Buy a shorter one. Welding Cast Iron is a pain and to do what you want would require cutting out a section and re-welding the whole thing. Baseboard hydraunic heaters can be shortened but cast is a no go.
In most cases, YES they can be shortened and NO sealant is normally needed. It depends on the push nipples.
A column radiator is used to describe a typical cast iron radiator. The term describes the vertical columns that make up the radiator. The radiators can also be made out of steal and not cast iron. The steal is welded together.
A household radiator is cast iron. An automotive radiator would be aluminum or copper.
There are several companies who produce or sell cast iron models of radiators. For example, try the company 'Cast Rads' of the 'Radiator Center' for these radiators.
1/2" - 2" depending on demand
The boiler has a circulation pump that circulate the water
Depending on condition, between $50-$200 seems to be going rate.
Iron, cast iron is just iron
Yes, but be sure to install a small automatic air vent in the small tapping on the top at either end.
Cast iron is fabricated in blast furnaces where iron ore is reduced by coke to cast iron, according to Wikipedia.
no cast iron is more superior than foregn iron
Grey cast ironWhite cast ironMalleable cast ironDuctile cast iron