finishing stainless steel

[RickP]

I just had some stainless steel chainplates fabricated. The shop did not mirror finish polish them - they have a smooth, but dull greymetal/gunmetal finish (they used 303 stainless bar stock)

Any suggestions on how to improve their appearance? I had read somewhere that you need to be careful in finishing stainless as it can release some of the carbon and thus the steel will begin to rust. thanks!

Rick

[fenixrises]

Hi Rick,

Well....this is a bit of a job. First you need a heavy duty 8" bench grinder. To it add an 8" cloth buffing wheel. Get a bunch of sticks of jewlers rouge(rather like hard putty sticks, different colors=different grits). Apply rouge to buffing wheel, apply SS flatbar to rouged wheel. Repeat process until satisfied with the finish. Be very careful when doing this. Wear eye protection and gloves. The metal gets hot and can inadvertently be "grabbed" by the wheel. Afterwards you can have the SS passivated. This is a special acid dip that causes the chromium on the surface to rapidly oxidate, thereby giving the SS the "stainless" quality.

Or you can pay someone to do it for you.

Happy sails and be careful!
Fred B.

[Parfait's Provider]

The Carolina Fleet had two presentations by riggers today. On stainless, I got the impression than anything less than 316 wasn't going to hack it in a salt water environment.

[Greg Ross]

Applying a finish on Stainless or just using tools on and around stainless will supply the iron particles that will cause the rust stains. Grade of stainless referrs to the chemistry and mechanical properties, 316 vs 303 or 304, the chrome and nickel percentages are higher in the 316 giving better corrosion resistance.
Here's a link that's been posted here previously, some good info;
http://www.bosunsupplies.com/knowledge.cfm