One common mistake I see with new fixture table owners is they ground the welder to the table. This can cause damage to the machined flat surface from arcing. The arcing comes from a air gap in between the table and the part. This damage can be on the top or at the grounding clamp. It doesn’t matter what material the table is made from. Hard steel, Cast iron, regular A36 plate, the arc will eat away the material or raise a high spot that is really hard.
[grid][en.composer.grid_surround][/grid][grid][en.composer.grid_surround][/grid][grid]
All the table manufactures recommend not ground the welder this way. It’s good practice to ground to the part not the table.
Siegmund has a nice blog post about this topic. The Importance of Proper Grounding for Your Welding Table | Siegmund Welding Tables USA (An Official Division of Quantum Machinery)
Here’s how to repair the damaged area that works best for me. Your going to need a stone and some motor oil, or the Fireball Table Maintenance Kit . Any motor oil will do, the thicker the better. Dump a small amount of oil out on the damaged area and lightly rub the stone over the area with light pressure. The oil will help the stone glide over the table top allowing the stone to only touch the high spot. Rub with short strokes until you feel the high spot disappear. Your going to feel the stone being held down to the table top due to the suction from the oil.
Clean up the mess with a rag and wd-40 and your ready to go. Your going to see some cosmetic damage but it won’t affect the performance of the table in any way. I hope this trick helps. Jason