Granite is in igneous stone and made by cooling down of lava at high pressure. They are one of the harder stone, and has some pores as well. Polishing granite edge is a common task for any granite related DIY project and need little mechanical skill to get professional finish on edges.
Step 1: Get a Good Quality Diamond Dry Polishing Pads Set
Polishing granite edge needs a complete set of diamond polishing pads starting grit 50, 100, 200, 400, 800, 1500 and 3000 grits. You need to use them one by one to attain the excellent finishing.
Step 2: Attach Velcro Backing Pads to Grinder
Attach the velcro backing pads to the grinder's arbor rotating clockwise and hand-tighten it so that it is not loose when working. Note always use low speed grinder or variable speed grinder for dry diamond polishing of Granite.
Step 3: Clamp Granite Firmly
Place a thin piece of wood over Granite and clamp it tight to prevent it from moving while polishing. Ensure the clamp is not directly on granite, and is over wood piece to avoid any damage to granite surface shine.
Step 4: Start Polishing With Grit 50
Now, you are start dry polishing of granite. Attach grit 50 dry polishing pad to the Velcro holder and run the grinder at low speed. If you have a variable speed grinder start at speed 2 or 3 that represents rpm less than 1000.
Step 5: Polish From Left to Right
While polishing, move the grinder from left edge of granite to right. Before you finish polishing with grit 50, ensure all saw marks and scratches are almost gone from granite edge. Position the grinder in slight angle and gradually polish the granite edges from one side to another. Be careful at bottom edge to remove objects, do it slowly.
Step 6: Move to Polishing With Grit 100
Now remove 50 grit polishing pads from velcro backer and attach the 100 grit pad, continue the same process like before. After successful polishing with grit 100, there should be any visible saw marks on edge.
Step 7: Move to Polishing With Grit 200
Remove grit 100 pads from backing pad and attach grit 200 polishing pads and continue polishing from left to right.
Step 8: Move to Polishing With Grit 400
After completion of polishing with grit 200, the surface should look very smooth however mostly no shine. Now you can move to grit 400 and continue the same process. At end of grit 400, you may see slight shine on granite.
Step 9: Move to Polishing With Grit 800
Now take out grit 400 pad, and attach 800 grit polishing pad and keep polishing from left to right. At this stage you would see slight shine on granite. For granite those are very hard, it is normal to not see any shine after completion of grit 800 polishing.
Step 10: Move to Polishing With Grit 1500
Now take out grit 800 polishing pads, and attach grit 1500 polishing pads to backing pad. Keep polishing from left to right evenly. At end of this stage, you must see low gloss to high gloss on granite edge. If some part of the granite has uneven or low shine, do polish more to achieve same level of shine across the surface. When you achieve same level of shine, you are ready to move to grit 3000 the final step of polishing granite.
Step 11: Move to Polishing With Grit 3000
Now take out grit 1500 pad and attach 3000 grit and polish from left to right, continue the process and stop when you are satisfied with the shine of granite.