You are a brave soul my friend for attempting that. work must be securely braced, and even then there will be a lot of warpage. .080 is not friendly in long lenghths.
my first attempt would be a 1/2" tack every 6" with the smallest ceramic cup you can get and a 1/16 th tungsten...
flat plates 040 316 ss 6" X 6".....have to butt weld with fusion technique..................have machine as low as it will go, lincoln square wave 175 with argon and 1/16th tungsten.....problem is not heat.........but blowing through.
have clamped flat bar below seam for heat...
