Question about plumbing fittings/threads

TimFrederickQC · Apr 11, 2017

So I just picked up this 92 gallon corner acrylic on CL for a decent price, just a few scratches that need addressing. I want to fill with water for some time in my garage to do a leak test, but first need to call the FIVE feed/return lines. Not sure why so many. Anyhow, 3 are in the rear corner overflow, two in the bottom of the tank. I have capped them all with teflon tape on the threads, however I seem to be having trouble with a larger black fitting on the rear underneath. The outside of the male threads is 1.5" diameter, but when I tried a 1.5" cap it was too large. Went back for a 1.25" threaded cap which seems the right size, but as gently as I start to thread it, it seems to tight almost stripping feeling after just a few rotations. I don't want to strip the threads if the cap is incorrect and then have leaking. I assumed everything is NPT threads, but could it be something different?

mcarroll · Apr 11, 2017

Ah, you're talking about the threads that the bulkhead nut threads onto! That could actually be totally custom since they never expect anything other than the nut that came with the bulkhead to be threaded on there.

Bump! :)