I had to get into a heating vent, which involved removing the paint over the screws. Some truly horrible colors were lurking under the white paint!
The layer next to the metal was dark gray (nearly black) and much thinner than the neon green and mud brown layers. Perhaps it wasn’t paint but some kind of primer? The metal looked like copper but a magnet sticks to it.
Why would the manufacturers copper-plate the underlying metal if it was going to be primed and painted anyway? What is the dark gray layer?
Janet
P.S. The house was built in the 1930s.
Replies
Most likely this vent (I assume you mean a "register") was originally copper or brass plated -- brass detailing was very popular back pre-war (and actually well into the 50s).
You're right, it's a register. And the metal has blackened at the upper center--maybe this is why it was painted. The current furnace uses gas, but I don't know what was originally there. Could a different type of furnace have caused the blackening over the years?
And while I'm on the subject of blackening: There's some of it behind the lamp that is over the front door. It's an electric light now, but I started thinking about Charles Boyer trying to drive Ingrid Bergman insane... did they have gaslights in the 1930s, and would it cause the stone to get sooty?
Janet
The type of furnace wouldn't have made a lot of difference, but certainly dust, soot, and grease/oil can accumulate on registers over time. But the blackening you describe is fairly typical of cheap brass-plated steel, from what I recall -- just a chemical reaction, perhaps accelerated by the heat, and possibly added to by fumes escaping from the furnace.
The blackening behind the light could possibly be soot, but incandescent lamps create airflows which, over time, can cause fine dust to accumulate near them. Not at all unusual to see such a dark area behind an old sconce.
That fits. Our house was built as sturdily as the others in the neighborhood, just not as expensively.
Janet
Uh-oh. Did builders use asbestos in the 1930s? The outside of the duct is covered in something that isn't paint. More like paper glued onto the metal.
When I say "duct," I mean the metal tube in the walls/ceilings that carries the hot air. It is grey-colored and soft--the tabs for attaching the register are very easy to fold over.
that is probably asbestos.
That's really bad news. Well, I know that do-it-yourself asbestos removal is more dangerous than leaving it in place. Is there any way to stabilize it so nothing gets into the air when the register is re-installed? What about covering it with paint?
Janet
There are three ways to deal with asbestos
one is to ignore it, obiously.
The most expensive and least favorable is to remove it. I say least fav because the process itself releases fibres into the air and onto surfaces that are currently stable if left un disturbed.
The third, and for this sort of situation is to encapsulate. Some do this with a wrap of fibremesh and plaster, but most often a godd oat of the right paint will seal this up sufficiently that strands oif fibre will be unlikely to find their way into your lungs while you sleep.
There could be many reasons why the old register had a blackened spot, one of which ius that the old heater was a ccoal or oil that had a cracked plenum allowing some soot to pass from the combustion chamber into the plenum and thence the ducts to the house
Google Reggio register and you may find a replacement register cover that delights your eye, if not your pocketbook.
A thick coat of oil paint is what many authorities recommend.
That's what I'll do. No primer required?
Janet
Ideally you should use an oil primer first, to soak in a bit and bind the outer layers together. But if the (oil) paint you have seems to soak in a bit and doesn't just stand on the surface then that should be fine.
To a degree you need to play it by ear -- you don't want whatever treatment you use to cause more fibers to come loose, so if the paint's just beading up on the surface and rolling off as you paint you need to re-think. But it's not rocket science -- the goal is to turn the outer 1/32 inch or so into a reasonably solid shell that will contain everything and be reasonably resistant to mechanical damage.
I'd paint the asbestos with oil base aluminum paint. It's thin and soaks in fast, the aluminum particles bond to each other and help hold the fibers together.
The register may have been "black oxide" treated at the factory. It's a fairly common treatment to slightly reduce the formation of rust.
It is called a "baseboard
It is called a "baseboard register," I've just learned, and it looks almost exactly like this:
5260206407_08ce5c1ee4.jpg
The only compatible replacements I could find are two models by Mission Metalworks.
I think the blackening is the chemical reaction that DanH described, not soot, because it wouldn't come off with paint remover or detergent.
Janet
Now that the nasty lead paint is gone, what kind of primer and paint are good for a heat register?
Janet