Thursday, February 18, 2021

Scratchbuilding the Robertsdale Engine House - Part 3

 With the roof trusses in place, I constructed the roof panels using laser cut sheets of variable width shake shingles from Bollinger Edgerly Scale Trains (B.E.S.T.).  The sheets come in 4x12 and 6x12 sizes, which meant I had to cut and paste sections together to shingle the 60 foot long engine house and the 40 long extension and shop.  I made one side of the roof 1/16 inch less from eave to peak, and butted the shorter panel to the panel facing the aisle, eliminating the need for a roof cap.  I really liked the appearance of the shakes, and began to think about what color to make them.  Here is a shot of the engine house from the front.  


And here is a photo from the rear.  The roof is not yet on the extension.  The holes in the roof are for the smoke vents, which I made from 5/16" square styrene tubing



With the roof sections cut and assembled, my next thought was what color to make them.  I had painted the sides with a red primer from Home Depot, and liked the look.  I first tested a spray can of roof primer from Home Depot -- the color was designed to color flashing and roof pipes in an aged brown.  But when I sprayed a scrap of leftover roofing, the spray paint came out too thick and dark.  So I tried various weathering mixes from Hunterline, including brown, gray and driftwood.  I liked them all, but decided to go with a light gray that resembled the weathered color of shake shingles one sees here on Cape Cod.  The label said the dye was mixed with alcohol, so I felt safe brushing it on the wood shingles.  I brushed it on both sides just in case, to prevent any warping.

At first it looked great, but then I noticed that the wood was starting to warp anyway.  I quickly laid the panels flat on a sheet of glass with lead weights.  But then I noticed that the warp was more severe along the eaves than the peaks, giving each longitudinal roof section a fan shape.  The eaves were expanding lengthwise more than the peak!  I attributed the difference to the laser cuts that made the bottom of the roof thinner than the top. I quickly checked the bottle of weathering mix and found that the mix  was only 70% rubbing alcohol!  It pays to read the label carefully.  The mixture was 30% water!   I thought the shingles -- which were not cheap -- were ruined.  I left the roof panels on my workbench and went to bed.

To my amazement, when I lifted the weights off the next day, the warp had largely disappeared!  As the water content evaporated, the wood returned to its original shape.  There is still a subtle warp, so that the bottom of the roof sections sag slightly in the middle -- a nice touch, as it turns out, making the roof look a bit aged and sagging slightly like a wood passenger car.  The light gray stain turned out rather nice.  Here you can see the engine house on the layout with the roof in place.  The smoke vents have been painted and installed.  The styrene foundation is also visible.


And here is a photo of the entire structure with all roof panels in place.  This is the view seen by visitors, since the left side of the building faces the aisle and there is no really good view of the opposite side.


In my next post I will show how I wired the engine house for lights and added additional roof detail along with shop equipment and workers in the rear extension.

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