Stainless Steel sheet that can be polished up like a Mirror?

M

Manix

New member
I brought a small sheet of SS 301 0.7mm thick that was advertised as polished up. It had the sheen of paint that was wet sanded with say 3000grit sand paper. Also it had a grain to it, like brushed finish you find on laptops.

So I polished it up using my d/a with coarse foam pads & compound M105 & noticed after about 4 sessions (each 2 passes then clean off) the level of gloss & reflection sharpness stopped increasing. In fact a Polish with M205 on softer pads seems to make only a tiny difference.

I have reached it`s maximum level of gloss with no sign of any swirl at all in any angle in sunlight. But this grain stands out bad.

Up close like a few inches or on very low angles it`s like mirror sharp, but from a few feet back straight on it`s alot less sharp.

You can clearly see the grain that is always there which I suspect is why its not like a mirror. Strangely after I polished it up the sheet developed a few random straight fine marks in it, they are within the steel itself & nothing on the surface.

Are there any grades of SS that can be polished up like a mirror without this grain?

thanks
 
Manix said:
I brought a small sheet of SS 301 0.7mm thick that was advertised as polished up. It had the sheen of paint that was wet sanded with say 3000grit sand paper. Also it had a grain to it, like brushed finish you find on laptops.

So I polished it up using my d/a with coarse foam pads & compound M105 & noticed after about 4 sessions (each 2 passes then clean off) the level of gloss & reflection sharpness stopped increasing. In fact a Polish with M205 on softer pads seems to make only a tiny difference.

I have reached it`s maximum level of gloss with no sign of any swirl at all in any angle in sunlight. But this grain stands out bad.

Up close like a few inches or on very low angles it`s like mirror sharp, but from a few feet back straight on it`s alot less sharp.

You can clearly see the grain that is always there which I suspect is why its not like a mirror. Strangely after I polished it up the sheet developed a few random straight fine marks in it, they are within the steel itself & nothing on the surface.

Are there any grades of SS that can be polished up like a mirror without this grain?

thanks
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Stainless Steel is surprisingly easy to make shine.

You can sand the crap out of defects as long as you finish with 1500 grit or higher.

But you must use metal compounds on wheels to finish out.

I had a set of stainless steel tips for the exhaust that had been on my car for 2 years.

Sanded, used grinder on welds and generally abused them.

1500 grit final sanding and metal compounded out just fine using sizal whel and cotton buffing wheel.

Stainless Steel is all the way through the metal, so not like chrome or adonized that is on the surface.

There are different grades though, so some better than others for longevity.
 
Manix said:
I brought a small sheet of SS 301 0.7mm thick that was advertised as polished up. It had the sheen of paint that was wet sanded with say 3000grit sand paper. Also it had a grain to it, like brushed finish you find on laptops.

So I polished it up using my d/a with coarse foam pads & compound M105 & noticed after about 4 sessions (each 2 passes then clean off) the level of gloss & reflection sharpness stopped increasing. In fact a Polish with M205 on softer pads seems to make only a tiny difference.

I have reached it`s maximum level of gloss with no sign of any swirl at all in any angle in sunlight. But this grain stands out bad.

Up close like a few inches or on very low angles it`s like mirror sharp, but from a few feet back straight on it`s alot less sharp.

You can clearly see the grain that is always there which I suspect is why its not like a mirror. Strangely after I polished it up the sheet developed a few random straight fine marks in it, they are within the steel itself & nothing on the surface.

Are there any grades of SS that can be polished up like a mirror without this grain?

thanks
Click to expand...

Stainless Steel is surprisingly easy to make shine.

You can sand the crap out of defects as long as you finish with 1500 grit or higher.

But you must use metal compounds on wheels to finish out.

I had a set of stainless steel tips for the exhaust that haf been on my car for 2 years.

Sanded, used grinder on welds and generally abused them.

1500 grit final sanding and metal compounded out just fine.
 
As you stated, the brushed-stainless steel, is just that: brushed with a grain pattern or texture with wire brushes during the manufacturing process for appearance reasons. You can, indeed, "buff" stainless to a high mirror-like luster, but since your sheet already has grain structure on it, this is a VERY tedious process to do.
Also, as you may have found out, stainless comes in various "grades". 400 series is cheap stainless and the lower-numbered grades are actually magnetic and will rust (think Chinese-made "inexpensive" cutlery). The 300 series is most common, usually 302 or 304, which is most likely what you have. Surgical stainless is usually 316.
Stainless steel is very difficult to work with from a machining and welding standpoint because of its high chrome content. Unless you have access to a grinder Or are willing to sand with emery cloth on a vibrating sander for a long time, your stainless steel grain may not come out. That, and you will produce the blackest, dirtiest hands and work area imaginable!
Having worked in mechanical design on food grade machinery that required stainless-steel for wash down requirements, one of the biggest over-looked areas in stainless steel was not specifying the proper finish on stainless steel sheet work. It can be rough grained (1A or 1B ) or all the way to a mirror-like shine (4A). Why was this important?? Imagine getting your food processing machine with enclosure boxes and doors, guards and covers in three different grain structures running in "different" directions on the same machine! It looked "cheap" and very unprofessional. So not only was it important to specify the grade of stainless steel, it was also very important to specify the finish on the sheet metal AND the direction of the grain structure on the drawing orthographic views (front view, top view, left or right views , for those who took drafting in high school) of the guards and covers so it looked uniform though-out the whole machine. A supervisor had to "emphasize" this to an "uninformed" CAD drafter (me!) that this needed to be specified (IE, written or denoted within the bill of material metal description) on all detail drawings for enclosure boxes and doors, guards and covers to avoid this embarrassing visual faux pas on future machinery. Not all stainless steel sheets are alike, and if you do not tell your sheet metal fabricators or vendors what is EXACTLY required, you could end up with something other than was the design-intent !!
 
grungy said:
Metal polish is what is needed, not paint polish.
Click to expand...

Are you saying paint polish won`t do the job? It looks like it will. The low angles are free of any visible swirl and like a mirror, its only straight on that the surface is funky.
 
Lonnie said:
As you stated, the brushed-stainless steel, is just that: brushed with a grain pattern or texture with wire brushes during the manufacturing process for appearance reasons. You can, indeed, "buff" stainless to a high mirror-like luster, but since your sheet already has grain structure on it, this is a VERY tedious process to do.
Also, as you may have found out, stainless comes in various "grades". 400 series is cheap stainless and the lower-numbered grades are actually magnetic and will rust (think Chinese-made "inexpensive" cutlery). The 300 series is most common, usually 302 or 304, which is most likely what you have. Surgical stainless is usually 316.
Stainless steel is very difficult to work with from a machining and welding standpoint because of its high chrome content. Unless you have access to a grinder Or are willing to sand with emery cloth on a vibrating sander for a long time, your stainless steel grain may not come out. That, and you will produce the blackest, dirtiest hands and work area imaginable!
Having worked in mechanical design on food grade machinery that required stainless-steel for wash down requirements, one of the biggest over-looked areas in stainless steel was not specifying the proper finish on stainless steel sheet work. It can be rough grained (1A or 1B ) or all the way to a mirror-like shine (4A). Why was this important?? Imagine getting your food processing machine with enclosure boxes and doors, guards and covers in three different grain structures running in "different" directions on the same machine! It looked "cheap" and very unprofessional. So not only was it important to specify the grade of stainless steel, it was also very important to specify the finish on the sheet metal AND the direction of the grain structure on the drawing orthographic views (front view, top view, left or right views , for those who took drafting in high school) of the guards and covers so it looked uniform though-out the whole machine. A supervisor had to "emphasize" this to an "uninformed" CAD drafter (me!) that this needed to be specified (IE, written or denoted within the bill of material metal description) on all detail drawings for enclosure boxes and doors, guards and covers to avoid this embarrassing visual faux pas on future machinery. Not all stainless steel sheets are alike, and if you do not tell your sheet metal fabricators or vendors what is EXACTLY required, you could end up with something other than was the design-intent !!
Click to expand...

As far as I can tell the grain look is just the grain that ss has & not brushed, it`s like woods grain, it`s from when the steel is formed & is what all steels do. no amount of leveling down will get the grain out. It seems you can`t get SS like a mirror because most steels have a grain. For me mirror is like the surface of a HDD platter but they are a coating of some sort.
 
Some stainless steels can indeed be polished to a flawless, mirror-like shine. I have a few stainless items that are utterly perfect even under extreme magnification...or at least they were before daily use took its toll.
 
Accumulator said:
Some stainless steels can indeed be polished to a flawless, mirror-like shine. I have a few stainless items that are utterly perfect even under extreme magnification...or at least they were before daily use took its toll.
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What type or grades are those?
Can you give me some advice on what to look & ask for when wanting this kind of stainless?
 
Manix said:
What type or grades are those?
Can you give me some advice on what to look & ask for when wanting this kind of stainless?
Click to expand...

Sorry, I don`t know...utterly ignorant about it. But my watches and some of my cutlery are stainless and these items were perfectly finished when they were new. The blade on one of my knives had gotten a bit marred up and the knifemaker repolished it (to again, a perfect finish) when doing some requested tweaks. Consider this- the *edges* of my ss knives, even the cheap 420 beaters, are mirror-perfect (under magnification) even though the flats of the blades are of varying textures/finishes.

I do know what you mean about "coarse-grain stainless", like..the OE exhaust on my Crown Vic. No idea at all whether that would polish up the way we`re discussing...heh heh, not sure I`m ever gonna find out either, but I *kinda* suspect it could be done. Eh, just guessing though (and thus probably just wasting bandwidth :o ).

Maybe see if you can find any info on Caswell`s website.
 
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