Instructables

How can I sand stainless steel down to a flawless mirror finish? What is the best way? What tools should I use?

I have a stainless steel filing cabinet painted khaki. I want to remove the paint and give the underlying steel a mirror finish. Removing the paint is not a problem. The problem is I don't know how to give it a mirror finish. The finish I want is so that I would be able to see my reflection just as if I were looking in a normal mirror.

Here's an example of what I'm trying to achieve, starting from an old, painted filing cabinet. If I could make it look that good or better, I'd be satisfied.

I have tried several methods which I found on the internet but none of them seem to be working. I have tried sanding by hand starting at 60 grit and going up to 220 with regular sandpaper. I have also tried using emory sandpaper which says it is for metal. I used coarse up to fine. Neither of these are resulting in a mirror finish. With the regular sandpaper, after using the 220, I can sort of see my face if I get really close and look at it from exactly the right angle, but can't make out any features.

I also tried using various dremel tools attached to my electric drill. These give a much different finish than what I am trying to achieve. It ends up looking like brushed aluminum. You can't see a reflection in this because it's too diffused.

Then I tried using a sandpaper wheel attached to my angle grinder. The sandpaper wheel was made up of many sheets of sandpaper, shaped into a wheel. It sort of worked, but was very uneven. I could see my reflection in little parts but most of the rest of it was scratched up.

Then I tried using a belt sander, using paper from 50 up to 120. The result was similar to a stainless steel refrigerator, but messier. There were a lot of lines or grooves, and they were not straight.

So the best I have achieved so far is a finish close to that of a new stainless steel refrigerator or stove, where you can't see your reflection, but the sanding grooves are clean and straight. I got this through a combination of the angle grinder, the belt sander, and hand sanding from 60 to 220. I also tried a small section purely by hand, using regular sandpaper from 60 to 150 and got slightly better results - meaning there are fewer lines. But the reflection is still barely visible; it's still way too cloudy. These results could look nice but they're not what I want. I'm really trying to get the perfect mirror finish.

I've tried to upload pictures of what I've got so far. Don't know if they will make it into this question or not.

Picture of How can I sand stainless steel down to a flawless mirror finish? What is the best way? What tools should I use?
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Re-design4 years ago
keep working untill you pass 1500 grit. You will probably have to get the 1500 at an auto parts shop. Now you are half way there. Get at least 3 grades of polishing compound while you're getting the 1500 grit. The the guy there what you're doing they will get you what you need. You also need a polishing disk to fit a highspeed driil. You can not do this by hand. You have to get the power tools involved with this at some point. What you are trying to do is get all the scratch marks as small as the grit you are using will go and then go to a smaller grit. now when you have all of the scratches as small as you can get them you go to a smaller gritl. Do this until you get the finish you want. Believe me there is not shortcut. You have to be very careful at every grit not to make a scratch that you can't fix with the grit you're working on. It's easy once you realize what you're working with. It ought to be brilliant when you're finished. Good luck.
noahbody_ (author)  Re-design4 years ago
Would polishing disks provide the same results as the orbital sander suggested by orksecurity above? At what point would you switch to these polishing disks? Do you go in a straight line with the polishing disks? Or in a circular motion? Does it matter?
The orbital sander works better because the random lines help hide the scratches. If you use a disk, then move it around a lot and go in different directions. Remember you can't get a perfectly smooth metal, you can only make the scratches so small that it looks smooth. After you get it the way you like it you MUST clear coat it or it will rust. Since you said a magnet sticks you have plain steel with will rust even inside with a low humidity. You've sure collected a lot of comments!
I would go with oil over clear coat
Well, it's a file cabinet. Unless it's going to stay out in the shop oil might not be the best choice for inside the house or office. Even out in the shop oil is going to get dirty. An it would have to be reoiled occasionally.
marcelus2 years ago
Why not use a sanding block to work finer and finer grades of silicon carbide paper (up to 2000 if needed) into the metal. Follow the grain of the metal and wash away the debris with soapy water. You should find that near reflection is possible around the 400 mark and distance images are clear by the 800 mark .You could go as high as 2000 if you wish.

Once you accomplished the sanding, which you will find is the mainstay of the procedure, you can move on to polishing. You can either try in succession: turtle wax and a liquid metal polish or "Autosol" metal polish and scratch remover. Both combinations will result in a smooth and silky finish. Best regards.
xarlock6673 years ago
Sounds like a lot of work, and some fun. Polishing metal is difficult enough when you have a hard flat piece. When you have soft and irregular metal like your sheet metal filing cabinet, it is a real pain. Since you have already tried a few methods, you should know that 200grit is kinda vaguely shiny... Go MUCH higher. And for the love of all things shiny stop using a damned angle grinder for polishing! First, use some 400 grit, and then work up to 800, then 1200, then if you want really really pretty get a cloth wheel and some jeweler's rouge. They use it for polishing stones and it will make an actual mirror finish. Expect to spend time on this project.
spylock4 years ago
Give it a good going over with very fine sand paper,then follow up with steel wool,buy then it should be good and shinny,thats when I would take a wax such as simoniz and wax on,wax off hard then use a buffer,repeat the steps and you will have a mirror finish,you could also use chocolate instead of simonize,it works very well for polishing metal and you can snack while getting the job done.
Have you tried sanding stones? They make some very fine "grit" sanding stones that people use to sharpen and polish knives and swords. Get one of them and a lot of elbow grease will work just fine.
noahbody_ (author)  RedneckEngineer4 years ago
Hadn't thought of those, where do you get them?
I've seen them in Home Depo I belive. I'm sure any decant hardware store should have or be able to get them if you ask. My brother collects old wood cutting axes and uses them to bring the rusted axes back to a mirror like finish. Hope that helps!
psymansays4 years ago
Is electroplating an option?
Electroplating will only change the surface color, the lack of polish will still be there. In polishing, the scratches of the previous finish have to be scratched out with finer scratches (the 220 took out the 60, now you have to take out the 220...). Electroplating is so thin that it doesn't fill scratches.

Here's one answer from http://www.finishing.com/355/59.shtml :
"Start with say a 220 grit sand paper and work up, all the way to 1200 grit or even 1500 grit.(if you can find it)
Also remember to "cross thatch" your sanding, meaning go one way with the sander till your satisfied all the previous scratches are sanded out. then move up a grit and sand the other way..start at 220 grit then go 320 then go 400 then 600 then 800 then 1000 then 1200 then 1500 if you can find it...time consuming yes very costly yes very.
Sand paper is not cheap and neither is your time
When you are happy with the sanding then guess what, time to polish that baby till it hurts your eyes.
For this a green rouge would do perfect with a braided cotton cloth and a high speed buffer."

And work the finer grits wet if you can. It keeps the dust down and makes the sandpaper last longer. You are also only getting about a third of the way across, try to work all the way across to cut down on the curved scratches at the end of your strokes.
noahbody_ (author)  jtobako4 years ago
So for example, I should be going vertically with the 100 and then horizontally with the 120, is that right? And I should use a long stroke going all the way across the surface instead of working on shorter sections? And I can wet the paper? Won't the paper fall apart if I do that? Or should I get some other kind of sandpaper? Good eye, by the way, you could tell from the photo I was not getting all the way across with the strokes.
Get 'wet-or-dry' paper, not the stuff meant for wood. If you don't want to do long strokes, do circles (like an orbital sander or car polisher). That way all the lines look the same rather than a long streak with a curve at the end.
noahbody_ (author)  jtobako4 years ago
I tried the crosshatching with 320 and 400 paper. It works! But it looks like I'm going to have to start all over because now I can really see the scratches that I didn't rub out at the beginning. I can almost see my reflection around these huge scratches though. And the 320 and 400 paper gets clogged really fast. Like, after 2 strokes. So I have to switch out the paper almost immediately. This will definitely get expensive.
lemonie4 years ago
Are you sure that's stainless? I wonder why someone would build that from stainless and then paint it... L
noahbody_ (author)  lemonie4 years ago
It was built years ago, like in the 1960s or 1970s before we started importing everything from China. It's really heavy and solid, not like the ones they are selling at Wal-Mart now. On the back, it says 'Hillside Metal Products Newark NJ USA'. I think all the filing cabinets made back then were painted, usually grey or beige.
Yes I've seen them, but not in stainless, it seems unnecessarily extravagant? L
noahbody_ (author)  lemonie4 years ago
I don't actually know much about metals. It might just be basic steel.
Yes, it might go rusty on you after you spent a lot of time polishing it... At today's prices stainless is more than 4x the price, due to the chromium & nickel content. L
noahbody_ (author)  lemonie4 years ago
I just slapped a fridge magnet on it and it stuck. I guess that means it's not stainless. Because the same magnet doesn't stick to stainless bathroom fixtures.
Not necessarily, but sprinkle a few drops of water on it, check back tomorrow. L
If it isn't stainless (and it probably isn't -- who would use stainless if they were going to paint it?), then after you get it polished you're probably going to want to put some kind of varnish on the surface to protect it. Try a small area first to make sure the varnish itself doesn't cause trouble... but something oil-based would seem a good bet.
orksecurity4 years ago
To get a mirror finish out of the metal by itself, you need to go _way_ past 220 grit. Keep going through 400 and 600. Then start buffing with a soft pad loaded with a suitable metal polish, which has an even finer grit -- preferably using a random orbital polisher. (You should probably wear a decent dust mask, if you aren't already doing so; small particles are not good for your lungs.) Depending on what you're doing, you may need to go through several stages of progressively finer polish too. Websearching on "how to polish metal" will find more detail.
noahbody_ (author)  orksecurity4 years ago
So you're saying to switch to an orbital polisher after 600. Others are saying to keep going with the sandpaper up to 1500 and then switch to polishing. Which is the better method? I wear a gas mask when I'm taking the paint off, but don't usually bother when I'm just sanding the metal because it seems like most of the dust got created when stripping the paint.
The important thing is to keep going up through finer and finer cuts until the scratches become insignificant. Whether they're attached to sandpaper, or carried in a polishing compound, are really matters of convenience and control; I'd say take your pick based on how the material seems to be responding and how patient you are. Dust mask: Aggressive sanding/polishing can throw up a fair amount of abrasive as dust. Breathing it is not recommended. Your call, but I think the safety warning is appropriate.
i would use steel wool it comes all the way up to 0000 and is really fine so once your done with the sandpaper go to that i use it to polish aluminum and it works like a charm only downside lots of elbow grese is involved. when using steel wool use a synthetic lube like paintball oil and it turns out nice
noahbody_ (author)  ecknight67544 years ago
Do you mean to use steel wool instead of the finer grades of sandpaper or instead of any polishing disks? Are some grades of steel wool coarser than sandpaper? At which sandpaper grade would you stop and which steel wool grade would you start at?
you will have to experiment when to stop using sand paper and start using steel wool but going ahead and polishing wont hurt anything just make it that much better here is a link that describes the diff grades of steel wool

http://www.steelwool.biz/Steel_Wool_Grades_Uses.htm