Templot Club Archive 2007-2020
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posted: 17 Jun 2008 20:50 from: Martin Wynne
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Dear all, On model railroading groups over the pond, there is frequent advice to heat rail in a domestic oven before use to temper and de-stress it. I've been in two minds whether to regard this as a joke, and whether heating rail to not much more than soldering temperature is really going to have the slightest effect on it. I know heating to higher temperatures, for example to dull red heat from a gas flame, significantly anneals and softens rail, making it ideal for such jobs as forming rail-built buffer stops, but then it is dreadfully prone to kinks if used that way for track building. But low-temperature oven-tempering keeps cropping up, and again today, from a source I regard as authoritative: Oven tempering of nickel silver only requires about 250 degrees and you leave it in the oven long enough to get the rails to that temperature (30 minutes or so). Allow to cool slowly at room temperature - don't cool fast with water or you'll essentially anneal and soften the rails and when you solder to them it will then induce new stresses. As far as I know, oven tempering of nickel-silver rail is unknown here in the UK. Countless UK layouts have been built with untempered NS rail, without the sky falling in. Or any problems at all that I know of. So I still don't know whether to take this seriously.  Comments anyone?regards, Martin. |
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posted: 17 Jun 2008 21:12 from: Phil O
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Hi Martin During my time as a boilermaker we only used tempering to reduce the hardness/brittleness of the material after hardening. IE chisels and gouges (medium to high carbon steel) heat to cherry red and quench in sperm oil. Then re heat to straw and dipped again. Aluminium and copper require annealing because they work harden and fracture if worked excessively. As to nickel silver I’ve not come across tempering being used, I suppose if you were excessively bending it at the same point it would eventually fracture as with any metal it will work harden and fail, Gold excepted. I hope this is some help.  Cheers Phil |
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posted: 17 Jun 2008 21:17 from: John Lewis
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Martin Wynne wrote: As far as I know, oven tempering of nickel-silver rail is unknown here in the UK. Countless UK layouts have been built with untempered NS rail, without the sky falling in. Or any problems at all that I know of.I suppose you could write a "Templot Cookery Book". First source your rail. Do not mount in chairs or on sleepers. Preheat the oven to 250 C/Gas no.6 for 10 minutes Place the rail on a baking plate and cook for 30 minutes. Turn off the heat and allow to cool for a further 30 minutes. Enjoy ...! Actually I would have thought that about 5 minutes in a pre-warmed over would have been more than long enough. John |
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posted: 17 Jun 2008 21:25 from: rodney_hills
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Hello, Ed McC just confirmed that it's 250 degrees F. i.e. 121 deg C. Not that hot. Original discussion seemed to be about small-section rail, eg code 55, presumably vignoles (FB) section. Maybe something to do with the way it's drawn by the manufacturer? They must have big ovens in the USA - if they're dealing with 1-yard straight lengths of rail. Regards, Rodney Hills |
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posted: 17 Jun 2008 21:48 from: Andy Reichert click the date to link to this post click member name to view archived images |
rodney_hills wrote: They must have big ovens in the USA - if they're dealing with 1-yard straight lengths of rail.Ed is from Texas! The rest of us just have normal (US) sized ovens. Andy |
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posted: 17 Jun 2008 23:32 from: Jim Guthrie
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Martin Wynne wrote: As far as I know, oven tempering of nickel-silver rail is unknown here in the UK. Countless UK layouts have been built with untempered NS rail, without the sky falling in. Or any problems at all that I know of.Martin, I know that in model engineering, heat treatment of metals is sometimes recommended in some circumstances to relieve stresses in metals before cutting or machining, but I don't know if the same principles would apply to nickel silver rail where there would be little cutting or machining in the majority of rail used on a layout. The only heat treatment I've used on rail is with the 2mm Association Code 40 "squashed wire" rail, which comes in a coil and can be a bit problematic to straighten. So cut it into half metre lengths - grab one end in a vice and hold the other end in a clamp and apply a Graskop RSU at full whack to the rail and give a good yank when it goes black and smokes - voila - straight rail I give a few more yanks which I think work hardens it again so that it doesn't kink when you look askance at it. Jim. |
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