Janet and Joel,

The main thing for success is making sure there is sufficient counter sink
relief for a gasket of bed-it around the fastener and then tighten the
hardware down gradually so the "tape" can flow, ideally over the course of
several days or weeks. For bolts make sure the bolt doesn't spin when
tightening - only the nut should be allowed to spin. For self tapping
screws (e.g. on the chain plate covers) this isn't an option and the seal
definitely isn't as good - the key is to not spin it any more than
absolutely required.

For fasteners I make a little "snake" of tape (roll it in your fingers like
when making pasta by hand) and then wrap that around the fastener head
before I insert it in the hardware. Then I also put another roll around the
fastener after inserting it through the hardware at the bottom of the
hardware surface. Also put tape flat on the bottom of the hardware as
continuously as possible but try not to build up to much thickness (not
more than a layer or two of tape). Then install the hardware and all
fasteners at once with the fasteners already sticking all the way out of
the part you are installing.  Make sure you don't let the fastener turn /
only turn the nut when tightening!

For the chain plates, likewise, make little rolls and jam them down around
the chaine plates in the gap with the deck as far as you can with a
little screwdriver, etc. Then keep building it up until you have a bead of
bed-it that is maybe 3-5 mm or 1/4 inch proud of the deck around the chain
plate.  After installing the hardware and tightening you can trim off the
excess easily with a sharp utility or exacto knife and roll it away.
Cutting first is important since otherwise you can end up pulling the seal
right back out again.  When you tighten again the next day or next week or
next season a little more will squeeze out and need to be trimmed again. A
bit more effort than 3M products for sure but well worth it in the end.

As others suggested, a counter sink bit is perfect for the holes that
screws and bolts go in.  Don't be shy - you want a nice 3/16-1/4" counter
sink here as long as there is sufficient material. If there isn't and or
you are into the core, then the best thing is to drill out a much larger
(e.g. 1/2 inch) hole through the top skin and core (don't worry if you go
all the way through) - put some unthickened epoxy in and spread it around
the surfaces of the core, then fill the hole with thickened epoxy. After
the epoxy cures, drill the new hole for the fastener and counter sink the
top of it before installing the hardware.

I suggest using a utility knife and or isolating multi-tool to cut a bevel
relief around the chain plates. Also, as Jack said, correct any rotten core
first if you can. Of course, simply resealing it will be an option for a
little while but likely will not hold up as long and the core will need to
be replaced eventually if it is rotten. I chose to put thickened epoxy
around the chain plate instead of core material and replaced core with 1/2
inch G10 fiberglass boards where the tabs for the bulkheads come through
when I did my refit in 2020 - see photos here:
https://photos.app.goo.gl/8W4AdgmKqKxARvsY7  Unfortunately, I didn't get
any photos of the actual process of sealing and installing the plates
around the chain plates. Sorry!

Nathan
S/V Wisper
Portland ME
1981 C&C 34 CB

On Tue, Nov 11, 2025, 02:31 Joel Delamirande via CnC-List <
[email protected]> wrote:

> Any tricks with butyl tape I didn’t use bed it
> I sealed the screw hole with epoxy and butyl tape and still leaked
> I put 4200 instead it stop for a bit than it restarted again
> Does have a video how to do this properly
>
> Joel Delamirande
> *www.jdroofing.ca <http://www.jdroofing.ca>*
>
>
>
> On Mon, Nov 10, 2025 at 11:02 PM John Christopher via CnC-List <
> [email protected]> wrote:
>
>> You can use a chamfer drill bit.
>>
>> /John
>>
>> On Nov 10, 2025, at 10:15 PM, Janet Schilling via CnC-List <
>> [email protected]> wrote:
>>
>> Great advice gentlemen! Thank you. I ordered some Bed-it. To bevel under
>> the chain plates what did you use? Some kind of wood rasp or file? Can I
>> use one of my countersinks I use on wood to countersink the bolt or screw
>> holes on the deck to rebed them with a little of the butyl tape?
>>
>> Thanks again.
>> Janet
>>
>> Sent from my iPhone
>>
>> On Nov 10, 2025, at 9:45 PM, John Read via CnC-List <
>> [email protected]> wrote:
>>
>> 
>> Janet.  Agree with Nathan's process. In my case tried various sealers
>> without success mostly because would not stick to stainless chainplates.
>> Over 10 years ago I pulled the chainplates, cleaned them, ensured no
>> degraded balsa in deck or plywood, beveled the deck top side,  installed
>> chainplates, put in butyl so filled bevel and proud of deck, installed trim
>> on top of butyl.   No leaks since
>> John Read
>> Legacy Ill 1982 C&C 34
>> Noank, CT
>>
>> On Mon, Nov 10, 2025, 9:22 PM Nathan Post via CnC-List <
>> [email protected]> wrote:
>>
>>> Janet,
>>>
>>> I used bed-it butyl tape https://bed-it.com/ on my chain plates when I
>>> did a refit in 2000. So far no leaks! If your boat is set up like my 1981
>>> C&C 34 it is best if you can remove the stays entirely so the plate comes
>>> all the way up. Should be able to use a halyard to the toe rail as a
>>> temporary stay. I cut a quarter inch angle into the fiberglass around the
>>> chain plate to ensure that the bed-it would have room to make a seal.  Put
>>> a nice rolled bead in there and then put tape on the bottom of the plate
>>> before screwing it back down.
>>>
>>> I generally use bed-it for everything above the waterline by the way.
>>> Seems to work pretty well even around self tapping screws and is much
>>> easier to both use and to replace than 3M products or other sealants.  Does
>>> take a bit more time to seep out so you have to tighten screws
>>> progressively and cut away the excess a few times over successive weeks.
>>>
>>> Nathan
>>>
>>>
>>>
>>> ~~~
>>> Nathan Post
>>> +1 (781)  605-8671
>>>
>>>
>>> On Mon, Nov 10, 2025 at 8:58 PM Janet Schilling via CnC-List <
>>> [email protected]> wrote:
>>>
>>>> What kind of sealant/caulk is recommended? It was suggested that the
>>>> horizontal deck plate could be unscrewed and lifted enough off the deck to
>>>> add sealant of some kind underneath, then screw back down.
>>>> Thanks.
>>>> BTW, we removed the old caulk around all the port lites and redid with
>>>> Dow 795 and tightened all the screws. It was a success! Not perfect, but no
>>>> leaks.
>>>> Janet
>>>>
>>>> Sent from my iPhone
>>>> November is the time of the year when my Internet bills come in.  It's
>>>> also the time when you can show your appreciation of this list and the C&C
>>>> Photo Album.  Please help by making a small contribution using PayPal at:
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>>>> greatly appreciated.
>>>>
>>> November is the time of the year when my Internet bills come in.  It's
>>> also the time when you can show your appreciation of this list and the C&C
>>> Photo Album.  Please help by making a small contribution using PayPal at:
>>> https://www.paypal.com/paypalme/stumurray  All contributions are
>>> greatly appreciated.
>>
>> November is the time of the year when my Internet bills come in.  It's
>> also the time when you can show your appreciation of this list and the C&C
>> Photo Album.  Please help by making a small contribution using PayPal at:
>> https://www.paypal.com/paypalme/stumurray  All contributions are greatly
>> appreciated.
>>
>> November is the time of the year when my Internet bills come in.  It's
>> also the time when you can show your appreciation of this list and the C&C
>> Photo Album.  Please help by making a small contribution using PayPal at:
>> https://www.paypal.com/paypalme/stumurray  All contributions are greatly
>> appreciated.
>>
>> November is the time of the year when my Internet bills come in.  It's
>> also the time when you can show your appreciation of this list and the C&C
>> Photo Album.  Please help by making a small contribution using PayPal at:
>> https://www.paypal.com/paypalme/stumurray  All contributions are greatly
>> appreciated.
>
> November is the time of the year when my Internet bills come in.  It's
> also the time when you can show your appreciation of this list and the C&C
> Photo Album.  Please help by making a small contribution using PayPal at:
> https://www.paypal.com/paypalme/stumurray  All contributions are greatly
> appreciated.
November is the time of the year when my Internet bills come in.  It's also the 
time when you can show your appreciation of this list and the C&C Photo Album.  
Please help by making a small contribution using PayPal at:  
https://www.paypal.com/paypalme/stumurray  All contributions are greatly 
appreciated.

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