Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

That pretty much sums it up for me...

The main reason though, for my Wilesco oil addiction, is that its viscosity suits a Jensen perfectly, since the internal oiling has to be sucked in through the exhaust.
As already stated, as soon as we get to "grown up" toys, i would never use anything but fatter steam-oils, and on both types a good quality automotive oil for the rest.

One thing to keep in mind for future reference though, is that once you go all in, and finally purchase that >100 years old steam engine, it would be a wise move to use a simple mono-grade mineral oil on the outer parts, as theres some reports of newer oils attacking the old old-paints on those.