The proper way to weld the stainless is TIG or tungsten inert gas. It should be a variable frequency welder for maximum control. To control the heat you would use heat dam putty or just wet rags. Make sure that the welder uses the correct alloy filler rod or the weld color won't match and he may "blow-through". Do not use MIG you cannot control the amount of filler materiel as well or the heat. If you are real careful and slow and use the minimum amount of heat you do not have to worry about the fiberglass underneath. After grinding and graining you will probably have to go over the entire hood to get the finish to match. You should be able to find a welder capable of this work in any big city because all kitchen work is custom and most of it must be done in the field. You can also look for someone who does "hollow metal doors" or elevator doors. Many times these manufacturers work with stainless steel and are very capable in repair and graining. David Teitelbaum vin 10757