Painting and finishing. Quite few stages to this, and it takes some explaining. So here goes...

Once upon a time painting was by hairy stick; black underneath, grey body, decals, and maybe a rinse with dirty thinners for weathering. Brushes got ruined poking matt black enamel into remote corners of the chassis and the enamel thinners gave me a headache. Can't say I enjoyed that part of the job. Martyn Welch's landmark book on weathering, the availability of many more good colour photos in publications and online, some of the remarkable work turned out by railway and military modellers in recent years and the availability of a whole range of painting and weathering products based on acrylic paints has changed all that. The painting and weathering challenge is more a part of the creative process now, and I find it more enjoyable. There's a downside though, painting and finishing requires a bit of planning, uses a greater variety of equipment and material and takes longer. I think the end justifies the means.

I'm going to try a paint technique borrowed from military modelling, 'chipping', to have the rust coming through the paint on the body. The principle is that the body is under painted with the base rust colour, a layer of chipping fluid is painted on top of that, then the grey body top coat on top of that. The chipping layer effectively reduces the adhesion of the grey to the rust layer beneath and allows some of the grey to be 'chipped' or worn off to reveal rust beneath. The idea is to create the effect of patches of rust showing through poor paint, that is almost impossible to do by brush.

Overall primer first, and I'm using rust coloured acrylic primer from AK Interactive. For chipping to be successful we need the base layers to stay stuck to the model when we distress the top coat. The primer needs to go on a clean surface. The model has had a final session in the hot ultrasonic tank and any remaining finger marks are removed with a wipe of IPA. The primer is applied by airbrush in a few thin coats. I effectively spray outside in the doorway of the garage/workshop. It's a good day for spraying acrylic today; little wind, cool and damp. The acrylic dries slower in these conditions and has less tendency to clog on the tip of the needle, but it takes longer between coats. In the summer when the air is warm and dry you can work at lightning speed with acrylics, one coat straight over the other, as long as you keep the needle clean.

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The primer has dried overnight and it's time for the chassis and undergubbins to be sprayed a filthy sort of black. I'm using acrylics for all of this. It's earth brown and rust red with a few drops of black. No need for masking since the airbrush is accurate enough and a little overspray on the lower body won't hurt at this stage. Then it's time to over paint the primer with the base rust colour for the body. Examination of colour photos shows that well established rust is very dark brown, certainly not a red rust. AK Interactive have a shade for just that purpose called 'chipping colour' and it looks about right to me. The inside of the body gets the same treatment. I add a drop or two of rust red at the end to produce a little tonal variation to the base layer. Off to a warm place to dry.

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There's some mottling over the base rust using a small piece of kitchen sponge and some red/brown colours; Vallejo Flat Brown and Orange brown. This creates a little texture, which will help when we come to rub off the top coat, and some variation in the rust colour.

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When that lot is thoroughly dry it's time to spray on the chipping coat. I'm using AK Interactive Worn Effects. This should produce a fine wearing away of the top coat with mostly small rust patches showing through. It's a colourless coating that is airbrushed on in a couple of thin coats and left to dry for around an hour. The top coat is sprayed on the body over the top of that. There's a lot of nonsense around BR freight grey and some far fetched shades that claim to be accurate. I have a couple of test strips with most of these greys painted on. Comparing with a variety of period colour photos, none of them seem right to me. The best match I've found is actually one of the acrylic primers that I use, Vallejo acrylic-polyurethane Surface Primer 73.601. It's far from an exact science of course, and weathering will alter your carefully chosen top coat anyway.

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The top coat is left to dry for about 40 minutes before we start to distress it. The top coat is moistened with water and can be scrubbed away with a variety of tools to reveal rust underneath. On this model I used an old toothbrush, an old stiff bristled paint brush and a cocktail stick. Have a decent photo or two to hand and use them as a guide. Initially scrubbing and stippling with the toothbrush takes paint off edges and texture, so the sponged rust texture starts to show through first in tiny speckles. If you work at those areas a bit harder then larger patches of rust are revealed. The cocktail stick is used to poke away in the corners where the brushes don't reach. When the rust is how you want it rinse off the debris under the tap and leave it to dry.

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There's some work to do with a small brush to touch in some rust patches that were missed, and there's some black/brown to add in areas that accumulated a mixture of rust and coal dust, typically around the bottom side doors and the lower part of the end door. There are a few bits of grey overspray to touch in on the chassis, and it's still quicker than masking!

Time to add decals and markings before further weathering. The end door diagonal stripes are officially 2-1/2" wide, that is about 0.8mm in 4mm scale (and just less than 1.5mm in 7mm). All of the waterslide decals I've seen for these stripes are far too wide. You can cut a decal to width carefully, and then it's a pain to get on straight and in one piece. I find it easier to lightly scribe the outline of the stripe onto the paint with a ruler and the tip of a 10A scalpel blade. Painting carefully inside the scribed line with a loaded brush lets the paint flow to the line. Nice and neat, and it's easier to weather a painted line than a decal. I don't use pure white, I add a little grey to tone it down. Note that the position of the stripes varied. Officially they are supposed to point to the end door hinge line rather than the top corner of the body panel. Photos show that some went to the top corner anyway. The 24-1/2 ton yellow triangles are done in a similar manner using photos and features on the body as a guide. The yellow triangles seem to have faded significantly in use, some of them almost indistinguishable from the grey body in a black and white photo. Bright yellow won't look right on a scruffy wagon. I've used a sort of pale buff yellow for the triangles. Black number patches are painted on in black with a touch of white to kill the absolute blackness.

Decals are from Fox. I'm building a 1/115, and from Larkin the number range is B281150 to B282149. The Fox sheet allows me to make up B281193. Tare seems to vary a lot, which is surprising for a a bunch of wagons to the same design. Maybe variations in steel plate thickness? Anyway, the closest reasonable tare weight on the Fox sheet is 10-5. Many of these wagons had allocation instructions on them - 'To work between xxx and xxx' sort of thing. Larkin lists the known initial allocations, and a few more can be made out from photos. Seems like these markings were not always respected and not always maintained once the wagons had strayed from the original working. Some painted over, some altered, some just left to disappear under rust and dirt. I've added a mostly disfigured legacy allocation from the ModelMaster 4698 wagon markings sheet. Waterslides on with no problems, and smoothed on with Micro Sol. Incidentally Fox recommend application to a gloss surface but I've never had any problems on matt. There'll be a coat of varnish on over the top to hold the whole lot together anyway.

There are a few arcane shunters' chalk marks added with a grey /white and a fine brush. Best I can do but they're not entirely convincing. Scope for improvement here I think. Anybody know a better method for adding chalk marks?

Rusk streaks go on next using artists type oil paint and solvent. Tiny blobs of rust reddish rust colour are placed on some of the rust patches using the tip of a fine brush. Once they've dried for an hour or two (they don't actually dry in that time, they just be come a bit less mobile) the rust streaks are added by dragging down from the blobs with small brush moistened with solvent, in this case an odourless turps substitute. Because the oils have a very fine pigment and don't dry quickly they can be messed and tweaked with almost ad infinitum, and can produce very fine shading. They can even be completely wiped off if it all goes horribly wrong. Take care to make all the streaks vertical as any gravity defying streaks really stand out. Some rust chips are applied by brush to the white stripes and the yellow triangles and rust streaks are added to make the markings become part of the wagon livery rather than something sitting on top of it. There's a lot you can do with oils, but here the technique is confined to simple rust streaks and staining. Again, this technique is borrowed from military modelling.

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Some more work with the airbrush to finish off. I've added a black/brown haze in areas where coal dust collected and didn't weather off too quickly, typically in corners, round doors and beneath the top coping channel. There's a bit more earth and rust around the chassis and the lower edge of the body. Finally a very faint overall coat of the black / brown tones it all down and brings the colours together, rather like a filter. When that lot is completely dry I apply a coat of ultra matt acrylic varnish (AK Interactive Ultra Matte Varnish) to hold it all together.

Finally it's done! It took about as long to paint and weather as it took to build. Looking at the final photo I should probably have been a bit more restrained with the brown / black shading but overall I'm happy with the result. Unfortunately it makes my much older 24-1/2 tonner look a bit pants!
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There's still one more thing to do, add a load of coal...