Painting aluminium components

[Mart1williams]

I'm starting to rebuild an old 40+ which my son found at the tip and gifted to me when we discovered its age matched mine. Like me it is run down cosmetically so I want to freshen it up. As part of this I'm interested to know what people normally do to finish the aluminium components such as crankase, cylinder head and gearcase and whether these were these painted from new or left bare? As acquired they all have a thick brush applied coat of silver and it is hard to discern any original finish. Finally for a 1958 40+ can anyone advise if the correct colours for the flywheel and the engine block (I'm assuming siver and black respectively)?

Any help and advise would be much appreciated.

[charlesp]

The early gearboxes/water pump housings/props were polished, later ones painted. I can't remember when that changed but I'm pretty certaqin they were painted by 1958. Hammerite Smooth Silver in an aerosol is a very close match - very close indeed.

The blocks were a glossy black.

The crankcase was bare aluminium, as with bracket fittings, tiller arm, and cylinder head.

The flywheel on yours would originally have been a Villiers, and these were just 'engine turned' ie bare metal. A polished finish (with the polish marks going round the flywheel) is a good approximation. I have known people run up the motor with a piece of emery cloth held against the flywheel rim - I have to wonder how much abrasive bgets sucked down into the carb which is of course inches away!

A word of warning here - most of the paint bought from, say, Halfords, dissolves instantly on contact with petrol. Bizarre really for stuff sold through a motor car chain, but it's true.

[atoyot]

How about the gold flywheel color on a '78 model 40+? I'd hate to have to go with just any random, gold-ish tint though willing to try.

-ted

[Mart1williams]

Many thanks for the quick reply. Thats just the information I was looking for.

[RickUK]

On aluminium surfaces, used a 'specially alloy' primer before colour spraying - even with Hammerite, which in the small print on the tin also recommends their own brand of primer for ally, which I have never managed to find for sale - at least at the common sources!
In stripping the silver paint, you might find traces of a light green primer - maybe only on older motors - which is chromate based, and as a consequence no longer available, or only as special supply - eg. aircraft industry.
Let the primer cure for a few days before top coating, and even leave the Hammerite to cure for a few days before subjecting it to any abuse, despite what it quotes a a drying time.
I think drying times quoted are often only touch or 'handleable' dry.

With the nature of brass, I have never understood how Seagull were able to black paint direct on tanks to be petrol resistant without a bond primer, but a long cure does make a difference.

Rick.

[phil]

Hi Atoyot,
I've used and been happy with Tremclad hammered gold over an acid etch primer, I prefer Pro Form acid etch primer as it is light gray and covers much better than the greenish stuff. If Tremclad isn't available there in the U.S., I believe its part of Rustoleum so you might check to see if they have the same product. Paints that don't appear to be fuel mix safe, often appear to gain some fuel resistance with time as has been mentioned.

[atoyot]

Hi Atoyot,
I've used and been happy with Tremclad hammered gold over an acid etch primer...

I found some etch primers under the Tremclad and Rustoleum labels. Duplicolor, who seems to do mostly automotive paints, also has one. These were web searches and I hope to find them locally.

The original though, which may still work with those choices, was to use auto touch-up paint in spray cans since auto paint holds up to limited exposure to fuel spills. For curing, there's a lab oven I could use over a weekend that runs around 70C all day and night anyway.

Thanks for the lead on etching primers.


-ted

[phil]

I have spilled fuel mix on the hammered gold that was mentioned, had been on about 2 weeks, no problem. Luckily we don't have the alcohol laced fuel here, so that may be a difference.

[Collector Inspector]

I have had outstanding success with VHT Engine Enamels in cans, available down here, probably in old limy as well.

http://www.vhtpaint.com/engineenamel.html

You have to heat or bake them to say 120deg C for an hour and they are resistent to everything you would want or, not want to spill on the surface.

Heaps of colours and the "as cast Aluminium or just plain Aluminum comes up a treat!

Regards

B