Soldering query

martin goodall
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Joined: Fri Oct 02, 2009 6:20 pm

Soldering query

Postby martin goodall » Fri Jul 13, 2012 2:05 pm

I intend shortly to construct a coach body using etched-nickel sides and ends supplied by the late Trevor Charlton. Both Trevor himself and other model-makers have made it clear that a good hot soldering iron is needed for this task (specifying not less than a 60-watt rating), because the etched nickel sheet is around 27-thou thick and will drain the heat from a less powerful iron before a soldered joint can be properly made.

At present, I have in my armoury an 18-watt Antex iron, a large and very unwieldy 75-watt Solon iron (about 40 years old, one careful owner, extremely low mileage, in fact hardly ever used – basically due to its lack of manoeuvrability) and a London Road Models RSU (designed by the late Mike Grey), which I confess that I have yet to fire up, although I have had a hands-on demonstration of one of these beasties.

I was thinking of buying an Antex or Weller 60-watt iron (although I see that Squires offer only the 50-watt and 80-watt models in the Antex range), but was wondering if this is a task – i.e. soldering along seams, rather than spot soldering - that might feasibly be performed with the RSU?

Do members think the RSU could do the job; or should I order a new soldering iron effectively to replace my unloved Solon 75-watt? If I buy a new iron of not less than 60-watt rating, what iron would members recommend?

allanferguson
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Re: Soldering query

Postby allanferguson » Fri Jul 13, 2012 4:15 pm

I have soldered together a number of these zinc sides for Caledonian coaches, which I got from Phillip Millard about a hundred years ago, it seems. I used my 48w temperature controlled iron with Carr's yellow flux, and 145deg solder, and had no problem getting good joints. I was very punctilious about cleanliness, and I made sure there was nothing else around to soak up the heat (e.g. sides and ends held in wooden, not metal, jigs) Another suggestion has been to use Carr's 100deg solder, but I have not found this necessary. I did find it impossible to assemble the guards' duckets, though!

I don't have an RSU, so can't comment on it's suitability for this job.

Allan F

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Wizard of the Moor
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Re: Soldering query

Postby Wizard of the Moor » Fri Jul 13, 2012 6:45 pm

I often use an LRM RSU for soldering seams. There are three key points to remember:

1. Don't wipe the RSU probe along the joint. Instead, perform a series of tacks.
2. Holding the parts square and with a conductive path for the RSU juice can be tricky.
3. Don't move the RSU probe along the joint :)

You might find it easier to tin the edges first with one of your conventional irons, then find a way to clamp the parts together. The old Exactoscale assembly jig is very good for this.

Tack the parts in the center of the joint with a quick zap from the RSU. Check for correct alignment.

Continue zapping, alternating either side of the first tack so as to even out the heat build up.

Allow to cool. Check again. Marvel at how little cleaning up is required.

Once you get used to the RSU, it is very easy to control the heating of the joint via short zaps of power. It is also much easier to adjust the alignment of parts with an RSU compared to a conventional iron.

If you move the RSU probe whilst the power is on then a badly pitted surface will result due to the inevitable arcing.
James Dickie

My workbench

David Thorpe

Re: Soldering query

Postby David Thorpe » Sat Jul 14, 2012 8:06 am

Our local Aldi is currently stocking among its specials a 135W gas soldering iron/torch - http://www.aldi.co.uk/uk/html/offers/sp ... 7-06-17-51. I've never used one of these, but at only £14.99 I thought it was worth getting to see if it would be any good for those jobs with which my 35W iron has difficulty.

DT

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Jol Wilkinson
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Re: Soldering query

Postby Jol Wilkinson » Sat Jul 14, 2012 8:21 am

Martin,

are they nickel silver?

All the TC coach parts I have are etched zinc, etched from one side with a green backing and the windows were punched out. As far as I know this was Trevor's usual method of producing parts.

27 thou is also thick for N/S etches, .015" or .018" being the norm in 4mm.

If they are zinc, then you can use low melt solder. I recently assembled a TC 50' LNWR coach body using Carr's 100 deg. solder with an Antex 50W TCU.

Jol

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Paul Townsend
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Re: Soldering query

Postby Paul Townsend » Sat Jul 14, 2012 10:43 am

TC sides are Zinc.
I have used low melt with phosphoric acid flux and either an obsolete 50watt thermostatic iron or Weller current 50/60w thermostatic iron...no probs.

martin goodall
Posts: 1425
Joined: Fri Oct 02, 2009 6:20 pm

Re: Soldering query

Postby martin goodall » Sat Jul 14, 2012 10:49 am

Sorry. My mistake. I was in a zombie-like state after a very hard week's work, and wasn't thinking straight.

Jol is absolutely right in saying that the Trevor Cahrlton etchings are pure zinc (i.e. one part of the usual alloy of brass, and a component of nickel silver - which is zinc, copper and nickel). They are not nickel or nickel silver.

I confirm that my etched parts have a green backing and the windows have been removed. The turned under is also helpfully pre-formed.

I am very interested in what Jol says about being able to use a lower melting point solder (100 degrees), but presumably the iron still needs to have enough oomph to avoid the heat being drained away by the metal parts one is trying to join.

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Jol Wilkinson
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Re: Soldering query

Postby Jol Wilkinson » Sat Jul 14, 2012 12:19 pm

Martin,

as I said, I used a 50W Antex TCU, which worked okay with a 3mm bit, 100 deg. solder and 6% LRM Phosflux. So as Paul confirms, a 50 watt Antex or Weller should do the job.

Jol


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