Hi,I just bought a portable 6" jointer planer and started using it on some reclaimed lumber of various widths. I have never used a jointer before but I need it due to the irregular cut wood. I have watched a number of videos on Utube but they never seem to bring up my issue? I am doing something wrong when I am using the planer because a piece of wood starts at 3/4" but many times it ends up at a different thickness throughout the board length say 3/4" on one end and 5/8" on the other. Is it because I am putting too much pressure on the board as it goes through the jointer or is it something else. Are you suppose to put pressure on the board as it goes through the jointer (using the paddles provided) or just enough to hold it through the cutting process. Could it be that the wood is so cupped on one end that it ends up being thinner than the rest of the piece by the time I get it flat? Any thoughts?