How to Bring Welded Stainless Steel to a #8 Non-Directional Mirror Finish
By Gordon Heck
The polishing of the weld on stainless steel in order to bring it back to a #8 finish takes some time and practice.
We suggest you make up several test panels prior to attempting the polish on your finished product.
The ease with which you will be able to bring the finish back is directly related to your patience, as well as the quality and size of the weld.
If the weld is small in bead size, we suggest using a 320-grit drum on a Dremel or another style of tool grinder. It will be best to have your workpiece fixed in a vice or otherwise held down to a table.
Generate the contour of the radius of the part to within .01 or more from the surface. Change to a much finer grit drum and bring the radius down to the surface of the workpiece.
COMPOUNDS AND WHEELS
The following wheels and compounds are listed by P/N# and page number, using McMaster Carr Catalogue #119. These are what we use and are listed below simply for your reference. You may use any compounds or wheels you prefer.
It is best to use a dual spindle buffer, so you can move back and forth from the aggressive buff to the polishing buff when required.
First, use an aggressive buff, P/N#4832A151 page #2661 and compound P/N #4784A1 page #2664, applying firm pressure of the workpiece going across the weld and then also cross buff by going the length of the weld. Use plenty of compound and pressure to remove all scratches and bring the finish to a polish that shines and is scratch free.
Change to a Mirror Finish Flannel buff, P/N#4817A15 page #2662 and a coloring compound P/N#4785A2 page #2664. Use firm pressure, following the same pattern as above and finish to a bright mirror finish. It would be best to go the length of the weld first and then go across the weld. Pressure should change from light to heavy upon both entering and exiting the workpiece.
As stated earlier, it is best to run some test samples prior to working on the finished product.