Epoxy Re-Coat Windows

Hi guys,
Question on painting a Farmall A. I am in the planning stages of restoring an old Farmall and trying to figure out the best way to handle the painting aspect. First off, I have very little experience spray painting therefore my question may seem very basic. I enjoy reading the Paint and Bodywork forum and have picked up a little knowledge about the subject.
It sounds like if you are looking for a quality finish then Epoxy Primer is the way to go. If so here is my question.
I plan on picking away at the restoration at a leisurely pace. If epoxy primer has a re-coat window only up to 7 days is there a work around for the time constraint ? From what I read you can a abrate the primer if your outside the window but I wonder if that gives you the same adhesion as if you applied the top coats within the primer window ? Also I can see where sanding / scuffing up large sheet metal parts like the gas tank, hood, fenders is possible how would you handle doing a satisfactory job on parts that have a lot of nooks and crannies like a carburetor or cast iron parts for example.
I have read a few post on rust converters and was wondering if you could apply that to buy enough time to be at a point where youre ready applying the top coats ? Thanks in advance for any suggestions.

Caution: Not all epoxy pimers have 7 day windows. For example, PPG's OMNI epoxy primer has a 3 day re-coat window. Make sure to get the manufacturer's technical data sheet for any product you are thinking of using. For the OMNI product, if outside the re-coat window, the instructions are to scuff (I use a maroon Scotch-Brite hand pad) AND THEN TO RE-APPLY a coat of epoxy prior to top coating within the window. The hand pad makes it fairly easy to get into corners - at least easier that with sandpaper. That's the workaround, but it's always best to stay within the re-coat window in the first place.
OMNI Epoxy Data Sheet

Regarding rust converters: If for some reason I can't apply epoxy right away after prepping rusty material (w/o sandblasting), my preferred product is Picklex 20. It's not cheap, but it goes a long way and comes in a spray bottle. It's also available on Amazon. That will protect the material from further rusting until such time that I can apply the epoxy primer. My preference is to always avoid any kind of self-etching primer.
Picklex 20

Some epoxy primers the recoat window is closer to 7 hours. In any case if you are prepared for it that doesn't need to be a problem. First off epoxy primer doesn't sand very well but is a great barrier for rust. If you need more time to topcoat the epoxy primer with the finish paint all you have to do is coat over it with a filler primer within the window. On sheetmetal this is a good idea anyway. The filler primer sands like primer should and you can use it to cover slight imperfections you didn't know were there. After the filler primer is on you can take pretty much all the time you need to put the finish paint on. The filler primer doesn't have a recoat window. On sheetmetal some people use two different colors primer so when you sand it you can see the imperfections. For example your first coat of primer is black and the second is gray when you sand it you see a spot of the black primer coming through the gray you know there is a bump in the metal. Or you sand most of the gray off and there is a spot where the gray isn't sanded at all you know there is a dent there. These minor imperfections you couldn't see it until you started putting the finish paint on and would be more difficult to fix at this point. The procedure is called a guide coat.

In 1999 I restored a tractor over the winter and used top notch PPG materials including DP40 epoxy primer and DAR urethane top coat. On sheet metal I did as Stephen suggested and primed it with sanding surfacer primer in the recoat window, however the castings got nothing but DP40. The primered parts sat for months before everything was ready to top coat. In 2000 I did another one the same way. Those paint jobs still now look like the day they were painted except where it has been knocked off. I would not sweat the recoat window on castings, they are rough enough for the top coat paint to grab on to something unless you gind them smooth.

Great to see Rod (HN) still posting info here. Your responses & personal website have provided significant knowledge/insight about painting.....What happened to CNKS?

(quoted from post at 04:29:32 04/18/23) Great to see Rod (HN) still posting info here. Your responses & personal website have provided significant knowledge/insight about painting.....What happened to CNKS?

Click to expand...

CNKS passed away around three months ago.

Thanks for the kind words. I haven't done any painting in years, mostly due to having higher priorities. However, I do browse here on a fairly regular basis, w/o posting. I don't know about CNKS apparently not posting for some years. Maybe he's been away for the same reason(s) I have. I hope he's OK. None of us old-timers are getting any younger!

So sorry to hear that. Thanks for posting it.