Sealing stainless bilge pump thru-hulls

[TimC2520]

I am in the process of changing the 2 plastic bilge pump thru-hulls with stainless steel. The hull is a 2520. The forward one is roughly 5-6" above the water line, the aft is about 10+-" above the water line.
What type of sealant would you use? 4200? 5200?
The plastic one's were a real pain to get off and remove the old sealant. It definitely was not your "run of the mill" silicone sealant, but I'm not sure if it was 5200. Any suggestions?

 

[MaxOut]

I would use 5200. More glue and shouldn’t ever need to replace the stainless ones.

 

[grouperjim]

Tim:

yeah, 5200 would be fine.

FWIW dry fit it first to make sure the hull surface on the inside is true to the finished hull on the outside. if not, then the SS flange on the outside won't lay perfectly flat against the hull when you tighten the nut on the inside. when i swapped mine out i had to use a dremmel to flatten the surface on the inside.

have fun. was easy enough to do but not exactly quick and easy if you know what i mean.

 

[TimC2520]

Thanks guys,

I've fingered tightened them only so far and they look good.
I'll be sealing them up with 5200 hopefully this weekend.

 

[DaleH]

Ehhhhh, no need for 5200 in that application ... besides, removing 5200 isn't all it's cracked up to be ...

 

[TimC2520]

One thing I did notice when I removed the originals was that the factory must use some silicone sealant on the threads before they slipped the hoses on to help insure no leaks I guess.

 

[MaxOut]

One thing I did notice when I removed the originals was that the factory must use some silicone sealant on the threads before they slipped the hoses on to help insure no leaks I guess.

Good call, I would smear the sealant in the hole in the boat, on the first 1/2" of the threads and the outer lip of the through hull. Install nut, clean off excess sealant while still wet and forget about it. I also would put sealant on the barb before installing the hose as well. I’m sure silicone would be fine for this application but I would use 5200.

 

[TimC2520]

I'd bet it was 5200 on the outside of the hull and in the hole itself as
I had a heck of a time cleaning it up and getting the old stuff off the hull.
Had to use a new razor blade, some acetone and tons of elbow grease.
Whatever was used on the barb (inside) cleaned up with just my finger nail. I bought new hose also figuring what the heck, might as well since I'm in there and the old one's have 10 years on them.

 

[Hugs Tug]

Tim,
I for one would never use 3M 5200 sealant, it is just too unforgiving when you go to dis-assemble.
What you should use is the 3M 4200 fast set. It has almost the same properties of 5200 and can be removed without causing undo labor and possible gel coat damage.
A good case in point, install a thru hull ducer with 5200 and remove it for what ever reason. How hard will it be compared with a product (4200 fast set) that will seal the same way with the same effect?
All my hull penetrations were done with the 4200 fast set just for that reason.

Just my $0.02 worth.
Tom

 

[MaxOut]

Here is a link from the 3M site regarding Sealing & Bonding

Marine Application Profile

http://multimedia.mmm.com/mws/mediawebs ... ZFCOrrrrQ-

Good for reference.

 

[gw204]

There's a product called Anti-Bond that softens 5200 (and others) so it can be removed. Works pretty well.

Why worry about removing an SS thru-hull that's 6" above the water line? Put in on there and forget about it...forever. 5200 or 4200 for me.

 

[grouperjim]

mine are never coming off thats for sure.......and they do look damn good. 8)