I have been using ACF 50 for some time now. Designed to prevent corrosion on aircraft. I use it on motorcycles, cars and the bare metal of workshop machines.

Even bare steel hand tools that have been treated with it, stored and then wiped off and used, don't corrode afterwards if left lying about without being treated again.

I haven't conducted any tests as you describe but what I have found is that I don't have to waxoyl the underneath of the car every year anymore, so the oil is having some benefit.

I've always used Waxoyl but I modify it by thinning with white spirit (to help it flow better) and also adding some clean engine oil (to help it cling better). I use the cheapest engine oil from the supermarket.

Using white spirt to thin Waxoyl is not modifying it, that is what the manufacturers use.

Putting oil in it is possibly not a good idea, if it made it better don't you think the manufacturers would do that?

But what proof have you got that it clings better, have you done several test panels and exposed them to severe conditions and compared them after certain time periods?

Not sure of the logic here, but it seems to be along the lines of

"If anything was better than anything else, it would get copied, so everything would end up the same"

i.e. "Everything must be for the best, in the best of all possible worlds" (I know that one)

I wouldn't necessarily expect Waxoyl to mix very well with oil, but I havn't tried it, so I don't know.

When I tried Waxoyl alone, a long time ago, it was difficult to spray, didn't penetrate rust or creep very well, and it formed a skin which cracked, under which it seemed likely that rust would progress.

Oil, OTOH, soaks in to rust rather well, creeps along weld seams, and its film is to some extent self healing,

(It does, however, wash off exposed surfaces, vegetable oil less so).

I don't have comparative test data for my homemade and commercial rust treatments, which I should have, but OTOH I've never seen comparative test data from the commercial treatment suppliers either, who should be better placed and more motivated to provide it.

But I suppose if they are all the best, they don't need to?

I've always used Waxoyl but I modify it by thinning with white spirit (to help it flow better) and also adding some clean engine oil (to help it cling better).

The usual purpose of oil is to prevent things 'clinging' ??

Unless it is Magnatec oil which "clings" to the wearing surfaces - or so Castrol's advertising used to allege :-)

Caterhams are well known for terrible corrosion despite being mostly made of aluminium and glassfibre which makes most buyers think they do not rust. The chassis is powdercoated steel tubing and the alloy panels are rivited to this. So we have no protection in the drilled holes, different metals, no protection on the bare alloy and powdercoat that has a habit of falling off faster than the actual car goes, the rivets are alloy and steel, it could not be worse. CarSOS rebuilt one some time ago and it was a right shed.

When I got my chassis late in 1992 I waxoyled on all the hidden panels and tubes before I did another thing. Even if you pay ££££££'s for a factory paint job they only paint the outer panels, the underside etc are left bare metal. I made sure the waxoyl got right down into all the "grot" traps (there are plenty - its a 1950's design).

The car went on the road in early 1993 (28 years ago) and whilst its fair to say its seen very little salt but it has been used regularly in all weather conditions from March to late October.

Other than a bit of powder coat that has fallen off the nose cone fixing on the chassis (more waxoyl) its perfect, no corrosion. When you need to do any work I always clean off the old waxoyl and redo it before refitting parts, daft not to whilst you have access. Its like new alloy and powder coated tubes once its off.

Waxoly has proved its worth (I have used it on other older cars in the past as well) and all I have added is white spirit to make it spray. And I don't use the Waxoyl sprayer, its rubbish, I use a garden sprayer, much better.

The Caterham sounds rather similar to the old Series Landrovers. They can be immaculate on the aluminium panels but rotten as an old pear underneath in the chassis and bulkhead.

Believe me, just like Land Rovers Caterhams can be very bad on the outside panels as well as the tubes and inner panels. Along the bottom of the sides the alloy turns to dust. Rogue traders simply add filler, paint and sell at top price only for the buyers to find they have bought death on wheels later.