Painting over Imron

You should not have any trouble painting over IMRON. I'd recommend a good soap and water wash, followed by a degreasing with a wax and grease remover such as PPG's DX 330 (or DuPont equivalent) as a start. Scuff sand the resulting surfaces with 400 grit or finer and have at it. For respiratory safety without a supplied-air mask, I'd suggest an acrylic enamel that can be used without a hardener additive. In PPG, that would mean OMNI MAE. There's also Centari in the DuPont lineup which would be an excellent choice but it's more $$$ than OMNI. In DuPont's "economy line" that is competitive with PPG's OMNI, there's NASON FASTDRY. There are also some other possibilites in the commercial (not automotive) line ups of both PPG and DuPont but I am not familiar with them.

If you want to price out Centari for comparison, make sure you get quotes on the correct formulation. It's available in three different ones. The one you want is called "Centari With Ultra 1K Pak". That's the only Centari formulation that can be used w/o a hardener additive. Another issue that you want to consider between OMNI MAE and Centari 1K is the possibility of recoating. The ability to recoat in a reasonable time could be important if you get runs or excessive orange peel. PPG does not recommend recoating the MAE, period. DuPont claims the Centari 1K can be recoated after 4 hours. I cannot personally confirm a recoat on either one as I use formulations that require a hardener.

Rod

This is exactly the information I need. One other question, what about a primer? I would guess there's a specific primer for the Omni.

I believe that epoxy primer is the best bare metal primer available. In the OMNI line, that means MP170. It is a two-part product that uses a catalyst but it does not contain isocyanates so a standard, cartridge mask is satisfactory. You can download a technical data sheet on the MP170 here. You can also download the tech sheet for the OMNI MAE acrylic enamel w/o hardener here.

If your IMRON is in good shape, you shouldn't need a primer - unless you get down to bare metal in spots. Be aware that the epoxy is a non-sanding primer that is not intended to fill sandscratches. For any scratches coarser than about 220 grit, you will want to apply a surfacer over the epoxy and sand that with 400 grit prior to applying the finish color coats. For a surfacer that can be used w/o supplied air, you are pretty much limited to the OMNI MP181. The tech sheet for that is here. Also be aware that with the MP170 epoxy primer, there is a time window of three days after application where it must be topcoated with either a surfacer or a topcoat. After the time window, scuffing and reapplying the epoxy is needed before continuing.

Rod