solder problem

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clivef5915
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solder problem

Postby clivef5915 » Wed Jul 01, 2020 10:39 am

Hi all,
When Bath Queen Square was relocated during a house move the track ends were soldered where the boards were rejoined. During the recent very hot weather,(and nearly every time there is a heatwave) track expansion and contraction, although minimal, has resulted in a number of solder joints breaking between the track ends resulting in a loss of electrical connectivity. A bit of a pain having to clean and resolder every time I want to play trains!
So the quick question is -- is there a specific solder to use with Peco nickel silver track that will cope better ?
Cheers to all
clivef
viewtopic.php?f=22&t=40184/Bath Queen Square - as never was !

Bigmet
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Re: solder problem

Postby Bigmet » Wed Jul 01, 2020 11:22 am

Probably not the answer you want, better not to do that. If the movement is enough to break the solder, then it will distort the rails if you take that weakest link away. Allowing the rails to move with expansion gaps is the better plan, making the electrical connections with wires that can flex.

Is that feasible?

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Bufferstop
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Re: solder problem

Postby Bufferstop » Wed Jul 01, 2020 1:18 pm

If the board joints are intended to be more or less permanent, leave the rail ends about 1mm apart but fit fishplates. Don't rely on them for continuity either run extra track feeds, or solder short links which bridge the gap. It's quite prototypical, I know they do it for a different reason but if you study a fishplated joint on the real thing you will see a bit of thick wire spot welded to the web of the rails either side of the joint. It's there to avoid the high resistance there would be through the bolted joint of the fishplate.
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Peterm
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Re: solder problem

Postby Peterm » Thu Jul 02, 2020 1:03 am

I've soldered my track ends to pcb, but the other ends of these are on joiners and free to expand. I've made these joints larger than normal because we get regular high temp's here in summer and then down to single figures overnight in winter. Just make sure every piece of rail has a feed.
Pete.

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Bufferstop
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Re: solder problem

Postby Bufferstop » Thu Jul 02, 2020 9:59 am

I've found no particular problem with soldering Peco's nickel silver. If you can solder beneath the rail is best, but you can't do that once it's down. Use a swiss file to clean the spot. - Use a hot iron,- even a very hot iron, getting heat into the rail quickly is important. Use 60:40 lead alloy solder with a flux core. Tin the rail by apply the iron and solder to it, then tin the end of the wire. Apply flux paste to the tinned rail Finally bring wire and rail together with the iron applied to the joint until the solder flows. Remove the iron but hold the wire still until the solder is firm.
If the joint looks dull grey it has failed, it will be weak and eventually fall apart. Use wire which is as flexible as possible. Use any clips or clamps that you can devise to hold all the bits in place whilst you work, you only have two hands!
Don't let anyone tell you that lead alloy solder is illegal. In the UK it is legal to use it yourself, for your own purposes. It's only illegal to use it on work for a customer, on water supply pipes, or by an employee working for you. Which is very fortunate for railway modelling, as the lead free stuff is totally unsuited to our needs.
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Flashbang
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Re: solder problem

Postby Flashbang » Thu Jul 02, 2020 10:48 am

Hi
Regardless of what solder or how well the rails are soldered, if you haven't allowed for expansion in the rails leading up to the soldered joints then the force exerted in the rail due to expansion will often cause a soldered rail holding joint to fail.

Simply cut through the rails a little back from the soldered joint and allow around a 1mm gap. Ideally cutting the rails through when the air temperature is around 20C as this then allows for further expansion and of course the opposite contraction when its colder. If the track is cut through in a straight piece of track and between sleepers, then often no joiner (metal Fishplate) is needed as the sleepers and rail chairs either side of the cut retain the rail in alignment. The thickness of a Dremel disk slit should be roughly sufficient. :D Then bond around the gap on each side with some fine flexible wire or install an additional dropper pair to the the rails after the cut and before the end soldering area.
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clivef5915
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Joined: Fri Feb 16, 2007 10:30 pm
Location: was Poole, now Corfe Mullen, Dorset

Re: solder problem

Postby clivef5915 » Wed Jul 08, 2020 12:17 pm

Many thanks for all the replies. I have left gaps where fishplates are used which take up the expansion, it just seems that the solder joint wants to part for some reason. Taking the advice, I will now fit some bridging wire at these joints which will solve the problem.
Cheers to all and happy modelling.
Clive
viewtopic.php?f=22&t=40184/Bath Queen Square - as never was !


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