Back to Basics with Blink Bonny!

[Blink Bonny]

Soldering - Part the Second!

The story so far. Our wire is tinned and we have applied flux to the cleaned up carbon brush.

Pick up a little solder and dip the iron in the flux again. This distributes the sodler around the tip, otherwise it just sits in a blob on the end. Now, touch the iron to the fluxed carbon brush backing. Fsss, then remove. The top of the brush should now be silver.

Next, reapply flux to both wire and brush, pop the tinned wire onto the tinned brush and touch with the iron. A quick fsss and jobsagoodun!

The most important thing about soldering is getting the gear right. The likes of B&Q only really stock solders for plumbers which have, by law, to be lead-free. Maplins only stock multicore electrical solder. What we need is decent, lower melt solder. As I say, I prefer 145deg solder, available from Carr's, Hobby Holidays and such like. I've found that Green Label flux is fine for all metals although paste flux, should you prefer this, is just as good. I personally prefer the liquid for kitbuilding but paste for wiring where its so much easier to overturn the bottle. I speak from experience.

That's it for now. I'll look at white metal soldering next.

That's easy btw. Trust me.

[Mercator II]

Perfect timing BB, I am about to build a w/m tender kit, just waiting on the 'ingrediants' to arrive, solder & flux enroute

I like the idea of this thread, passing on knowledge & skills to others, thank you for you timing in sharing, who knows, one day I might even tackle a brass kit


oOOOoo

Brian

[Blink Bonny]

Ay up!

Much as I like white metal kits but I find brass, if anything, wasier to work with.

[PGBerrie]

I always thought that brass (or nickel silver) was beyond me until I saw the Ndetail lady put together this kit at the N Gauge Convention in Stuttgart in about 20 minutes a couple of years ago. http://www.ndetail.de/product_info.php? ... usatz.html. (Sorry about the German, they used to have some of the site in English). So I bought the flux and the solder! Looking forward to the next installment

Peter
PS: Ndetail do a mean Nissen hut!

[earlswood nob]

Morning all
Keep up the thread BB as improved soldering technique helps one make such better models.
When I got back to modelling 3/4 years ago, I used modern lead-free solder to build an etched chassis/gearbox and although it worked it was not very good.
I then bought and read Iain Rice's book on chassis building and used 145 solder on the next one and it was so different.
Basic instruction like this can introduce new recruits to the enjoyment of building models.
Earlswood Nob
PS the chassis built with modern solder was stripped and rebuilt

[Blink Bonny]

Ay up!

EN has a good point there. Iain Rice wrote 3 good books, one on chassis, one on etched bodies and one on cast bodies. I heartily recommend them as a starting point. They're well written with w touch of much needed humour and are based on actual buiild projects.

[Blink Bonny]

Ay up!

Having dealt with soldering brass and nickel silver, let's move on to white metal.

This isn't hard and I reckon if you can solder a wire to a piece of track, you can solder white metal.

You will need:

A small iron - 15W suffices for all but DJH castings. A temp controlled or 12V iron is even better while you're learning.

Flux - liquid is definitely best for this.

A flux brush - I use kid's watercolour brushes, £1 a bag and all plastic.

70 Degree Solder.

It is possible to put a kit together using 145 but I wouldn't recommend it. Not at first anyway. And, once you get used to the job, only in an emergency.

First off - the workpieces.

These are not the best castings I've ever seen. The castings are free from pockmarks but heavily flashed. You can see it clearly on the front of the castings. Not as visible but just as bad is flash on the joint. This needs removing. I use a combination of a big, coarse cut engineers' file and sanding sticks for this. Pointless clogging up your needle files unless you have to, isn't it?

Apply loads of flux to the joint. Don't skimp. If you do, you may melt the castings. It is the flux and solder that transmit the heat. Then apply a little 70 deg flux to the iron and run it quickly along the joint. DO NOT LINGER OR YOU WILL MELT THE CASTINGS. Think of the SAS. In and out before anyone knows you're there. If the joint doesn't "take", reapply flux and re-solder. Once again the fssss of the flux evaporating is the signal all is well.

And there you go. The joint at the top os how it should look when you're finished. The solder has run along and into the joint. Lower down is a poor joint. Here you will see a big blob of solder a sure sign of a weak joint. Now run some flux into the top of the joint and wipe some solder down it.

I now have a firebox for an LMS Patriot that is smooth and strong, merely needing some fine finishing before further assembly continues.

Sometimes we need to join brass components onto white metal. This is trickier but do-able. For this, I am going to solder in the rear body fixing bolt.

First off, clean both the bolt and the casting. Ideally, you should countersink the hole, giving space for the solder to flow into.

[Blink Bonny]

Ay up!

Part the next.

Apply flux to the screw. Then.....

..... lightly tin the screw using 145deg solder. This is because although 70deg will "take" on brass and n/s, the bond is brittle.

Finally attach the screw with 70deg and plenty of flux. The 70deg will "take" properly on the 145deg solder so a good, strong joint will result. This is a place where you can use 145, especially given the heft of these castings but remember that white metal has a melting point in the region of 110deg. So you need to be even quicker. Best use 70 deg I reckon

Next up, I shall be dealing with the thorny problem of attaching brass etches to white metal components. Easy! Plus how to make your own footsteps.

[mick b]

You MUST not hold the iron in one place on the Whitemetal castings at any time. The whitemetal will melt in seconds if you do so or you are not careful. It is different from normal soldering more like welding where you place a layer on top of the whitemetal and persuade it to run in the joint. Avoid soldering near detail, as it will melt !! solder from the inside whenever possible.
You can also cut small pieces of solder , place next to the part, plenty of flux and melt it into the part with the Iron, you can also do this with brass and other metals.
Some metal can only be soldered with special fluxs e.g aluminium.

[Blink Bonny]

Ay up!

Good point, Mick. Thanks.

[2512silverfox]

Thirty years ago, I used to do a lot of contract work for MRM Co (Kings Cross Models) and they taught me how to white metal solder using their EAMEs flux and lowmelt. Personally I would never use anything but a temperature controlled iron with low melt and white metal castings. Reduce the temperature until the low melt just melts and then go ahead using a 12% Phosphoric acid flux. You will not have any problem with dwelling and the solder is more controllable.. Not mentioned but equally important is the necessity to neutralise the acid flux as quickly as possible after you have finished soldering or you will find the casting stained and you will have to rebuff them before attaching any other parts. Ammonia solution works best for this in a large tupperware type container (always wondered what Tupperware was for!).

[Atlantic 3279]

Also, if you're a self-reliant cheapskate like me, and confident that you can do 240V wiring to a safe standard, you don't go and spend a packet on a de-luxe temperature controlled iron or "soldering station". Instead you buy a dimmer switch and wire your basic 25watt iron through that.

Does ammonia do a better netralising job than sodium carbonate solution Nick? I've never tried it. Soda also degreases and doesn't smell, but if ammonia has an advantage I'd consider it.

[earlswood nob]

Afternoon all
I have a dimmer switch wired between a plug and trailing socket. I have several scratch marks filled in with magic marker on the dimmer switch to indicate suitable settings. I can switch soldering irons if I want something with greater heat capacity or needing a smaller bit for details work.
I find keeping the bit clean helps better soldering.
Earlswood Nob

PS The Ammonia should work the same as the soda, but I wouldn't fancy the stench. You would have to work with the window open.....in this weather??
Caustic Soda would also work and remove all the grease, but might remove other things.

[Danby Wiske]

Caustic Soda would also work and remove all the grease, but might remove other things.

Like fingers, for instance...

[earlswood nob]

Hello again
You've got it Danby
I have just looked up the effect of ammonia on brass.
It can cause stress corrosion cracking.
This was discovered by cartridge cases cracking which was caused by airborne ammonia.
I'll stick with soda crystals
Earlswood Nob