Painting underside of rear fender

[Athame57]

My rear fender has a lot of blemishes appearing under it now, so sometime soon I'll be taking it out for a good sprucing up. Is it a bad idea to paint beneath it, how should I best go about the job?

[ozzybud]

It was the standard Honda flash Chrome from the factory which is very thin. I would suggest scrubbing with Scotcbrite or steel wool. Then use Por-15 or a similar rust neutralizer. Then rattle  can some silver metallic paint over that. It will be easy to keep clean and look attractive.

[Bradders]

I have just done the underside of both of my mudguards, I derusted as much as possible with I think it was Kurust and painted with silver Hammerite. I’m pleased with the look but I guess only time will tell how it lasts. I never use my bike if the roads are wet or salty though.

[davidcumbria]

After rust treating and paint spraying I think a protective coating of xcp rust prevention spray should keep it good. It is much more robust than acf50 ( does way better on tests ) and forms a hard protective skin.

[DomP]

Another option after treating the rust with something like deox gel is bilt hamber dynax ub, it's a dark brown/black coloured self healing underbody wax.

[Laverda Dave]

This is an interesting thread. I'm collecting my chrome from Ashford Plating on Monday and will paint the underside of the front and rear mudguards, the chainguard (although flung off chain lube will help keep that rust free) and the underside of the points cover to stop the potential arcing from the points.
I remember froma previous thread posted by Ken (Oddjob) a while ago where he mentioned about rust forming in the rolled edges in the mudguards.

[McCabe-Thiele (Ted)]

On my 500 I used the Zinc Galvanising paint followed by a silver engine paint when base coat completely dry.