Wayne - the reason for all the questions is to attempt to determine if you really have a porous carburetor.
The only carburetors of which I am aware that have a reputation for being porous are the new imitation AFB 4-barrels. I won't mention the name of the company selling them as that might trigger a "Peggy attack" on the thread
(Not a complaint Peggy, I respect the work you do, and the line you have to not allow us to cross).
Your carb is a Zenith type 228. Not saying that one doesn't exist, but I have never seen a porous type 228.
I would not be afraid to try your Zenith again, and try to determine where and when it is dripping.
But to answer your original question:
Carburetors constructed of brass or cast iron, IF SUFFICIENTLY VALUABLE, could be glass-beaded, dunked in a degreasing solution, rinsed, again glass-beaded, and soldered, or nickel-plated to fill a leak.
Carburetors constructed of aluminum can be TIG welded.
Carburetors constructed of zinc alloy ("pot metal") such as your Zenith may be replaced.
Jon
