Hello,

I am trying to find information on steel boiler room doors.  These are
the types that are usually found in old factories and warehouses. 
These doors are usually on a sliding mechanism and clad in either tin
or copper or bronze plate.  They are very heavy and often have a
hanging counter weight attached to slide the door closed once it is
opened.

As I said the doors are clad in metal and I would assume that they
were usually made by hand.  The folds where the tin is held together
on the door are visible.

I am interested in pictures and manufacturing techniques.

Thanks,

Mike