I see your point, but these are much newer cars, and are those roofs really galvanized? I would think metallography would improve from early galvanized roofs to a more recent time. I’m thinking of the old galvanized wash tubs I’ve seen, and the one I have. I don’t dates for the FRISCO cars, or the photo date, so no way to tell how old these roofs are.

Nelson Moyer

[Edited Message Follows]

Nelson
Here’s the two photo I used as reference so I didn’t over do the flaking.  The lighter, galvanized areas seem the have the same color but I agree it would seem some areas would age but I don’t see it on these images.  
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Charlie Duckworth 
Omaha, Ne.

Charlie, as I’ve said, I really like your approach to weathering. I’m trying to work up the nerve to start weathering my fleet, but starting on some plastic cars to work out techniques. Roof paint failure is perhaps the most difficult part to get right, largely because there are few color photos to work from for the Hutchins and early Murphy roofs. Galvanized steel is difficult to model well. I’d like to know more about where and how paint fails on individual cars. With the early galvanized roofs, does it chip and flake or peel off in patches and sheets? B&W photos I’ve seen show most of the panels bare metal, but I can’t tell if that’s paint failure of just an unpainted roof with painted seam caps. It seems like paint fade would occur over time, so that some sections would look like unoxidized metal, while others would be darker from oxidation.

Your basic galvanizing method is good, but there’s a uniformity as all the patches of paint failure are the same color, implying they all happened at once. The ‘grayness’ of the patches is quite light, perhaps a function of lighting for photography, but it seems to me that it should be a little darker and perhaps a little more metallic, and there should be some variation between patches, maybe smaller  ones lighter than the larger patches.

All this is speculation as I try to figure out how I should proceed, and I’m relying heavily upon paint fade pioneers like you and other who have been experimenting with galvanized steel effects. I’d like to see a robust discussion of techniques, supported by photos, with the goal of enhancing the realism of weathered galvanized freight car roofs.

Nelson Moyer

Been exchanging emails with Ed Hawkins on the early use of galvanized roofs and the Hutchins DryLading steel roof and one called the Universal Type Hutchins roof used 1/16” steel galvanized panels.  Paint doesn’t adhere to galvanized steel so here’s my paint failure on the L&A Sunshine kit using water based oils.  I like to use these paints as they dry slowly allowing me to lightly dry brush over them - something you can’t easily do with enamels or acrylics.  

Mopac was a large owner of the Howe Truss design and Ive probably built 5-6 of Martin’s kits since he first released them.  I’m pleased with the weathered boards on the sides and just used the technique on an NOT&M boxcar I’m building.  

 

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Charlie Duckworth 
Omaha, Ne.