The steel frame parts on every Brompton bike are powder coated (rather than using wet paint) in order to give an even and durable finish. The plastic powder is sprayed at the frame part and attached with an electrostatic charge, it is then baked in an oven to melt and adhere it to the frame.
We offer a palette of 12 colours, two of these can be combined to make a bike that is even more personal. We group these colours into Mono, Classic and Bright themes – all interchangeable with up to 2 per bike permitted.
We also offer some premium finishes - Raw Lacquer and Flame Lacquer. These are finishes which are painstakingly achieved, showing the quality and craftsmanship of the hand-built frame. Each bike made with the Raw Lacquer finish has a unique appearance due to variations in the surface colouration of the metalwork and brazing; it doesn’t have a ‘perfect’ look and should be considered an industrial finish.
It is normal for the look and colouration of the Raw Lacquer finish to vary from bike to bike and also on each frame part – there will be a difference in the finish of the fork, main frame and rear frame. There may be noticeable variation compared to other bikes in stores or those featured in our brochure or website.
The Lacquer finish uses the same powder coating process as our other frame colour options (with the plastic powder having no pigment); as such it gives identical durability and protection from corrosion. The steel frame parts on all Brompton bicycles will age and a patina will form over time; the purpose of the raw lacquer finish is to allow the natural aging and altering of the bicycles appearance to be visible, and this will happen differently for every example. The phosphate treatment our steel undergoes prevents this cosmetic corrosion from becoming structural.
Before painting, each frame is pretreated with an iron phosphate coating, this prevents any surface corrosion penetrating through the metal, therefore any rusting on the inside of the frame tubes is purely cosmetic rather than a structural problem. The electrostatic spraying of powder paint means the powder cannot enter into the inside of tubes easily and means that there is no paint on the inside of tubes beyond the first 3-10mm. Consequently the inside surface of the frame on a Brompton is unpainted and can appear ‘rusty’ but this will only be a surface discolouration due to the iron phosphate coating.
As the steelwork is protected from corrosion there is no need to apply any rust proofing or similar to seal the tubes. Blocking the ends of the tube can do more harm than good and can actually trap moisture inside the frame and not allow it to breathe.
The powdercoat will often become chipped or otherwise worn through normal use - this is part and parcel of bicycles getting used as they should. We would recommend sealing areas where the powdercoat is breached with a clear lacquer. If using coloured paint, test an inconspicuous area for colour matching first.
Over time, the powdercoat will come off the clamping surfaces of the hinge, where the two halves meet and where the clamp plate sits. This is due to the pressure on the paint exerted by the clamp and by the dynamic load imposed by riding. This is particularly true of the mainframe hinges, which sees a much higher dynamic loading during riding, but can also apply to the handlebar hinges. All Brompton bikes will experience this over time, it can be accelerated by the hinges being closed aggressively and the clamping surfaces bashed together. It should not prove a problem as even if the paint comes off, the steel has been phosphated prior to painting and therefore the steel will only exhibit light surface rusting/discoloration, and will not see significant rusting to the point of structural failure; As such its normal wear and tear and not a functional problem.