best sealant for hatches and windows?

[ChasB]

<ul type="square">Would this do the job?

<u>BoatLife Life Seal Sealant</u> Cartridge

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________[/list]

 

[pappaecho]

Be very wary of sealants with solvents which attack acrylic plastics such as Plexiglass and Perspex. They cause stress cracking, which can wreck everything.
If you have plastic windows, I would suggest that you use a known product for the job, such as Sikaflex, and ensure through their technicial data sheets that the product is Ok on acrylics.

 

[VicS]

[ QUOTE ]
Be very wary of sealants with solvents which attack acrylic plastics such as Plexiglass and Perspex

[/ QUOTE ] Polycarbonates are even more susceptible to damage (cracking) by solvents I understand.


Sikaflex 295 UV is specifically for plastic glazing and is UV resistant.

291 is the all round adhesive sealant and 292 is a high strength elastic, gap filling, adhesive

 

[ChasB]

Oh bugger. I fixed the leaky perspex on a hatch last year with some black rubberised sealant already on the boat. No cracks yet... Have to keep an eye on it.

Thanks.

This boating lark is nothing but problems.

 

[ChasB]

What about 290DC ?

What I want to do is install these hatches. There should be no contact with the perspex. The boat is fibre glass.

I'm also wondering about a suitable sealant for the existing hatches - the rubber seals are perishing.

 

[michael_w]

Depends on if you want them to open or not. /forums/images/graemlins/cool.gif

 

[ChasB]

They come in two parts. One bolts on the outside (or is it inside?) and the other part from the other side, This is where the seal is.

But you've now made me wonder...

Shucks, back to the boat again...

Damn, yes you're right. I need sealing tape. What type is suitable?

 

[pvb]

[ QUOTE ]
I need sealing tape. What type is suitable?

[/ QUOTE ]Look at the Seals Direct website.

 

[ChasB]

Thanks. Any tips?

 

[VicS]

[ QUOTE ]
What about 290DC ?

[/ QUOTE ] That is a caulking compound for timber decks.

The web page is http://www.sika.com/industry/cmi-customer_group/cmi-marine-products.htm

 

[aidancoughlan]

Tip 1: Avoid Sikaflex, or anything that sticks like hell - you need a sealant not a bonding agent, and may need to remove the hatches at some point.

I did lots of scratching around looking for a way to seal 4 windows recently. I went with Trade Selanants MarineSeal 033 - a putty which you mix before use - it remains flexible so that you can remove the windows if you wish. I got the recommendation from
http://www.btinternet.com/~inadee/windowprocedure1.pdf
MarineSeal is on
http://www.marinemastics.com/marineseal_033.htm

Other recommendations were to use a "Butyl mastic" (I did source one, but dont remember where - but it was supplied by Eagle Boat windows or CJ Internation boat windows). Apparently this seals without 'glueing'.

Another strong recommendation (I would consider next time) is to use a self-adhesive tape made from neoprene or closed-cell-foam - there are several sold for hatches/windows etc., and these too could at least be removed if you need to re-fit.

 

[ChasB]

Cheers! /forums/images/graemlins/cool.gif

Sorry about late reply. /forums/images/graemlins/blush.gif

 

[tazzle]

I reglazed my perspex side windows as part of a recent refit; I would have used Eagle Boat Windows (£470 quote) except their lead time of 4-6 weeks was a no-no. So I did it myself using clear-cast (optical quality) perspex from The Plastic Shop trimmed to shape with a jigsaw with acrylics blade, bedded in the frames with Sikaflex 295 - cheapest from Seascrew - others seem to charge £20 / £25 a tube. Cost for the perspex (delivered) and 2 tubes of 295 was about £115.

After I'd finished, one of the yard lads offered helpfully "I used to use that Sikaflex 295, but the windows always leaked after, so I use putty now. At least with putty if they leak you can take them apart again and re-do them". Ha. Thanks. Helpful.

A monsoon deluge the day after I'd finished was a decent test - not a drip.

But I must admit if I did it again I'd try the putty.

 

[30boat]

I use a technique that works beautifuly for hatches and I don't see why it shoudn't work with pesrpex windows.I always use good quality silicone sealant,never Sikaflex or similar.I now this goes against the grain for many but believe me ,it works.First I mask the area,then I apply a layer of sealant with a spatula trying to make it as level as possible,and then leave it to cure for two or more hours.Before fitting the hatch I apply another fresh ,thin layer on top of the already cured one.Imediately after I put the hatch in place and do the bolts up by hand only.I tighten them hard the next day.
The advantages are that it doesn't stick and there is always a thikness of cured sealant that acts as a gasket.If it starts leaking it can be retightened.