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sewer covers

dian

Titanium
Joined
Feb 22, 2010
Location
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covers and grids. what are they made of? i mainly wonder why they dont rust. they only get brownish.
 
Many here were made in India since the 1980's. My water meter cover and box are plastic. AFAIK cematary grave vaults are still concrete. When we had my grandparents grave opened to inter my brother the paperwork said old liners might be tin, redwood or brick and would not be repalced or repaired.
Bill D
 
Worked for the sewer plant for 32 years and all the frames and covers were cast iron. Sometimes they would be stuck from grit getting between the cover & frame or frozen in the winter. When that happens you would beat them with a sledge hammer to get them loose. Every now and then you would have to climb to the bottom of the manhole to retrieve the broken pieces.
 
I'm believe the ones in Cleveland are some variety of wear resistant steel, I know they were welding them to the frame when the Formula 1 races were in town. Apparently the low pressure from the ground effects were popping the manhole covers into the air when they drove over them.
 
My Great grandfather made large church altars and such in Chicago around 1875. They would haul them to the building site on sunday mornings with no other traffic. Story was they would commonly break cast iron manhole covers with the carriage wheels. The draft horses did not break through just the wheels.
Bil lD
 
i know they are cast. but why dont they rust?

If on a road perhaps it’s due to the oil coming off the cars? They probably do rust over then seal themselves off to the air like Corten steel does. Steel railway rails don’t rust either when in use, but when abandoned they do and I’m not talking about the running surface, all over they rust differently when out of service.
 
They do rust. Years ago I made a potters wheel and used a manhole cover for the kick wheel. They are really tough and hard to machine if I remember. I think cars driving over them keep the top relatively clear of rust but I know the one I used did rust a little. I think cast iron is one of those things that gets a layer of rust on it and more or less protects the base metal. The reason I say this is that abandoned farm equipment that sits out in a field gets really rusty but not very pitted as other steels.
 
covers and grids. what are they made of? i mainly wonder why they dont rust. they only get brownish.

That is rust.

Flakey rust is what your wanting.
Caused by dirt piled against it, or other means.
Also the higher amounts of carbon in cast iron cause the iron to only get rough, not so much "flakey"

Read up on "Corten Steel" to see the various kinds of "rust".
 
There is copper in the alloy to enhance the iron's self-passivating characteristics.
Same as Corten or A588 steel.

-Doozer
 
I have read that a F1 car has enough downforce that once up to speed they can drive on the ceiling. It is 1-2 tons of downforce at speed. They had to regulate the skirts from being too low. They would go over a slight bump and loose the downforce unexpectedly causing them to spin out of control just like driving on black ice.
They also outlawed the oversize cooling fans sucking from underneath the car.
Bill D.
 
They also weld them down for the Presidential motorcade.

Could be they are using nickel welding rod.
 
I'm not sure I'd use one for anything that would rotate very quickly. Not talking about a potter's wheel, but a lathe backplate or something like that. Probably be OK 99.9% of the time, but if something like that ever cut loose at speed...
 
Some years ago Texas State U. was replacing all of the old "Southwest Texas State University" manhole covers, they were rather ornate, I thought about getting them but could not think of a use besides stepping stones. Came across an ebay ad a year or 2 ago for someone selling old manhole covers as "patio medallions", damnit, I should have thought of that:bawling:
 
Ground effect of cars lowing air pressure enough to pull up a regular man hole cover. Urban myth ....no way no how.

Regardless of what ever air effects a F1 car may generate, there are enough drain cover accidents caused by the cars dislodging them that they are welded and clamped from below. It's common enough that they designed special drain covers with integral clamps, and they seem to have at least one car destroyed a year my them coming up.
 
It is fifty years ago but I saw a local foundry making manhole covers. Their primary product was large valves and hydrants.
As I walked by they had cope and drag ready to assemble and they had pushed hundreds of nails into the sand. The idea was that the head of the nail would contact the molten iron and conduct the heat away into the sand so that the surface of the iron was chilled to give it a hard skin.
 








 
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