is about 99.9% of auto trim.
just an fyi some of the lower grades of stainless are magnetic and will rust.but the trim on autos don`t they just dull.but they polish out pretty good.