How to achieve a mirror finish on stainless steel is one of the most popular challenges we get asked by polishers and engineers. There really is a three stage process and if you follow this then you should get there easily. In three steps you should be able to achieve the mirror finish you are after.
A mirror finish, is a highly shiny, reflective surface free of any scratches or marks. It means that the surface will have an RA value of less than 0.2. Mirror finishing is the highest level of metal cutting and is the most effective means to improve the service life of mechanical components.
This stage is a crucial step in the process to achieving a mirror finish on stainless steel, or when polishing any metal. Do not forget to cross hatch and to get a certain amount of heat on your wheel to ensure the compound melts.
Dry Sisal polishing mops are made from sisal material which makes for a coarse cutting mop.
Used with a coarse cutting compound for scratch removal pre-polishing. This is normally the first stage mop to flatten the metal surface in preparation for polishing. These mops can be used for rust removal, machine line removal, casting surface removal, scratch removal and weld blending.
This first polishing cutting and flattening stage is very important therefore it shouldn’t be rushed. The subsequent polishing processes after this phase should be very quick and will only be as good as the pre-polish phase.
All metal polishing needs a mid stage – dont rush to the final finish. This is because you have created lines during the first stage with the dry sisal and if you skip straight to the last stage, you wont have got those lines out. Mid stage polishing is required for stainless steel as you are still preparing the metal for the final polish.
White stitched polishing mops can be used with a cutting compound or a finishing compound and will do both jobs.
Stitched mops are the most common polishing mop. These mops are made from soft layers of calico which have been stitched together to give rigidity. They are most the versatile mop and could be used as a one operation for a general polishing. This type of mop is useful on such a range of materials it is popular with most users.
This stage is when you can really begin to get that shine and reflective look on your metal. It can be very satisfying to begin to see the work of the first two stages coming out.
A loosefold mop is a popular choice for this final finishing process. The softest mops is a Reflex mop which is used in the jewellery industry for precious metals – sometimes this soft mop is not necessary on harder metals. But it’s down to the polishers preference. Yellow Bronco mops are becoming more popular but for most metals, you can’t go wrong with a general loosefold mop WDR which is a soft calico or a felt.
We sell a selection of starter kits which have small bars of compound and wheels or mounted mops and points for helping you to get the mirror finish you require on stainless steel.
For more tips and techniques take a look at our You Tube page or contact us directly to have a chat about your metal polishing.
A mirror finish on stainless steel is not just aesthetically pleasing, but it has a few other benefits depending on exactly what you're fabricating. Keep reading to see if a mirror finish is what you really want, and find the processes and products that will get you a great end result!
Mirror finishes are often chosen for stainless steel products that need to look attractive, like balustrades, architecture, kitchen/bathroom tap-wear, or artworks. The benefit to a mirror finish, is not just that it looks great, but that it is highly corrosion resistant. This is due to the polishing procedure which removes deep scratches which can harbor corrosive particles. This is where mirror finishes are particularly useful in coastal architectural projects which can be exposed to salt air.
A mirror finish on stainless steel is a highly reflective, smooth finish with a scratch free appearance, achieved through polishing the stainless steel. Also known as a #8 finish, a mirror finish can be achieved mechanically, using a progressive series of abrasives and polishing compounds.
To get to a mirror finish, you'll work your way through leveling the weld, then sanding, progressively using finer abrasives, before polishing for that truly reflective finish. Here's a step-by-step guide:
If you're aiming for a mirror finish, you're probably wanting your fabrication to look its best, so will want to remove the weld. If you're not needing to remove the weld, skip to step 2. Using a Deerfos Bora9 Fibre Disc , P120, set your sander to 5,000-7,000 RPM and carefully level the weld without gauging or distorting the work Bora9 Fibre Discs use a new generation ceramic grain for aggressive, cool cutting and long life caused by the sharp crystal shaped grain. They also utilise a specialised top coating to reduce clogging, friction and heat build up, maintaining the sharpness of the grain.
Now you've leveled the weld and removed any heavy fabrication marks, it's time to bring these areas up to the base product finish, it's time to sand the whole piece and get it ready for polishing.
A. Start with a Deerfos SA331 Velcro Sanding Disc, P120 grit and sand over the area you've used the fibre disc on in Step 1, or where you've marked the steel in the fabrication process. Setting your sander to 4,000-6,500 RPM, move at a 90° angle to the scratches made in the previous step so make sure the previous scratches are removed. The original finish of the stainless steel you are fabricating with will determine how soon you will need to start sanding the whole piece. Sand the fabricated areas until you have them to about the finish of the original sheet, and after you have done this you will then need to start sanding the whole surface. Repeat each next step:
The higher the mirror finish you want, the more you will need to sand. From this point, the higher you sand, the better mirror finish you will get. These next steps take longer to sand each grit out, to get the prefect finish.