Below waterline sealant - Seacocks

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Sailfree

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Trying to get everything ready for what for me will be a new boat maintenance job.

Got nearly all the bits delivered from ASAP.

Notice the ball valves are stiff so intended to grease the ball both sides with marine grease (white). Any problems forseen - I assume there is an internal seal of some type on the ball or is it just antight fit ? I usually grease them from the outside each lift out by poking grease down on a brush but there is never a way (post installation( to grease the other side without removing the hose so thought a good greasing before installation would be good.

I intend to grind off the outside flanges as easiest way to remove the thro hull fitting as can't visualise how to use a metal bladed Fein multitool without it going for the softer GRP hul? Any advice?

Doing research it appears there are various sealants Sikaflex 275, Sikaflex291, 3m Marine Sealant 4200, PU40 (toolstation). and SABA sealant (which one?). Read some complain that Sikaflex went off in 2 mins rather than the 7min on product sheet. As I am a seacock virgin I want a good product but longer setting time would be preferred - any recommendations. For 9 fittings how many tubes?

Obviously want seacock to sit with fully accessible valve handles so they won't be screwed down tight. Read that some use oneof the above sealants on the threads, others use loctite or PTFE tape or SS pipe sealant cord. Any recommendations?

Thanks for advice - i am sure not only me will benefit from it.
 
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Angle grinder with a thickish disc and work round and round the hole as gently as you can until you can see the join between the flange and tube sections, then wiggle the fitting from the inside to crack the last bit of metal and pull through
For skin fitting flange use Sikaflex
For threads use PTFE tape or spread sika flex round male part and screw in
Hole this helps
Martin
 
Don't worry too much about getting the handles lined up, Screw the valves down onto the skin fittings orientate the whole assembly then lock in place with the back nut. No need to grease the balls. They run a composite bearing.
 
Tranona said:
Don't worry too much about getting the handles lined up, Screw the valves down onto the skin fittings orientate the whole assembly then lock in place with the back nut. No need to grease the balls. They run a composite bearing.
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I assume you are suggesting apply sealant to back of hull flange and nut. Sealant on thread scew down seacock. Orientate whole assemble and tighten backnut squeezing hull sealant? If I have understood you correctly and I use Sikaflex it all has to be done in under 2 min (as reported by one poster - when it went hard) - hence my sequence of questions.
 
I cut through the nut on the inside of the boat with a angle grinder with a metal cutting disc in it, then pushed the skin fitting through, I did not want to damage the gel coat on the outside. Tranona is correct, buy (from ASAP) back nut so that the handles finish in the correct place. I used Sikaflex below the waterline and on the threads of the seacocks. I take it you are fitting DZR hardware?

I did not experience the Sikaflex going off that quick at all.
 
Yes to sequence - you might try a dummy run first. Personally I would not use Sikaflex - and don't know any that has such a short open time. My sealant of choice is a Polysulphide such as Boatlife or Abro which is not an adhesive. Do it up hand tight , leave to cure for a day and then nip it up to compress the sealant.
 
galadriel said:
I cut through the nut on the inside of the boat with a angle grinder with a metal cutting disc in it, then pushed the skin fitting through, I did not want to damage the gel coat on the outside. Tranona is correct, buy (from ASAP) back nut so that the handles finish in the correct place. I used Sikaflex below the waterline and on the threads of the seacocks. I take it you are fitting DZR hardware?

I did not experience the Sikaflex going off that quick at all.
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Backnut is a new one!! You obviously talking about a extra locking nut, not the backnut on the thro hull fitting to nip that up tight. It would have to be a thin backnut as existing fitting often not showing much thread.

Yes replacing all thro hull Jeanneau fitting with DZR. bit concerned to read on Jeanneau 43 thread that one 10yr owner had a couple crumble on removal.
 
Sailfree said:
I assume you are suggesting apply sealant to back of hull flange and nut. Sealant on thread scew down seacock. Orientate whole assemble and tighten backnut squeezing hull sealant? If I have understood you correctly and I use Sikaflex it all has to be done in under 2 min (as reported by one poster - when it went hard) - hence my sequence of questions.
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It was Loctite 275 that went off that quickly, you wont have any problems with the Sikaflex.
 
I use a Dremel with cutting disc to remove the fitting, much easier to control than an angle grinder. Last fitting I replaced I used a locally available sealant, made by an offshoot of the Bostick empire. There's lots out there, all pretty much the same. I used a smear of the stuff to make the joints between the fitting, the valve and the hose tail.
 
smithy said:
It was Loctite 275 that went off that quickly, you wont have any problems with the Sikaflex.
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Loctite 275 is completely the wrong product for the application. It is a quicksetting thread locker. I only discovered recently, from Loctite technical, that it sets much quicker on brass than on steel and slower on stainless.
The correct product here is Loctite 572 which is a slow setting thread sealant specifically for pipework. I have a bottle in front of me with this job coming up!
http://www.loctite.co.uk/fullproduct-list-loctite-4995.htm?redDotUID=1000000IXOY
Bargain here http://www.ebay.co.uk/itm/1-BOTTLE-...DIY_Materials_Plumbing_MJ&hash=item338ac23321
 
Sailfree said:
Backnut is a new one!! You obviously talking about a extra locking nut, not the backnut on the thro hull fitting to nip that up tight. It would have to be a thin backnut as existing fitting often not showing much thread.

Yes replacing all thro hull Jeanneau fitting with DZR. bit concerned to read on Jeanneau 43 thread that one 10yr owner had a couple crumble on removal.
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Yes, I fitted the skin fittings and let the Sikaflex go off thoroughly. The following weekend I added an additional thin nut and screwed the seacock down onto it. Some threads on seacocks are not tapered so you need a back nut. Here, I looked them up for you. I cant see why they are not supplied as part of the fitting in the first place.

http://www.asap-supplies.com/marine/dzr-lock-nuts
 
It is normally recommended that ball valves should not be greased. The seats are a plastic material that could swell in contact with hydrocarbons. New valves may be stiff due to roughness of the ball but this should reduce after a little use.

The sealant you choose is simply that - a sealant. It is not an adhesive, it's just there to fill small holes and roughness that might let water in. You want it to last a long time in contact with water, so a good polymer is ideal. I have used Sikaflex 291 for the job for many years but most other marine polymers would do equally well.
 
I never used a setting sealant on any of my skin fittings. All I ever used was water pump grease. It's very thick and at or below waterline never gets warm enough to run. They have never leaked. The problem with using conventional sealants is that if when fitting the seasick or in the future you remove the sea cock, you turn the skin fitting even slightly, you break the seal and are more vulnerable to leaks.
 
smithy said:
It was Loctite 275 that went off that quickly, you wont have any problems with the Sikaflex.
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Sikaflex is good reliable stuff. The advice I got was to NOT QUITE fully tighten everything up initially, but to leave the Sikaflex and return for the final tweak ?24 hours? later. that seems to work.

it is always interesting putting the boat back in the water after a seacock change! I usually dab the seacock with tissue paper handy to check if any water is getting in..
 
I do wish people would refrain from advising "use Sikaflex". Unless you specify which of the dozens of Sikaflex products, the advice is useless!

The idea of using a sealing compound under the flange is to create a gasket, which is why many people pull down on the nut until sealant is expelled all around the flange and then leave it to set before final tightening. But it is important to prevent the fitting from turning when tightening so as to maintain the integrity of the surface contact. Better thru hull fittings have lugs inside so that you can insert a tool, a lump of wood or a chisel for example to hold it still. Some advise that once fitted, a fillet of epoxy should be created around the fitting on the inside to totally seal it and lock the holding nut in place - a bit "belt and braces", but offers great peace of mind. A backnut can then be used to lock subsequent items ( seacocks or bends) in the correct orientation. Note that, although it is a secondary effect, PTFE is not a sealant as such, it is intended to smooth the threads to ensure complete engagement. Typically, with PTFE a taper joint will engage one extra turn. Of course with such good engagement, the threads do seal.

If you're really going for the Rolls Royce fitting method, then seal the inside of the hole with epoxy before fitting... Did you know that RR used to use (tapered)cotter pins to assemble a chassis, so that the end of the pin lay flush on the outside? Strangely similar to the way the head of a keel bolt is upset to lodge in the keel. I seem to be rambling again.

Rob.
 
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