Let's Get Involved - Your 20-step guide to a work-worn CDA with James — Accurascale Skip to content
Let's Get Involved - Your 20-step guide to a work-worn CDA with James Makin

Let's Get Involved - Your 20-step guide to a work-worn CDA with James Makin

Let's Get Involved" is back! Today we have a weathering guide of our love CDA China Clay hoppers by James Makin.

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In the meantime, scroll down and be inspired! Take it away, James!

China clay trains have long held a special appeal for many rail enthusiasts, possibly the picturesque Cornish scenery, the quaint country branchlines and almost wall-to-wall Class 37-haulage being strong factors making these such popular subjects, in both prototype and model form.

The release of the modern-era CDA wagons made for a very tempting idea – to backdate the models to recreate memories of late 1990s china clay wagons, bearing their original blue livery of English China Clays, albeit with the distinctive logos long-since torn from the hopper bodies, and covered in a good layer of the iconic ghostly-white china clay dust.

This step-by-step article takes you through some of the key steps in weathering a china clay CDA, with the aim of inspiring and encouraging modellers to dig out the brushes and get stuck in!

The starting point for the project was a set of the Accurascale EWS hoppers – any of the releases could be used for this back-dating exercise. The beautiful shiny hopper bodies weren’t to stay like this for much longer!

The wheelsets were removed before and put to one side to weather separately later on. To remove each wheelset, a cross-point screwdriver was used to first unscrew the angled plastic framework that sits below the axles, before subsequently easing the wheelset out of each pinpoint axle bearing using a flat-bladed screwdriver, taking care not to bend the sides of the chassis outwards too much.

Seeking to replicate these wagons in their earlier unbranded English China Clays (ECC) blue guise of the late 1990s, the newer EWS logos, TOPS panels and details all needed to be removed. Fortunately, all of the Accurascale printing removes very easily using a sparing amount of Humbrol enamel thinners, applied to the end of a cotton bud, and rubbed gently over the printing. The branding soon lifted to reveal unblemished paintwork beneath. At this stage, the EWS red tarpaulin cover and metal framework were both repainted blue to replicate the former ECC livery, using a fine paintbrush to get into all the nooks & crannies around the hopper body.

Before applying any new decals, it is always recommended to spray a coat of gloss varnish to give a good surface onto which the decals can sit. Railmatch Gloss Varnish was sprayed on, and left to dry for a couple of days before applying a set of period CDA decals from Railtec Transfers. Next, and possibly the most essential part of this weathering project – the entire wagon was given a coat of Railmatch Matt Varnish, which was then left to harden fully for 1 month before starting the next stage.

The reason for the layer of matt varnish is to give a good ‘key’ for the subsequent weathering tackled later in the project, which would otherwise not stick to the satin sheen of the wagons as they arrive out of the box.

One month later, with the Railmatch Matt Varnish fully hardened, a start was made on replicating the peeled-off ECC logo remnants on the side of each hopper body. Following prototype photographs, a rectangular outline was masked off on the bodyside using low-tack Tamiya modelling tape, and the ragged line touched in with Humbrol blue No. 109 and left to dry for a few days before the weathering fun could begin.

A start could now be made on the true weathering! Overall, each CDA hopper exhibits a muted white shade, due to the build up of china clay dust on the wagon, and an effective way of replicating this in miniature is to apply an all-over coat of white paint, which is then subsequently removed to leave a faded white filter over the top of the entire wagon.

For this, neat Humbrol No.34 matt white was liberally painted onto the wagon, starting with the roof and hood, and applying to a section at a time before removing with cotton buds and kitchen towel, to leave the desired pale white residue across the surface of the model.

Here we can see the removal process in action, as the cotton bud is moved vertically downward in all cases, to mimic the movement of rainwater on the top of the wagon hood, washing the china clay dust downward on the wagon. The same process is repeated across the whole top of the wagon.

Moving down to the sides, the same white enamel paint is applied to the entire hopper body, frame and everything in-between, before being removed in a downward motion once more. It’s worth working on only a small area of the model at a time to avoid the paint drying on the wagon before you can remove the bulk of it. If the paint does start to dry, just add a small amount of enamel thinners to soften, and apply more fresh, neat, white paint.

Taking a quick step back to check on progress, it’s now possible to see the immediate difference that the white paint layer makes to the overall colour of the wagon, once removed. The top wagon still appears factory-fresh, and just one application of the white paint has completely muted the colour palette, and the white paint gathering in the recesses gives the effect of china clay dust clinging to the wagon, just as in real life.

The reason that the white paint layer is clinging to the wagon is purely down to the layer of matt varnish added earlier in the project, without this, the white paint would wipe straight off, and not give us the effect that we’re looking for, so this image goes to show how the matt varnishing stage is key to the effect here.

One might assume that china clay wagons would just be weathered white, but by looking through prototype pictures, it soon becomes apparent how many other different tones all blend in – especially the rusty brown streaking emanating from the vents on one side of the wagon, and from other fixtures attached to the aluminium-bodied hoppers themselves.

Having put the wagons to one side for a few days to allow the white-paint layer to harden, the rusty shades colours could now be added. To recreate the rusty streaks, Humbrol No. 62 Matt Leather brown was added sparingly onto a medium-size brush and stippled onto the sides in the general area where the streaking was observed.

Having drybrushed on the brown paint in the key areas required, the next stage was to start blending this into the white bodyside of the wagon, so a cotton bud, dipped in Humbrol enamel thinners was then rubbed over the top, and working vertically downwards, started to soften the brown and wipe it down the sides. This can be manipulated, following prototype photographs, until you are happy with the appearance.

As a word of caution, it’s wise to allow a few days paint hardening time between applying the earlier layer of white paint and this brown paint, just so that your enamel thinners doesn’t eat through the white layer.

One side of the CDA contains the side vents which produce the distinctive rust marks down the hopper, where rainwater washes rusty brown deposits down the side. This was recreated in miniature by using a small 5/0 paintbrush, dipped in Humbrol 62 brown paint and wiped almost dry with a kitchen towel, before being dragged down the side of the wagon, building up the intensity of the streaking to match prototype photographs.

Practice makes perfect on the streaking finish, and it took a few attempts to get the streaking to the desired level, but if you go over the top, don’t panic, just simply add more enamel thinners to dilute the finish or wash away and start again. It’s all about experimenting and seeing what works well, and important to match to real life pictures as the intensity of the streaking varied over time.

Next, a gentle overall dusting of matt white enamel paint was applied with an airbrush, helping to further tone down the wagons all over, including the underframe. A trusty-but-ageing double-action Badger 175 airbrush was employed for this task to give a good level of control over air pressure and paint volume, however there are a decent range of good-value modern airbrushes out there that can give a great introduction to airbrushing without requiring too much of a financial outlay.

Eagle-eyed viewers may notice that the wheelsets have not yet been re-attached to the wagons during this weathering process, and that was because they are receiving a separate makeover of their own. On the far-left side, you can see how the wheels arrive from Accurascale, which are then covered in dark grey enamel paint (centre), which is then removed with cotton buds, to reveal the desired look on the far right hand side.

The dark grey paint was applied across the entire wheelset, including the rear of the wheels and axles – everything barring the wheel tread itself. Once dried, a layer of white paint was dry-brushed across it, to represent the build up of china clay dust and dirt, as seen on the prototype CDAs. The wheelsets were then refixed to each wagon, the plastic brackets screwed back into place and painted white to match the weathered chassis.

With the white dusting complete on the wagons themselves, final details can be added such as the greased buffers, replicated by dipping a cotton bud into a dark grey paint (Humbrol No. 32), drying off slightly, and then repeatedly dabbing onto the centre of each buffer.

The underframe of a CDA has a number of yellow-painted levers, handles and axlebox covers, all of which generally would be kept fairly clean and show through the layers of china clay deposits on the underframe. These were added with some pale yellow – Humbrol No. 74, and carefully added using a small 5/0 paintbrush.

One anomaly spotted after trawling through far too many photos of CDA wagons, was that the corners of the blue framework appeared much cleaner than the sides – presumably as the sides saw the china clay deposits streaming down the sides. A cotton bud, dipped in enamel thinners was gently rubbed across the corners of the blue framework to remove some of the white dusting and bring out the brighter blue paintwork in this area.

Last but not least, the final task was to add some weathering to the buffer shanks – from photographs, these took on a rusty brown finish after a while in service, so the shanks were touched in with some Humbrol No. 186 using a fine paintbrush.


Overall, the CDAs make for a great fun weathering project, to transform the box-fresh models into the iconic ghostly-white china clay trains that Cornwall is famed for, in the eyes of many a rail enthusiast.

The wagons are now ready to enter service, and in their late 1990s condition, represent the ideal train to run behind a Class 37 or perhaps a great reason to treat yourself to the forthcoming Accurascale EWS Class 66!


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