Type of bulkhead (wet side + dry side) - threaded + threaded; threaded + slip or slip

[byee]

I wrapped 3 layers of Teflon tape onto the 3/4" return and hand tightened into the bulkhead based on the threads in comparison to the 1" herbie drains which I was able to easily hand tighten all the way.

Perhaps I need to try other 3/4" MPT's.

I decided to test anyways by re-installing the 3/4" return into my cube. Needless to say......it's got a slow leak

Any suggestions?? I've tried 2 bulkheads and 2 different brands of 3/4" MPT's......gets very tight after a few turns into the bulkhead even with the use of Teflon tape.

[MitchM]

I only use silicone for threaded ABS or PVC bulkheads.
It's a great lubricant which makes for smooth tightening.
I used to use teflon tape but it was a real pain to clean off the threads if I took it apart. Teflon tape didn't allow for smooth tightening. The nut would always "jerk" as it tightened up.
If you've ever used a torque wrench, you know what I'm talking about.
You want a smooth tightening, not a jerky one.
I waited 1 day before filling, but 1 day is nothing in this hobby.
Make sure the rubber gasket on the wet side seats evenly.

[WarDog]

Something is not right here. Either your bulkhead threads or your MPT threads are hooped, or are not MPT at all, but you have used two and are seeing the same results. Hmmm. I have 2 suggestions. 1) Teflon goes clockwise around the threads, so as it doesn't unwind as you tighten. 2) You may want to use wrenches to assist in tightening, however go slow and careful not to split female threads. If all else fails get yourself some slip slip bulkheads. Hope this helps.

[byee]

The threads are not damaged. I took my return and a spare MPT SLIP to JL this morning to test fit. They were all really tight.

Teflon tape is wrapped clockwise, basically in the same direction as tightening the return.

Im shying away from using wrenches to tightening just in case I need to remove for maintenance.

Thanks for the insight.