The SHRA's Milwaukee Road Roundhouse in Sioux City is getting a totally new roof. Now that the deck is almost complete, and it's safe to walk on the roof without fear of falling through rotten decking, I've noticed that our roof vents need some work. And I need some advice.

There are two types of vents:

1. ca1953, the Milwaukee put four electrically powered exausting vents on the roof, presumably to actively suck out diesel fumes. These are "Octagon Aeromatic" models, and are made of galvanized sheet steel. Along the tops of the vents and on several cross members, the galvaniation has worn off and rust has begun. Does anyone have advice on a way to stop the advance of rust while preserving the vents' appearance? I was thinking of removing the rust, applying gray primer, and then a gray topcoat. After that, I was thinking of doing a little "Martha Stuart-esque" sponge work and dab on some splotches of darker gray to make it look a little more like galvanization from the ground.

Any better ideas?

2. The remaining vents are the original 1917 cast iron passive vents. They're getting to be a bit pitted on the surface. Would it be appropriate to apply a rusty metal primer and then paint them black or a "rusty metal" color?

Thanks

TSS

tsschult@usd.edu

Please look over the previous thread on rust killing coatings and treatments before patching and recoating.

Dave

irondave@bellsouth.net

> Please do something about those vents! The Western Railway Museum has an Interurban car that had its roof destroyed because it was stored under a leaking vent. Who knows how many other historic cars will be damaged while they are "inside and out of the weather"

Ted Miles


ted_miles@NPS.gov

Thanks for the comments. Rudd sent me the primer on rust converters and cold galvanizing coatings via private email. I now have a good idea of how to proceed.

Don't worry about leaking vents; with a totally new roof, including new boxes for the vents to sit on, we should be in good shape.


tsschult@usd.edu