Having been quite pleased with my second outing with Spray.Bike I’m contemplating doing one of my favourite bikes.

It’s a Trek Crossrip: aluminium frame and carbon (legged) fork, currently with matte black paint. I need to check the graphics but I think they’ll sand off with the paint rather than being vinyl decals.

Question is: those who have sanded back aluminium and carbon before, what grade of grit do you recommend for getting the paint off without lunching the aluminium or the polymer on the fork? (I realise that’s more a matter of taking care than anything; and I’m somewhat helped by not needing to remove all traces of paint, so I don’t need to dig too hard into fiddly areas.) And… any other pearls of wisdom? Or tales of woe…?

I could just spray over the existing paint but that feels like too much of a cop-out. And it reduces tyre clearance, innit 😉

Do you need to get the paint off? You only really need to give the old paint a key for the new paint and with a matt finish you’re part-way there
Wet and dry 800 grit (or finer-bigger number) used wet and rinse with clean water. IPA on a cotton bud to degrease the fiddly bits
Any chips in the ally will oxidise almost immediately so ideally you’d use a specific primer, or you could ignore them and be prepared to do an occasional touch-in

Reply To: Sanding down painted carbon and aluminium…?This guy…….
https://www.pinkbike.com/news/going-full-retro.html

Do you need to get the paint off? You only really need to give the old paint a key for the new paint and with a matt finish you’re part-way there

I don’t need to, no, and the last job I did was indeed just spraying over an existing matte black paint job (albeit a box fresh one, rather than one that’s currently covered in crud).

Wet and dry 800 grit

Jolly good, pretty sure I’ve got some 800, maybe 1200, but I think that’s the finest I’ve got kicking about.

IPA on a cotton bud to degrease the fiddly bits

Punk or Dead Pony Club? 🙂

Any chips in the ally will oxidise almost immediately so ideally you’d use a specific primer, or you could ignore them and be prepared to do an occasional touch-in

Mm, this was another thing I was pondering. Spray.Bike have both carbon and metal primers and I’m wondering how essential they are, given that they’d add £20 to the cost. Obviously if I paint over the existing finish then they’re not needed, but if I sand it back then I don’t want to spend ages doing that and sticking £40 of paint on it just to have to do it all over again when it falls off because I didn’t use primer 🙂

Maybe I’m starting to lean a little more towards just spraying over the existing paint.

🤔

Just for the weight weenies out here, weigh it before and after. See how much weight the primer, paint and lacquer adds for curiosity.

Thanks

Your two tone bike above looks brilliant btw