Polishing Stainless Steel

A. The material used in the felt wheels is not a single material, but a series of grits & compounds, applied in sequential order, to remove scratch lines through ever-finer polishing. Mirror polishing is achieved by starting with a course polishing media, then using a finer one to remove the polishing lines, with the process continuing for 4 or more steps, ending with a very fine buffing compound. The wheels are changed too; fine media isn't put on a wheel formerly carrying course media. Can you barrel/vibratory finish to do most of the work, and then hand buff with the fine polishing compound?

Q. Hand polishing is not a problem, but it is taking too long. The components are small 8 mm diameter tubes ending in a cone shape at the end with small holes in the cone end from 1.5 mm to 2.5 mm. It traps dust from the felt wheels and polishing compound that has to be removed.

The ceramic media is giving a good finish, but not a mirror finish, so the possibility of using chemicals as used in the polishing wadding might be worth trying.

A. Hi there, based on my experience, my company used two types of polishing compound to polish our product (stainless steel cookware). one is wadding polishing compound, another one is liquid. And the liquid is more expensive than the others; of course its quality is better than others. best regards

A. Hi Ted. If the blemishes are superficial, citric acid may remove them.

adv.
You might talk to Stellar Solutions [a finishing.com supporting advertiser] about Citrisurf.

Regards,

A. I cleaned the external stainless steel shell of commercial toll booths which had been totally neglected for almost two years and which were in filthy condition on commencing cleaning work. I tried a great variety of products and followed lots of varying advice.

The conclusion I reached was that the best cleaning procedure involved
1. De-greasing with a standard de-greaser sprayed on, wiped off and allowed to dry
2. Wadding (e.g Domestic Duraglit etc.) applied in small areas at a time with lots of elbow grease and remove tarnish as you go
3. Final wipe down with a baby oil (e.g. Johnsons Baby Oil). This step was given to me by a house-proud housewife and it really was a useful tip for getting a nice clean tarnish free finish combined with protection going forward

A. Nothing can top a hand buff finish in appearance. However, you can drastically reduce your processing time by using mass finishing equipment. Then again, a lot has to do with the surface finish of your parts prior to processing. A rough surface of over 35 RMS may still require a belt or wheel to reduce the surface profile. The next step would be a mass finishing system. The machine size and system depends on the volume of parts needed to be produced in a given period of time. Next, the media depends on the metal being processed. You may need to do more than a one step operation to get a mirror finish, but it still may not match a hand buffed finish. If that is still needed, a very short hand cycle maybe required.

A. It sounds like you are buffing before the surface has been brought to the proper finish.

Remember that each step to a finer grit should only happen after the current grit has removed all scratches left by the proceeding process. Moving prematurely will result in both taking a long time to polish, and reducing the quality of the finish.

Any time a step takes too long, it is probably because you didn't take long enough on the previous step(s.)

Check your surface under a 10-20x magnifier and choose the grit which is sized one size smaller than the largest scratches you see.

Any time it seems to take too long, try stepping back one or two levels of grit.

There really is no way to get a better surface finish I know of, chemical polishing methods depend upon the mechanical surface to be smooth first.

A. My advice would to polish the surface to as near a finish to mirror as you can then have the part electropolished which is the opposite of electroplating but instead of putting a coating on the surface as in plating it is carried out on a reverse polarity which removes the top surface of the metal.
The only problem is it will not remove scratches, it will take out the surface inside the scratch so the scratch remains.
Hope this helps
Colin

A. Reading between the lines of several entries here, there might be a misunderstanding about what those polishing compounds are and do.

They're not acids that melt the metal and let it flow to smoothness. Rather, they are like exceptionally fine-grained sandpaper.

As an aside, although people use power shovels to dig out the earth for the foundations of buildings, if you had eternity you could do it with a teaspoon. Similarly, you can remove deep scratches with a very fine mirror polishing compound . . . but it would take virtually forever.

Practically, the only way to mirror polish metal is in a series of steps. First you use a compound that is course enough to remove every scratch in a practical amount of time, but fine enough that the scratches it creates in the process are smaller than the scratches you started with. Then you use a finer compound, but one that is still course enough to remove the scratches from the first compound in a practical amount of time. Then you use a finer compound ... In other words, mirror polishing is simply a great deal of work :-(

Good luck.

Regards,

Hi Viet. We have many other threads about polishing stainless steel on this site. Just put "polish stainless steel" into the search engine.

However, since you are dealing with different kinds of shapes and metals, you might benefit from the more tutorial approach of a general book about polishing. Thrashing from one thread to another can be a very hard way to learn the basics :-)

Luck and Regards,

A. Unless someone is working with the same process, it is difficult to say yes to your question. Suggest you try it and then if it doesn't work, re-post your question explaining the new problem. You are basically working with the same materials and process and that normally should achieve the results you are looking for.

A. I assume when you are talking thinners, you are talking about a solvent based product. If that is true, it is not a good choice. There are way too many problems with that. You might want to try a paraffin based product, but I'm not sure that would work any better.

A. It would be better if you could share more on the end application of the product. It may be harmful if you [use] thinner/solvent as lubrication media while buffing. I would suggest electropolishing as this would be easier and faster. Good luck.

A. You could try extrude honing .

adv.
Jignesh,
Contact me directly about the method of electropolishing internal diameter of long tubes for pharmaceutical and food industries. We have developed a device and method that works together with Universal Electrolyte for various types of stainless steel ID and OD electropolishing. This method was successfully implemented at BAMA facilities in Italy.

A. Best wishes Bridget. Your picture is cut off so we can't fully read the label, but it looks like the cake server is made of stainless steel. This means it is the same material through and through, not just plated, so you should be able to mechanically polish/buff it before you engrave it.

It is something you theoretically could do, but experience is the best teacher, so you would want to practice on scrap, and you're getting married in 30 days and will surely be very busy. Unfortunately I don't know who in your area can do such work but if you have a motorcycle enthusiast in your extended family, they may know. If not, a local antique shop may have contacts.

Regards,

A. I am an expert on hand polishing stainless still, so let me give you some guidance.
Polishing metal is a lot like polishing automotive clear coats, depending on the damage you start with different size wet sanding paper. In your case I would start with 1000 grit wet sanding paper with soapy water do it for about 5 minutes, then move to 1500, then 2000, after that fine polishing compound and you will have a very nice almost mirror like surface.

A. First, she obviously doesn't have the time to do this by hand herself. Second, from the photo she supplied, the surface is already obviously well beyond 2000 or even 3000 grit wet sanding and polishing.

Wouldn't she be better off, if she REALLY feels the need to do this, to take it to a professional refinisher. What you're telling her to do will result in a finish far below what she obviously has now.

A. Hi Randy. You tried solvents and cleaners, but did you try citric acid passivating solutions?

Regards,

A. Randy,
A "brown tint" could be a lot of things, though two main possibilities come to mind.

Discoloration from the heat treatment or welding? It needs descaling, either mechanical (grinding/polishing) or acid (pickling).

Iron oxide corrosion? Rust removal and passivation, plenty of available products for that.

Solvent cleaners, detergent cleaners, and alkaline cleaners aren't likely to do anything for either issue.