I have cleaned up and stripped the paint on my car to bare metal in some places but I am not done yet. It is already starting to rust. I need to put something on there that will come off easy when I am ready to weld and por15. Someone suggested motor oil. Any ideas?

just go buy a couple of cans of cheap primer, if you put oil you will have to degrease the car completely and you will risk killing your new paint job, or just por-15 now and light sand after you will be able to paint

If you are leaving the car indoors like inside a garage you can probably leave it for at least a month (depending on the humidity) and it should be fine. I live very close to the beach and did just that before doing the POR-15. When you use the metal-etch stuff it takes care of the metal surfaces, rusty or not. Chances are that any rust you get now will be very very thin. POR-15 sticks to rust well anyway...

Actually,

IMHO the cheap primer is not a good idea really..
cheap (non catalyzed) primer is actually somewhat water soluble... There could be rust underneath it which could haunt you later. Also, you have no Idea how it would work as a substrate with final paint, so it would have to be completely removed at a later date anyways which could be a pain in the butt...

buy some metal ready and use that...
b

I have used Ospho very successfully. You need to put it in a spray bottle, spray it on lightly, then give it a light rubbing with a scotch brite pad. This will convert any rust to iron oxide(?) and will protect the metal for about a month. If you do have some converted rust areas, you can always go back and grind/sand it down to bare metal, or just leave it. When you're ready to paint, spray it on again, rub it down, then wash it down with water, finally wiping/drying it clean. Immediately paint it as the metal will now be exposed to the elements. And definately use good primer. Good luck.

Thanks everyone. I just got my shipment of por15 and metal ready today and will get to work.

POR15 Metal Ready will protect it as long as you dn't load the car on a trailer and drag it 1000 miles at times in the snow.