Sealing through-bolt holes?

What kind, options, etc.

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Tony Hain
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Location: Queensland Australia

Sealing through-bolt holes?

Postby Tony Hain » Sat Aug 08, 2015 1:51 pm

What do most people do to seal through-bolt holes (eg prop strut, rudder etc)?
1. Do you oversize drill the hole. Fill it with epoxy and then drill it to correct size ensuring the hole walls are sealed with epoxy.
or
2. Just rely on a sealant eg 3M to prevent water seepage into the hole?
Thanks for your replies.
Tony Hain
"Never under-estimate the bounds of human stupidity" (Robert Heinlein)
and on a more optimistic note "nor the capacity for human brilliance"

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Bill Edmundson
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Re: Sealing through-bolt holes?

Postby Bill Edmundson » Sat Aug 08, 2015 2:35 pm

Tony

I'm not good to reply to this. I epoxied the holes and used 3M sealant. I still have leakage. Be very generous with the sealant!

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

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Roberta
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Re: Sealing through-bolt holes?

Postby Roberta » Sat Aug 08, 2015 4:31 pm

I also epoxied the holes to seal the wood. Then I used copious amounts of 3m 4200. It was a mess, but I have no leaks at the shaft log, intake, fin, or rudder port. I literally filled the bolt holes, pushed the bolts through, and added more. It oozed everywhere, but is easy to clean up when soft.

Roberta :D
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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kens
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Re: Sealing through-bolt holes?

Postby kens » Sat Aug 08, 2015 5:11 pm

Drill the holes a little over size, then encapsulate them very well, maybe even ream the holes if the epoxy gets too thick.
Then , take your part (strut, rudder port, etc.) and apply mold release. Mix a batch of epoxy filler and mold the part to the boat, bolt it down slightly. let this cure.
Remove the part and clean up rough edges, then seal it back down for final installation.
you will now need only a modest amount of sealer, and you have a well formed gasket seal.

I have no leaks in any of my running gear.
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

Ozzieboat
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Re: Sealing through-bolt holes?

Postby Ozzieboat » Mon Aug 24, 2015 8:32 pm

Tony
I coated the holes in epoxy, then when cured assembled the strut and all other through hull fittings with generous amounts of sealant. No leaks. I used Sikaflex Pro sealant, looking for one that is more sealant than adhesive. Lucky I did as I had to remove the strut some time after the build was completed and even without bolts it still didn't want to come off. A bit of heat broke the seal. For any screws that were used on deck fittings I dipped the threads in varnish before screwing them in.
ozzieboat

Tony Hain
Posts: 308
Joined: Fri Aug 26, 2011 3:01 pm
Location: Queensland Australia

Re: Sealing through-bolt holes?

Postby Tony Hain » Mon Aug 24, 2015 11:07 pm

Thanks everyone for answering my question. I will slightly oversize the holes and epoxy the seal with plenty of sealant.
Tony Hain
"Never under-estimate the bounds of human stupidity" (Robert Heinlein)
and on a more optimistic note "nor the capacity for human brilliance"


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