How to finish stainless steel?

Date 02-03-2003 21:23

Hi folks:

Got my first look at unfinished stainless steel a couple of days ago. I'm just curious: how do you go about finishing stainless steel? I'm not thinking in terms of an industrial process, more something along the lines of what I could do in my garage workshop at home. Do you just sand it to get a nice smooth finish? Apply some sort of clear brush-on polymer? Any ideas? If it were just sanded, it still wouldn't rust, right?

Also, is the finishing dependent upon the specific alloy, or is it pretty much "in general"?

Thx!
Dave

By dee

Date 02-04-2003 01:18

Dave,
What kind of result are you looking for? Stainless is used all the time in varieties of finishes including polished, brushed, machined (like the "Spirit of StLouis" airplane Lindberg flew) and even painetd. I heard a rumor that DeLorean autos are being painted now that they've aged and turned a bit grey and pitted, but I don't know. Generally it isn't painted. If painting is your goal seek advice directly from paint manufacturer fro the system they recommend.

Perhaps a belt sander with something like 300-400 grit belt may be capable of providing a suitable, attractive finish without painting and too much handwork. I dunno... test it first. Polishing it out and buffing it up to a mirror gloss is a LOT of work.

Take a look at the stainless steel products (and how they're finished) in the marketplace and in industry already. Its pretty much an "in general" process.

regards
d

By jwright650 (*****)

Date 02-04-2003 16:12

Dave,
Try this link, http://www.bright-works.com
You might be able to get some idea how much work you will want to put into this to achieve the luster you are looking for. Various compounds and grits to choose from to polish with. Watch out for the 400 series stainless steel because they have enough ferrite in them to rust.
John Wright

By GRoberts (***)

Date 02-04-2003 19:43

Actually, some of the 400 series stainless steels have little to no ferrite in them as they are martensitic stainless. The main problem with stainless steel rusting is contamination from free iron, which could come from tools, contaminated grinding wheels, polishing wheels, etc. All stainless steels, regardless of their microstructure (ie austenitic, ferritic, or martensitic) have enough chromium in them to form a passive oxide film if treated properly. Stainless steel will corrode in certain environments, but it is not in the form of iron oxide, or rust. But as John pointed out, some stainless steels will corrode in milder environments than others, and some of the less corrosion resistant stainless steels are in the 400 series. But they will all stand up in the right environment. The key is knowing what it will be exposed to, and which stainless steels are designed resist corrosion in that environment.