Re sealing bulkhead in plastic boat^

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e-wan
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Re sealing bulkhead in plastic boat^

Post by e-wan » Sun Feb 16, 2014 7:10 pm

Hi

I need to re-seal the bulkhead between the cockpit and day hatch in a Nordkap Rm having identified a small leak just to one side of the keel line. Would slikaflex or marine silicone sealant or bathroom sealant be appropriate?

thanks

Ewan

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PhilAyr
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Re: Re sealing bulkhead in plastic boat

Post by PhilAyr » Sun Feb 16, 2014 8:04 pm

Hi Ewan,

Now I know why you were thinking of a watertight box for your battery !

Sikaflex or no nails. Definetly not bathroom sealant !

Phil

e-wan
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Re: Re sealing bulkhead in plastic boat

Post by e-wan » Sun Feb 16, 2014 8:26 pm

PhilAyr wrote:Hi Ewan,

Now I know why you were thinking of a watertight box for your battery !

Sikaflex or no nails. Definetly not bathroom sealant !

Phil
this stuff?
http://www.unibond.co.uk/en/diy-adhesiv ... proof.html

It looks cheeper than Sikaflex, anyone compared the 2 of these on a plastic kayak?

Ewan

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MikeB
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Re: Re sealing bulkhead in plastic boat

Post by MikeB » Sun Feb 16, 2014 9:25 pm

I've had good results using that, albeit in other applications than a plastic boat - I hear it works ok on them tho. However, Sikaflex is regarded as the gold standard. Use tape to get a neat edge.

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Tempest170
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Re: Re sealing bulkhead in plastic boat

Post by Tempest170 » Mon Feb 17, 2014 1:56 am

Not sure if this is available to you but I used this to reseal the bulkheads on my old plastic Tempest before I sold it. Worked wonders but is messy. According to the manuf. "Stays flexible too - allows for structural movement. Has excellent resistance to weathering and salt water." http://www.3m.com/product/information/M ... alant.html

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Krautsgalore
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Re: Re sealing bulkhead in plastic boat

Post by Krautsgalore » Mon Feb 17, 2014 7:21 am

Another alternative would be Marine Goop, as far as I know this is used by Prijon when mounting the closed cellfoam bulkheads in their HTP (plastic in plain english) boats, like on my Barracuda. They sent it to me when I asked for a sealant/adhesive to carry out (emergency) repairs.

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asmar
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Re: Re sealing bulkhead in plastic boat

Post by asmar » Mon Feb 17, 2014 8:12 am

Sikaflex will work fine. I used the same in a Valley Etain which has same bulkhead like the Nordkapp (not foam) and after a year of really hard use with hundred of rescues is still dry.

CharlieS
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Re: Re sealing bulkhead in plastic boat

Post by CharlieS » Mon Feb 17, 2014 4:05 pm

I rang Valley and they sold me a tube of something when I did the same job on mine.
It might have been possible to get similar stuff cheaper, but it did the job very well.

Their advice was to clean the surfaces, dry them, pass abead of glue around, and then run round the join with a finger (inside a surgical glove). (Sorry if that's obvious - it wasn't to me at the time)

Charlie

john.ruston
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Re: Re sealing bulkhead in plastic boat

Post by john.ruston » Mon Feb 17, 2014 7:49 pm

Sikaflex make a lot of things. I would recc.for sealing your bulkhead Sikaflex 211. A 600 ml.cartridge will set you back a bit over ten quid. Skins in about an hour in cool place. Fully cured around 24 hrs. I wouldn't trust it not to leave a sticky black stain on you bags for a few days but will set like vulcanised rubber after week. How hard does it set? Well it is hard to make a thumbnail impression after a month. preclean surface with with MEK or Acetone, light abrasion with 400 paper is good. Unless you buy a very fancy gun it's OK to apply with spatula (best is a model makers or sculptor's tool).
This stuff will also glue foam to PE quite well. A ethafoam strip glued into an open V on a PE cockpit coaming just got ripped out after 5 years in situ. Quite good.
Shelf life unopened is said to be a year so perhaps you want to line up several jobs and deal with them in one go. I have an open cartridge which I am now going to give to a club colleague. Can you let us know how you get on?

e-wan
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Re: Re sealing bulkhead in plastic boat

Post by e-wan » Tue Feb 18, 2014 11:35 pm

i contacted valley to see what they said and got the following response.

"You can reseal your bulkheads using PU sealant..

1. Clean the are with acetone and allow to air dry.
2. Flame treat the area using a blue flame. DO NOT OVERHEAT! only pass the flame over the area, moving quickly. The area should not become glossy or overly hot!!
3. Apply PU sealant and then smooth with a wet finger.
4. Allow to dry overnight or longer.

You should than have a dry bulkhead."

I'm a bit wary about this approach as there is some old sealant from a previous repair attempt that i have not been able to completely remove and therefore I would be heating this up as well.

Ewan

e-wan
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Re: Re sealing bulkhead in plastic boat

Post by e-wan » Tue Feb 18, 2014 11:46 pm

If i go with sikaflex 211 might better adhesion be gained by abrading with course sandpaper?

Chris Bolton
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Re: Re sealing bulkhead in plastic boat

Post by Chris Bolton » Wed Feb 19, 2014 7:54 am

Abrading the surface with sandpaper is likely to help with any sealant. If you are using Sikaflex, I would use 291 or 291i, which are marine grade, rather than 211 which is not. I'm not saying 211 won't work, but it may not last as well, and if you're going to the trouble of doing the job you may as well use the best material. 291 is about the same price per cartridge, and although the cartridge may only be half the size that won't matter, as you won't need a whole cartridge and it doesn't have a long shelf life once open.

Teaman
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Re: Re sealing bulkhead in plastic boat

Post by Teaman » Wed Feb 19, 2014 7:13 pm

http://www.ebay.co.uk/itm/HA6-Clear-RTV ... 53f43d53d7
Is this stuff any good? it's a lot less money than silkaflex.
I only have a rotamod kayak.(old RTM YSAK?) with a loose front bulk head and a weeping rear "fnarr"

john.ruston
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Re: Re sealing bulkhead in plastic boat

Post by john.ruston » Wed Feb 19, 2014 7:38 pm

To Chris Bolton and ewan: Thanks for the opinions. Next time I'll go with your recc. for Sikaflex grade. Always good to get second opinions ! Mind you my old stuff is actually working. The tip about flaming is a good one but needs a bit of bottle - and bulkheads are a bit awkward to get at. Cheers, John

Teaman
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Re: Re sealing bulkhead in plastic boat

Post by Teaman » Wed Feb 19, 2014 8:11 pm

john.ruston wrote:To Chris Bolton and ewan: Thanks for the opinions. Next time I'll go with your recc. for Sikaflex grade. Always good to get second opinions ! Mind you my old stuff is actually working. The tip about flaming is a good one but needs a bit of bottle - and bulkheads are a bit awkward to get at. Cheers, John
wouldn't meths and a lighter work? or make it too interesting

flat earth sails
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Re: Re sealing bulkhead in plastic boat

Post by flat earth sails » Wed Feb 19, 2014 8:43 pm

Much to Lyns annoyance I keep all the workshop sealants in the fridge or freezer at home, including contact cement for folder reapers and the sica goes in the freezer it extends the open tube life heaps you need to let it thore out before you sing.

e-wan
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Re: Re sealing bulkhead in plastic boat

Post by e-wan » Wed Feb 19, 2014 10:19 pm

i've been reading the spec sheet for Sikaflex 291 and it states that the best join is achieved if the sealant is applied with both edges at the mid range of likely movement rather than compressed together.

Think i will try taking the boat inside and warming with a hairdryer or heat gun as a slightly safer option than using a blowtorch in the small space down the back of the seat.

Ewan

NigeC
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Re: Re sealing bulkhead in plastic boat

Post by NigeC » Thu Feb 20, 2014 12:46 am

Guys,

I've been in engineering for longer than I can remember so do know a little about sealants.
THE best you will get is Tiger Seal, it's a PU base and it will do this job with ease and be permanent, applied with a caulking gun.
Tiger Seal

If you want the same PU sealant in a pressurised container (easier to apply in confined spaces) use Normfest Silon Black.
Silon Black

Regards,
Nige

Colin C
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Re: Re sealing bulkhead in plastic boat

Post by Colin C » Thu Feb 20, 2014 8:30 pm

e-wan wrote:Think I will try taking the boat inside and warming with a hairdryer or heat gun as a slightly safer option than using a blowtorch in the small space down the back of the seat.
I may well be wrong but I dont think that the intention is to heat the area but to change the balance of positive and negative ions. I seem to remember that the advice was to do this on PU canoes to allow stuff to stick to it. Someone else may well come along and confirm this or tell me my memory is fading.

Colin

Ken_T
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Re: Re sealing bulkhead in plastic boat

Post by Ken_T » Fri Feb 21, 2014 8:51 am

Hi,
Colin is correct. The intention of flaming is not to heat the area, after the process the plastic should just be a little warm, if it is hot you are being to enthusiastic. The idea is to partially oxidise the area to increase the surface energy, the problem with polyethelene is it has very low surface energy. Roughing the are to incease the surface are is good too, but do the flaming after roughing as flaming only treats the first few molecules which are easily removed with sand paper. We may have a chemist on this forum who can explain things better, I am an engineer.
Ken

john.ruston
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Re: Re sealing bulkhead in plastic boat

Post by john.ruston » Fri Feb 21, 2014 10:40 pm

Above.To Colin and Ken_T. Surface energy; YES. I heard this from a rep at Advanced Adhesives of Newcastle. Speaking of their new product PP3000 (a 2 part methacrylate mix) intended for PE and other "low energy" materials he told me that they use a wetting agent to overcome some issues caused by these wrong ions. I bought some of the adhesive and I'm finding it does work very well. Use cold.
The web address is http://www.advancedadhesives.co.uk .
Has anyone tried the West G/Flex 650 Epoxy repair kit (another 2 part) which makers say is good on a wide range of materials including PE specifically canoes and kayaks (Force Four current catalogue) ?

e-wan
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Re: Re sealing bulkhead in plastic boat^

Post by e-wan » Mon Feb 24, 2014 11:10 pm

I have now identified that the leak which I need to fix is between the black lines on the photo below
[img]http://img.tapatalk.com/d/14/02/25/buzy6yba.jpg[/img]

however there are some cracked sealant from a previous repair already there.
[img]http://img.tapatalk.com/d/14/02/25/6ave6ypa.jpg[/img]

I should be able to pick some but not all of the old sealant away so might try and build up a thick layer of sealant over the top.

Ewan

john.ruston
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Re: Re sealing bulkhead in plastic boat^

Post by john.ruston » Tue Feb 25, 2014 9:54 am

Nice pics. Something really has given up the ghost there ! Hardened and shrunk?? Leak tracing - there used to be a wee gadget for searching out leaks in car body work ... an ultrasonic beeper which the user put on one side of a panel and a "mine detector" thing to scan the other side for a signal. It worked really well. Good luck with the Goo.

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