Anyone used Sika Transfloor 352 to seal a water ta

[Rohorn]

Hi,
I have keel water tanks in my Dean cat. At the factory, the tanks were made separately and lowered into the hollow keels, some places touching or with a few millimetres gap, then glassed-in with no access. I've had persistent seapage into and out of the tanks for years, but only recently, after one keel was holed in a grounding, could I see the construction inside and understand the problem.
I posted here a few weeks back on this, about foam injection, and everyone advised not to inject closed-cell polyurethane foam into this void because it will go soggy in quite a short time and be impossible to get out.
I contacted SIKA on this and asked if they had a very liquid gubbins I could pour in through a "riser" pipe which would permeate up throughout the void and set flexibly like the stuff which is used to pot electronic components. I calculate about 35 litres to seal round each keel tank.
I got a helpful guy at SIKA who proposed a 2-component polyurethane called Transfloor 352 VSL which is normally poured over decks to form a level surface on which to lay teak decking without water entrapment below.
I'll do some tests myself with small quantities to work out a modus operandi, but does anyone out there already have experience with this stuff?
Is the viscosity low enough for it to fill up around this narrow void between the tanks and the keels?, (the keel tanks are 3 metres long and 50 centimetres deep.
Does it really stick to GRP?. How clean does the GRP have to be?

Sorry to be longwinded but I bet this stuff is expensive.
Cheers....R

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[oldsaltoz]

G,day Roger,

Have you also considered the density of this stuff? will it float? will is stand up to constant moisture exposure? will it stick to a wet and unprepared surface? will it fill all the voids?

I think I would first speak to the manufacturer and find out how they would access the tanks internals.

Adding a filler has limitations, expense, more weight, and possibly more problems, like how will you remove it if/when it fails.

Some years back I was working on a Cloud Nine Cat that had what looked like ozmosis in the keel, when I ground it out I found the water tank inside the keel had been leaking fresh water.

Nothing for it but to cut the top off the tank. I did this with a router, first a small hole so I could measure the distance to the edges of the tank, then removed the whole top flish to the inside edge.

Sanded the lot and applied one layer of rovings and 3 coats of resin, with a wash down and light sanding between coats, then some flowcoat designed for freshwater tanks.

I then used the router to cut a rebait along the top of the tanks and added some new cross members for support, then glued the tops on with more epoxy; closed cell balloons at the top and inside edges and a fibre mix between them.

Also adding 4 inspection hatches for future access and cleaning. No problems after that.

I can only hope this helps you...



<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.

 

[Rohorn]

G,day Oz. Thanks for your info. Your comments are valid and much appreciated. It would be great to have access to the top surface of the tanks......I'd simply open them up and put in flexible tanks! Unfortunately on the starboard side Deans put a full scale bathroom complete with bath over the top. There's just space for me to have made a small hatch at the aft end of the tank The port side could be better, it has a wooden carpeted floor in the kitchen area over the tank, but inside the tank there are baffles, so these would have to come out anyway for a flexi tank solution, meaning four hatches.....a major carve up I'm hoping to avoid.
SIKA is a serious major chemical outfit. This stuff they are proposing is used to bed down teak decking so it's got to be adhesive and watertight. I'm not bothered about weight...the Dean is a real load carrier....but this stuff must be runny like water to flow up through this narrow void, then stick like hell to the grp surface inside, which I hope to flush out with a suitable solvent first to degrease. Then it must set without contracting and splitting or cracking, but remain flexible...like their Sikaflex. That's a lot to ask! It will be dry in there when this operation takes place. If it fails, then it stays there.
If the void is largely filled with this stuff, then the volume of trapped stinky water will be greatly reduced which can't be bad anyway.
If I possibly could, I'd go for flexible tanks, but I guess I should try this first.
Cheers......R

SIKA

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[ccscott49]

I think you can get thinners/retarder for the polyurethane type sikaflex, you can for coelans, which is also polyurethane, so it might also work for the sika .... You can try asking sikaflex themselves for a thinners, then mix it up and pour it in! I reckon it will do the job! IMHO

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