Silicon bubbling

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GeoffSchultz
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Location: BlueJacket: Guatemala
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Silicon bubbling

Post by GeoffSchultz »

We stored BlueJacket in Panama last year and will store her there again this year. It rains a LOT down here. When we returned we noted water damage on the wood next to the mast in the salon. After doing some detective work, I noted that the silicon around the stainless mast ring had failed. I cleaned all of it out and reapplied silicon. That was in February. Just yesterday was I looking at it and noted that there are bubbles appearing under the silicon and I can see that it will fail again. The attached photo shows this.

The questions are:

What's causing this?
What do I do to keep this from re-occurring?
What product should I be using?

-- Geoff
20150419-170953.jpg
20150419-170953.jpg (192.52 KiB) Viewed 5512 times
BlueJacket
1997 Freedom 40/40
http://www.GeoffSchultz.org

midnightsailor
Posts: 140
Joined: Thu Aug 06, 2009 1:21 pm
Location: Greenport, New York

Re: Silicon bubbling

Post by midnightsailor »

I am not sure if this helps but first. silicon is really not an adhesive, its a sealant and has little tendency to stick to things it is better used as a gasket where it is held in place under some type of clamping pressure, so I think what is happening is that the silicon that is exposed begins to fail in that it stops adhereing to the gelcoat and/or stainless and then moisture works its way under causing cloudiness and bubbles. This is my theory. and is based on my experience. There are some silicons that do have more adhesive properties than regular silicon sealant, such as glazing silicon used in bedding portlights. Also, there is a product called "Lifeseal" which is a combination of silicon and polyurethane (polyurethane is an excellent adhesive ) . I have had very good luck using this product when I need a good sealant adhesive for bedding hardware. Also used it when I worked for Marine electronics installation and sales company for sealing around wires that pass through openings, or to seal electrical connections. Make sure not to confuse it with a similar product called LIfecalk which is polysulfide . Also, Lifeseal I find, has a poor shelflife so I only buy the small tubes. It does come in large size tubes that fit calk guns but unless you buy it and use it all immediately it will harden before long. I have bought unopened large size tubes from marine stores and frquently found the contents already hardened, so I only buy the small tubes now. ANyway you might try this , or if you cant find it, atleast try to use somthing that has good adhesive properties too. Just stay away from regular 5200 because that is TOO good an adhesive, you will almost never get it off as I am sure you know. Most sailors are familiar with 5200 but in my opinion it has almost no place on a boat unless your building one and use it to seal the hull to deck joint! Hope this is some help, Rick
1982 Freedom 33 Cat Ketch, Hull # 53, Standard Booms, deep keel ,tall rig
An armed man is a citizen, An unarmed man is a subject. George Washington

calumf
Posts: 1
Joined: Tue Mar 10, 2015 8:00 am

Re: Silicon bubbling

Post by calumf »

Would butyl tape be any good here?
I have used it to bed deck hardware and have had good results and it's more pleasing to work with than silicone style products.
Would the extra stick that would be had by using an adhesive be worth having when such a large plate system is in use?

daletournier
Posts: 181
Joined: Wed Aug 18, 2010 6:25 pm

Re: Silicon bubbling

Post by daletournier »

Hi Geoff, im not claiming to be an expert here but I don't think all silicons are created equally. I'm a big fan of Dow Corning 795. It has a good adhesive element as well as a 50% expansion rate. I recently replaced my windows using it. May be worth looking at.
Cheers Dale.

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GeoffSchultz
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Location: BlueJacket: Guatemala
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Re: Silicon bubbling

Post by GeoffSchultz »

Thanks to everyone for your suggestions. Because I'm in Panama and have *very* limited access to anything other than the normal marine adhesives, I used 4200 Quick Set. Let me tell you, when it's upper 80s, the term "quick set" is an understatement. By the time that I had worked my way around the mast with the caulking gun, it had already begun to set up. I was able to tool it, but had problems when removing the masking tape and the edges aren't the prettiest.

I've also pretty much determined what the issue is. The mast ring is stainless which is bolted to an aluminum bottom plate and there's nothing separating the two. As a result you have electrolysis. I spent a hour or two with dental tools carefully cleaning out all any corrosion that I could get to and get down to bare metal. I then used a stainless steel brush to clean it all up and then wiped down with acetone before applying the 4200.

I think that the best solution would be to place some kind of plastic barrier between the two. Alternately perhaps I could apply some kind of epoxy paint on the 2 surfaces. However, I'm trying to get the boat ready to store for hurricane season and just don't have time to work on this now. But I'm open to suggestions!

-- Geoff
BlueJacket
1997 Freedom 40/40
http://www.GeoffSchultz.org

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sailmon
Posts: 237
Joined: Sun Feb 22, 2009 6:53 pm

Re: Silicon bubbling

Post by sailmon »

Interesting discussion. There are probably a number of reasons to stay away from butyl tape for this application - but I find it intriguing. We don't take our mast down often - but I recall that the clean up job - cleaning silicone from the mast, partners, mast ring, etc. is a major and unpleasant task. When we retire and head off cruising in 18 months (let the countdown begin), we are going to head south via the "Loop". We plan to sail from Cleveland to Chicago, truck the mast to Mobile, and motor the rivers. We will need to re-step in Alabama and sail south to Fla, Bahamas, British and US VIs, etc... hopefully able to visit Cuba as well. Once ready (after a few years), will head back north - and ultimately return to great lakes via the Hudson River/Erie Canal - again dropping and re-stepping the mast. Would really be great if butyl could work and we didn't need to clean the silicone each time we un-step.
Sailmon (Captain Bob Allenick)
S/V Her Diamond
1991 Freedom 38
Cleveland, OH

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