What sealant for windows and through-hull bolts?

[calvong]

Hi all,

Bought a 1979 mirage a month back and just took her out for a first proper sail yesterday.

It rained heavily (am in Singapore) and was able to spot a few leaky points where rainwater was trickling in:

1. Port-side window - this is a long single window which needs new sealant around it)
2. Bow and aft starboard - a few bolts need resealing

Can I ask for opinions on what's sealant I should use? Previous owner moved from Sikafix to a 3M marine silicone sealant (black silicone). Should I continue with the 3M or is there a better product?

 

[calvong]

Also, in the meantime before I have time to reseal the window and bolts, what can I use to keep the water out? Plumbers putty? Or should I roughly encase with a layer of silicone which I then peal off when I do the permanent job?

Tks folks.

 

[john_morris_uk]

In my experience you won't get a proper and reliable seal until you take the window out and clean all the surfaces and rebed it on an appropriate sealant.

FWIW I still use Sikaflex as it has never let me down. Other's may persuade you to try other products and I might try them myself one day, so take your choice. There is a Sika product especially for windows. I am interested to hear why you have a through hull 'bolt' in the bow area? There is a real benefit to be gained by fitting the item (window or bolt) and NOT tightening it right down immediately. Wait for the sealant to 'go off' and then tighten the fitting. The only time I've had a fitting leak was when I fitted a chain plate to the deck and tightened it up so much that there wasn't any sealant left underneath.

Kitchen roll and white spirit cleans up the excess sealant. (The white spirit doesn't dissolve the sealant, but acts as a lubricant and allows you to wipe away the excess leaving a clean edge.

I have heard some people swear by Captain Tolley's Creeping Leak cure or whatever its called. I've never used it, but if its cheap and some is available nothing ventured, nothing gained for the windows? I don't think its supposed to be used underwater.

 

[calvong]

John thanks for reply. A typo - I meant through deck and not through hull.

Yes, intend to do a proper fix ie take window off, clean and reseal. But won't be able to do so in the next fe weeks so am looking for a stop-gap temporary fix. Wondering if plumbers putty or a rough coat of silicone that I can peel away later.

 

[john_morris_uk]

John thanks for reply. A typo - I meant through deck and not through hull.

Yes, intend to do a proper fix ie take window off, clean and reseal. But won't be able to do so in the next fe weeks so am looking for a stop-gap temporary fix. Wondering if plumbers putty or a rough coat of silicone that I can peel away later.

I suppose you could give it a try, but I suspect that the putty won't be as effective as the silicone?

I strongly suggest that a temporary cure would be best effected by this stuff: http://www.captaintolley.com

 

[vyv_cox]

Don't use silicone!!! It has pathetically low strength and almost no adhesion. By far its worst property is that it inhibits the cure of many far better sealants, including Sikaflex. I spent some time yesterday cleaning off sticky sealant that normally works perfectly well but had been put over some silicone, causing black marks on everything that came into contact with it. It can also prevent paint from curing properly, even years down the line, unless removed perfectly.

Like John Morris, I have never had a problem with Sikaflex 291, although nowadays I mostly buy PU40, same stuff at half the price.

 

[northwind]

Butyl tape..

http://www.pbase.com/mainecruising/rebedding_hardware

 

[Sailfree]

Like John Morris, I have never had a problem with Sikaflex 291, although nowadays I mostly buy PU40, same stuff at half the price.

When I recently did Seacocks was very pleased with PU40 especially that it has good working time when I discovered I had to unscrew a number of fittings and tilt them to have enough room to screw on valve in tight positions.

 

[Alpha22]

Abormast BR.... is the daddy!! Like butyl tape, only better.
NEVER use silicone on a boat!! NOTHING will ever stick to the area where you put silicone.... the remains have to be mechanically removed (sanded). Wiping with acetone, petrol or meths will not shift it!!!

 

[Fantasie 19]

Butyl tape..

http://www.pbase.com/mainecruising/rebedding_hardware

+1

 

[Slowtack]

I found Lexan good for perspex window sealing job. I use polysuphide (eg Lifecalk) for deck fittings as it retains elasticity and accommodates movement unlike some polyurethanes (Sikaflex etc) which are tremendous adhesives and great for sealing where little movement is involved. I generally use Sikaflex for underwater applications. Used Tec 7 recently to bed ropeclutches, seems excellent.

 

[Boathook]

Abormast BR.... is the daddy!! Like butyl tape, only better.
NEVER use silicone on a boat!! NOTHING will ever stick to the area where you put silicone.... the remains have to be mechanically removed (sanded). Wiping with acetone, petrol or meths will not shift it!!!

Agree with Abormast BR. Tube always on board.

 

[LittleSister]

TEMPORARY FIX SUGGESTION - When I once had a leaking window I effected a temporary seal by taping over the window/cabin join (all the way round the window) with gaffer tape (aka known as duct tape, duck tape, gaffa tape etc.). Not ideal, but it's what I had to hand, and it did the job until the end of the season when I could take the window out and do the job properly. Note if you leave it on that long the glue is a bit of a faff to get off, but not too bad.

There may well be better tapes available to do the same job. I'm fairly convinced that wide tape of some description is the way to go for a temporary job, and that the chances of getting an effective seal by applying sealant or whatever over the join are slim. (And I seem to recall you have impressive rain in Singapore at times!)

 

[wooslehunter]

+1 for Arbormast. Used it last year to re-bed a window held in with screws through the frame to a metal frame on the inside. It never sets but squishes into everything, it's is easy to clean up after & not too expensive.

+1 for never use silicon.

You can use Sika but expect to have one hell of a job getting it out again if you ever need to. It's also expensive & a tube has a short shelf life.

 

[Poignard]

Anyone tried CT1?

The reason I ask is that I have some Perspex window panes to fit and a tube of CT1 left over from another job.

 

[Ammonite]

+1 for Arbormast. Used it last year to re-bed a window held in with screws through the frame to a metal frame on the inside. It never sets but squishes into everything, it's is easy to clean up after & not too expensive.

+1 for never use silicon.

You can use Sika but expect to have one hell of a job getting it out again if you ever need to. It's also expensive & a tube has a short shelf life.

I'd steer clear of Arbormast if you have windows that are screwed directly to the cabin sides without a frame. It softens on a hot day and squeezes out. Not a major problem but it looks a bit of a mess. Next time I'm going to use CT1 - great stuff if you don't want to get something apart in a hurry

 

[vyv_cox]

I'd steer clear of Arbormast if you have windows that are screwed directly to the cabin sides without a frame. It softens on a hot day and squeezes out. Not a major problem but it looks a bit of a mess. Next time I'm going to use CT1 - great stuff if you don't want to get something apart in a hurry

Yes, that was my experience on one window. I found it very difficult to get it to look clean and tidy because of constant extrusion. I bedded the other three windows on foam tape, far easier and cleaner and the windows can be removed easily if needed.