Can a stainless npt fitting thread into plastic?

[The motor guy]

I have a plastic live well in my boat and I want to setup a drain hose for it at the bottom. I'd prefer to just use a rubber washer and a regular threaded nut, but everything i find is not. So if I use an npt fitting and Teflon tape, will that work on plastic?

 

[StevieC]

There is nothing stopping you from threading metal into plastic with or without using teflon tape. When you use the teflon tape and NPT style fittings they seal with applying pressure to the threads with the tape in-between to take up any remaining gaps and it might cause the plastic you are threading into, to crack under stress if it's not thick in the surrounding areas and not of dense plastic material, or it could cause the plastic threads to buckle under the pressure from the metal fitting if it's too tight because the surface area of the plastic threads are rather thin in NPT fittings. Just some things to think about.

You might be better off using coarser threads when going into plastic.

 

[Imp4]

Ugh, c'mon StevieC.
A few less commas please....

 

[double vanos]

Use Rectorseal T+2. Good stuff. Since I started using this I don't have Teflon tape anymore, not necessary.

 

[bugeye]

The stainless will just cut and cut new threads. Will never tighten with tape. Use the Rectorseal and allow to cure.

 

[Yah-Tah-Hey]

Use a brass NPT/hose barb. Should be able to find one at any of the big- box hardware stores or a vehicle parts store.

 

[BrocLuno]

Just don't tighten to severely. The steel is much stronger than the plastic. Hand tight should do it

 

[Yah-Tah-Hey]

Originally Posted by Yah-Tah-Hey
Use a brass NPT/hose barb. Should be able to find one at any of the big- box hardware stores or a vehicle parts store.
Even better than that, use a nylon NPT/hose barb fitting. Believe I saw this item at Menards.