Repainting aluminium

[belgiangoth]

Considering purchasing this second hand

Is this something you could just get re-powdercoated or is it something you would just touch up with metal paint?

[Jdsk]

What is it? And is it removable?

Jonathan

[belgiangoth]

It's an attachment for a muguard (for a trike), yes it is removable.

[Jdsk]

It's aluminium so it's not going to corrode. (Corrected below.)

I've been pleased with stuff that I've had powdercoated... but none of that has involved HPVs.

How about tidying it yourself, then getting a quote for blasting and powdercoating from someone local?

Otherwise I'd use Hammerite over their Special Metals Primer.

Jonathan

[peetee]

Aluminium might not rust but it most definitely corrodes. Normally it produces a white powdery oxidisation that readily lifts paintwork. I have seen many badly pitted and powdery aluminium frames that have reacted to salts in rainwater sprayed on the frame from the bike wheels and passing traffic.

[TooManyBikes]

I built a kind of off road capable tourer/road/gravel bike using a late 90's cyclocross alum. alloy frame with steel forks which had some pretty bad stone chips, mostly on chainstay and underside of downtube, and areas of missing powder coating on the drop out area, I got a small tin of Humbrol or Revell model enamel paint in the nearest colour match, and touched up the chips, came out pretty well and would definitely do the same again on future small areas of paint or powder coating damage.

[Jdsk]

I stand corroded.

Jonathan

[belgiangoth]

Aluminium might not rust but it most definitely corrodes. Normally it produces a white powdery oxidisation that readily lifts paintwork. I have seen many badly pitted and powdery aluminium frames that have reacted to salts in rainwater sprayed on the frame from the bike wheels and passing traffic.

So, it that the "going to snap in a brittle fashion" corrosion?

And where would you class this on the irretrievable corrosion ----------------------- just needs paint likert scale?

[peetee]

I think it unlikely that it will snap. It has quite a big cross-section, I would surmise this is to prevent it flexing rather than bearing any continuous substantial load, which it would be capable of in a static capacity.
But then again, if the metal is flawed and corrosion has set in...
Clean back to bare metal and assess the depth of the degradation and if there are any cracks.

[simonineaston]

In my experience, I've had mixed results painting ali. The usual diy advice is to sand it clean, degrease with whatever - detergent acetone - then soon after, apply zinc-based primer, then apply an oil-based paint. When I've done that, the result has been either good adherance / long-lasting finish or else, patchy loss of coat, sometimes months after application, sometimes years... I think it depends on exactly how clean you get the piece.
Perhaps a specialist finisher a better bet, due to their having access to the appropriate chemicals for dipping pieces - adds to expense tho'.