Sunday, 31 January 2016

Malthoid Roofs

I have been struggling with time issues over the past few weeks but other activities seem to be getting in the way. Consequently, I have only had to opportunity to concentrate on one aspect, the overhaul of the three passenger carriages transferred from the South Coast Railway plus the construction of one extra Camco FO kit.

A number of modellers have made the point that most observation of the layout and rolling stock is done from above, perhaps a similar angle to the photo opposite (a Lachlan Valley Railway trip to Kiama last December). As a consequence, I feel I need to get the roof appearance as close as possible to the original. In particular, I have been attempting to capture the appearance of the malthoid roofs on passenger carriages.

As an aside, pun intended, even when viewed from the side,  the texture and shape of the malthoid strips are  very apparent.

A number of authors have written about techniques to replicate malthoid roofs. Of these,  I have found that Alex Brown's article in the June 2005 edition of AMRM (p38-41) and Ian Phemister's blog post
are my 'go to' references although, I'm sure there are many others. 

Both authors start with the removal of the existing ventilators, the fixing of some form or textured material in strips to simulate the malthoid, the installation of replacement ventilators and, finally, painting and weathering. Alex used masking tape strips to simulate the malthoid while Ian cut a tea bag into strips for the same purpose. I have found that both work but I have adopted the masking tape option as my preferred alternative. I also found it convenient to drill holes in the roof where the replacement ventilators are to be located before applying the masking tape strips. Once all of the masking tape strips are in place, I also apply a coat of PVA glue, or more recently, WeldBond, to create a seal across the whole surface before replacing the ventilators and painting.

Commercial replacement ventilators, both mushroom and torpedo types, have been used, sourced primarily from Hobbyland at Hornsby.

Painting is completed using a mix of spray and brush. The one thing I have noticed looking at photographs taken in the 1960s and 70s is the considerable variation of condition and weathering between individual carriages. These range from an almost brand new appearance presumably having just emerged from an overhaul to a very degraded condition. This provides plenty of latitude within the limits of weathered black and silver, with/or without navy dressing ends. A spray with Dullcote and then soot in varying degrees finish off each roof.

The final two photos provide a comparison between the prototype and the model. Probably another application of Dullcote is appropriate but I think the texture is there.