Epoxy Filler

Poignard

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I'm still not entirely clear what the OP wants advice on.

If it is fairing dents etc. in a bolted-on lead or iron keel, then epoxy with an easily sandable filler such as micro-balloons is what I would use.

If it is for the joint between a bollted-on keel and the hull, where flexibility is required, then I would use CT1.
 

Ceirwan

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I hadn't realised CFS would mix up a batch of filler for you. That's handy to know, thanks.
 

Birdseye

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Hi Ceirwang

Fairing in a Dehler 36 keel to hull it has always been done with Sikaflex but the finish has never been achieved even when wet and dry sanding, using all recommend grades. As to the amount of movement this is up for debate.
I was intrigued to see on my Starlight that Bowman had faired just the joint by using a rubber sealant, handled in such a way that the result tooked like a 1mm thick 20 mm wider rubber band all the way round the joint. Certainly worked well and I cannot believe that it would make any measureable difference to boat speed since it was smooth surface and had almost no cross sectional area forwards.
 

Cowie

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I was intrigued to see on my Starlight that Bowman had faired just the joint by using a rubber sealant, handled in such a way that the result tooked like a 1mm thick 20 mm wider rubber band all the way round the joint. Certainly worked well and I cannot believe that it would make any measureable difference to boat speed since it was smooth surface and had almost no cross sectional area forwards.
Sounds good its always a pain area
 

Cowie

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Why do you want it to remain flexible around the keel. Is it a Bavaria?
Absolutely not a Bavaria, am sure they are a good boat but not my weapon of choice for offshore racing, raced the match versions.
There's no flex more than is normal, the only reason for changing product. I am a believer of always look to improve
 

Cowie

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Hi Ceirwang

Fairing in a Dehler 36 keel to hull it has always been done with Sikaflex but the finish has never been achieved even when wet and dry sanding, using all recommend grades. As to the amount of movement this is up for debate.
I have been using Sikaflex and your correct the finish has never been great. This is part of the reason I was going to try something diffent after 15years , Like all boats there is a small amount of flex due to the matirals and appendages.
 

westernman

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I have been using Sikaflex and your correct the finish has never been great. This is part of the reason I was going to try something diffent after 15years , Like all boats there is a small amount of flex due to the matirals and appendages.
Wouldn't polyester be better than epoxy for this kind of application?
 

Neeves

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A bizarre thread.

If the intent is to reduce the development of a hair line crack as such a development would impact performance during racing I might have thought the impact of the crack on performance would not be measured (though the movement of the keel/hull joint might have more impact). I'm unaware, I need to get out more, of any epoxy offering flex in the application described (no matter what the filler) and CT1 or a Sika is commonly the sealer/filler of choice for hull/keel joints.

Minimising the size of the joint by applying epoxy to the hull, laying a peel membrane and then attaching the keel, setting off and then re-sealing (as described earlier) so as to minimise the joint size seems a much more fruitful route.

Jonathan
 

westernman

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Why this obsession with epoxy filler?
There are other things which are less brittle than epoxy and still stick like **** to a shovel.
 

Cowie

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Was only a question, in general thankfully boats back in the water. I plan to lift it out in 4 weeks or less. So we'll see if there's a issuse. If so the filler will be removed and be replaced by sikaflex.
There is a 7 day window before we return to the water .
 
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