Murder of a Garratt Pt 2 – The Resurrection begins
Well, that caused a stir with comments like “you’re mad” and “you’d have been better off with a kit”. I would refer you to my comment “I wouldn’t have started from here”. It took me three years to pluck up the courage but once the first cut was made there was no going back.
At the end of episode one I said I had plans for Sunday to get more done before the T20 cricket on the TV. It didn’t quite work out like that. Some progress was made with the CAD and the M1.6 screws turned up but domestic chores and an urgent mod to a customer printed patterns were all that got fitted in around the cricket. The cricket was T20 England vs Pakistan at Old Trafford. England won and it was a cracking game.
Keen to crack on, Monday I returned to the model room and it became apparent that most of a day off had a benefit. I realised that a) the job had expanded across all three workspaces, b) I’d might a right bloody mess and c) hopefully the destruction phase is over. First job then was an epic tidy up of all three workstations. On the main bench it needed a deep clean with all the cutting disc shrapnel that had got everywhere.
TOP TIP: calendar pads provide an easily replaceable work surface and notepad in one. That said, in this digital age, what was once a freebie are now harder to find.
Tidy up done today’s actual priority task is the CAD for the new manifold, top feed, injectors and check valves so I can print them overnight as patterns to be sent off for casting whilst I am away. The originals on the model are a little malnourished.
I have 196 scanned drawings of the NGG16 but 2D is only so much help. Several parts need to be redrawn in 3D CAD which tends to reveal deficiencies in the 2D drawings.
Allow me to try to explain with an example.
Taking this first triangle. It might look like a standard 3, 4, 5 triangle but on a 2D hand drawn drawing you can write any old nonsense on it as I have or just not put anything. You can’t (shouldn’t anyway – ever) scale off the drawing as they have been copied that many times over the years they can be distorted in all directions.
This is the quality of a lot of the source material.
Now, do the same in 2D CAD and you can see that its decided that one line is vertical, the other horizontal (see the little green marks) and, having dimensioned the 3 & 4 sides as what are referred to as driven dimensions, ie I said what size they were and shown in black type. The program itself has worked out the other side has to be 5 and shows that in grey and basically won’t let you mess with the truth.
In 3D CAD you then add the third dimension
So working with those drawings and a lot of photographs that allow you to
invent interpret dimensions not given to get to something that looks right you end up with 3D models in CAD for the parts needed. Of course for a model we’re only interested in the outside and not the inner workings but you end up with something like this.
With those drawn the next thing is to print them on the 3D printer at the finest resolution as I had set myself the target of sending them off to be cast in brass before I left home on Wednesday.
As 3D prints they are quite fragile and as they should be shiny brass, at least in parts, and I want to solder to them the best option was to use these as patterns to cast in brass.
Annoyingly the 196 drawings don’t include details of the injectors and ejector so I am looking for them whilst in Wales at Boston Lodge.
RED or BLACK, RED or BLACK, RED or BLACK, RED or BLACK
As supplied the loco is gloss black but with a desire for it to be red like #138.
Right, so even if it stayed black its going to need a lot of work. Gloss black masks all the detail in the shine so that you just can’t see it. Any engine more than a couple of days out of the works exhibits all manner of shades of black and, it doesn’t matter how well its cleaned grot starts to accumulate around components and that subtly changes the shade of the colours.
Very quickly the work/walking surfaces go generally matt and raised edges get a metallic shine just by being walked on. In the extremes you’d get greasy gunge around the motion that’s a smoky grey/black with a shine to it, the tank and cab sides that have a wiped gloss finish with the start of discolouring around bolts and rivets whilst higher up and on the top of the tanks it’s a more matt finish with a bit more grey in it.
That’s just the body colour. The model has a shiny silver smokebox. If they’re ever painted silver they don’t stay that way for long. Now they’re painted with heat resistant black paint and often done when the engine is hot.
But you were on about doing it red?
So, there is a cunning plan. As a one-off engine you’d airbrush it and hand line it. I’ve done hand lining with bow pens and have a superb set that was fettled up for me by a master of such things but to do a smart and consistent job you need to practice and you need to do it regularly. I have hand lined a couple of loco’s that actually won modelling competitions but I don’t really enjoy it.
When I wanted my Double Fairlie Merddin Emrys painted and lined I had Warren Heywood do it and a superb job he made of it.
So, there is a cunning plan for which this engine is a guinea pig. Imagine, if you will, something like a range of semi kits for say, Quarry Hunslets, in which all the tricky stuff has been done and you just have to assemble it. Painting and lining is always going to be a pain in the nether regions but how about you spray it car spray black and then add its red, blue or green body colour complete with its lining as a big transfer. Its only what they do on the big railway with vinyl wraps.
That’s the theory anyway. I was somewhat dreading the practical application as thinking it through in advance made me realise that the opportunities for it to all go horribly wrong were many.
TOP TIP: This one I learnt when I worked for York Model Making. Stick a length of masking tape on the back of your ruler in from the edges. It stops the ruler sliding about and if you are using it with ink or paint it stops the edge lifting and smudging your work.
Firstly, I cut the panel out with the scalpel and ruler cutting through partly into the black border. I then free handed it around the curves.
Having checked that everything was ready and that I had run out of excuses it was time to start.
The decal was placed in water to activate its adhesive and to get it to slide off the backing paper. Whilst it was soaking the side of the tank was liberally brushed to Decal Set. This enhances the glue of the decal which was now slid off the backing paper onto the tanks side. The edge of kitchen towel was used to wick the excess fluid off the model. A combination of the pin and the brushes were used to get the decal in the right place. It was then dripped with decal sol on to the surface. This softens the decal so it can sit down around details. It was then left several hours to dry.
On return it was now stuck in place but I could see some small air bubbles. These were pierced with the pin and the whole decal soaked with the softening solution again. This was repeated two or three times each time the decal snugged down a bit more.
I was happy with result so it was time for a more difficult bit. The coal bunker end.
It didn’t go well. On the one hand the decal would flex or thread around the detail whilst on the other main part wasn’t sticking in place and sliding around all over the surface.
It was getting late and I was getting cross with it so the only sensible course of action was to leave it alone. I was hoping the main body of the decal would stick in place and then perhaps I could just soften the bit sticking up so as to poke it into place.
Remember, I am making this up as I go.
Next morning it had all set up and it became clear plan A wasn’t going to work. instead I cut the sticky up bit off with a scalpel and then softened the small remaining sticky up bit and tamped it into place with the soft bristle brush. The of-cut was flattened and trimmed and then applied from the other side so there is just a bit behind the detail with no decal. Part of the scalloped corner didn’t survive so as I had a spare decal I cut a section from that and applied that to the model. The bunker end required a lot of softening, tamping and pin popping before it sat down around all the detail.
With two sides and two ends done I think we can say this is going to be red after all.
That’s it for this second instalment. Next up will be to finish the decals and decide on the paint mix for the areas that I can’t do with decals. I have bought a selection of reds in acrylic paint. I sprayed a sheet of brass with the same gloss black and will mark this out with masking tape into squares and spray samples of the colours and even then may end up mixing them.
There will be no more progress for a couple of weeks as this is my home for the next ten days.