i did a small one years ago,clean it real good and use on of those green scrubbie pads and rough it up til there is no shine on it.prime the bare spots with grey oxide primer and use a good enamel paint it will not come off unless you hit something hard enough to take it off.if you do the bottom rough it up with something a little more coarse like corse steel wool,wash it good and rub it down with laquer thinner and it will work fine.