For my 80th birthday last week (5/7/25) I received a copy of Your Life is Manufactured by Tim Minshall about manufacturing processes and how they can be improved. An excellent book, well worth reading.
It got a good review in the Sunday Times so I put in on my Amazon wish list. This got me thinking about how sustainable my loco manufacturing is.
Materials
I always use the minimal size material for turning and milling. This has the multiple advantages of minimising costs, machining time, power usage and waste (swarf).
That started off as two advantages, but like Monty Python’s Spanish Inquisition sketch just kept on growing.
It would be interesting to find out what the total energy consumption is involved in ore extraction, and conversion to final metals but I cannot seem to find a source for that data.
Anyway I suspect that I have very little choice in the matter.
The materials I use are (in approximate descending order of consumption) -
Nickel silver sheet
Brass rod, strip, hex and larger rectangular sections, plus thick wall tube for the tank loco gas tanks
Copper tubes for boilers, lubricators, tender gas tanks and assorted feed tubes
Stainless steel rods
Cast iron for some wheels, 3D printed SLS stainless steel for the remaining wheels
3D printed SLS stainless steel is also used for dummy backheads, coupling rods and possibly other parts that were previously cast
Brass castings are now giving way to 3D printed UV cured resin that is proving both strong and temperature resistant, but I will continue to use brass for the flimsier castings or those in a vulnerable position.
Mild steel rods – I try to avoid this as far as possible to minimise rust
The above materials (and their uses) are carefully selected to minimise corrosion and maximise performance, ease of production and durability.
I used to use a lot of brass castings, but those are gradually being replaced by other materials. The reasons behind that are lower energy usage, speed of development and bringing production back under my control.
3D printed SLS stainless steel requires very expensive machines so I am leaving that to the professionals. I cannot find any figures for the power consumed by these machines but I suspect it is a lot less than casting iron.
The resulting models can be mostly glued together (customers option) with some parts requiring soft soldering. I do all the silver soldering. Gluing requires less power than soldering!
The completed model (after testing) just requires a single coat of aerosol black etch primer, minimising paint, equipment and power consumption.
Livery is applied with vinyl wraps. I laser print the prototypes on A4 sheets, but production versions are professionally printed on larger sheets.
A water based varnish is then brushed on – customer’s choice of matt, satin or gloss. Weathering can then be applied if required.
I fully assemble and test the radio control system using a double sided PCB for the Tx. I will make my own PCB for the prototype but the production version will use a professionally made PCB.
Incidentally I have run into a strange problem with laser printing the masks for my PCB.
It prints fine on an inkjet printer but the laser printed version of the same file has a cobweb of fine lines joining bits of the mask that are filled in to prevent etching. Both printers are Canon ones.
My suspicion is that the fine lines are so fine that etchant will eliminate them on the actual PCB.
The software is TurboCAD, but an enquiry on the net suggests that AutoCAD has a similar problem. I hope it will not affect the vinyl wraps – they were fine on my previous laser printer **. I will have to wait and see.
** scrapped due to jamming the paper. It was obsolete and would probably have needed new toner cartridges soon anyway.Power
Electric power (most days) comes from my solar panels. My 16 year old Honda Jazz will probably require replacing before too long (presumably by an electric vehicle) so I will have to make sure the new car
can be used to store spare power from the solar panels during the day so can be used as a backup supply for evenings and very grey days.
Propane gas is used for silver soldering – I will have to work out how much is used per loco, but it is fairly minimal.
Propane gas is also used to power the locos (or “meths” if the customer insists – for tender locos only) but there may be a future possibility of electric heating if the push on EVs improves the power density of batteries.
As you can see from the above material usage I am trying to minimise the power consumption used to build the locos – hence the move from brass casting to 3D printing.
At present Chinese production of 3D printed SLS stainless steel is much cheaper than anything closer to home, but involves a long journey back to the UK. So far the prototype parts they have done for me have been flown back to the UK.
They do not seem to offer a choice of slower, cheaper and more climate friendly transport.
Plus a reluctance to purchase anything from a country supplying war materials to Russia.
There is also a trade-off here between production volumes and parts coming into the UK below the de-minimis VAT threshold.
My production volumes are low enough to escape VAT – apart from that which I pay on incoming parts, materials, tools etc.
Waste
The major waste is swarf – someone once asked online what do most people make with their CNC machines – back came the instant answer – swarf.
I bought a vacuum cleaner attachment for my mill/lathe so I can in theory collect all my swarf (provided I remember to change the bag between different materials). But how do I recycle the swarf?
Just found Bromley Scrap a couple of miles away which would help with that.
The lathe attachment I have just designed (and am currently assembling) for my CNC mill allows me to pass rods up to 1” diameter through the headstock so that will minimise off cut waste and reduce costs.
Waste from the 3D printed resin parts is usually minimal – careful design generally minimises the need for supports.
Those parts are then washed in Bio-Ethanol but eventually that debris will need removal and disposal.
The biggest part of the resin washed off is just uncured liquid – leaving it longer to drain before removing from the build plate will help.
I have already printed an angled build plate holder that helps with draining.
I try to reuse packaging (dunnage) from things coming into my house to separate and protect the parts in my loco kits.
Repair/recycling
My locos are all designed for easy repair and come with fully illustrated instructions with 3D views to make that as simple as possible.
I will try to ensure that all my designs are available for as long as anyone needs them – so spare parts can be produced by anyone long after I am pushing up daisies.
Hopefully my locos will never need to be recycled and will keep running until everyone tires of railway modelling as a hobby, or runs out of garden space for the railway.
Even then they will be attractive Shelf Queens.