Now before anyone gets the idea I was dumping on resin in my last post, I wasn't. It's a great way to get highly detailed models of stuff Tamiya or AMT will never release. You just need to tackle it properly, that's all.
So I soaked the chassis in a mix of Tamiya thinner (an expensive mix of n-propanol and butyl alcohol) with pharmacy-bought iso-propanol for an hour while I ran out to get automotive primer at the local auto parts store. This took off most of the Tamiya primer as well, and required a lot of scraping in corners where the toothbrush doesn't reach. A small brass wire brush in the Dremel helped here but be careful not to dig in too deep.
Next was two coats of Dupli-Color primer/sealer, the heavier of the two Dupli-Color primers available. It fills in small scratches and pinholes, and is probably a good choice for resin even if you haven't had to scrub off some earlier problems. This is drying overnight while I decide whether to risk the Tamiya white again, or to move to an enamel from Testor's. There is a problem with pale Tamiya colors and this is unrelated to styrene versus resin. However the Testor's will be harder to fix if it goes wrong. Decisions, decisions... meanwhile I painted the engine block red using Testors in a bottle, so there is progress. Stay tuned! Pictures will come as there is something to document.