Which Sealant?

flyingscampi

flyingscampi

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What sealant should I use to to reseal:

chainplates?
clutches?
aluminium deck glands?
iroko instrument binnacle to fibreglass?

I was going to use a polyurethane adhesive/sealer like Sika 291 for all of the above but I want to check it's the right stuff to use for all the applications!
 
I use exterior grade DIY sealant and never had a problem. As in most cases the item is bolted / screwed tight to its mounting and the sealant is mostly squeezed out providing seal in the uneven areas. Not really put to any test is it .. seriously. I know some will shake their heads in alarm ... as I said - many years and no failures yet.
 
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You will not go far wrong with Sika 291

[/ QUOTE ]

Never said you would ... I don't knock Sika ...

but my sealant is half the price and avilable in the shop I can near walk to ... In fact it's the same sealant we use for our work on ships and fuel installations ! Oh and I gave some to my builder working on the house ... /forums/images/graemlins/laugh.gif
 
Yes, I agree. I've recently been attaching some equipment to the outside of my camper van. The instructions recommended a Sika product, not 291 but something similar intended for motorhomes. My local camping shop don't stock Sika so I bought their alternative. In use and once set it's virtually indistinguishable from Sikaflex 291. It cost £7, as opposed to £10 plus? in most chandlers.
 
I am not a chemist or marine adhesive expert but one has to ask why all the main manufacturers of yachts and motorboats all us Sika and specifically Sikaflex 291 for adhesive and sealing jobs. I can asure you if there was a cheaper alternative that had the same properties they would probably use it. If it was me I would use Sika and not some household product not designed for the marine application.
 
<<< all the main manufacturers of yachts and motorboats all use Sika and specifically Sikaflex 291 for adhesive and sealing jobs. >>

Do you have some inside information or is this just an assumption? I would be very surprised if this were true.
 
Bit of both to he honest, have been in the factories for RM, Beneteau, Halberg Rassy, Swan, Dufour and Sunseeker to mention just a few and all were using Sikaflex....granted maybe my comment that all use this product was a little assumptive.. /forums/images/graemlins/ooo.gif
 
You have to remember that they as large scale users would be using quantities that are usually delivered ex factory and at prices that would give your pocket book a xmas feeling !

If you were Sikaflex producer and you had large contracts to supply ? What are you going to do - let competing product fill your market ? You could likely match cheaper product price also.

We aren't talking odd tube here and there as we use !

I can tell you that Sikaflex is also the advised glue / sealant when I did RC Yachts ... most of us used B&Q though !
 
polysulphide sealant for permanaent waterproof jobs - silicone sealant where no bond required.

Sikaflex and many others make both, silicone is widely available from any number of outlets and only the superstitious use the more expensive Sika one. The original was by Dow Corning.

Horses for courses!!

Have any of you tried to dis-assemble anything put together with polysulphide??

The only one IMHO which has no part to play in marine use is acrylic sealant
 
"silicone is widely available from any number of outlets and only the superstitious use the more expensive Sika one"

Hear hear! /forums/images/graemlins/grin.gif

If sikaflex had just come onto the market how many would be saying "I wouldn't use that stuff - Blogg's Sealants are the only ones to use in the marine environment, because that's what all the boat manufacturers use isn't it?"

/forums/images/graemlins/laugh.gif
 
Charles has mentioned a property that in right circumstances is excellent, but can prove disaster.

Sika as adhesive is renowned for its hold. Strand Glass used to have on display in Portsmouth two blocks stuck with Sika ... with heavy weight pulling it apart. Was there for years. It was advised as used for joining various model hulls and decks together - I think I'm right that full size builders some used it as well with reduced mechanical fixings.

The adhesive property for me is not desired when fitting a Display, a stanchion base etc., I want sealing with ability to take apart later without destroying area around it !

To be honest I even devised for myself another method staying away from liquid based sealants - D section window self-adhesive sealer rubber. Buy it in rolls ... just sealed my cockpit sole with it .. sole can be unscrewed lifted ... job done ... sole back agin and screwed down ... luvly jubbly.

When refitting my Dual digi display in cockpit - the old sealing rubber had perished - so bought thinner section of D seal and used that ......... better than original flat sealing rubber !
 
Sika for most underwater jobs but polysulphide is often a better option for most jobs above the waterline. It is much easier to scrape off excess after it cures (after a week!) and you can work with it during the winter, it stays liquid.
 
I have always used exterior weather grade sealant from DIY for such jobs as fitting speed logs ... etc. so why Sika ?

If somone can give me a proper detailed explanation of why Sika instead of the standard response ... Oh - use Sikaflex ... Oh - use Oxalic Acid .... Oh - use xxxxx ..............

I honestly believe that these products get advised because they have built up a mystique and market that says this IS the ONLY product ...........

Boat environment is not unique despite many claims that it is. I have never seen Sika products on a ship for sealing jobs that many here would automatically shout SIKA !!
 
[ QUOTE ]
polysulphide sealant for permanaent waterproof jobs - silicone sealant where no bond required.
{snip}
Have any of you tried to dis-assemble anything put together with polysulphide??

[/ QUOTE ]

Err... Yes.

I think you might mean 'polyurethane' - Sikaflex 291, etc. which does indeed stick things together exceptionally well.

Polysulphide - Life Caulk, etc. is the soft-ish stuff that looks & smells like goose poo, and never really sets which means it is relatively easy to dismantle things sealed with it. IMHO, the best stuff for bedding fittings, etc. below the waterline (and can be applied under water). Can be permanent, but doesn't have to be.

Andy
 
Quite simply

because bullshit always baffles brains.

And of course because the people here are only using penny-quantities.

In fact, here's a marketing idea for Sikkens, why not supply your adhesives in small tubes like mini-CDs. No one ever uses the whole tube.

Fee only £40 as it was about 20" thought
 
Re: Quite simply

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because bullshit always baffles brains.

And of course because the people here are only using penny-quantities.

In fact, here's a marketing idea for Sikkens, why not supply your adhesives in small tubes like mini-CDs. No one ever uses the whole tube.

Fee only £40 as it was about 20" thought

[/ QUOTE ]

Can we share royalties ?

As they say .... Nout as gullible as folk !
 
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