Can I use RTV silicon to seal around bolts used to mount kicker to transom

[hydrojohn]

I need to seal around the bolts used to mount my kicker motor to the transom. Obviously needs to be water proof and durable, but I do not want it to be permanent. Since it is above the waterline I was thinking about using some Permatex RTV silicone that I have on hand. Is this a good choice? I have read many use 3M 4200, but I would have to get some.

 

[Georgesalmon]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

Anything that's in the water needs a sealant that is made for that. Silicone is not recommended below the water line. Get some 4200, 5200, Sikaflex, etc. Though it says permanent you can get 5200/4200 sealed stuff off with a little work.

 

[crabby captain john]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

4200 and less chance of a problem....

 

[kfa4303]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

+1 NEVER use "silly cone" on a boat. Either 3M 4200 or 5200 are your best choices. You should be able to find it at lowes/hd. It's a little messy, but will clean up with a bit of acetone.

 

[redneck joe]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

Silicone breaks down under sunlight (UV). Use the right product.

I've heard the 4200/5200 is as well?

 

[Pale Rider]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

R Room
T temperature
V vulcanizing

west marine has a few good choices. Lifeline sealant/silicone for under the water line is decent as is the 3M products already mentioned.
Silicone and structural sealants are UV inhibitive. it all depends on the application for what works better than others. But you shouldn`t have any issues with RTV, the Right stuff/permatex or any other low modus heavy bodied silicone sealant.


I`d be a bit cautious with using say the clear, or translucent blue types as they make for a decent adhesive while sealing when there are others easily available...

BTW, West marine brand white silicone in the 10 oz cartridge is good silicone/sealant. I`ve used it in many applications.
The 5200 sealants is great for sealing the shoes on jets ski`s as well...

 

[Frank Acampora]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

Yes, use black RTV silicone. It is UV resistant just by nature of the black colorant. I use it all the time to seal engine mounting bolts and have no trouble.

When you drill the bolt holes for the kicker mount, use a countersink or a larger sized drill and chamfer the top of the holes. This allows the sealant to actually form a sort of O-ring and provides a well so all the sealant is not squeezed out when you insert and tighten the bolts. Put a little sealant into the bolt holes to coat the raw wood inside the transom if you are bolting to a spot that has wood. In any case, back up the nuts with extra large stainless fender washers, available at Fastenal and some big box stores.

 

[smokeonthewater]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

no use 4200... silicone is the wrong product

 

[robert graham]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

The motor mount bolts on my 1999 Yamaha were/are mounted with a clear silicone sealant and it's just like new...no deterioration at all...

 

[smokeonthewater]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

the motor mount bolts on lots of motors are sealed with clear sillycone... the problem isn't discoloration or deterioration but rather separation from the transom and leaks which rot transoms... they don't all fail but they are MUCH more likely to fail n leak than those sealed with poly (5200/4200)

BTW I seal mine with 5200 and they aren't actually permanent... they just require a couple smacks of the hammer to remove the bolts and sometimes a little cleanup with a razor blade before putting the motor back on

 

[metriccrescentwrench]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

I've rebuilt three boats now, all used silicone as the sealant of choice. I've seen how it can break down, there's no way in hell I'd use it on a boat. I'll stick with 3M 5200 for below the waterline and anywhere that water intrusion could possibly be an issue.

 

[agallant80]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

Like anything on the internet you can keep on looking around until you get the answer you want. Just think of it this way. 4200/5200 is pretty much the standard in the marine industry. Over an extra $5 and a trip to Lows would you want to risk water intrusion? Its going to be allot more work to rebuild the transom then the trip down to Lowes....

 

[Bob_VT]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

My vote is the 3m5200 (even though it is called permanent) and you should not have problems.

No one has mentions this and it is VERY important. Seal the inside of the holes that pass through the transom. Smear a layer of 5200 on the exposed wood. (Wear rubber gloves!!!) Sealing the bolts to keep the water out of the boat is half of the equation........ what is just as important (maybe more) is to seal the transom wood from becoming water-soaked.

 

[superbenk]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

No question, 4200/5200. I've tried to use silicon before on the boat and within a few trips out it deteriated & came off. Completely useless.

 

[sphelps]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

Just installed transom wedges and used silicone ... :facepalm: Was worried about the being permanent thing. The guys that installed my o/b used silicone so I figured it was ok .. I may cut the extra back and install some 5200 around the exposed area .
On the other hand , I have a seacast transom so at least I don't have to worry about rot ..

 

[Thalasso]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

When your done and have any 4200 left over put a screw in the end put in a zip-lock bag and put in the freezer. It will last for years.

 

[smokeonthewater]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

Just installed transom wedges and used silicone ... :facepalm: Was worried about the being permanent thing. The guys that installed my o/b used silicone so I figured it was ok .. I may cut the extra back and install some 5200 around the exposed area .
On the other hand , I have a seacast transom so at least I don't have to worry about rot ..

with a seacast transom I wouldn't worry BUT if you choose to reseal you really need to remove ALL the silicone first... the 4200/5200 won't be of any benefit unless the silicone is completely removed

 

[redneck joe]

Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom

Like anything on the internet you can keep on looking around until you get the answer you want. Just think of it this way. 4200/5200 is pretty much the standard in the marine industry. Over an extra $5 and a trip to Lows would you want to risk water intrusion? Its going to be allot more work to rebuild the transom then the trip down to Lowes....

this one.