Re: POR15 sheeting off:
Likely that was poor prep - used with the primer that stuff usually sticks like grim death.
TBH I would not use used motor oil and Diesel mix - that stuff is nasty with combusion products, acids and the like and really is not environmentally friendly.
If you feel the need to use an oil mix use cheap hydraulic oil or the like - that won't have all the engine nasies in it and won't make so much of an environmental mess.
Were it me I'd be wirebrushing off the loose and flaking paint, cleaning it thoroughly with a non-petrochemical solvent, then applying a phosphoric acid treatment of some sort over the rust (which will turn the rust to iron phosphate). You can then paint over that with chassis black or whatever. Don't use Hammerite...useless crap since it's been reformulated.
Re: Ezi-Outs and the like: Be very careful using them, as if you snap them (not at all unusual) then you have a hardened bit of steel stuck in the broken bolt. I can't stand the damn things - don't have them in my shop and haven't for a very long time. Personally I drill undersized, working my way up till I'm just under the bolt size, Then you can typically collapse the remains of the fastener and extract it with little to no damage to the threads if still present.
Sounds like you're having fun with it - enjoy!
Alan
