Ok cool deal Don! Mine isn't turning black, I don't know why but it isn't. There are a couple of places that it is and the rest is just a darker rust. I did exactly what the can says and sanded it down smooth where there is little rust. Either way it doesn't matter because the rusty spots I am going to cut out and put in patches but I just don't want it to spread anymore than it is since it will be after christmas before I even get started on the body work. I am wanting to do my front end and mechanical stuff first (which the new 351W has been in it, I just haven't finished up the wiring or figured my throttle cable problem out). I was just out looking at my 48 Coupe and seen that the rusted floors and all are not as bad as I thought and I can make them myself because the rusted out parts are just flat sheets of metal with VERY little bends. I will just need to buy floor supports. I will use this extend on the floors and see what happens.