Thru hull plumbing fittings

[getfished]

The base to my livewell pump cracked. I removed it. Now I need to replace it. After I acquire the necessary parts my question is what kind of sealer should I use for the thru hull fitting ?

[M-D]

I use 3M 4200 for thru hull fittings.

[rojoguio]

I use 5200 Fast Cure for my customers boats for liability reasons. They are removable after curing and I have never had a leak.

[getfished]

I use 5200 Fast Cure for my customers boats for liability reasons. They are removable after curing and I have never had a leak.

How does this work ? Seems like I hear often that the 5200 is next to impossible to remove in the event you need to. Not doubting your experience. Of course I want something that will provide a watertight seal and is developed to be used below the waterline.

Another question : Whatever product I use, should I use my finger to spread a layer of this around the inside of the hole through the hull to prevent water intrusion ?

[rojoguio]

Bud it is not easy to get the fittings out but they are removable. I do not put 5200 on the inside of the locking flanges but it makes it's way there all by itself. 5200 locks around the threads of the fittings and hull opening. Also it is runny, I like to put a good bead of sealant around the flange then let it sit on the work table for a little bit to help it set up enough to stay on the flange. Transom reinforcement plates in the bilge get a bead on the inside to glue it to the hull.

I am curious, what kind of thru-hull fitting are you installing below the waterline that needs to be easily removable. The usual stuff is intended for permanent installations. If I am installing a hose on the inside of the hull I make sure the fitting is well sealed because hoses tend to have weight themselves with the fitting expected to secure it on the inside at the attachment point and to be a security point for wires, other hoses, or other stuff that needs securing.

Looking at thru-hulls several ranges of materials and costs are available. 2 composite materials are used Plastic & Nylon. Plastic thru-hulls are $6-9, Nylon $15-35, the difference? Plastic mounting flanges can be knocked of simply catching it on a obstruction (especially if sealed with silicon) when the weight of your boat bears down on it. Nylon fittings, just plain Tough. So your flange has popped of, does water rush in? Not if you used 5200. Not assuming Your using the cheap stuff but another DIY person may read this 5 years from now so we want them to know the big picture. I personally install Nylon, Brass, or 316 Stainless with 5200. I hope this helps.

[getfished]

Thank you for the reply. I am going to replace a livewell fill pump in a bassboat. The install requires attaching the pump to a base that has a thru hull threaded nylon tube that has a locking nut on the outside of the hull. It basically should be considered a permanent install in that the pump cartridge should snap off the base for future replacement. As long as the base holding the cartridge doesn't crack or break the thru hull fitting won't need to be removed/replaced.

[rojoguio]

Yeah, they are in the plastic category. I usually put a 3/4In suction screen over the threads sticking out. If you like those be sure not to cut the pump housing threads too short. The plastic the screen is molded into will break before the locking nut. If you can pickup a Nylon locking nut you are better off. On pump housings I do put a small bead of 5200 on the inside too.

[Scott S.]

5200 is CRAZY strong. I had a V8 Rude hanging off the back of my boat. I was going to re seal everything at the beginning of the season, pulled out All of the bolts from the custom set back. It didn't come of, I was lifting the ass end of the boat off the trailer. I let the hoist down and the motor and jack plate were stuck to the boat. I put new sealer on the bolts and went with it.

[rojoguio]

You will never have to apologize for a failure using it.