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08-04-2018, 16:41
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#31
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Senior Cruiser
Join Date: Oct 2007
Location: 29° 49.16’ N 82° 25.82’ W
Boat: Pearson 422
Posts: 16,306
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Re: Wet balsa core repair options?
Quote:
Originally Posted by Terra Nova
Plenty of misinformation here but this is so wrong. As if you can dry out wet balsa core in 15 minutes using a blow dryer!
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Exactly.
Depending on how wet and how far into the deck it penetrates it could take days or weeks or it could never get totally dry.
__________________
The water is always bluer on the other side of the ocean.
Sometimes it's necessary to state the obvious for the benefit of the oblivious.
Rust is the poor man's Loctite.
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08-04-2018, 17:52
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#32
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cruiser
Join Date: Jan 2012
Location: Lake Ontario
Boat: Ontario 38 / Douglas 32 Mk II
Posts: 3,250
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Re: Wet balsa core repair options?
Quote:
Originally Posted by Terra Nova
Plenty of misinformation here but this is so wrong. As if you can dry out wet balsa core in 15 minutes using a blow dryer!
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Incorrect assumption.
The purpose of using the blow drier and flushing with Methyl Hydrate is not to "dry out the balsa", but rather to quickly drive out moisture and remove slime and rot from the surfaces to have resin applied.
The idea that all wet balsa core must be removed for the composite to be sound is false.
There is no question that wet balsa is not as good as dry balsa; but wet sound balsa is no reason to require balsa removal and replacement.
Again, almost every 25 year old balsa cored boat has some moisture in the deck somewhere, and it can stay there forever and never be a problem. Only where it has rotted or delaminated does it need to be repaired.
Preventing more moisture from getting in is key.
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08-04-2018, 19:18
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#33
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Registered User
Join Date: May 2014
Location: USA
Boat: 41' yawl
Posts: 1,187
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Re: Wet balsa core repair options?
Quote:
Originally Posted by ramblinrod
The purpose of using the blow drier and flushing with Methyl Hydrate is not to "dry out the balsa", but rather to quickly drive out moisture and remove slime and rot from the surfaces to have resin applied.
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But if the surrounding balsa is wet, how long do you suppose your superficial dry spot is going to stay dry?
Is that fast hardener you are using, or only slow? Do you feel lucky? [emoji23]
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08-04-2018, 22:11
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#34
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cruiser
Join Date: Jan 2012
Location: Lake Ontario
Boat: Ontario 38 / Douglas 32 Mk II
Posts: 3,250
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Re: Wet balsa core repair options?
Quote:
Originally Posted by chris95040
But if the surrounding balsa is wet, how long do you suppose your superficial dry spot is going to stay dry?
Is that fast hardener you are using, or only slow? Do you feel lucky? [emoji23]
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Balsa core is never dry.
Right from the balsa core factory the actual moisture content is around 10-15%.
I typically use cabosil thickened unwaxed Isopthalic polyester resin catalyzed with 0.5 to 1.5% MEKP based on temperature.
Luck has absolutely nothing to do with it. ;-)
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08-04-2018, 22:31
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#35
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Registered User
Join Date: Feb 2011
Location: Virginia
Boat: Shopping for a 30-ish cat
Posts: 418
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Re: Wet balsa core repair options?
Quote:
Originally Posted by ramblinrod
...I typically use cabosil thickened unwaxed Isopthalic polyester resin catalyzed with 0.5 to 1.5% MEKP based on temperature...
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May I ask why you choose polyester over epoxy resins?
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09-04-2018, 03:47
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#36
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Registered User
Join Date: May 2014
Location: USA
Boat: 41' yawl
Posts: 1,187
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Wet balsa core repair options?
Quote:
Originally Posted by ramblinrod
Balsa core is never dry.
Right from the balsa core factory the actual moisture content is around 10-15%.
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Obviously none of us are talking about the natural moisture content in the wood.
Do you dry off after taking a shower, or just go ahead and get dressed? I mean, our bodies are about 66% water, right? [emoji849]
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09-04-2018, 08:47
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#37
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cruiser
Join Date: Jan 2012
Location: Lake Ontario
Boat: Ontario 38 / Douglas 32 Mk II
Posts: 3,250
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Re: Wet balsa core repair options?
Quote:
Originally Posted by prof_mariner
May I ask why you choose polyester over epoxy resins?
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For every job, I choose the resin I believe is best suited for the application, based on my 35 years of experience using polyester and epoxy resins.
For boats made of polyester resin (most I encounter), if there is no compelling reason to use epoxy resin, I tend toward polyester, if for no other reason than to help avoid epoxy resin sensitization, for myself, my customer, their family, and their crew.
Again, this is just one reason; there are many issues to be considered.
For polyester FRP repair, I almost always use polyester resin, especially inside the boat, and anywhere matching the polyester resin gelcoat is desired.
When epoxy resin is the clear winner, that is what I use.
Filling and fairing cast iron and lead keels, epoxy primer or barrier coat before anti-fouling, and epoxy primer before 2-pack topside paints, are my most common uses of epoxy resins.
I rarely encounter epoxy cold moulded boats, as few production models exist in our market, and most DIY builders repair their own, but that is another application where epoxy resin would be the clear resin of choice.
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09-04-2018, 08:59
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#38
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cruiser
Join Date: Jan 2012
Location: Lake Ontario
Boat: Ontario 38 / Douglas 32 Mk II
Posts: 3,250
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Re: Wet balsa core repair options?
Quote:
Originally Posted by chris95040
Obviously none of us are talking about the natural moisture content in the wood.
Do you dry off after taking a shower, or just go ahead and get dressed? I mean, our bodies are about 66% water, right? [emoji849]
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Training a blow dryer on the surface and flushing with Methyl Hydrate a couple times is akin to your showering and towelling off analogy I s'pose.
Anyway, it works.
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09-04-2018, 09:05
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#39
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Registered User
Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,477
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Re: Wet balsa core repair options?
The problem I see is not the Injectadeck product itself, it's what's inside the deck. Water and wood mush sometimes. I don't think just injecting something into that garbage is a "fix" at all. The stuff I took out of my 44 footer V berth was black rotten plywood. It came out as stringy smelly mush.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard
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09-04-2018, 10:14
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#40
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cruiser
Join Date: Jan 2017
Boat: Retired from CF
Posts: 13,317
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Re: Wet balsa core repair options?
Just a reminder, in a public forum no one knows you're a dog.
Sometimes those speaking with the most confidence are giving the falsest information and the worst advice.
You can get a feel for credibility when exposed to a member's posting history over time, so do your due diligence in the archives if someone comes out with radical claims that go against the elders' majority opinion.
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09-04-2018, 11:46
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#41
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cruiser
Join Date: Jan 2012
Location: Lake Ontario
Boat: Ontario 38 / Douglas 32 Mk II
Posts: 3,250
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Re: Wet balsa core repair options?
Quote:
Originally Posted by john61ct
Just a reminder, in a public forum no one knows you're a dog.
Sometimes those speaking with the most confidence are giving the falsest information and the worst advice.
You can get a feel for credibility when exposed to a member's posting history over time, so do your due diligence in the archives if someone comes out with radical claims that go against the elders' majority opinion.
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I concur completely that one should always consider the source.
I advise my children, friends, and customers to do this every day.
Question the validity and integrity of every forum post, YouTube video, or manufacturers marketing propaganda.
To avoid deception and misinformation, apply critical thinking
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09-04-2018, 23:57
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#42
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Registered User
Join Date: Oct 2014
Location: Florida
Boat: Scout 30
Posts: 3,112
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Re: Wet balsa core repair options?
[QUOTE=ramblinrod;2612781]For every job, I choose the resin I believe is best suited for the application, based on my 35 years of experience using polyester and epoxy resins.
For boats made of polyester resin (most I encounter), if there is no compelling reason to use epoxy resin, I tend toward polyester, if for no other reason than to help avoid epoxy resin sensitization, for myself, my customer, their family, and their crew.
How noble. 35 years of experience & you don't know that sensitization only happens when you come in contact with uncured epoxy. Once epoxy is cured it is inert. You might make money squirting epoxy into wet decks or using polyester resin for secondary bonds because it's cheaper but you're not doing your customer or "their family" any favors.
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10-04-2018, 08:31
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#43
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Registered User
Join Date: Mar 2015
Location: Boston's North Shore
Boat: Pearson 10M
Posts: 839
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Re: Wet balsa core repair options?
[QUOTE=Scout 30;2613155]
Quote:
Originally Posted by ramblinrod
For every job, I choose the resin I believe is best suited for the application, based on my 35 years of experience using polyester and epoxy resins.
For boats made of polyester resin (most I encounter), if there is no compelling reason to use epoxy resin, I tend toward polyester, if for no other reason than to help avoid epoxy resin sensitization, for myself, my customer, their family, and their crew.
How noble. 35 years of experience & you don't know that sensitization only happens when you come in contact with uncured epoxy. Once epoxy is cured it is inert. You might make money squirting epoxy into wet decks or using polyester resin for secondary bonds because it's cheaper but you're not doing your customer or "their family" any favors.
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I want to highlight the point made, polyester resin used to form secondary bonds is weaker than epoxy. A secondary bond if formed when attaching new resin to previously cured resin. Epoxy is superior to polyester when making secondary bonds.
The disadvantage to epoxy is it takes longer to cure.
Second point; leaving wet core in place will result in delamination if the deck is subject to freezing temperatures.
I strongly suggest ignoring the advice to use polyester resin for repairs.
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10-04-2018, 10:10
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#44
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cruiser
Join Date: Jan 2012
Location: Lake Ontario
Boat: Ontario 38 / Douglas 32 Mk II
Posts: 3,250
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Re: Wet balsa core repair options?
[QUOTE=guyrj33;2613407]
Quote:
Originally Posted by Scout 30
I want to highlight the point made, polyester resin used to form secondary bonds is weaker than epoxy. A secondary bond if formed when attaching new resin to previously cured resin. Epoxy is superior to polyester when making secondary bonds.
The disadvantage to epoxy is it takes longer to cure.
Second point; leaving wet core in place will result in delamination if the deck is subject to freezing temperatures.
I strongly suggest ignoring the advice to use polyester resin for repairs.
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I have seen lots of DIY projects destroyed, abandoned, made inferior, or costing way more than necessary, in materials, sweat equity, storage yard fees, and loss of use. In every case, the DIYer will swear their choices were justified.
Occasional an owner will hire us to clean up the mess they have created.
Any boat owner is free (maybe) to choose their marine service provider, as have many of my happy and loyal customers who when faced with a “the only solution is” proposition, sought a second opinion.
Of all of the polyester secondary bonds I have performed, I have not had one failure.
In my opinion, the adhesion strength difference of materials is much less than many believe, and irrelevant, when one assures the strength of materials chosen are adequate for the application.
Thank you for your input.
However, I will continue to offer my customers options that I am willing to stake my reputation on, and discuss the risks and benefits of each.
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11-04-2018, 07:42
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#45
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Registered User
Join Date: Oct 2014
Location: Florida
Boat: Scout 30
Posts: 3,112
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Re: Wet balsa core repair options?
Quote:
Originally Posted by Cheechako
The problem I see is not the Injectadeck product itself, it's what's inside the deck. Water and wood mush sometimes. I don't think just injecting something into that garbage is a "fix" at all. The stuff I took out of my 44 footer V berth was black rotten plywood. It came out as stringy smelly mush.
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I get what you're saying having done a similar repair myself. Supposedly that's exactly the kind of problem Injectadeck works best at solving. They say that the foam is attracted to moisture & the more the core is rotten the more the foam can displace it. In fact, if the core is dry you have to add water to it. Like you my first reaction was this is cutting a corner & that's never a good thing when boats are concerned. However, the more I've thought about it the more I think it would be worth trying. I've seen a few boats for sale recently, including a Krogen & a Tayana, that the sellers were having a hard time giving away due to extensive deck leaks & damage. If damage like that can be fixed in a much easier & more cost effective way there might be some really great deals out there.
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