Which Sealant

marine grade silicone or sikaflex seem to be the most popular for waterproofing holes drilled through the hull.

Russ said:

I have had a look at a couple of other post's and maybe it's just me, but I cant find a sealant that is preferred by our members. I want to install deck mount Berkley rod holders on the Caymans :lol: 8) just want to be sure of the sealant. Whats the general preference.

fishing Russ

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If its for plastic its OK as far as I'm concerned, used both Selleys Fish tank sealant which covers both water and plastic requirement [this is also under my fishfinder transducer], and my espri holders got acrylic paintable sealant because that was in my shed and all we ever used above the waterline on the big boats.

Was only ever fussy underwater, and there Sikaflex is streets ahead of everthing.

When you are going to use so little why not use what you can buy in a tube [the fish tank] or around the house [the paintable]

Thanks fella's Hey my bro just lost a bid on a Lowrance X51 fish finder and Garmin Geko hand held gps on ebay they sold for $314.00. We just got a second chance bid option so he may get it for his high bid of $300.00 not a bad score, it's in Victoria with a bit of luck he might live around Dromana, then my other bro can pick it up for him.

Im so excited :lol: Im like a 41 year old kid.

fishing Russ

Hi Russ,
I have a Berkley Rod holder on the front of my Swing, I drilled the holes the same size as the bolts so it was a tight fit. I then used Sikaflex(Black) as well as the bolts to secure it as well as waterproof it, and it works a treat.

I use sikaflex to seal my kayak mods.

Dan

I wouldn't put sikaflex on a seal. Poor thing. That would be cruelty to animals. 8)

How much do you really think fixings leak?

Ive added rod holders and a mounting bracket for the fish finder and have taken it out on 2 fairly wet days - I don't find much water ingress, if any at all (can pretty much soak up in 1 car sponge - suspect most comes from the centre and rear hatches). The bolts aren't a tight fit (say 4.5mm into 5.0mm) and I've used a washer under the deck. I think if you're doing things like adding a flush mount or hole to pass electronic cables through you'd need sealant. Any thoughts?

Possibly sealant good for peace of mind and to hold nuts in place - really should get some of those nylock? nuts.

Also heard mention of lexel available from bunnings on this forum.

PhilipL said:

How much do you really think fixings leak?

Possibly sealant good for peace of mind and to hold nuts in place - really should get some of those nylock? nuts

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Philip
I agree there would be be minimal intrussion of water,
If only using screws I never worry with sealant, and only seal bolt and large holes cut in the hull.

Use ordinary nuts on bolts so I can finger hold nut until firm and then apply a spanner to lock up, then smear of sealant on thread right up to nut; with a nyloc needing a spanner all the way I find the plain nut simpler, and it wont unwind after 24hrs when sealant sets on bolt thread

Great post Russ, I was just wondering how I would seal all my stuff to the kayak I'm building. Anyone know which number Sikaflex it is as I think there are a few available?
Cheers, Nick

Hi Flump. Sikaflex 241 is the go.

I recommend you go to the tutorial in the Jem site re epoxy end-pours first. A bit of extra work but well worth it IMHO

Hi all,
Just be aware, sixaflex comes in black as well. When I was goobying up my transducer, I had not noticed the colour on the tube. Not that it makes any difference to the job, unless you are after a particular cosmetic effect. I did have one fail with sikaflex, dont know what caused it, I attempted to stick a plastic tray in the hull to mount my battery, and after a couple of weeks the sikaflex turned to soft soup in part. However the transducer is as tight as a bulls ar ar ar (se in spring) :shock:

Cheers all andybear

Hi guys,

I wrote to Sikaflex and got the following response from their technical department

"Unfortunately Sika does not have a product that will adhere to polyethylene. Due to the polyethylene having a very high surface tension or static charge adhesion cannot be guaranteed even with the use of primers. "

Therefore I wouldn't rely on it for any load bearing applications

PhilipL said:

How much do you really think fixings leak?

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I thought this but discovered my rear hatch in the swing has a leak. The water seems to come through the bolt holes. It's not enough water to cause a safety issue, but if I stick things like a change of clothes in the hull, or tackle bag with spare reels, I want it to stay dry. I'll now have a battery in there as well, so don't particularly want it getting wet (if I ever manage to get the *&*&^#@ transducer working properly).

My plan is to pull the hatch collar out of the hull, pull the silicone off and re-do it with sikaflex (does it come in clear?).

cheers Peter.

Chillihilli said:

My plan is to pull the hatch collar out of the hull, pull the silicone off and re-do it with sikaflex (does it come in clear?).

cheers Peter.

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Mate if you got a tube of the Selleys Fish Tank sealant which is clear, and is compatible with the poly hull; and a tube would do the rear hatch ring applying generously.

Selleys and others also have a clear marine silicone sealant. They will do the job and have the right cosmetic outcome.