I'm using a #6 cup at 7 litres a minute on 2mm and 2.5mm MS and haven't thought about changing, as this is working well.
7L per min = 14.837Cf per hour

Thanks Jody. I started out at 80amps but that seemed too much and I was getting undercut so worked my way down to 55. 1mm electrode? At that amperage it's the size recommended by the machine but I would consider your advice first.

I went Orange...A single phase machine that will go to 230amps, Kemppi Mastertig. AC/DC with the option of pulse and the weight is 15kg.

As a test for myself(Haven't done this before) I'm joining 2 sections of 38mm stainless X 1.6mm tube, one joining into the other at 90deg. I'm using a 1.6 thoriated tungsten and 1.6 filler at 55amps DC-. So far the result has been a bit hit and miss. I've avoided any undercut but the joint is either...