Product Report:
I used the SM-664D Etching Primer from Supermarine (white, not pink

). Since the Ironsides paint I selected is a two part, I would have expected a two part primer, but this was not the case. The 664D is highly recomended for Ironsides compatiblity and an epoxy substrate.
Per instructions (see: my signature line), I scuffed my epoxy, which was previously finished to 220 grit, with 150 grit. I rolled on two coats of 664D with foam rollers and allowed it to cure a full day.
I sanded to 180 grit using a 3M foam sanding block from Lowe's. As the block started to loose its bite, I wrapped the same brand of 180 grit sandpaper around it and continued.
The primer is a joy to sand. That really says it all. It levels great and works down quickly with even pressures. Had I used my DA palm sander, I think it would have been far too aggressive. Hand sanding is always best before finish coats in my book. I elected to dry sand because Lowe's didn't have any wet/dry paper in 180 grit. The result was more dust than I wanted but I had the shop vac turned on and handy through the whole process.
My previous experience with automotive two part primers had me scared, because they are like iron to sand. It was a nightmare. I'm happy to give SM-664D a nod of approval. I would recommend it at this point, but we'll see how it looks and wears with time.