Alternative to etching primer for outboard.

[rex_seadog]

On my outboard leg and prop I have a few bare patches that I need to prime and touch up before antifouling with MPX. (Auxiliary engine left down in the water). According to the tin I need to use an etching primer on the bare aluminium before using the antifoul primer. As I only need a thimbleful, rather than buy a large expensive tin of the proprietary stuff, is there anything else that I can use. I presume the etching primer is acidic - if so will a rust netraliser (phosphoric acid, I think) or any other acid product that I may be able to obtain easily (oxalic acid, even vinegar??) do the job?

It claims in www.bosunsmate.co.uk that etching primer is not necessary for outboard legs but suggests the use of cellulose primer. Does anyone have any experience of this?

Thanks.

 

[Lakesailor]

I painted my garage door, which was galvenised and bought a tin of etching primer specifically for the job. It was a small tin (about 250ml) and only cost about £4.
It might have been a Finnegans product. Bit sketchy on the details.
Try this etch primer
Near the bottom Etch Primer (PS2) 125ml for £3.50