painting weathered aluminium

[ladylola]

When the weather warms up a bit I intend to repaint some garden furnature. It is aluminium that has in several places lost its paint covering and the metal is weathered as a result. I was intending to use a rotary wire brush to clean off any loose paint (it's cast with leaves and flowers so sanding with paper would be almost impossible) and then to repaint the whole thing(s).
What would be the advise concerning primer, something like zinc phosphate or is there anything more suitable? It's going to be topcoated in gloss of some colour so I was most likely be undercoating as well.

 

[misterhelpful]

I don't often paint aluminium but have used Zinnser Bullseye (which is a suitable product) for a couple of similar jobs.
Make sure any powdery film is washed off the bare aluminium first. Zinsser recommend something like an ammonia/water solution for this but I've only used soapy water and rinsed it off quite successfully.
Can't recall using zinc phosphate on aluminium myself but it is my No.1 primer for other metals. (May require an etching primer first on alu )

It might be worth reconsidering the wire brush (try a stiff nylon brush, but obviously difficult if you plan on using a rotary one) as any filings that wear off the brush and get stuck to the table could become rusty.

 

[ladylola]

I take your point about the wire wheel, but do have a couple of brass brushes that I was intending to use.
I mentioned about the zinc phosphate as I've used that on other metals too but like you not on ally. I've also got a gallon of micasious iron oxide paint but I'm fairly certain that wouldn't be suitable, pity.

 

[misterhelpful]

Yep, brass bristles would be a better option.

I agree that the micaceous paint would probably be unsuitable.

 

[Nige F]

Upol acid 8 etch primer comes in a spray can - apparently for the bare bits