What colour is a Mk1 coach roof under the black stuff ?

[rob D2]

Hi,

hoping to increase the realism of some of my BGs by trying to get the worn roof effect .....I don’t think it’s pure metal , looks greyer than that ?

 

anyone have any idea what might be a suitable colour ? I’m going to make a stencil and airbrush I think .Like the first coach below , not my picture , taken from Flickr 

 

[Wickham Green too]

Galvanised steel ...... so zinc coloured ( matt silver if you like ).

[Steamport Southport]

It was the steel showing through where the paint had peeled.

 

It started happening when they stopped painting over old paint and was stripping them back to the bare metal during repaints/repairs. So it was only one or two coats of paint rather than several.

 

 

Jason

[HGR]

23 hours ago, Steamport Southport said:

It was the steel showing through where the paint had peeled.

 

It started happening when they stopped painting over old paint and was stripping them back to the bare metal during repaints/repairs. So it was only one or two coats of paint rather than several.

 

 

Jason

 

The roof of Mk.1 coaches was made of galvanised steel sheets. When new, this is a very silvery shiny surface, but turns a dull grey as it starts to oxidise. The sheets are welded across the width of the roof, producing the bead that is visible on the outside. They are hidden behind the aluminium alloy gutter channel at the cantrail, which covers the roof - bodyside join. The width / 'length' of the steel panels depended on the type of stock and the builder or works. Some simply used a common width of sheet across the full length of the coach, resulting in a fixed number of equally spaced weld lines regardless of the interior layout. Some stock, for example Eastleigh produced D/EMU coaches used a selection of different widths of roof panels, with or without ventilators, to suit the compartments or seating bays they covered, or other areas such as cab, van, etc. Hence the ventilators on a hauled Mk.1 FK don't line up with the compartments, but on a Southern Region EMU they are nicely symmetrical with the doors / windows.

 

New roof panels were painted with a black bituminous 'high build' (thick coating) paint. Galvanised surfaces are notoriously horrible to get paint to stick to. Unfortunately a steel coach roof gets extremely hot in strong sunlight, so the expansion / contraction is quite significant. The paint hardens and loses its pliability with age, so it gradually cracks and flakes, and areas fall off exposing the grey galvanised steel beneath.

 

When vehicles came into works for classified repairs, each roof panel was considered individually. Any panel where more than a quarter of the paint had flaked off had to be completely stripped, weld to weld / gutter to gutter, and was then repainted with the high build roof paint. The method of stripping was usually tediously by hand with scrapers, but some coaches bear the scars or pock marks of the application of far more brutal methods !

 

If however, the paint was generally sound, any loose flaking was cut back to a firm edge, then painted with what was described as 'cosmetic' roof paint which was low build, that being much thinner coating thickness. This was quite noticeable on close inspection, but looked OK when the vehicle returned to traffic. How long it lasted thereafter before starting to crack and flake was another matter.

 

The original B.R. roof paint was black. Ideal in steam days, but the worst colour you could use for steel under direct sunlight. Later a grey version was available as an alternative colour used in the blue / grey era.

 

 

 

[Grovenor]

And some got painted with a shiny 'aluminium' colour very noticeable when new.

[HGR]

3 hours ago, Grovenor said:

And some got painted with a shiny 'aluminium' colour very noticeable when new.

Do you have examples of which vehicles please ?

 

I have a vague idea that some Pullmans were originally built with 'silver' roofs, but not sure if this was untreated new galvanised, or was painted steel. Some of these later were carrying white painted roof. The silver grey reappearing on more recent umber and cream repaints.

 

[9C85]

On 02/04/2021 at 19:55, rob D2 said:

Hi,

hoping to increase the realism of some of my BGs by trying to get the worn roof effect .....I don’t think it’s pure metal , looks greyer than that ?

 

anyone have any idea what might be a suitable colour ? I’m going to make a stencil and airbrush I think .Like the first coach below , not my picture , taken from Flickr 

 

I have done a couple of Lima GUVs by simply putting patches of blu-tak over the existing grey roof and then spraying with roof dirt. Lift the Blu-tak afterwards to reveal the grey patches. I initially made the mistake of painting the area to be revealed in a rust colour, but after having it pointed out that the roof is galvanised, I managed to remove most ot the rust with thinners & cotton bud.

 

[rob D2]

9 minutes ago, 9C85 said:

I have done a couple of Lima GUVs by simply putting patches of blu-tak over the existing grey roof and then spraying with roof dirt. Lift the Blu-tak afterwards to reveal the grey patches. I initially made the mistake of painting the area to be revealed in a rust colour, but after having it pointed out that the roof is galvanised, I managed to remove most ot the rust with thinners & cotton bud.

 

That’s good but wouldn’t work with Bachmann GUV I don’t think as roofs already almost roof dirt coloured 

[9C85]

3 hours ago, rob D2 said:

That’s good but wouldn’t work with Bachmann GUV I don’t think as roofs already almost roof dirt coloured 

Ah, I see. I have used Halfords grey plastic primer on at least one reworked GUV. But I don't think I did a flaky roof on that one - but IIRC it wasn't far off the 'new roof' look