Another couple of suggestions.
If you're going to be soldering complex shapes with a lot of joins (say, a DH.2 tail, or a stripdown kit), or particularly if you'll be soldering white metal parts, you will really benefit from a proper, temperature-control iron. With white metal, you can set the temperature below the metal's melting point, so you don't have to worry about ruining the castings. With complicated, multi-step soldering, you can do things in stages using solders with different melting temperatures, so you don't have to worry about melting your previously-soldered joins. Hakko are probably the biggest brand around the world, and their FX-888D is an excellent iron for around the price of a mid-range airbrush. They also had an analogue iron, which is discontinued, but has been widely pirated and is basically the default iron in Chinese factories. They're pretty inexpensive, and work perfectly fine for modelling purposes. Weller also has a well-regarded temperature controlled iron.
Suggestion #2: get a variety of solders with different melting points. For complex soldering jobs, it's really easy to re-melt one join while you're working on another, which can be a massive hassle. With different temperature solders, you can start with the hottest stuff, then step down to something cooler so it's impossible to melt the previous joins. Standard 50/50 lead solder melts at around 192' C (which is the same range as most white metals). Tix solder is common with model railroaders, and melts around 150`C. Model railroad shops will also sell low-melt solder that melts at (around) 100'C, 70'C and 50'C, so you can cover a pretty wide temperature range. Protip: you can also use two alloys, called Wood's Metal and Rose's Metal, as low-melt solders. Functionally identical to stuff sold *as* solder, the only difference is that they're sold in bulk packs of pellets, rather than pre-formed sticks. They're readily available on eBay, and much cheaper than sticks of 'proper' solder.
And I'd re-iterate the importance of flux. It's also worth noting that stainless steel - which is used in some PE sets - needs a special flux. You can't use the standard stuff you'd use on brass or nickel. And IIRC, Aluminium also needs a special flux, though it's pretty rare as a PE material.
Very helpful information, many thanks!
