How do you polish / finish stainless steel?

[DaveO]

I'm considering a little project using stainless steel, looking at an online source that gives this description:
304 Stainless Steel Rectangular Bar, Unpolished (Mill) Finish, Annealed, Standard Tolerance, Inch, ASTM A276

I've never worked with stainless before. What would it take to bring the "unpolished (mill) finish" to a shinier finish? Not looking for a mirror finish, just something pleasing to the eye.

Does stainless steel have an equivalent to mill scale that comes on carbon steel?

[Rambozo]

No mill scale, stainless is pretty much good to go for a lot of things. You can add a brushed finish or polished if desired. To polish you use a buffer and stainless buffing compound. A nice satin finish can come from scotchbrite wheels or pads.

[DVA]

I like the brushed look personally. I would use 120 grit to put on the brushed finish. Many sheet metal shops have sanders that can apply the finish and will not charge too much money. If you apply the finish personally, the brushed finish can be applied by a belt sander or block sanding in one direction.

[its_34]

This is a piece of 304 flat bar, as received. No scale as Rambozo said, very easy to finish and even easier to scratch!

[DaveO]

Thanks for responses. I wouldn't expect "easy to scratch"... does that vary between varieties of stainless?

[its_34]

Thanks for responses. I wouldn't expect "easy to scratch"... does that vary between varieties of stainless?

"Easy" is relative to carbon steel, but it can be a big issue if you selected SS for appearance reasons.

Grades will affect toughness, but your choices can be limited since you will be welding. The matensitic 400 grades are used for knife blades and tools when hardened. Welding is likely a complicated process, if possible, but I'd defer that question to some of the experienced folks.

[youngnstudly]

In the sheet metal trade, it's common to use a 3M Scotch-brite belt that you slip onto your belt sander to produce the "grain" finish. It really speeds up the process of blending welded areas to match factory #4 finishes on stainless sheet (after you grind them down far enough), but you can use it to apply that same grain on most any shape or thickness of stainless. Especially if you get the belt that fits a common portable belt sander.

Touching up scratches or nicks in polished stainless can be a real chore, but with the brushed finish, you simply run a scotch-brite pad over the surface to match what's already there. Stainless steel degreasers or cleaners work well with the scotch-brite pads too.

[DaveO]

My "project" is just a support for a shelf in the kitchen so it will be mostly concealed. Not a tool-grade stainless application, that's for sure, didn't mean for the thread to run that way.

Rambozo mentioned Scotchbrite too, and I was thinking about a pad in an angle grinder. I should get some scrap to practice on, and I just remember the brick and mortar supplier nearest me doesn't carry stainless, go figure.

[Rambozo]

Way back when I was a yoot, working in a restaurant, I remember a stainless cleaner/polish called Sheila Shine.
Low and behold the stuff is still around. We used this with and without Scotchbrite depending on how messed up things were.
http://www.sheilashineinc.com/

[youngnstudly]

Dave, if you're matching other stainless in the kitchen, you may not be happy with the finish left from a grinder (a non-specific pattern). If you have no stainless in the kitchen, than it obviously won't matter one way or the other. Whatever makes the "Mrs." happy and allows you time in the garage for welding! Win/win!

Way back when I was a yoot, working in a restaurant, I remember a stainless cleaner/polish called Sheila Shine.
Low and behold the stuff is still around. We used this with and without Scotchbrite depending on how messed up things were.
http://www.sheilashineinc.com/

I was wracking my brain trying to remember the Stainless cleaner we used in the sheet metal shop. Granted, we used a few different ones, but one in particular that worked well (not cheap). I know there are several good cleaners that are highly recommended, so it probably doesn't matter anyways! It's like arguing which motor oil is the best for the family SUV sitting in the driveway.

[DaveO]

Dave, if you're matching other stainless in the kitchen, you may not be happy with the finish left from a grinder (a non-specific pattern).

Good to know- we do have some other stainless in the kitchen, so looks like I'm in the market for a belt sander that will take scotch brite!

The longer story: my wife wants to increase countertop surface area with a raised surface over the half of the cooktop that she's not working on at any moment. So I'm thinking of a frame on legs, just high enough to clear knobs and whatever else, and able to hold a piece of matching countertop, x2 to cover both sides if necessary. Still preliminary at this moment, although after reading up on stainless on the forum I just asked River Weld to send me a gas lens.

[sportbike]

Do a goo0lle search for "flap drum", then click on images. It may give you some ideas.

[youngnstudly]

Just to be clear Dave, if you are just putting the grain on a small frame with legs, you could probably get away with doing it by hand with the Scotchbrite pad. No need to purchase a belt sander and the special belt just for that one (or 2) project(s)...unless you want to. Do you plan on blending the welded areas so it looks like the whole thing was made from one piece, or leaving the (pretty) beads exposed for all the world to see?

Do a goo0lle search for "flap drum", then click on images. It may give you some ideas.

I've never seen a grinder in that configuration before, that's cool and would be much easier to use than the setup we had at work. We always used the flap drums but they were mounted on a straight grinder (long, awkward, and a little difficult to keep steady while trying to blend just the weld bead and NOT the machine finished stainless around the weld!). They did work well mounted in a small electric drill though. The grinder we had was similar to this one:

[its_34]

I would agree that going with a hand-finish or a flap sander would be better than a belt. If the belt is wide and the plate is not very flat, you may end up with a heavy polish on the high spots and have diffculty getting a uniform finish without removing a lot of surface. I would expect the Scotchbrite belts to be much better than grit in this regard.

My vote would be for leaving the welds exposed and not blending. I did this with a small bathroom towel rack and thought it looked really good as-welded.

[youngnstudly]

My thinking was that if Dave's wife wanted to tell her friends about the fancy stainless work that was in her kitchen, Dave might want to make the part he's fabricating look like it's a factory built part. While I do enjoy pretty welds, I also appreciate all the work that it takes to make something look like it was machined from a single piece of material, instead of welded using several pieces of material. If the finish work was blended nicely, anyone that glanced at it would think that it was a standard kitchen accessory bought from large chain appliance store. But it's mostly the wife's call since she's your customer (so to speak).

Keep in mind that welding is like a drug....the more you build things for your spouse, the more projects they ask you to build later on (once they gain confidence in you)! The trick is to not get hooked and overdose.

[DaveO]

Right now I'm planning a rectangular frame in SS angle to support the raised surface, with a round rod bent in a square U shape underneath for legs. Legs would be under the "short" side of the rectangle only to allow sliding the structure from side to side. That's the reason for using angle, to support the long span of whatever the surface material will be, and to prevent the surface from sliding sideways off the support. It would be cool to find some marble, maybe, I just haven't got that far yet.

The amount of exposed weld would be minimal, determined mostly by whether or not I choose an inside or outside weld at the corners, and color or texture matching of the SS is a nice-to-have rather than a gotta-have. I'm thinking the most visual impact will come from the surface material.

Near term I'm planning to get some steel round rod to practice precise bends with an OA torch and welding a length of round rod to a flat surface. Not sure, though, what OA heating does to the SS... do colors from heating buff out?

[its_34]

Sounds like a nice look. How large of a bar and what bend radius? Cold-bending would be best if the bar diameter is not too big and/or radius not too small. The heat discoloration could prove difficult to remove and acheive a uniform finish (it's also complicated by the new shape).

[jakeru]

DaveO, consider getting a scotch-brite hand pad, (or 2 or 3) and do some experimenting to see if it will work for you. They aren't that expensive and they are very handy. I'd recommend the maroon color pads, and use an old pair of scissors to cut off whatever size piece you need from the pad. (You can make a single hand pad ho a long ways doing this...) You'll get a sense of how much effort it takes and whether it will work for your application, or if something else (probably more expensive) will be necessary. They can also put a "grained" finish on aluminum very easily, and are useful for pre-welding prep.

[DaveO]

All the angles would be 90*, and rod diameter I'm thinking 1/4" or so. Sounds like I should plan on cold bending.

Edit: I had the browser open for so long I missed Jakeru's post- I'll give the maroon Scotch brites a shot.

[its_34]

1/4" is definitely a cold bend and to just about any radius you want. With that it will also be very easy to tack up a simple bending jig or just find something round (pipe, rod, etc) and form a nice, smooth bend and make the parts consistent.