My black Thorn frame and rack have a few small rust blemishes, which look pretty minor, and chiefly a cosmetic issue as far as I can see. I'd like to treat/repaint them. I am thinking of using Hammerite, though it is annoying that the smallest tin is 250ml. My questions are:
1) Is Hammerite a good option?
2) Should I apply a rust inhibitor to the rust patch before painting, if I do use Hammerite?
The frame is, I think, powder-coated, and was originally a low shine finish, but I have polished it with Autoglym Super Resin polish (I'd rather polish my bike than my four-wheeled chariot ) and I think it looks pretty smart. So a high-gloss paint should blend in O.K.
Yes, for genuinely tiny touch-ups, Humbrol Gloss Enamel is effective, comes in a huge variety of colours, comes in tiny tins, and is pretty freely available.
Whatever paint you decide to use, surface prep is the key (often both senses). Definitely degrease, for which you can buy special impregnated wipes in places like Halfords if you don’t have the necessary chemicals to hand, and usually rub to a dull finish using very, very, very fine “wet or dry” paper.
Whether you need a primer depends a bit on the nature of the damage, but if you are back to bare metal you will, and I would recommend an etch primer. Halfords do a spray can one, which could be used with masking, and great care not to get it where you don’t want it.
There are specialist places that will mix and sell tiny quantities of colour-matched paint (there a good one in Watford, but I can’t remember what it’s called!), and besides Humbrol another specialist modellers’ paint supplier is Precision Paints. They do the whole system of degreaser (horrendous stuff!), etch primer, and gloss topcoats in a bewildering array of colours, either acrylic or enamel, which is useful if your bike is the same colour as a 1950s bus, or a 1930s railway locomotive (if you show it, I can probably tell you whether it is)!
Warning: be very, very, very careful about using primers and top-coats from different suppliers, or even from different systems (oil-based enamels; acrylics; cellulose) within a single supplier’s catalogue. They will often react adversely with one another, ruining the finish.
I haven’t mentioned Hammerite: their stuff is very good, but I regard it is a bit difficult to control for tiny jobs, it’s not really formulated to brush to a fine finish over very small areas, which model making paints are.
Last edited by Nearholmer on 2 Sep 2024, 1:54pm, edited 1 time in total.
Following advice given previously on this forum, I now use Owatrol for small rusty patches. In effect, it's like a colourless paint that penetrates rust & sticks well to bike frames. Reasonable price too for 125ml.
Many thanks for your advice. I had forgotten about Humbrol enamel in its ideally-sized tins. I certainly spent many happy hours painting battleships with it in my youth, and they never rusted . I have located a retailer shortish ride from me, though I'll have to keep focused when I go into the shop, since it looks to be full of tempting things. BTW, I'll heed your advice, and search the forums in future.
) and I think it looks pretty smart. So a high-gloss paint should blend in O.K.
