Lon, I've been so frightened of welding on a housing that always have my buddy do it at his fab shop. I line everything up and tack it together and have him do the finish welding. I guess he heats the housing around on the other side where there was no weld with a torch to equalize the heat all the way around the tube. I've also seen him do some magic with wet rags, but never tried to learn the technique myself.