Primer, paint, sandsheets recommendations?

[tweedi]

Hi All

I am about to restore a a steel frame with quite a few paint chips. Rust has been removed by soaking in evaporust, inside has been protected with T9 boshield.

I would now like to fix the paint chips before assembling. I have the enamel paint matching (humbrol model paint).

Can you recommend:
- A primer to apply to the steel (some patches are clean and bare steel, some have been covered with rust converter thus more dark)
- The sanding sheets you use between layers, I assume 1000 or 2000?
- A clear coat that I can apply on top of the humbrol enamel paint to protect it all?

Do you also have any recommendations regarding how to treat the very ledge between the original paint and the paint fix? Should I cover a bit of original paint in order to properly cover and seal?

Any hindsight much appreciated!

 

[Cloverleaf]

Make sure none of the internal protective wax can seep out into the areas surrounding the weld breathers, that'll ruin your paint faster than you can blink.

Get some panel wipe to clean the frame down with before painting. Soak it, wipe it off, and repeat until the rags are clean. Don't use rags with lint, or which have been anywhere near car polish etc (silicones, another way to ruin paint).

Primer. I'm assuming no spray gun so will recommend aerosols. It's not necessary on steel but I've usually got a lot of Upol's excellent etch primer kicking about for stainless and aluminium so tend to just use that as I find it bonds well to all but plastic. You can get 2k aerosol primers but I'd not recommend them unless you know what you're doing and have a suitable mask and environment to use it safely. Depending what colour you're wanting to paint you may need to top the etch with a different colour primer (or just use a different one) anyway, in which case both ProXL and Lechler are very good primers.

If you're not leaving it more than 24hrs between coats you should be able to get away with minimal scuffing. On an MTB I'd recommend a green or grey scotch pad as it'll be much easier to get into the nooks and crannies without risk of any corners from the paper going through thin layers of paint. Make sure you follow the Humbrol recommendations on coating times though as enamel can be a bit funny, and it's not something I've really bothered using since I was a kid making airfix kids as IMO there are cheaper and much better quality paints out there, especially now production has gone to China.

Top coats are going to be difficult with enamel. Nothing from the likes of Halfords or any auto paint will work as they're solvent rather than oil based, it'll need to be a Humbrol Enamel one IMO. Not sure if they do anything suitable. If you haven't already bought your paint I'd suggest that you will have an easier time of it with an acrylic rather than enamel spray but that's just my opinion based on familiarity.