Sometimes its really difficult dealing with metals like copper and brass (Two metal that we'll be dealing with) . Mirror finishing a metal like the copper plate I have shown in this Instructable, isn't really hard or difficult to achieve, especially when your projects requires metal parts. A dull non-finished metal part look's tacky than an well finished part. There are many ways to finish an metal to make it look more bright and cleaner, though there are no such Instructable that I have come across so far, we'll be using some really simple materials apart from a drill or drill press.
Sand paper of 400, 600, 800, 1000, 1500 and 2000 grid.
3m polishing compound or any other polishing compound.
Polishing wheel or buffing wheel.
Soft tissue (Soft toilet papers works best cause they are really soft).
Sterile rubber gloves (Optional)
Well drill press is optional, drill press can be used for a very high grade mirror finishing or else you can use the traditional method, hand and a cloth.
Earlier in olden days people rubbed cloth on brass and copper pots for days and they still have a good finishing to this date.
Step 1: Heavy Metal.
Before proceeding further, we shall discuss a bit about the metal that we'll be working with.
Major problem, Metal poisoning.
Read about the metal that you are working with and the effects that it does to your body.
Copper and Brass.
Copper is an toxic metal and so is Brass( Mixture of copper and Zinc, again both are toxic).
Copper toxicity, also called copperiedus, refers to the consequences of an excess of copper in the body. Copperiedus can occur from eating acid foods cooked in uncoated copper cookware, or from exposure to excess copper in drinking water or other environmental sources.
More about Metal toxicity: http://en.wikipedia.org/wiki/Metal_toxicity
Points about metal, metal poisoning, copper and brass are refereed from Wikipedia.
Step 2: Let's Begin.
Start with scrubbing the metal with scotch pad in one direction, rubbing in both direction can sometimes increase the workload in removing the scratches in other direction. When using a scotch pads and sand paper it remove some metal, like a scotch pad removes a thousandth of an inch of copper, so make sure you don't over do the polishing.
Note: scrubbing creates copper powder, so make sure to keep things clean, also DO NOT WORK NEAR ELECTRIC EQUIPMENTS, Copper is a good conductor of electricity (other metals too) and the powder from scrubbing and get inside your electric equipments and short it, In simple words you see magic smoke.
Step 3: Order of Work.
I have arranged the process in a much simple step.
1. Rub scotch pad
2. cleans it with Acetone and cloth or tissue
3. Rub with 800 grid sand paper
4. Repeat step 2
5. Rub with 1000 grid sand paper
6. Repeat step 2
7. Rub with 1500 grid sand paper
8. Repeat step 2
Step 2. "Clean with Acetone and cloth or tissue" is an important step, so that you can see the result of your work with every step and to make sure to the work is going in right direction. Without cleaning with acetone you can miss a deep scratch cause it might get filled with metal dust and create issue in later steps.
Step 4: Crucial and the Best Part.
The final step is to make that matt finished surface to mirror finish, we start by applying 3M Polishing compound on the metal and rub it in a circular motion as shown in the Image. Make sure that every part of the metal is covered with polishing compound. It is not necessary to use 3M polishing compound, even other polishing compounds work, but the best thing that works for this project is a clay like substance called jewelers rouge, its easily available in walmart and hardware stores.
Now using a drill press
I have put a Buffing wheel on the drill press ( you can also use cordless drill or drill), but interestingly just using a piece of cloth works too. Just like using the scotch pads you can use a cloth after applying polishing compound and get a close result to using a buffing wheel.
Step 5: Are You Satisfied?
Well I wasn't!!
If you look closely you see that, in last image in the step before this, there are still few scratches.
So what do we do?
Repeat the entire process again. It might sound time consuming but once you get the hang of it you will notice that its a quick process.
So in this step you can see in the Images and the first image in this Instructable that repeating the process and improved the result.
Step 6: What Else Can Be Done?
Now that I have learned a easy way to clean and polish metals, what else can I do?
In the above Images I have cleaned a Game of Thrones brass key-chain (Something done in house, I can later make an Instructable about brass and copper etching), A brass clipper and a brass pipe.
More about pipes and circular objects.
I have used a little different method the clean the brass pipe.
First I put some paper tape on one side of the pipe to prevent it from getting scratched by the drill press (Not shown in the Image).
Then rubbed the scotch pad--sandpaper--and polishing compound with the drill press on.
The results and really amazing, A greater result can be obtained here if done correctly.
Step 7: What Have I Used This Method So For?
There are so many used, but what have I done.
Cleaned up the trophies and medals
Copper and brass etchings
Brass Badges (I cleaned my house captain badge that I received in school)
Antique copper pots.
Even the metal clipper on my Pen!!