Stus-List Re: Bottom paint gallons

[Peter McMinn via CnC-List]

Thanks, Dave. That’s reassuring😅

On Thu, Aug 26, 2021 at 8:01 PM Dave Godwin via CnC-List <
cnc-list@cnc-list.com> wrote:

> Pete,
>
> Two gallons should be more than enough.
>
> I’ve always purchased two gallons and had nearly half to a third of a
> gallon left over. In non-racing application with a foam roller it has been
> sufficient. And this is on the full keel version.
>
> Best,
> Dave Godwin
> 1982 C&C 37 - Ronin
> 1998 Mast & Mallet Thomas Point 34 - Katana
> Reedville, VA
>
>
> On Aug 26, 2021, at 6:41 PM, Peter McMinn via CnC-List <
> cnc-list@cnc-list.com> wrote:
>
> Fist time bottom painting my 37. I bought the paint but now thinking 2
> gallons isn’t enough for two coats. Pettit Trinidad (hard) label says
> theoretical coverage is 450 ft²/gallon.
>
> The 37 is 28’ at the waterline.
>
> 2 gallons more than enough or not enough?
> Thanks to all of the subscribers that contributed to the list to help with
> the costs involved.  If you want to show your support to the list - use
> PayPal to send contribution --   https://www.paypal.me/stumurray  Thanks
> - Stu
>
>
> Thanks to all of the subscribers that contributed to the list to help with
> the costs involved.  If you want to show your support to the list - use
> PayPal to send contribution --   https://www.paypal.me/stumurray  Thanks
> - Stu

-- 
Peter McMinn

 _/)
Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu

Stus-List Re: Bottom paint gallons

[Tom Buscaglia via CnC-List]

Same here…

Tom Buscaglia
S/V Alera 
1990 C&C 37+/40
Vashon WA
P 206.463.9200
C 305.409.3660


> On Aug 26, 2021, at 8:01 PM, Dave Godwin via CnC-List  
> wrote:
> 
> Pete,
> 
> Two gallons should be more than enough.
> 
> I’ve always purchased two gallons and had nearly half to a third of a gallon 
> left over. In non-racing application with a foam roller it has been 
> sufficient. And this is on the full keel version.
> 
> Best,
> Dave Godwin
> 1982 C&C 37 - Ronin
> 1998 Mast & Mallet Thomas Point 34 - Katana
> Reedville, VA
> 
> 
>> On Aug 26, 2021, at 6:41 PM, Peter McMinn via CnC-List 
>>  wrote:
>> 
>> Fist time bottom painting my 37. I bought the paint but now thinking 2 
>> gallons isn’t enough for two coats. Pettit Trinidad (hard) label says 
>> theoretical coverage is 450 ft²/gallon.
>> 
>> The 37 is 28’ at the waterline.
>> 
>> 2 gallons more than enough or not enough?
>> 
>> Thanks to all of the subscribers that contributed to the list to help with 
>> the costs involved.  If you want to show your support to the list - use 
>> PayPal to send contribution --   https://www.paypal.me/stumurray  Thanks - 
>> Stu
> 
> Thanks to all of the subscribers that contributed to the list to help with 
> the costs involved.  If you want to show your support to the list - use 
> PayPal to send contribution --   https://www.paypal.me/stumurray  Thanks - Stu
Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu

Stus-List Re: Bottom paint gallons

[Dave Godwin via CnC-List]

Pete,

Two gallons should be more than enough.

I’ve always purchased two gallons and had nearly half to a third of a gallon 
left over. In non-racing application with a foam roller it has been sufficient. 
And this is on the full keel version.

Best,
Dave Godwin
1982 C&C 37 - Ronin
1998 Mast & Mallet Thomas Point 34 - Katana
Reedville, VA


> On Aug 26, 2021, at 6:41 PM, Peter McMinn via CnC-List 
>  wrote:
> 
> Fist time bottom painting my 37. I bought the paint but now thinking 2 
> gallons isn’t enough for two coats. Pettit Trinidad (hard) label says 
> theoretical coverage is 450 ft²/gallon.
> 
> The 37 is 28’ at the waterline.
> 
> 2 gallons more than enough or not enough?
> 
> Thanks to all of the subscribers that contributed to the list to help with 
> the costs involved.  If you want to show your support to the list - use 
> PayPal to send contribution --   https://www.paypal.me/stumurray  Thanks - Stu

Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu

Stus-List Re: Bottom paint gallons

[CHARLES SCHEAFFER via CnC-List]

Two gallons shoud be right for the 37. 
My 34R is 35.5 long and has a 30 ft waterline and uses about 80% of a gallon 
per coat.  75% in cooler weather.  90% in hot weather.

Chuck Scheaffer Resolute 1989 C&C 34R

> On 08/26/2021 7:11 PM Bob Tallman via CnC-List  
> wrote:
>  
>  
> Might not be sufficient.  My 121 (40') took one gallon to put on a thin 
> coat, planning for just one season.
>  
> I think you will need a 3rd.  I would buy it and see.  Better to have it 
> than not.  You can return it.
>  
> Also, will you be hauling each season, multi season requirement?
> 
> Bob Tallman
> rltall...@verizon.net
> Cell: 631.387.6748
> 
> On Aug 26, 2021 6:41 PM, Peter McMinn via CnC-List 
>  wrote:
> 
> > > 
> > Fist time bottom painting my 37. I bought the paint but now 
> > thinking 2 gallons isn’t enough for two coats. Pettit Trinidad (hard) label 
> > says theoretical coverage is 450 ft²/gallon.
> > 
> > The 37 is 28’ at the waterline.
> > 
> > 2 gallons more than enough or not enough?
> > 
> > > 
Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu

Stus-List Re: Bottom paint gallons

[Marek Dziedzic via CnC-List]

Pettit has a bottom paint calculator (here: Pettit | Quantity Calculator 
(pettitpaint.com)).

When you enter L=37 and beam=12 (I am guessing), they claim that you need 1.2 
gallon. But if you use the 450 sq ft/gallon, they claim you would be fine with 
0.8 gal.

Defender has its own: https://www.defender.com/html/bottom_paint_calc.html

Based on my own experience (I used 2 quarts on a 27 ft boat with 10 ft beam), 
the way they calculate is a bit tight. You might be able to make it under 1 gal 
for a single coat, but it will be tight. It might almost be a question how hot 
it is when you paint. A spare quart might be in order.

Marek

1994 C270 ”Legato”
Ottawa, ON



From: Peter McMinn via CnC-List
Sent: Thursday, August 26, 2021 6:41 PM
To: cnc-list@cnc-list.com
Cc: petemcm...@gmail.com
Subject: Stus-List Bottom paint gallons


Fist time bottom painting my 37. I bought the paint but now thinking 2 gallons 
isn’t enough for two coats. Pettit Trinidad (hard) label says theoretical 
coverage is 450 ft²/gallon.

The 37 is 28’ at the waterline.

2 gallons more than enough or not enough?
Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu

Stus-List Re: Bottom paint gallons

[Bob Tallman via CnC-List]

Might not be sufficient.  My 121 (40') took one gallon to put on a thin coat, planning for just one season.I think you will need a 3rd.  I would buy it and see.  Better to have it than not.  You can return it.Also, will you be hauling each season, multi season requirement?Bob Tallmanrltall...@verizon.netCell: 631.387.6748On Aug 26, 2021 6:41 PM, Peter McMinn via CnC-List  wrote:Fist time bottom painting my 37. I bought the paint but now thinking 2 gallons isn’t enough for two coats. Pettit Trinidad (hard) label says theoretical coverage is 450 ft²/gallon. The 37 is 28’ at the waterline.2 gallons more than enough or not enough?

Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu

Stus-List Re: Bottom paint gallons

[Bill Coleman via CnC-List]

I would say it should be plenty. The first coat will take more than the
second

Bill

On Thu, Aug 26, 2021, 6:41 PM Peter McMinn via CnC-List <
cnc-list@cnc-list.com> wrote:

> Fist time bottom painting my 37. I bought the paint but now thinking 2
> gallons isn’t enough for two coats. Pettit Trinidad (hard) label says
> theoretical coverage is 450 ft²/gallon.
>
> The 37 is 28’ at the waterline.
>
> 2 gallons more than enough or not enough?
> Thanks to all of the subscribers that contributed to the list to help with
> the costs involved.  If you want to show your support to the list - use
> PayPal to send contribution --   https://www.paypal.me/stumurray  Thanks
> - Stu
Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu

Stus-List Bottom paint gallons

[Peter McMinn via CnC-List]

Fist time bottom painting my 37. I bought the paint but now thinking 2 gallons 
isn’t enough for two coats. Pettit Trinidad (hard) label says theoretical 
coverage is 450 ft²/gallon. 

The 37 is 28’ at the waterline.

2 gallons more than enough or not enough?
Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu

Stus-List Re: Replacing Cabin/Deck Balsa Core

[CHARLES SCHEAFFER via CnC-List]

Great pictures.
I'm finishing a similar project.  I too chose Balsa for core, because of it's 
superior bonding strength to resin.  The grain of the wood literally wicks up 
the resin so the bond becomes ten times stronger than foam board.  I took extra 
steps to seal the core and reinforced the deck with G10 under the clutches and 
winches; overbored every fastener hole and redrilled.  I also countersunk every 
penetration including the chainplate hole, so caulk forms a gasket or o-ring 
for each penetration.

You project has a very professional finish.  Thanks for taking the extra time 
to photogragh the work and for organizing it and sharing.

Chuck S


> On 08/26/2021 8:27 AM Nathan Post via CnC-List  
> wrote:
> 
> 
> Agreed with others on not using expanding foam for this.  I personally 
> used balsa wood to replace the rotted core as it has the best strength to 
> weight ratio and is pretty easy to work with.  There are structural foams 
> that can be used but most do not have quite as good mechanical properties as 
> balsa wood.  My other tip is that where you know you will be putting a hole 
> through it can be good to go with solid laminate in that area instead so you 
> don't have to carve out the balsa and fill with epoxy later.  Especially at 
> structural points (bulkhead bolts for example).  When I did this on my C&C 
> 34, I used 1/2" G10 plate.  Roughen both sides and bond in place of the 
> balsa.  Complete the lamination and painting and then cut or drill for the 
> fitting.  Adds a little weight and a lot of strength.
> 
> Some photos showing what I did to repair the core in my deck in 2020 are 
> here: https://photos.app.goo.gl/8W4AdgmKqKxARvsY7  These show the G10 plates 
> used where penetrations are made later for the bulkhead attachments and the 
> fan in the head.  I didn't do that around the chain plate and instead just 
> filled an area with thickened epoxy but on hindsight using G10 there too 
> would have been better and will avoid the problem happening again in the 
> future.
> 
> Note, in some cases, I rebuilt the deck laminate from scratch and in 
> others I laminated the original back in place and then created a tapered 
> grove and laminated the two parts of the top deck back together for strength 
> using narrow strips of fiberglass. I used weights to hold the G10 in place 
> while bonding it with thickened epoxy to the lower skin but then used a 
> vacuum system when doing the larger lamination areas after doing a wet layup.
> 
> Nathan
> 
> ~~~
> Nathan Post
> +1 (781)  605-8671
> 
> 
> On Wed, Aug 25, 2021 at 5:43 PM Andy Frame via CnC-List 
> mailto:cnc-list@cnc-list.com > wrote:
> 
> > > That pretty much settles this discussion!
> > 
> > Thanks to everyone for their thoughts.
> > 
> > 
> > On 8/25/2021 2:26 PM, Della Barba, Joe via CnC-List wrote:
> > > Expanding foam has no structural strength at all and is easily
> > > compromised by water. I would not even think of it for this use.
> > >
> > > Joe
> > >
> > > Coquina
> > >
> > > *From:* SV Mary Me via CnC-List  > mailto:cnc-list@cnc-list.com >
> > > *Sent:* Wednesday, August 25, 2021 12:19 PM
> > > *To:* cnc-list@cnc-list.com mailto:cnc-list@cnc-list.com
> > > *Cc:* SV Mary Me mailto:svmar...@pm.me >
> > > *Subject:* [EXTERNAL] Stus-List Replacing Cabin/Deck Balsa Core
> > >
> > > I've got some soft spots returning on the deck at the base of the 
> > mast,
> > > that a previous owner had made an attempt to shore up. According 
> > to the
> > > owners manual, the cabin-ceiling/deck sandwich is balsa cored, so 
> > I'm
> > > working with the assumption that this has rotted away.
> > >
> > > The local supply store has a plastic honeycomb panel to use as a 
> > base
> > > material for fibreglass work that could use to fill the space, 
> > once the
> > > rotted material is dug out. I also thought about using expanding,
> > > self-hardening construction foam that could be shaved and shaped, 
> > then
> > > 'glassed over.
> > >
> > > Has anyone used, or have any thoughts on using the expanding foam?
> > >
> > > s/v Mary Me
> > >
> > > 1975 C&C 24
> > >
> > > Labelle, Florida USA
> > >
> > 
> > --
> > s/v MaryMe
> > 1975 C&C 24
> > Labelle, FL USA
> > Thanks to all of the subscribers that contributed to the list to 
> > help with the costs involved.  If you want to show your support to the list 
> > - use PayPal to send contribution --   https://www.paypal.me/stumurray  
> > Thanks - Stu
> > 
> > > Thanks to all of the subscribers that contributed to the list to 
> > help with the costs involved. If you want to show your support to the list 
> > - use PayPal to se

Stus-List Re: Replacing Cabin/Deck Balsa Core

[Joel Aronson via CnC-List]

Love the box fan on the forward hatch too!

On Thu, Aug 26, 2021 at 10:47 AM Richard Bush via CnC-List <
cnc-list@cnc-list.com> wrote:

>
> Nathan, I second Bill's post, that is awesome work!
>
> Richard
> s/v Bushmark4: 1983 C&C 37 CB: Ohio River, Mile 584.4;
>
> Richard N. Bush Law Offices
> 2950 Breckenridge Lane, Suite Nine
> Louisville, Kentucky 40220-1462
> 502-584-7255
>
>
> -Original Message-
> From: Nathan Post via CnC-List 
> To: Stus-List 
> Cc: Nathan Post 
> Sent: Thu, Aug 26, 2021 10:24 am
> Subject: Stus-List Re: Replacing Cabin/Deck Balsa Core
>
> I didn't keep track of hours.  The deck repair was a weeks or two of
> evenings and weekends. Then another two weeks of sanding, prepping and
> painting and more time for replacing the windows and reinstalling all the
> hardware and life lines.  Including rewiring the mast, adding radar,
> designing, building and installing a new bow roller assembly, etc. the
> whole refit took me about 4 months.
>
> On Thu, Aug 26, 2021, 10:12 Bill Coleman via CnC-List <
> cnc-list@cnc-list.com> wrote:
>
> Wow, looks like you did a great job, looks nice.
> How long did it take you to do that whole operation?
>
>
> Bill Coleman
> Entrada, Erie, PA
>
>
>
> *From:* Nathan Post via CnC-List [mailto:cnc-list@cnc-list.com]
> *Sent:* Thursday, August 26, 2021 8:27 AM
> *To:* Stus-List
> *Cc:* Andy Frame; Nathan Post
> *Subject:* Stus-List Re: Replacing Cabin/Deck Balsa Core
>
> Agreed with others on not using expanding foam for this.  I personally
> used balsa wood to replace the rotted core as it has the best strength to
> weight ratio and is pretty easy to work with.  There are structural foams
> that can be used but most do not have quite as good mechanical properties
> as balsa wood.  My other tip is that where you know you will be putting a
> hole through it can be good to go with solid laminate in that area instead
> so you don't have to carve out the balsa and fill with epoxy later.
> Especially at structural points (bulkhead bolts for example).  When I did
> this on my C&C 34, I used 1/2" G10 plate.  Roughen both sides and bond in
> place of the balsa.  Complete the lamination and painting and then cut or
> drill for the fitting.  Adds a little weight and a lot of strength.
>
> Some photos showing what I did to repair the core in my deck in 2020 are
> here: https://photos.app.goo.gl/8W4AdgmKqKxARvsY7  These show the G10
> plates used where penetrations are made later for the bulkhead attachments
> and the fan in the head.  I didn't do that around the chain plate and
> instead just filled an area with thickened epoxy but on hindsight using G10
> there too would have been better and will avoid the problem happening again
> in the future.
>
> Note, in some cases, I rebuilt the deck laminate from scratch and in
> others I laminated the original back in place and then created a
> tapered grove and laminated the two parts of the top deck back together for
> strength using narrow strips of fiberglass. I used weights to hold the G10
> in place while bonding it with thickened epoxy to the lower skin but then
> used a vacuum system when doing the larger lamination areas after doing a
> wet layup.
>
> Nathan
>
>
>
> Thanks to all of the subscribers that contributed to the list to help with
> the costs involved.  If you want to show your support to the list - use
> PayPal to send contribution --   https://www.paypal.me/stumurray  Thanks
> - Stu
>
> Thanks to all of the subscribers that contributed to the list to help with
> the costs involved.  If you want to show your support to the list - use
> PayPal to send contribution --  https://www.paypal.me/stumurray Thanks -
> Stu
> Thanks to all of the subscribers that contributed to the list to help with
> the costs involved.  If you want to show your support to the list - use
> PayPal to send contribution --   https://www.paypal.me/stumurray  Thanks
> - Stu



-- 
Joel
Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu

Stus-List Re: Replacing Cabin/Deck Balsa Core

[Richard Bush via CnC-List]

 
 Nathan, I second Bill's post, that is awesome work!

Richard
 s/v Bushmark4: 1983 C&C 37 CB: Ohio River, Mile 584.4;

Richard N. Bush Law Offices 
2950 Breckenridge Lane, Suite Nine 
Louisville, Kentucky 40220-1462 
502-584-7255 
 
-Original Message-
From: Nathan Post via CnC-List 
To: Stus-List 
Cc: Nathan Post 
Sent: Thu, Aug 26, 2021 10:24 am
Subject: Stus-List Re: Replacing Cabin/Deck Balsa Core

I didn't keep track of hours.  The deck repair was a weeks or two of evenings 
and weekends. Then another two weeks of sanding, prepping and painting and more 
time for replacing the windows and reinstalling all the hardware and life 
lines.  Including rewiring the mast, adding radar, designing, building and 
installing a new bow roller assembly, etc. the whole refit took me about 4 
months.
On Thu, Aug 26, 2021, 10:12 Bill Coleman via CnC-List  
wrote:

Wow, lookslike you did a great job, looks nice.How longdid it take you to do 
that whole operation?  Bill ColemanEntrada, Erie, PA   From: Nathan Post 
viaCnC-List [mailto:cnc-list@cnc-list.com] 
Sent: Thursday, August 26, 2021 8:27 AM
To: Stus-List
Cc: Andy Frame; Nathan Post
Subject: Stus-List Re: Replacing Cabin/Deck Balsa Core Agreed with others on 
not using expanding foam forthis.  I personally used balsa wood to replace the 
rotted core as it hasthe best strength to weight ratio and is pretty easy to 
work with.  Thereare structural foams that can be used but most do not have 
quite as goodmechanical properties as balsa wood.  My other tip is that where 
you knowyou will be putting a hole through it can be good to go with solid 
laminate inthat area instead so you don't have to carve out the balsa and fill 
with epoxylater.  Especially at structural points (bulkhead bolts forexample).  
When I did this on my C&C 34, I used 1/2" G10plate.  Roughen both sides and 
bond in place of the balsa.  Complete thelamination and painting and then cut 
or drill for the fitting.  Adds alittle weight and a lot of strength. Some 
photos showing what I did to repair the core in my deckin 2020 are here: 
https://photos.app.goo.gl/8W4AdgmKqKxARvsY7  Theseshow the G10 plates used 
where penetrations are made later for thebulkhead attachments and the fan in 
the head.  I didn't do that around thechain plate and instead just filled an 
area with thickened epoxy but onhindsight using G10 there too would have been 
better and will avoid the problemhappening again in the future.
Note, in some cases, I rebuilt the deck laminate from scratch and in others 
Ilaminated the original back in place and then created a tapered grove 
andlaminated the two parts of the top deck back together for strength using 
narrowstrips of fiberglass. I used weights to hold the G10 in place while 
bonding itwith thickened epoxy to the lower skin but then used a vacuum system 
when doingthe larger lamination areas after doing a wet layup. Nathan

 
Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu
Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --  https://www.paypal.me/stumurray  Thanks - StuThanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu

Stus-List Re: Replacing Cabin/Deck Balsa Core

[Nathan Post via CnC-List]

I didn't keep track of hours.  The deck repair was a weeks or two of
evenings and weekends. Then another two weeks of sanding, prepping and
painting and more time for replacing the windows and reinstalling all the
hardware and life lines.  Including rewiring the mast, adding radar,
designing, building and installing a new bow roller assembly, etc. the
whole refit took me about 4 months.

On Thu, Aug 26, 2021, 10:12 Bill Coleman via CnC-List 
wrote:

> Wow, looks like you did a great job, looks nice.
>
> How long did it take you to do that whole operation?
>
>
>
>
>
> Bill Coleman
>
> Entrada, Erie, PA
>
>
>
>
>
>
>
> *From:* Nathan Post via CnC-List [mailto:cnc-list@cnc-list.com]
> *Sent:* Thursday, August 26, 2021 8:27 AM
> *To:* Stus-List
> *Cc:* Andy Frame; Nathan Post
> *Subject:* Stus-List Re: Replacing Cabin/Deck Balsa Core
>
>
>
> Agreed with others on not using expanding foam for this.  I personally
> used balsa wood to replace the rotted core as it has the best strength to
> weight ratio and is pretty easy to work with.  There are structural foams
> that can be used but most do not have quite as good mechanical properties
> as balsa wood.  My other tip is that where you know you will be putting a
> hole through it can be good to go with solid laminate in that area instead
> so you don't have to carve out the balsa and fill with epoxy later.
> Especially at structural points (bulkhead bolts for example).  When I did
> this on my C&C 34, I used 1/2" G10 plate.  Roughen both sides and bond in
> place of the balsa.  Complete the lamination and painting and then cut or
> drill for the fitting.  Adds a little weight and a lot of strength.
>
>
>
> Some photos showing what I did to repair the core in my deck in 2020 are
> here: https://photos.app.goo.gl/8W4AdgmKqKxARvsY7  These show the G10
> plates used where penetrations are made later for the bulkhead attachments
> and the fan in the head.  I didn't do that around the chain plate and
> instead just filled an area with thickened epoxy but on hindsight using G10
> there too would have been better and will avoid the problem happening again
> in the future.
>
>
> Note, in some cases, I rebuilt the deck laminate from scratch and in
> others I laminated the original back in place and then created a
> tapered grove and laminated the two parts of the top deck back together for
> strength using narrow strips of fiberglass. I used weights to hold the G10
> in place while bonding it with thickened epoxy to the lower skin but then
> used a vacuum system when doing the larger lamination areas after doing a
> wet layup.
>
>
>
> Nathan
>
>
>
>
> Thanks to all of the subscribers that contributed to the list to help with
> the costs involved.  If you want to show your support to the list - use
> PayPal to send contribution --   https://www.paypal.me/stumurray  Thanks
> - Stu
Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu

Stus-List Re: Replacing Cabin/Deck Balsa Core

[Bill Coleman via CnC-List]

Wow, looks like you did a great job, looks nice.

How long did it take you to do that whole operation?

 

 

Bill Coleman

Entrada, Erie, PA

 

 

 

From: Nathan Post via CnC-List [mailto:cnc-list@cnc-list.com] 
Sent: Thursday, August 26, 2021 8:27 AM
To: Stus-List
Cc: Andy Frame; Nathan Post
Subject: Stus-List Re: Replacing Cabin/Deck Balsa Core

 

Agreed with others on not using expanding foam for this.  I personally used 
balsa wood to replace the rotted core as it has the best strength to weight 
ratio and is pretty easy to work with.  There are structural foams that can be 
used but most do not have quite as good mechanical properties as balsa wood.  
My other tip is that where you know you will be putting a hole through it can 
be good to go with solid laminate in that area instead so you don't have to 
carve out the balsa and fill with epoxy later.  Especially at structural points 
(bulkhead bolts for example).  When I did this on my C&C 34, I used 1/2" G10 
plate.  Roughen both sides and bond in place of the balsa.  Complete the 
lamination and painting and then cut or drill for the fitting.  Adds a little 
weight and a lot of strength.

 

Some photos showing what I did to repair the core in my deck in 2020 are here: 
https://photos.app.goo.gl/8W4AdgmKqKxARvsY7  These show the G10 plates used 
where penetrations are made later for the bulkhead attachments and the fan in 
the head.  I didn't do that around the chain plate and instead just filled an 
area with thickened epoxy but on hindsight using G10 there too would have been 
better and will avoid the problem happening again in the future.


Note, in some cases, I rebuilt the deck laminate from scratch and in others I 
laminated the original back in place and then created a tapered grove and 
laminated the two parts of the top deck back together for strength using narrow 
strips of fiberglass. I used weights to hold the G10 in place while bonding it 
with thickened epoxy to the lower skin but then used a vacuum system when doing 
the larger lamination areas after doing a wet layup.

 

Nathan




 

Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu

Stus-List Re: Replacing Cabin/Deck Balsa Core

[Nathan Post via CnC-List]

Agreed with others on not using expanding foam for this.  I personally used
balsa wood to replace the rotted core as it has the best strength to weight
ratio and is pretty easy to work with.  There are structural foams that can
be used but most do not have quite as good mechanical properties as balsa
wood.  My other tip is that where you know you will be putting a hole
through it can be good to go with solid laminate in that area instead so
you don't have to carve out the balsa and fill with epoxy later.
Especially at structural points (bulkhead bolts for example).  When I did
this on my C&C 34, I used 1/2" G10 plate.  Roughen both sides and bond in
place of the balsa.  Complete the lamination and painting and then cut or
drill for the fitting.  Adds a little weight and a lot of strength.

Some photos showing what I did to repair the core in my deck in 2020 are
here: https://photos.app.goo.gl/8W4AdgmKqKxARvsY7  These show the G10
plates used where penetrations are made later for the bulkhead attachments
and the fan in the head.  I didn't do that around the chain plate and
instead just filled an area with thickened epoxy but on hindsight using G10
there too would have been better and will avoid the problem happening again
in the future.

Note, in some cases, I rebuilt the deck laminate from scratch and in others
I laminated the original back in place and then created a tapered grove and
laminated the two parts of the top deck back together for strength using
narrow strips of fiberglass. I used weights to hold the G10 in place while
bonding it with thickened epoxy to the lower skin but then used a vacuum
system when doing the larger lamination areas after doing a wet layup.

Nathan

~~~
Nathan Post
+1 (781)  605-8671


On Wed, Aug 25, 2021 at 5:43 PM Andy Frame via CnC-List <
cnc-list@cnc-list.com> wrote:

> That pretty much settles this discussion!
>
> Thanks to everyone for their thoughts.
>
>
> On 8/25/2021 2:26 PM, Della Barba, Joe via CnC-List wrote:
> > Expanding foam has no structural strength at all and is easily
> > compromised by water. I would not even think of it for this use.
> >
> > Joe
> >
> > Coquina
> >
> > *From:* SV Mary Me via CnC-List 
> > *Sent:* Wednesday, August 25, 2021 12:19 PM
> > *To:* cnc-list@cnc-list.com
> > *Cc:* SV Mary Me 
> > *Subject:* [EXTERNAL] Stus-List Replacing Cabin/Deck Balsa Core
> >
> > I've got some soft spots returning on the deck at the base of the mast,
> > that a previous owner had made an attempt to shore up. According to the
> > owners manual, the cabin-ceiling/deck sandwich is balsa cored, so I'm
> > working with the assumption that this has rotted away.
> >
> > The local supply store has a plastic honeycomb panel to use as a base
> > material for fibreglass work that could use to fill the space, once the
> > rotted material is dug out. I also thought about using expanding,
> > self-hardening construction foam that could be shaved and shaped, then
> > 'glassed over.
> >
> > Has anyone used, or have any thoughts on using the expanding foam?
> >
> > s/v Mary Me
> >
> > 1975 C&C 24
> >
> > Labelle, Florida USA
> >
>
> --
> s/v MaryMe
> 1975 C&C 24
> Labelle, FL USA
> Thanks to all of the subscribers that contributed to the list to help with
> the costs involved.  If you want to show your support to the list - use
> PayPal to send contribution --   https://www.paypal.me/stumurray  Thanks
> - Stu
>
Thanks to all of the subscribers that contributed to the list to help with the 
costs involved.  If you want to show your support to the list - use PayPal to 
send contribution --   https://www.paypal.me/stumurray  Thanks - Stu