As I think I’ve mentioned before, I just got a big box of HO stuff from a family friend. I finished going through it today, and found a nice suburban passenger station. It’s build and weathered very nicely, except the roof. It appears someone spilled plaster and it is stuck in between the shingles and there are big clumps of it on the roof. So, how do I go about doing this. I came up with two possibilities. First, I thought I would sand down the roof, and repaint it. My second idea was to cut sheet styrene to the size of the roof and glue that on, after sanding down the plaster and painting the styrene. Anyone else have any ideas, because I would really like to salvage the building. Thanks!
Well, if the plaster is still white, you could always buy a bunch of pigeons and/or dump ducks and mount them around the roof. make it look like you have a serious guano problem… 
Sand off what you can without damaging the roof and then soak it with hot water. It just may be enough to loosen or desolve the rest. Just my 2 cents worth. Good luck, Mike.
A package of Campbells Cedar Shingles will cost you about 10 bucks. It’s a bit time-consuming, but basically very simple to make a new roof for this kind of building. This is a scratch-built I’ve almost finished using this roof:
Yes try this [#ditto].
Use a bit of detergent in the water and brush with an old tooth brush after the plaster softens. You may need to repeat the process a few times.
Karl
Plastic roof + hot water could = warped roof [:O]
If there’s a lot of plaster you may want an anti-aircraft battery or patriot missiles to shoot down those pigeons/ducks…
OR
- Scrape the least bad parts clean of plaster
- cut out the really bad areas
- re-tile with different/new tiles of close to thesame size
- (many roofs get repaired in this sort of way)
OR
- Go even further and put a ceiling inside the roof
- insert roof trusses
- insert tiling battens
- with the model upside down this would actually be done in the reverse order.
- Turn the building right side up and add men (sorry “people”) working on repairing the tiles.
Hope these ideas help
If the roof is plastic, hose it down with LARGE amounts of WD40 to get the plaster off. Then wash it with soap & water.
If the roof is not plastic, make a new roof.
You can get small wire brushes at hardware stores…they’re like a toothbrush on 'roids. I would soak the plaster for just a few minutes, and then use a visor as you watch what the wire brush does to this compound. You can switch to a plastic brush as you begin to bare the styrene. In fact, my order of work on this problem would be soak, wire brush for a few strokes, paring knife to get some of the larger flakes still left off the styrene, more soaking, plastic brush, and then some light sanding with 400 grit or higher. I am pretty sure you can get most of it off with some care, and you may leave just a few scratches on the roof which, when painted, will not show, especially if you sand off the flashing that the brush leaves.
It is doable, but will take some time, patience, and determination.