I have seen metal "plugs" (and this may not be the correct term) used for the holes that are drilled in vent pipes, in order to test combustion appliances.
I'm referring to the type 1 vent pipe that is standard for atmospherically-vented gas appliances.
These plugs appear to be superior to HVAC foil tape. Any thoughts on this?
Also, does anybody know how to get their hands on these metal plugs? I use a 5/16" bit to drill probe holes.
Thanks in advance!