Hi everyone - just found this site whilst trying to research 'Geoffrey Butler'.
Been reading this very interesting and valuable thread (facts, courtesy of someone who really knows what he's talking about, rather than the hot air, poorly-based opinions and bigotry that seems to fuel so many other internet discussions) and I thought I'd register to enable me to chip in my twopenn'orth (and if the quality of this thread is typical of the site in general I can see myself becoming quite a regular reader).
Anyway, with regard to Dave's Waxoyl recommendations (which I heartily endorse, having used the stuff successfully on many vehicles over many years) I would also urge anyone dealing with a rusting frame to, first of all, kill/convert the rust before applying the wax, and the best way of doing this, in my experience, is to use a product called 'Bilt-Hamber deox-C'. This is a non-acidic 'organic' product that you mix with water before immersing the rusty item for at least 24 hours. It has an almost magical effect, converting all the rust into a grey metallic finish. After a good soaking, you rinse it off with clean water, dry it immediately (hair-dryer, fan-heater etc) then, also immediately, you apply whatever coating is appropriate to the job in hand - in this case, a good sousing of Waxoyl as described above by Dave.
One of the great benefits of the Bilt-Hamber method is that, as the whole work piece (bike frame in this instance) is immersed, all otherwise inaccessible rusted areas get the treatment too (you obviously need a large enough vat or dish to get a frame and forks in - in my case I knocked up a frame-shaped structure out of old timber (a sort of six-inch high fence surrounding the laid-on-its-side frame, which I then converted into an immersion chamber by laying a large piece of thick polythene sheet (from the garden centre) over the wooden framework, then laying the bike frame on top of the polythene so that the weight of the frame pushed it down inside the woodwork, enabling me to fill the whole lot with the Bilt-Hamber fluid. Knowing that I was going to leave it to soak for a couple of days, I also covered the top with more polythene so as to minimise/prevent loss of fluid by evaporation. Amazingly, when you've finished de-rusting the frame, you can decant the fluid into storage cans and use it again later for further de-rusting jobs. I should add that, other than having discovered this product (via a classic car mag recommendation some years ago) and tried it myself, I have no connections whatsoever with Bilt-Hamber (a German outfit, I understand) or any of their dealers, agents or any other interested parties.