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Thursday, February 21, 2013

Painting and Installing Corrugated Roofing


The Berry Machine Shop has been sitting on my modeling desk for several weeks untouched. But, with the layout running it was time to turn my attention to it again.
Perhaps the trickiest model roofing materials to work with are the formed metal sheets such as those offered by Campbell, Model Memories, and Builders in Scale. Out of the package this stuff is almost unusable since it’s too shiny and clean. You can chemically etch it with something like Archer Etchant, but frankly it’s a difficult to control process – and a vat of acid is not really all that welcome in our home.  
While it’s easy enough to paint the material, due to the nature of the material it seems to easily subject to chipping and flaking, leaving shiny silver spots on your otherwise weathered metal.  
Here’s the approach I’ve used with success on the Berry Machine main building roof. I started by painting the corrugated metal with ordinary spray can automotive primer gray. Let this dry completely – a couple of days at least.
Then I colored the panels by brushing on a combination of Raw Umber, Raw Sienna, Burnt Umber, Burnt Sienna, Yellow Ochre, White, and Black artist’s oil paints. 
A little paint goes a long way. I thinned the paint slightly (just enough to get it to brush evenly) with Odorless Mineral Spirits. I tried to get it to shift from light to dark across the width of the corrugated material, but frankly didn’t worry about getting the colors from one piece to another, or even along one piece, to match. Again, set this aside to dry completely for a couple of days. It looks pretty bad at this stage. 
Before cutting the material into 4-foot widths, I sprayed the pieces with Testor’s Dullcote. This sealed the roofing and also prepared it for the next step.
I cut the pieces into 4-foot wide strips. 

 Installing the corrugated roofing
Installation was pretty straightforward. I drew guidelines on the roof at the approximate location of the top of each row of corrugated panels. Then I applied double-sided tape to the roof. Installation was a simple as lining up the edge of the panel with the edge of the roof and pressing down. After I worked my way up both sides of the roof, I added a ridge cap fashioned from strips cut from the corrugated panels.
Once the panels were installed, I applied a wash of thinned Polly Scale Tarnished Black, Grimy Black, and Railroad Tie Brown to each of the roof panels. Then, as a final touch, I dusted the roof with with powdered pastel chalks. The completed roof, which may get another touch up of chalk once the building is installed on the layout, is shown above. 

3 comments:

  1. Marty,
    Looks great!
    What did you find was the best tool to cut the sheeting?
    Pierre Oliver

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  2. Thanks Pierre,

    For cutting with the corrugations I used a sharp hobby knife and light, repeated passes. Like cutting styrene sheet without the "Snap" at the end! Just keep running the blade until the metal is cut completely through. This stuff dulls a blade pretty quick - you can tell when the blade starts to "drag" that it's getting dull.
    For cutting against the "grain" (corrugations) use a sharp scissors.


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