sealant

[yachtShoestring]

I need to get some sealant to help with the on-going roof work, is 'marine sealant' different to what I can buy in B&Q ? There seems to be quite a price difference?

Any recommendations? /forums/images/graemlins/smirk.gif

 

[andrewbodenham]

There are hundreds of different sealant available, all with differing properties. To get a specific recommendation you'll need to tell us what the sealant is doing, what the substrate is, if it needs to be painted etc.etc.
There aren't many things sold in B&Q that I would put on my boat. Despite the apparent similarity of some products there are often good reasons why 'marine' products are so designated.
Fortunately the internet has introdced real competition in the market, so we no longer have to pay the crazy prices charged by many chandlers.

 

[alan006]

If we are talking about mastic sealants then I think there is a big difference.
Often polyeurethane mastics are used for marine use. In B&Q I think you will find they sell silicon and acrylic mastics. These have different properties to the polyeurethane mastics. The motor trade does use polyeurethane mastics for body repair work and I think this is very simular to the marine sealant.
I hope this helps.

 

[yachtShoestring]

Well i used Sikaflex, found it quite messy but easy to use. -Snapped a 'trigger gun' though!

Had to stop halfway through because it got too cold. :0(

 

[Slinky Spring]

What sealant would be best for bedding a centreboard case back into a clinker dinghy?

 

[oldharry]

Builders use a polysulphide mastic very similar to Sikaflex, except about a fiver a tube. There appears to be very little difference between it and the marine grade at 2 - 3 times the price. I know someone who used it to re-bed his bilge plates on a GRP boat, and now 5 years on it seems as good as new.

I used it myself to bed new Iroko rubbing strakes on a GRP hull, several years ago, with so far 100% success.

Cant really see there is much difference above the waterline to justify the much more expensive 'marine' grade?

Or have we both made an expensive longer term mistake!

 

[Casey]

I use marine grade polysulphide for preference. I find that anything bedded in it is easier to remove than Sikaflex and it is easier and less messy to use.

 

[yachtShoestring]

The other downside with Silkaflex is that dries in white, which is fine on white paint or if your going to over paint it.

Some builders sealants dry clear I think?

 

[Casey]

The only Sikaflex I have used has been a very messy black and polysulphide has been mahogany colour. I have only seen silicone in clear.

 

[yachtShoestring]

Grrr! If I knew Silkaflex came in mahohany colour i'd have bought that instead! Oh Well! Another excuse to visit the boat and do some "work" on the old girl.

 

[Forbsie]

Don't forget the baby wipes!!

 

[ErikBenson]

I went along the 'American' way and finally sourced some 3M5200 marine in mahogany.. . . .seems to do what it says on the tube. In France it is hells all difficult to find though. I got it in good old Scotland.