Cheers richard. Hopefully it will assist the OP but I have problems working out what to adjust to get a lower thinner welder with penetration WITHOUT blowing holes. I am welding 3 mm end plates to 6mm walled box. If I dont get it right first time the 2nd pass usually gets the edges which them melt quickly.Hight and build up of the weld. By going slower your not really penetrating deeper but you are adding more material on top and increasing heat input.