[Bob Carriere]

Some part of my failing memory tells me the coating they "use" to spray paint repaired radiators was some kind of tar based bitumen coating used primarily to prevent the old copper fins from corroding so fast.

The spray was done as a very light coat and may have been water base similar to the coating of railroad ties...... in fact radiators would have been taken out of the water tank after soldering was checked for leaks and the black spray was sprayed on after only a brief blast from an airline... no attempts were made to fully dry the core before spraying....... those were the days before environmental concerns......

Phil.... do you remember that far back..????

Bob