Butyl Tape VS Silicon

[jungpeter]

A mild note of caution regarding the use of butyl tape. I attempted to re-bed some stanchion bases this winter using butyl tape. After cleaning all vestiges of previously-applied sealant (3M 4200? who knows, but at least it wasn't silicon) off the stanchion bases, and mildly countersinking each screw hole in the gelcoat below the stanchion bases to provide a proper sealing "o-ring" for the tape, I dutifully applied the tape as recommended by Compass Marine. Next, I screwed the bases down, and applied "moderate" torque to seat the bases. Yup, as advertised, the butyl tape squeezed out around the perimeter of the bases (to some extent), and from under the screw heads. And cleanup was straight forward.

But....the bases would not seat properly. The tape was too stiff, as the temperature at the time was simply too cold (~35 deg F). OK, I'll hit the stanchion bases with a heat gun. Oops-careful! Don't want to scorch the gelcoat. Arrrrggg, stainless steel conducts heat poorly, so getting the tape soft post-application was a non-starter. No problem, says I. I'll simply wait until it warms up, and re-torque the screws. Well, after approximately two months of cold, wet weather this winter, I simply gave up (I did want to use the boat, after all). I removed the stanchions yet again, cleaned off the butyl tape, and re-bedded with 3M 4200. One shot deal, bases bedded properly in place, squeeze out cleaned easily with MEK, easy-peasy. 3M 4200 cured within 24 hours, even in cold and wet conditions, no leaks, works good, lasts long time.

So, my conclusion is that, although the butyl tape is theoretically ideal for bedding deck fittings, it's not a cure-all, nor as simple to use as advertised by Compass Marine and others, at least in cooler months of the year. And, as with the vast majority of the previous posters in this thread, I refuse to allow silicon seal anywhere near my boat. Both 3M 4000 and 4200 (but not 5200) work just fine for me.

Regards,

Pete

 

[Comodave]

I live in Michigan. I don't try to bed things when it is cold. Butyl tape needs to be warm to be able to flow out from under the fitting. The Compass Marine web site does talk about lack of flow in cold weather. It is pretty simple to wait until the weather warms up and then tighten up the fitting. If it is too cold to bed with butyl, it is probably too cold to be boating... most caulks want around 50 degrees also.

 

[psneeld]

Again,
Prep is everything! I've successfully re-bedded hardware that was originally installed with silicone with other caulks.
Not sure why I argue these things in places like this. It gets me nowhere...
Ok, no silicone, ever, ever, ever.
There!
Bruce

Then there are the ones who swear 5200 is devils glue....

Spend enough time fixing boats and all problems are solveable....and often much less of a problem once you learn what path to take.

Silicone is on my boat and has its uses....the last one I used it for was for a bead around an under countertop sink to keep the water from leaking through......silicone was fine for the job and probably easier and superior to most goo.

As usual, you have to be smarter than the tools, equipment and goo you work with.

Apologies to my friends who belive 5200 is devils glue and silicone is an alien life form.

 

[BruceK]

Is All Silicone Created Equal?

I discovered, virtually by accident, that not all silicone is created equal.
The "Bathroom" variety will certainly cause problems with residue, while the "Roof and Gutter" variety happily takes paint, and is not a creation of the devil.
Open to correction, but I believe "R & G" contains much less silicone and more "caulk", whatever that may be. Of course,the corollary of that may be it doesn`t last as long as the devil`s creation and may degrade earlier, causing different issues, like sealing breakdown.
There are times not to use Sikaflex/polyurethane sealants. Like when something has to be taken apart, eg. sealing the screw heads and where the screws enter the transom to fix name and port boards, which need regular removal for refinishing.
But, following the Aussie tradition of "having a bob each way", can any Aussies say where butyl tape is sold here. It may be ubiquitous in USA but I`ve not seen it here. Maybe under another name?
Even so, I accept that the mothers(bless their souls) of some TFers were frightened by silicone during pregnancy and consequently some views will never change.

 

[foggysail]

Butyl tape is easy and works well. Silicone, once it hits anything, will keep anything else from sticking to it. Do yourself a favor and remove any silicone sealant or adhesives from the boat.

CMS has a great article on how to use butyl tape for bedding hardware. Easy to do and will last just about forever. It is also inexpensive.

You're so correct! Great advice Dave

 

[healhustler]

Love the butyl tape, for sure, although the cartrage type is much more sensitive to UV than the Compass tape. In a comparison, I used 4200 on a few stanchions and butyl on a few others. If your stanchions flex, no contest. I even left the nuts off the bottom of one base bedded in butyl for two years. No leaks. I use it above the waterline wherever sealing against water intrusion is the priority. It is not an adhesive.

 

[BruceK]

Found this at Bunnings Hardware. https://www.bunnings.com.au/search/products?q=butyl tape&redirectFrom=Any.
Is it like the butyl tape you guys are using?

 

[Comodave]

Look in post #2. There is a link to instructions and purchase of the butyl tape.

 

[RT Firefly]

Greetings,
Mr. BK. Can't say if that's the same stuff but here in NA it is also used to seal windows into travel trailers (caravans in AUS I expect). Might try to source at an RV place.

 

[BruceK]

RTF, the Bunnings Stores product looks something like the stuff in post 2, though I think ordering was only for US residents, and there are others, like us. My search suggests the 3M product is not available here.

 

[Bacchus]

The burly tape I've used & familiar with doesn't have a mesh incorporated. I'm guessing there are + & - to the mesh but not sure it helps for bedding deck fittings?

 

[RT Firefly]

Greetings,
Mr. BK. After reading Mr. B's post above AND reading the actual description of the Bunnings tape I agree with Mr. B. The Bunnings tape is NOT what I have been using either and I don't think it would suffice for bedding. Thanks for catching that Mr. B.

 

[dhays]

FWIW, I bought the Butyl Tape from CMS for two simple reasons. 1) It was convenient. I knew I could get it from him and it would be the right stuff. 2) I have greatly benefited from his advice over the years on the sailing forums where he has posted as MaineSail. He has helped sort out battery issues on my sailboats in past. He has always been generous with it and has NEVER asked for anything in return. He also has never promoted his own little side business on those forums that I have seen. So I jumped at the opportunity to support him in a very tiny way buy buying some butyl tape from him. It was great for me, and hopefully helpful for him. I could have looked around and found an equivalent item for less, but I wouldn't have gotten the same return.

Kind of like I'm saddened that I never took the opportunity to purchase anything from Hopcar when he owned his company.

 

[BruceK]

Greetings,
Mr. BK. After reading Mr. B's post above AND reading the actual description of the Bunnings tape I agree with Mr. B. The Bunnings tape is NOT what I have been using either and I don't think it would suffice for bedding. Thanks for catching that Mr. B.

Thanks Bacchus and RTF. There are other products on ebay, I`ll look again. I need to bed a replacement windlass foot switch, but as it`s a semi permanent installation I could use Sikaflex. Bunnings is our major hardware store chain, if they don`t stock it no hardware store does.

 

[captBrett]

Silicon raises it's ugly head again! Go with byutal whenever and wherever possible. In an effort to end this ongoing discussion once and for all I offer the following words from the prophet Sir Mix-a-lot, "silicon parts are made for toys"!

 

[RT Firefly]

Greetings,
Mr. BK. I say again, try the RV places. Butyl tape is used extensively here in NA as bedding for caravan windows and vents. Surely the caravan vendors sell some similar material unless they are all using ....gasp...silicone.

 

[FF]

"..gasp...silicone "

New products can remove ALL traces of silicone , so the surface can then be painted.

 

[psneeld]

Got my last butyl from an RV place...

It was black to match my window frames....looks a bit better till its all trimmed off after it is done squeezing out.

 

[RT Firefly]

Greetings,
Mr. FF. "New products can remove ALL traces of silicone..." There are old products as well. The "classic" solvent used is/was toluene or xylene, BOTH aromatic hydrocarbons and extremely bad for one's liver. I try to use these solvents as little as possible.

 

[foggysail]

FWIW, I bought the Butyl Tape from CMS for two simple reasons. 1) It was convenient. I knew I could get it from him and it would be the right stuff. 2) I have greatly benefited from his advice over the years on the sailing forums where he has posted as MaineSail. He has helped sort out battery issues on my sailboats in past. He has always been generous with it and has NEVER asked for anything in return. He also has never promoted his own little side business on those forums that I have seen. So I jumped at the opportunity to support him in a very tiny way buy buying some butyl tape from him. It was great for me, and hopefully helpful for him. I could have looked around and found an equivalent item for less, but I wouldn't have gotten the same return.

Kind of like I'm saddened that I never took the opportunity to purchase anything from Hopcar when he owned his company.

GEES-- I remember MaineSail from the Cruiser's forum. Been awhile since I visited/posted there but I remember many of his fine posts especially pertaining to batteries.

 

[Pgitug]

We had a sailboat that had the worst caulk job I've ever seen. Chasing leaks, the PO had simply squirted a bead of silicone around the exterior seams of every fitting on deck and around the entire perimeter of the deck where it abutted the toe rail. And despite what he must have thought was an impenetrable water barrier, it still leaked. A child would have known better.



It took a long to get the bulk of it off and the surfaces never were entirely free of a greasy film that prevented anything from adhering to the fiberglass. Ultimately, I ripped everything off the boat above the waterline--including the teak toe rail and vinyl rub rail--and rebedded properly with Sikaflex. If I'd known about butyl tape back then, I'd have used it; all of the above-water-line fittings on the Defever are getting butyl.



To me, the choice between silicone and butyl for bedding fittings is the same as choosing between brandy or diesel for an after dinner drink.

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[BrianG]

Windlass bedding. Butyl or 4000uv?

 

[Comodave]

I would use butyl. If I were going to use a caulk, I wouldn’t, I would go with Sika 291. I have had much better results with Sika than when I was using the 3M products.

 

[FlyWright]

I used both. Where teak meets deck or teak, 4000UV or Sika equivalent. Where SS plate meets teak, quality butyl tape.

 

[Comodave]

We have teak toe rails on our boat. They were caulked and the caulk had become loose over time. We used Sika 291 for the teak to fiberglass joint. We used their primer on the teak first, $80 for a small can, but it has worked very well so I guess it was worth it. But for mounting things I use butyl when things are going to be through bolted. I really like the way Sika products perform in comparison to the 3M products. I used to use the 3M but it doesn’t seem to last as long as the Sika stuff does.

 

[BrianG]

Is Bed-it still the butyl of choice?

 

[Comodave]

I like it a lot. Plus it helps support CMS, who provides a lot of good DIY info. No affiliation.

 

[Bacchus]

X2!
I've used others that were not as good and agree w supporting CMS.

I like it a lot. Plus it helps support CMS, who provides a lot of good DIY info. No affiliation.

 

[BrianG]

CMS...Clever Men Society?

 

[FlyWright]

CMS...Clever Men Society?

Compass Marine Services Rod's username here is CMS.

Probably the best DIY advice you'll find anywhere on the interweb.