I do a lot of mig welding of stainless steel and carbon steel hoppers
for the food industry. After welding, we grind all the welds smooth to enable the hoppers to be easily cleaned. I have used many different flap discs, but, have found a great source of new ceramic grain flap discs which cut fast, cool, and really last a long time on stainelss steel. For carbon steel I use their zirconia flap discs. You can visit the following link to see where I get them. ([url]http://www.lehighvalleyabrasives.com . The prices are very reasonable and the quality is good.

Hope the above is helpful.