Welding thin steel with a stick welder is a real PITA.
Some advice from Graeme really works. What I always try and do (sometimes its not possible) is to clamp on a big lump of steel to act as a heat sink. Works like a dream - no more burn thrus
Incidentally, are 1.5mm sticks available anymore?
"Is it not enough simply to be able to appreciate the beauty of the garden without it being necessary to believe that there are faeries at the bottom of it? " Douglas Adams