Alloy corrosion

I am restoring a pair of garden lamps, the alloy castings are very corroded, what treatment should I give them before I paint them? Ken.

depends on how bad the corrosion is, but, if you want to restore a smooth finish, then I would suggest using a flexible car body filler such as P38 or U-Pol. Both are easy to sand to shape and will bond well to alloy castings.

CB

Hi Ken,

If they are whitemetal castings with a white powdery bloom, this could be tin oxide. Tin oxide catalyses its own spread so it's a good idea to get as much off as you can with a stiff wire brush then use zinc oxide primer before painting.

Neil

Thankyou for your thoughts , it is a "chemical " solution that I was looking for such as Jenolite, as the finnish need not be as good as body work etc as they will only be in the garden.

Shot blast them and paint immediately before the dreaded white powder comes back.

I would be interested to know how tin oxide would form on alloy castings. Alloy cleaner for car wheels can be obtained at autospare shops. I have a 6in powered wire wheel which is very efficient for such work. It is good on paint jobs as well. Tomol.

Hi Thomas,

'alloy' mean any mixture of metals, not just aluminium and magnesium alloys isued for car parts. I have some garden 'coach style' lamps and they appear to be 'white metal' - name for a wide range of low melting point alloys that are mostly tin with varying amounts of lead, copper antimony and other metals. Think Dinky/Matchbox cars (at least the old ones, I expect the new ones are lead free).

As Peter suggest the melting point is usually low enough that they can be easily melted with a blowlamp.

Neil

I would lightly blast off and apply a good etch primer straightaway then either powder coat of wet spray and make sure you get over 300 microns of paint or powder on.

Mike

I would lightly blast off and apply a good etch primer straightaway then either powder coat of wet spray and make sure you get over 300 microns of paint or powder on.

Mike