Tom's Workshop

I think most modellers would agree that they have kits that are gathering dust and waiting for the fairies to magically put them together in the middle of the night. Unfortunately this will never happen and unless you have deep pockets to pay to get a professional modeller to build them for you they will end up on eBay or you do it yourself. My only etch build has been a 51L LNWR carriage truck and box van and I was pleased enough with the results to think about tackling a loco. As I plan to build a joint GWR and MR layout my kits are a representation of those two companies. A good loco kit to start with I have been told is the Craftsman Models MR/LMS 1F 0-6-0T which I will embark on. I will add some 3D printed detailing to the loco that does not come with the kit which might also replace some of the castings that could be improved on. The Johnson boiler backhead did not come with the kit and I will either use an existing 3D printed one that I developed for a Cambrian loco or design one for the loco. No doubt along the way I will make a few mistakes and viewers will point out better ways of assembling parts of the kit and constructive criticism will be welcomed. If I can do a reasonable job then hopefully other first timers will not be put off assembling those etched kits languishing in their cupboards. The first part of the build will be the superstructure then the chassis.

 

Having started to put together this kit I realised my soldering skills were a bit scratchy as can be seen in fig.1 The solder joint for the footplate and valances is not as clean as I had hoped but it has done the job. The one problem I was having was getting solder to stick to the tip of the soldering iron, I’m using 60/40 Tin/lead alloy and telex soldering flux. It turned out that the tip was dirty and needed retinning and with the help of some useful Youtube videos on how to do this I now have a fully functional soldering iron tip. The most tricky part was soldering the valance to the footplate that did not come right to the edge of the footplate. I used a piece of card that I wedged between the side of the valance and the aluminium angle to insure that there would be a step between the valance and footplate. Bending up the splashers to form a right angle on the footplate was not as easy as I thought it would be and this would have been made easier if I had done this before adding the valances but it would have made adding the valances more difficult. Now that I had sorted out my soldering tip I added the 8BA nuts to the footplate and the solder flowed the way I wanted it to. Now as you can see the nut at the smokebox end needs to be moved over slightly to accommodate the smoke box front tab but by judging the size of the nut I will have to shave a bit off the tab for it to fit. For the next I will probably embark on is assembling the boiler but haven’t decided how I am going to solder the seam; do I just solder the bottom of the seam or cut a thin strip of brass and resistance solder over the seam inside the boiler. I think the second method would give a stronger joint. The next job would be attaching the smoke box inner and outer wrappers, fige.3 & drawing numbers 25&27, to the boiler. Do I just solder the bottom of the inner wrapper to the boiler or try and solder all the way round the rapper ? How do I solder the smoke box wrapper, fig.4, onto the inner rapper? I am modelling a Johnson loco that did not have rivet detail on the smoke box although the kit is for a Johnson loco there are etched rivet details on the wrapper. I suspect these can be sanded down before the wrapper is rolled.

 

Judging by your Fig 1 I'd say that your iron is running too cold. This soldering business is, to me, rather counter intuitive and I've come to realise that a large tip run at a high temperature is the default position. There will be more and better advice to come.

Brian

 

Thanks Brian. Here are my two soldering irons. I'm not sure what whattage the Antex one is, I think it maybe 25W but ended up using the solder station one which is 50W. Although the tip wasn't very clean when I started using it which probably contributed to the sloppy joint or maybe I didn't have it on the correct power setting. What is the most popular soldering iron for 4mm etched kits I wonder?

 

Tom,

You’ll get a lot of answers to that question, but I’d suggest you can drive a small nail with a big hammer, but the opposite ain’t true.

I purchased an Ersa RDS 80w temperature controlled iron in February, it unfortunately packed up last week, but was replaced within 48h which I can’t grumble much about, and they are justifiably popular, if a tad pricy, and you can swap tips to suit the job. I’m very pleased with it, and certainly think the cost is worth it.

Others may disagree with my choice of iron, but I think everyone will agree with “clean, flux, hot iron, fast, minimum solder to do the job”, and practice.

atb
Simon

 

Adrian
I find it easier if I have a small blob of solder on the tip of the soldering iron as that frees up my other hand if the piece I am soldering can't be clamped down. Obviously if you have a large area to solder it might not be so practical. Looks like I can buy some larger tips for the solder station which I will do. Interesting what you said about brass soaking up heat, it that why nickle silver is a better material to work with.

 

That's really what I was proposing, Tom, and in summary is the general advice. Those small tips look as though they'll enable the attachment of small parts and get in to the tightest corners. Not so! It's counter intuitive and a big iron bit and high temperature together with clean components will make the solder flow. It's difficult to generalise but an iron temperature of at least 100 degrees above the melting point of the solder you are using (low melt solders with white metal are a different and more specialised matter) will work better than small tips and low temperatures.

I suggest you use some scrap brass and just try joining parts in different configurations. Once you get it right you'll be amazed at how strong the joint can be.

Brian

 

Adrian has a point (no pun) when he refers to the small tips you have. Quite simply, with the amount of metal you have to solder, they just can't hold enough heat. I would suggest you use a solder where you know the melting point so you can set a more accurate temperature. It is not a good idea to just wind up an iron to a high temperature because it is possible to over-cook solder when it will no longer do what it is meant to do.

It was suggested to me some time ago, and I have used it successfully now for years, that you take the melting point of the solder, double it and add about 25C to give you a ball park figure for the temperature to set your iron to. So, for 147C solder:

147 x 2 = 284 plus 25 = 315C

You then adjust the temperature up or down a bit depending on the size of your bit and the amount of metal you are soldering together - more metal will absorb more heat. You will be more successful if you have a range of bits and change them to suit the job - and keep them clean! Personally, I never tin my bits as they then hold too much solder.

Don't think that heat and temperature are the same, either. Heat is energy whereas temperature is the measurement of heat. For soldering, you need a good supply of heat so with more metal to absorb the heat (as it warms up), then you need more metal on your iron - a larger (not necessarily the largest) bit. For 4mm modelling, I would suggest you need a minimum of a 50 Watt iron so that it can keep supplying enough heat (energy).

 

You're starting to run in to the problem of too many experts - of which I am not one. The practice of doubling the temperature of the solder is a good one and I've rarely found it necessary to go beyond that. Indeed, in my personal experience to use my iron (Antex Digital Station - can't remember the model number) beyond about 300 degrees C results in a tip which oxidises quickly and which makes it difficult to get a good contact with the work piece. Sometimes I go above that temperature for a higher meting point solder but then I'm aware that the cleaning of the bit becomes more critical. I also like to keep the tip clean so that it can pick solder up and transfer it to the work piece.

Some (who may be along in a minute) swear by the use of a miniature blow torch, but it never suited me.

In short you have to try to develop the techniques which suit you.

Brian

 

I was taught to solder using a ‘soldering bolt’, a large block of copper with a wooden handle like a screwdriver. When ready to solder the bolt had to be plunged into an open fire until a nice green flame appeared, the bolt was quickly cleaned with a file, dipped in flux paste and then tinned on a stick of solder. It was quite easy to make nice shiny joints but everything had to be ready, cleaned, fluxed and held in place. The bolt supplied instant heat and solder.

I still have a soldering bolt, which has been used on a few models, but nowadays it lives in a drawer having been replaced by a series of Solon and Antex irons and now an icon soldering station. However the lessons learned with a bolt have stuck. Clean, flux, heat quickly, job done!

Ian.

 

I was also taught to solder with my father's bolt - a chunk of copper rod probably about 3/4" diameter. My heating was done on the gas stove in the kitchen since we had dispensed with the use of the coal fire in the living room and I doubt mother would have let me solder on the living room carpet. Solder came in sticks - if solder wire was available at the time, I suspect that it would have been too expensive. I soldered up all my electronic bits and pieces using that bolt and you had to carry solder on the bit to make joints. Flux was Fluxite paste. My first electric iron came a good few years later - a Henley Solon which was hardly the bolt of choice for electronic work.

Jim.

 

I purchased a “bolt” at the Sellinge Steam Fair some years back for rather less than the several hundred grams of copper is worth, mainly for the pleasure of owning it, though I thought it might be handy for maintenance on my then garden railway

I believe it was a GPO Linesman’s’ tool. Never used it for soldering, but by ‘eck, it’d be handy for repelling boarders.

Merry Christmas
Simon

 

Having read these replys it seems there is more to soldering than meets the eye. Not sure about holding the solder with your mouth to solder unless you like the smell of solder fumes. I'm slowly getting the hang of this soldering science and realising that heat is the most important factor. What I would like to know is can you use a lower temperature solder on brass to solder something next to something that has been soldered with a higher temperature.

 

We lived in the country so no gas. My first modelling where soldering was needed was done on the kitchen table and the bolt was heated in the Rayburn.

I did buy an electric iron when I started building a layout in my bedroom. I don't recall the make but it came with a 2 pin plug which fitted a lamp holder! Needless to say I survived!

Ian.

 

My first st soldering iron was my father’s Henley Solon 65w with a 3/8” chisel bit. I drilled a hole in the copper tip and put a length of thick copper wire into it. That gave a decent amount of heat for 2mm scale soldering. Solder always moves to the heat and that provided plenty of it, especially with a bit of Bakers fluid to help the cause.
Tim

 

Yes, Tom. It is known as 'step soldering'. You solder the first piece with a high(er) melting point solder and for the next a low(er) MP solder. You do need to adjust the setting of your iron which is where the temperature controlled 'soldering station' is so helpful. You also need to be quick in and out with your iron to avoid heating up the work area too much. This is where resistance soldering is useful as the heat is very localised, so much so you can often dispense with the different MP solders.

You can even get down to using low melt (70C) solder though it does not on its own adhere well to brass or nickel silver, so you need to tin the metal with (say) 147C solder first or use 100C solder which does adhere to the hard metals.

 

Just to add my two pen'orth, where possible, I like to tin both surfaces with a thin smear of solder, add some flux and sweat the two parts together.
A good hot decent sized tip, to get the heat quickly into the joint. I use a 60 watt iron with about a 7 or 8 mm chisel tip, where possible.

 

I bought a Solon 65W iron, initially for 4mm loco modelling having found my father's 25W Solon iron just didn't deliver the heat quickly enough. By the time it had got the area of interest hot enough to melt the solder, previously soldered items that were close by, were at risk of becoming unsoldered. The 3/8inch chisel bit on my 65W iron roughly halved in size over a period of nearly thirty years before finally dropping off! The result of the combined attack by Baker's fluid flux and me cleaning the tip with a file/emery cloth!

But it made some beautiful joints!


Crimson Rambler