What a week.
I finally got to the bottom of what was going wrong with my unnaturally peeling paint job, with the help of Tosh from SGT. I’d been pretty sanguine about the whole thing, since I’d assumed I simply hadn’t prepped the surface of my SGT 416 receiver set properly.
It turns out that unless I had some kind of silicone oil litmus paper and the knowledge that it’s one oil meths doesn’t remove, I really couldn’t have done any more prep than I did.
As soon as the cause was identified, I had a look online and learned that coating a surface with silicone oil is quite possibly the worst thing you can do prior to painting it. It appears to be excluded from many professional painting environments, because preventing contamination is of the nth degree easier than cleaning it up. Also, there’s no real consensus on how best to remove it.
In the end, after exhausting all the options available to me and without access to industrial solvents or an ultrasonic cleaner, I went the surfactant route. I covered the affected parts with talc and used washing up liquid to wash everything off. I think it’s as good as I can get it, but I won’t know if it’s sound until I pick up the rattle cans again.
So, if you have the slightest inclination to paint your blaster in the future, don’t clean or polish it with silicone oil. It’s evil.
The other interesting thing is that the removal of silicone oil has highlighted the difference in tone and finish between upper and lower receiver. I haven’t been able to capture it that well in the pic, but to my eyes it is there:
It’s of no concern to me, but I’d assume the receiver set should be all one colour – given that the upper and lower are serial number matched.