Retail primer for diecast aluminium?

[Bob Minchin]

I have two outside lights made from diecast aluminium/zinc (aka Mazac) where the paint has come off in big flakes because the primer (in any) has not adhered to the metal. I have used a bead blaster at work to clean off the white powdery surface back to bare metal. Please can anyone point me to a source of etch primer that I can use to get a good key into the metal surface. Ideally this would be brush or aerosol applied.

I only need small quantities so a retail source would be ideal.

TIA

Bob Minchin

[The Natural Philosopher]

Try Halfords...I THINK they do a metal etch primer.

[fred]

In article , Bob Minchin writes

Knew I'd seen it somewhere . . . . .

but single pack it 27quid for 5l :-!

A quick google reveals many sources of 500ml tins, but mainly fancy stuff from International & the like at 16quid.

I notice from a technical sheet on it that it uses phosphoric acid as the etching agent, the same as is found in Jenolite rust treatment, could that be a cheap alternative to the real stuff?

[Andy Dingley]

Marmite is made with caustic soda, but I don't suggest spreading that on your toast.

-- Smert' spamionam

[fred]

It's the etch we're after init, does it matter which source of phosphoric acid we use for it :-?

ps: I'd rather gargle with the latter than have the former anywhere near me toast :-0

[Dave Plowman]

So it's the same acid as used for etching steel?