by Ångström
In this article, I would like to give some tips on working with metals, particularly with regard to putting together metal kits.
1. When soldering metal parts together, always use a separate flux rather than relying on the in-built flux in resin-core solder. There are two reasons for this. Firstly, a separate flux, such as Bakers Fluid which is the one I use, is more potent than resin and therefor makes soldering easier and neater since the solder will run into the joint rather than collecting in a blob. Secondly, by applying solder to the iron and flux to the job in advance, one hand is left free to hold the job. If you decide to use Bakers Fluid (obtainable from any hardware store), make sure you rinse the job in water afterwards, otherwise the residual flux will cause corrosion.
2. The best way of assembling a white-metal kit is to solder the major components together. White metal melts at about 150degC so be careful. The easiest method is to use "low-melt" solder obtainable from many model shops. This solder melts at 70degC. However as most soldering irons run at about 250degC or more, you can still be in trouble. The secret is to make the joint so quickly that the white metal does not have time to reach its melting point. Therefore make sure that all surfaces are burnished and well fluxed before applying the iron. Again I use Bakers Fluid although there are many Carr's products that are just as good. A word of warning is that low melt solder will corrode a soldering iron tip much quicker than regular solder.
Before attempting to solder the components of the kit together, practice on some odd scraps of white metal, or try soldering two pieces of solder wire together. Yes, it can be done. My slogan is "Never say you can solder, until you can solder solder-to-solder"!
3. When putting together etched-brass kits, care should be taken when there are right-angle bends in the components. If the component is etched half way through where the bend is to be made, there should be no problems. If not, it is better to guillotine the item along the bend line and then solder the two components together. This may seem a little ruthless, but I can guarantee that less time will be involved with this procedure and a far better looking job will result.
4. If a narrow metal strip is required for items like coal rails, instead of using the thin brass strip provided in the kit, or instead of guillotining up your own strip from sheet, start off with some nickel silver wire a little smaller in diameter than the strip width required, anneal it by heating to red heat with a candle or gas flare, and then flatten it by hammering. A much stronger job will result.
5. If you have access to a lathe, turn up your own chimney and dome for use with white metal kits. I have yet to see a good white-metal boiler fitting, and many of them are nowhere near the correct size or shape. The substitution of these two components, which more than anything else identifies the model with the prototype, will likely overwhelmingly change the appearance of your loco.
6. Turn up chimneys from clear Perspex rod. Apart from the ease of machining, the advantage of this material is that when paint rubs off the chimney rim, instead of the normal shinny metal showing through, the appearance will be black.