The bulkheads that I stock and use have standard pipe thread and I use
threaded nipples to connect to them - no chance for a leak as it's threads
fit tightly - no glue or silicone
Gale :~)
A few bulkhead questions.

If I have a 1" bulkhead, will standard 1" PVC pipe slip fit the bulkhead?
I
gather it will, as the elbow gizmo that came with the bulkhead fits inside
my PVC elbows. Although the bulkhead elbow fits the bulhead rather
loosely.

Do I use standard PVC glue to join them or will Silicone do?