View Full Version : Exaust Ports 3M 4200 or 5200

06-21-2009, 03:45 PM
A simple question for the experienced service people I'm sure. When Installing my exhaust ports, which sealant should i use. Since its a permanent install i thought 5200........but then again what i took off looked more like 4200 or lifecaulk......

Any Guidance is Greatly Appreciated,

Not that it matters but its a 77 S&S

06-23-2009, 12:25 PM
I Called 3M on this subject, They suggested 5200 but noted that many older boats were likely sealed with an equivalent of 4200.

Any additional Comment is appreciated

06-23-2009, 12:30 PM
I would personally use 4200, just in case I ever wanted to remove the item. 5200 pretty much means it is on there for the longhaul, unless you feel like removing the item and all the gel around it!

Good Luck!

06-23-2009, 04:05 PM
Good Point, My experience is all with much larger offshore boats........we never think about taking them back apart.

06-23-2009, 06:13 PM
4200. I sold it for 8 years. I never recommended 5200.

06-25-2009, 10:43 AM
I too woudn't use 5200, although I love the stuff (I think I've still got a little bit under my wedding ring that's been there for 10+ years!). Although the exhaust port may seem like a permanent install, I think that if you're muffler cracks or leaks, the only way it'll come out is through that exhaust port hole in the transom (without cutting out the floor)...

The port has a wide flange and enough fasteners that pretty much any sealant will keep the water out. 4200 it plenty good 'nough.

The transom wood core exposed by the hole is probably more likely to get wet from water inside the boat than from it leaking past whatever sealant is used for the port, therefore while you've got the ports removed, I recommend out that you seal the exposed wood core.

06-29-2009, 02:06 PM
Thanks for the tip on the transom holes, I just replaced that wood and i plan to glass the edges and paint it with Interlux 2000E to seal it out from water........or maybe gelcoat that part...I think i will go with the 4200 for the ports, 5200 for the screws 8o)

06-29-2009, 05:41 PM
4200 is more than enough for all of it, I wouldn't buy any 5200.