A little word to the wise..I've done things like this the majority of my life.
If you want it to last, spend the money and invest in POR-15.
Whenever I do a restoration, or modify any of my vehicles I use their products for rust inhibitors and panel repair. Bar none the toughest stuff I have EVER touched in my life. I use it on all of the frames, and undercarriage stuff. (Chassis black) You can simply roll it on or paint it with a brush.
I have gotten to where I even do the outside of the panels as well, but the trick to that is when you are doing an outside panel you MUST come back as soon as you get done with the panel and shoot it with an epoxy catalyzed primer. I have found out that the POR-15 is VERY hard to sand once it dries, and the more it sits in the sun the harder it gets. So, if you put it on the panel while its wet you get an excellent bond with the por-15 and the catalyzed primer to the sheet metal itself, and if you use a good UPOL high build primer you have plenty of meat to block down. If you are wanting to do a solid restoration on something I highly suggest doing it this way because that thing will be there until this rock we're on is no longer here.
Also, few tips of the trade for por-15. I highly suggest getting the 6-pack of the black material because you will learn a few expensive lessons the hard way. If you get a regular pint or quart can of it, you can only get the lid off 1 time. If there is ANY residue on the edge of the can or the lid and you put that lid back on there you better plan on cutting the lid off of it to get the product out..or jabbing a hole in it.
After you open the stuff up, make sure that you wipe the lid off with acetone, paint thinner etc and put a piece of wax paper over top of the can before you put the lid back on and keep it in the refrigerator. The refrigerator I've learned tends to make the lid easier to get off when you are going to work on it again. Keep in mind where ever you get POR-15, it is there to stay. This includes your skin. Pick up a few packs of the blue gloves and cheap paint brushes at harbor freight and a foam roller when you go to do this stuff and keep a few cans of very hot solvent around because if you get it anywhere you want to be able to get it off immediately. If you get it on your skin and you do not get it off before it dries you will be wearing it for about 2 weeks..it does not come off.
Best of luck with the restoration!
