# Sealing around speaker: Butyl tape or caulk?



## TakeFive (Oct 22, 2009)

I have a little topside leak that I want to plug. I've traced the leak to a poor exterior speaker installation by a prior owner. It's a Sony marine speaker that is glued in place by 5200 (I think) onto a coaming that is directly exposed to rainwater. On the starboard side it's water tight. On the port side, though, it leaks every time it rains. I went below and can see that there is sunlight passing through one part of the hole in the fiberglass at the bottom of the speaker. It appears that he did not use enough caulk to get a complete seal. So rainwater comes right through the grill and then seeps between the fiberglass and the speaker.

Because 5200 is so tough, I do not want to remove the speaker. It will almost certainly destroy the grill, the speaker, and possibly the fiberglass too. I want to reach back behind the speaker and slap some sealant into the void. If that does not work, then I'll have to risk removing it.

I basically have two choices - either squirt some 3M Marine Silicone in there, or take some butyl tape and roll it into a tubular shape and mash it into the void space.

Which would you guys suggest?


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## pdqaltair (Nov 14, 2008)

Caulk.

Butyl is good stuff, but really only works if you can get clean surfaces and then bolt them together as though it were a gasket.


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## baboon (Aug 7, 2008)

I agree butyl tape is most likely not going to work. Silicone might, but it's reputation for contaminating the surface so nothing else ever works again has been well discussd on this site. I have tried to fix leaks with stop gap measures on my boat in the past and it never worked.

Compared to other boat stuff a speaker is cheep. If it is 5200 it might be best to destroy the speaker in such a way that the outer ring and bulkead is intact. You could then grind down the 5200 to the original surface and put in a new speaker using a proper sealent or butyl. I that fails then it might be easy to just cut the whole thing out and put in a bigger speaker. This may sound exteme, but my limited experience with 5200 has convinced me to not even have a tube of it near the boat.


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## deniseO30 (Nov 27, 2006)

Rick use 4200 
http://multimedia.3m.com/mws/mediawebserver?mwsId=66666UuZjcFSLXTtMXfXnXfXEVuQEcuZgVs6EVs6E666666--&fn=60-4400-5507-1.pdf


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## TakeFive (Oct 22, 2009)

baboon said:


> I agree butyl tape is most likely not going to work. Silicone might, but it's reputation for contaminating the surface so nothing else ever works again has been well discussd on this site. I have tried to fix leaks with stop gap measures on my boat in the past and it never worked.
> 
> Compared to other boat stuff a speaker is cheep. If it is 5200 it might be best to destroy the speaker in such a way that the outer ring and bulkead is intact. You could then grind down the 5200 to the original surface and put in a new speaker using a proper sealent or butyl. I that fails then it might be easy to just cut the whole thing out and put in a bigger speaker. This may sound exteme, but my limited experience with 5200 has convinced me to not even have a tube of it near the boat.


Sorry, there are details that are just too time consuming to type out. Your suggestion will not work for me. It appears that the previous owner already enlarged a prior speaker, to the point where these speakers are as large as the available flat space. Going bigger is therefore not an option, and the risk of damaging the fiberglass by taking out the current speakers is too great. I will have to try a "stopgap" measure and hope it works.

I've got some leftover 4200 in the fridge, so if it is still good I will try that.


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## baboon (Aug 7, 2008)

Good luck, sorry things are too difficult to get at it another way. I have used dental syringes (the type they give you to rinse a socket once a tooth is pulled) to get thick stuff into tight spots. I have even been able to use them with thickened epoxy, so inecting 4200 with one might work. I have also tried using a standard syringe with a big metal needle (14 g) but that did not work out too well.


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## TakeFive (Oct 22, 2009)

It's time to reactivate this thread. Using 4200 to seal the speaker from behind last year did significantly reduce the amount of water leaking in, but did not completely eliminate it. For the past year I've taped plastic film over this speaker, but now I want to fix it.

The speaker grills have the Polyplanar logo, and after doing further research on their website I believe that the grills are integrated with the speakers. So just removing the grill is not an option. And removing the whole speaker/grill assembly really isn't an option at this point because I think the previous owner may have used 5200 to glue the speakers in.

Upon closer inspection it appears that there is incomplete bedding around the speaker grill. There are a couple of areas where there is clearly a gap of about a millimeter between the fiberglass and outside edge of the grill plastic.

I think the logical next step is to put a thin bead of caulk to plug these gaps around the outside edge of the speaker grill. I have some 3M marine silicone that I really do not like to use, but it's the only stuff that I know of the flows easily enough to penetrate the 1 mm cracks from above, and is also UV resistant. Plus, I can use a damp towel to wipe away excess (unlike polyurethane) and make the bead as narrow and inconspicuous as possible. I had used this same 3M silicone to plug the unused screw holes (through which a lot of water was leaking) two years ago, and it has held up well, stayed white and flexible, and maintained its seal in those spots.

Can anyone suggest a better caulk material that has UV stability and easy flow to penetrate a crack? Would an acrylic caulk be better? FYI, these cracks are too wide for Captain Tolley's to fill.


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## Tim R. (Mar 23, 2003)

Why not use a razor to cut the sealant from under the grill? Then re-bed with butyl.


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## TakeFive (Oct 22, 2009)

treilley said:


> Why not use a razor to cut the sealant from under the grill? Then re-bed with butyl.


Removing the grill is not feasible, for the reasons I stated above.


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## wmmulvey (Jun 14, 2011)

TakeFive said:


> I have a little topside leak that I want to plug. I've traced the leak to a poor exterior speaker installation by a prior owner. It's a Sony marine speaker that is glued in place by 5200 (I think) onto a coaming that is directly exposed to rainwater. On the starboard side it's water tight. On the port side, though, it leaks every time it rains. I went below and can see that there is sunlight passing through one part of the hole in the fiberglass at the bottom of the speaker. It appears that he did not use enough caulk to get a complete seal. So rainwater comes right through the grill and then seeps between the fiberglass and the speaker.
> 
> Because 5200 is so tough, I do not want to remove the speaker. It will almost certainly destroy the grill, the speaker, and possibly the fiberglass too. I want to reach back behind the speaker and slap some sealant into the void. If that does not work, then I'll have to risk removing it.
> 
> ...


TakeFive,

*(Sorry, I did not see your quote on Captain Trolley before I posted)*

You might want to try this product first. Less invasive and works.

Capt. Tolley's Creeping Crack Cure






I had several Port Lights leaking. I used Captain Trolley and it sealed them up
perfectly.

Regards

Bill


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## TakeFive (Oct 22, 2009)

Two nights ago I went to the boat and sealed the edges of the speakers with a very thin bead of 3M silicone caulk. Last night we got a deluge of rain and 45 mph gusts. Today I went to the boat to check on things, and the boat was 100% dry. The fix worked!

I've been bugged by this for 3 years without a permanaent fix. I had always resorted to taping plastic over the speaker. I knew there were cracks around that one grill, but always thought that the speakers underneath were independently sealed, so never thought of sealing the cracks. It was not until I noticed that they were Polyplanar speakers, looked at the Polyplanar website, that I realized that the grills were integrated with the speakers, and therefore there had to be a watertight seal around the edge of the grills.

So 3 years of frustration are finally ended.


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## ironhors42 (Mar 27, 2009)

There is a product call Debond that has been use for remove or dissolve 3m5200 so that you can remove your speaker and reseal properly again. I hope this help you with your project.


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## sww914 (Oct 25, 2008)

This is one of few places on a boat that I think that silicone is completely appropriate.


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## US27inKS (Feb 6, 2005)

I just rebedded the speakers on my boat. If they are built the same way as my speakers, the covers can be removed with some effort. The mounting screws had to be removed first, then carefully pry the covers off. There are tiny screws coming from the back to attach the covers. Once the covers are off, you can carefully push razor blades between the boat and the speaker. If it's done with 5200, you'll have to go very slow, but it can be done.

I considered Butyl to reseal with, but since the speaker body is plastic I didn't know if the butyl would be properly compressed between screws. So I went to Ace Hardware and bought a $3 tube of white Butyl caulk. So far so good.

Caulk, Butyl Rubber Sealant, "Ace"


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## sww914 (Oct 25, 2008)

I've been waiting for somebody to start posting detailed specifications on 5200 vs butyl vs 3M silicone and wax poetic on film strength and tensile strength and the half-lives of various sealants that might be used to seal a gap between a plastic speaker and a fiberglass bulkhead. Then of course it would devolve into a bitter pissing match between two guys who would probably end up friends in real life. I'm a little disappointed.


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## TakeFive (Oct 22, 2009)

Just a quick follow-up on my initial success story.

Yesterday evening we had another deluge of rain. I went down to check on the boat today, and it is absolutely dry everywhere, including the head and bilge. (Since I have an outboard, there is no packing gland to leak into the bilge.)

Previously, in addition to some water in the stern battery locker, I would get a few ounces of water in the head and in the bilge whenever there was a very heavy rain. I was always looking for separate leaks into those areas. Those areas are also completely dry now.

In retrospect, during some rain storms I had checked back in the battery locker and would always notice water drops on the various hoses back theere. Since the discharge ports for the holding tank and bilge pump are right below the speaker, any leaks in through the speaker would drop water onto those hoses. I had assumed that the water just dropped directly down off the hoses back there. But now it appears that due to surface tension, the water probably was guided along the outside of those hoses all the way from near the transom to the head and bilge pump amidships.

Moral of the story: Lots of things are interconnected, and solving the root cause can often eliminate multiple problems at the same time.


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