Problem with welding small dia tubes 6-12 mm,thickness range 1,5-2,5 mm to valve blocks/thickness 30-50 mm/.MIG process,by hand,wire dia 1,0 and 1,2.Many leaks.Any recomendations?Thanks.
You might be better to drill the blocks to accept the tube and then silver solder or braze the joint, no danger then of over penetration into the tube.