Ball Valve to Thru Hull

[firecadet613]

I'm rebedding all my thru hulls this year (after sealing the coring with epoxy).

I ended up replacing the generator and A/C thru hull, but not sure what I should use to seal the thru hull threads when I screw the ball valve on to it?

 

[sbw1]

I'm rebedding all my thru hulls this year (after sealing the coring with epoxy).

I ended up replacing the generator and A/C thru hull, but not sure what I should use to seal the thru hull threads when I screw the ball valve on to it?

Someday that fitting will need to be removed. 4200 works for that. 5200 will be a big mess to deal with if that is what you are thinking.

 

[firecadet613]

View attachment 99081
Someday that fitting will need to be removed. 4200 works for that. 5200 will be a big mess to deal with if that is what you are thinking.

I'm using LifeCalk for the thru hull to boat, but when I screw the ball valve to the thru hull fitting, do I need to put anything on the threads?

 

[sbw1]

I'm using LifeCalk for the thru hull to boat, but when I screw the ball valve to the thru hull fitting, do I need to put anything on the threads?

Since you are below thr water line you will need something. 4200 would be safe and strong. The fitting will be subject to constant vibratin. Stray currents could cause a leak to develop. 4200 is flexible and will mitigate that potential. I believe I would check with an experienced tech who has done the job multiple times, before finishing the job.

 

[Carpediem44DB]

I just did the same thing with my aft waste discharge thru hull. I bedded the thru hull with 4200 and used teflon tape on the threads at the valve and the hose bib on the other side of the valve. I am confident that I will never take it apart again and when I looked at what was there from the factory it looked like just plumber's pipe dope and it never leaked.
Carpe Diem

 

[Soulshine]

Pipe dope is fine.

The impulse to glue everything together with 4200 kills me.

It’s plumbing and doesn’t require sealing with unobtanium just because it’s a boat.

 

[ttmott]

I've had several changed over the years. There are three sealing situations that are different.
First is the backing plate to the inside of the hull (if there is one) - the backing plate must be installed with a thickened epoxy.
Second is the actual through hull which threads into the seacock base. If a Groco that base is triangular. Those threads are straight thread so the system can fully thread together. Lifecaulk or 4200 are needed here. this is the intersection between the outside and inside of the hull. First bed the triangular piece with the caulking on the inside then sparingly coat the threads on the outside piece and a coat of bedding on the flange of the outside piece then thread the outside piece into the inside piece. There should be some slots on the outside piece so it can be tightened. Install the screws on that inside baseplate that will prevent it from unscrewing and provides the 500 pound lateral force requirement by ABYC. Oh, and make sure to test fit those two pieces - I had to cut a length of the threaded part off so it would not bottom out on the inside piece.
Third is the through hull to seacock - those threads are National Pipe Taper (NPT) threads and require a thread sealant such as teflon tape or pipe dope or other tapered thread sealant.

 

[firecadet613]

Pipe dope is what I was looking for, thanks all!

It's a simple 3/4" brass thru hull. I had to trim them down some, as the normal length was just a hair too short and Groco's XLs are over 5" long.

I've sealed the fiberglass opening with epoxy and will use LifeCalk to bed when it warms up in a few months.

Wasn't sure on the pipe threads, the original surely wasn't installed with teflon tape, but pipe dope.

 

[Wylie_Tunes]

I'm using LifeCalk for the thru hull to boat, but when I screw the ball valve to the thru hull fitting, do I need to put anything on the threads?

Just use the same below waterline sealer you used to bed the t-hull.