08-27-2009, 10:50 PM
On corrugated steel or iron, the first rust usually appears at the ends of the sheets. On a wall or roof, it bleeds down fairly evenly onto the sheets below. As the rusting continues, some areas may do so more quickly than others, resulting in longer or heavier streaks. Rust also occurs at the fasteners (nails, screws or bolts), and at places where the sheets have been damaged by external forces.
Painted sheets may rust in the same way, or, as in the example below, very differently:
[album]1372[/album]
The roof of this freight shed, while not corrugated metal, still appears to have rusted away along its bottom edge (and partway up the far end, too), sufficiently so that it has been repaired by cutting away the rusted-out edge, which has then been replace with new metal. You can see how the rust from the original roof has washed down and streaked the newer patch.
[album]1373[/album]
For your structure, I'd suggest more uniform streaking all along the area below both rows of sheets (onto the horizontal material below floor level, too). Next, mask-off the upper row of siding, and then the lower row. Using the same colour as you used for the walls, spray the below-floor cladding from a high, steep angle, making a quick pass from left to right. This should put a very light coat of paint mostly on the lower part of that area. Remove the masking from the lower row of corrugated siding, and repeat with a quick spray pass, again from a high, steep angle, and yet again, after removing the tape, for the top row of siding. This should soften the rust effect without hiding it.
You can also add the rust staining itself with an airbrush: simply mask each of the vertical wall sections individually except for the bottom one, then aim your spray at the lower edge of the lowest row of masking tape. Remove the masking from the lowest wall section, and spray again, repeating until you reach the top.
This structure, at left, was built from some corrugated basswood siding that I had laying around (it encloses some electrical gear and the access stairs to the yard crane). After painting it a dark boxcar reddish colour, it was masked as described, and painted. There are no overlapping courses of material or even any lines showing the vertical separation between sheets: it's all suggested by the paint.
[album]520[/album]
This structure, done with a similar method, is roofed with separate sheets, and is meant to represent a roof which is repainted fairly regularily, even though it had already begun to rust (and continues to bleed onto the newer paint)
[album]288[/album]
Wayne
Painted sheets may rust in the same way, or, as in the example below, very differently:
[album]1372[/album]
The roof of this freight shed, while not corrugated metal, still appears to have rusted away along its bottom edge (and partway up the far end, too), sufficiently so that it has been repaired by cutting away the rusted-out edge, which has then been replace with new metal. You can see how the rust from the original roof has washed down and streaked the newer patch.
[album]1373[/album]
For your structure, I'd suggest more uniform streaking all along the area below both rows of sheets (onto the horizontal material below floor level, too). Next, mask-off the upper row of siding, and then the lower row. Using the same colour as you used for the walls, spray the below-floor cladding from a high, steep angle, making a quick pass from left to right. This should put a very light coat of paint mostly on the lower part of that area. Remove the masking from the lower row of corrugated siding, and repeat with a quick spray pass, again from a high, steep angle, and yet again, after removing the tape, for the top row of siding. This should soften the rust effect without hiding it.
You can also add the rust staining itself with an airbrush: simply mask each of the vertical wall sections individually except for the bottom one, then aim your spray at the lower edge of the lowest row of masking tape. Remove the masking from the lowest wall section, and spray again, repeating until you reach the top.
This structure, at left, was built from some corrugated basswood siding that I had laying around (it encloses some electrical gear and the access stairs to the yard crane). After painting it a dark boxcar reddish colour, it was masked as described, and painted. There are no overlapping courses of material or even any lines showing the vertical separation between sheets: it's all suggested by the paint.
[album]520[/album]
This structure, done with a similar method, is roofed with separate sheets, and is meant to represent a roof which is repainted fairly regularily, even though it had already begun to rust (and continues to bleed onto the newer paint)
[album]288[/album]
Wayne