Sealing The Deck Core From Moisture (how to)

[Maine Sail]

Hi All,

For years I have been trying to describe, as have others, in words, how to "pot" or fill deck hardware penetrations with thickened epoxy to seal the decks core from further moisture damage.

I have also been trying to describe why a slight bevel to each hole that penetrates the deck is a good idea. Sometimes folks understand it via words, and sometimes they don't.

I have had this article on my mind for years and finally over the last month or so had the chance to make it all happen with some late nights in the barn.

As far as I know this is the only article of it's type that uses deck lamination cut-a-way samples to show what goes on inside the deck when you "pot" with epoxy and countersink the bolt holes..

I hope this helps make some sense of something that really isn't all that difficult to tackle just difficult to describe..

If you see any typos, and I'm sure you will, please let me know and I'll fix them as soon as I can. I'm not a writer, but do have a lot of tricks & techniques I've learned over my years of boating that I like to share with fellow boaters. Some of these I feel can best be illustrated through pictures, with the help of some words of course..

Click this to read it:
Sealing Deck Penetrations To Prevent Core Rot (LINK)



And some of the photos from the article;

 

[kloudie1]

As usual, Main.. an outstanding article.. great pictures.. Thanks for this one !!

 

[Richard Bryer]

Very well done, Maine- great pictures and easy to understand. Thanks

 

[TimCup]

Main Sail, it's hard to believe-

we get you for free!

By the way, your countersink argument has made a believer out of me. I wish the publications I pay for had this kind of attention to detail. The pictures are quality, the descriptions are concise and easily understood, and your opinions are delivered as exactly that, as opposed to others that offer their thoughts as fact. Your passion is obvious.

Since next Thursday is coming fast, I'll say it now- I'm thankful for Maine Sail!

Cup

ps- in typing your name, I realize I spelled it as "Main" in an earlier post... no disrepect intended.

 

[Bob S]

And just in time. My next project is removing the vent stanchion cleaning and rebedding it.

Thanks!

 

[Don S/V ILLusion]

good suggestions.
Anyone not familiar with the techniques involved in fiberglass repair, as well as a host of other repairs typically needed on a boat, will find a myriad of useful practices described in great detail along with numerous illustrations, on the WESTSYSTEM.com web site.

It is on the internet or hard copy can also be purchased at many chandlers.
There are also descriptions therein of a number of projects that otherwise can seem overwhelming.

 

[sailingdog]

Maine Sail-

You might want to mention what temperature you'll have 20 minutes of pot life at on the bottom of the first page, and maybe include a small chart of rough working time and temperatures.... since epoxy is highly temperature dependent.

Quite well done otherwise. Kudos to you.

 

[BobM]

Maine,

I just bought a life time's supply of butyl tape. You've converted me. But I'd like to know if you use it on your chain plates and how? By the way I think you would be doing a great public service if you did a how to on chain plates. Almost everyone has had or will have problems (except the Freedom owners and a few select others with free-standing rigs). Thanks, BobM

 

[Rich (P303)]

Very nice job Maine Sail... pics is words a thousand words to us Frenchmen.

I need to do my stanchions at some point in time (especially if the boat doesn't make it to the water next year due to $$$$$). I know you have worked on some P303's. I'll give you directions!

 

[ITMaster]

As always Maine Sail, this is excellent and well appreciated. I got sidetracked and lost in your site roaming around and reading. Enjoyed the article on baseline temp measurements for the engine. Good idea, I'll have to do that since I have the IR Heat gun already. Your right about it being free

thanks again for some more reference materials.

Tom

 

[Jim Seamans]

Mainesail, I do believe

We all need to buy you some beers

:wow:

 

[Ross]

Mainesail, You have produced another excellent piece of work!!
I noted one omission. I don't know about balsa core but foam core has a low compression strength and just sealing the core won't be enough to provide a base that will support bolt tightening. With my Airex core, I always remove a substantial plug from the inside and replace it with locust bedded in thickened epoxy. I think that your paper will be complete if you add that detail.

I use a 1 inch hole saw to cut the foam and a 1+1/8 inch holesaw to cut the plug. That way I get a tight fit with the plug.

 

[Maine Sail]

Mainesail, You have produced another excellent piece of work!!
I noted one omission. I don't know about balsa core but foam core has a low compression strength and just sealing the core won't be enough to provide a base that will support bolt tightening. With my Airex core, I always remove a substantial plug from the inside and replace it with locust bedded in thickened epoxy. I think that your paper will be complete if you add that detail.

I use a 1 inch hole saw to cut the foam and a 1+1/8 inch holesaw to cut the plug. That way I get a tight fit with the plug.

Was meaning to add that but totally forgot. Here's what it says now..

"While I have chosen to illustrate this using a balsa core you should be aware that most builders do not use foam or balsa directly beneath high load deck hardware. More often than not you'll be dealing with marine grade plywood under deck fittings. Plywood can handle the compression loads far better than either balsa or foam cores and this is why it's laminated into the deck beneath deck hardware. Plywood is hard to carve out, comparatively speaking, and one more reason why the bent nail trick is not as easy as some would make it seem."

 

[Ross]

Very good! Well done.

 

[Richard19068]

Unbelievable

It is amazing how much time you must spend preparing these articles so you can give them away free to us. I recently read a short article in one of the major magazines that covers the same topic and it pales in comparison to your detailed explanations and photos.

Thank you so much.

 

[Ross]

It is amazing how much time you must spend preparing these articles so you can give them away free to us. I recently read a short article in one of the major magazines that covers the same topic and it pales in comparison to your detailed explanations and photos.

Thank you so much.

The few times when I tried to publish a paper, the editor limited the space that she/he was willing to devote to the subject and fully detailed articles were all but imposible. Mainesail's essay would occupy several pages that the editor would rather sell for advertizing. His work is certainly worthy of publication but it shouldn't be abridged by restrictions of print space

 

[Napa Ed]

Good article

Like the bit about butyl tape.
I would like a bombproof process description for redrilling on center. All that work and then to redrill off center would be a shame. Using deck hardware as a template ensures the relational distance of the holes, but all could still be offset. I had thought at first you had drilled up through the original 1/4 hole to maintain accuracy. I'm thinking that removing the duct tape from the underside while the resin is semi rigid will allow an drill bit to be spun by hand to create a divot. Any ready made shapes like a pencil eraser that could be inset in the 1/4" hole as a space saver to be removed later? Something either removeable or softer than the inner skin to encourage the drill bit to walk on center, then drill up from the inside.

 

[dvideohd]

The only other useful thing you could do is to sing your "sea chanty" collection while filing all those deck holes..

truly a direct and and great study!!!

--jerry

 

[Maine Sail]

The few times when I tried to publish a paper, the editor limited the space that she/he was willing to devote to the subject and fully detailed articles were all but imposible. Mainesail's essay would occupy several pages that the editor would rather sell for advertizing. His work is certainly worthy of publication but it shouldn't be abridged by restrictions of print space

Ross,

You hit the nail on the head. I have been contacted by a number of the magazines and had this exact discussion. The other discussion revolves around the time warp these publications are stuck in! This is the day and age of the internet and they need to wake up and compete to survive.

I actually sell photos to one of the biggest sailing publications yet I refuse to even have a subscription to it based on principal.

These mags want the articles to be 100% their sole property. What this means is that they will not allow dual publishing rights so they could stay on my site while at the same time being published!

This mentality, in this day and age of the internet, is utterly ridiculous especially when I have offered them articles FREE OF CHARGE to avoid the sole publishing rights issues. Nope, they'd rather pay me so they have all publishing rights..

Sorry but they are just not worth selling the sole publishing rights to for a measly $300.00-$600.00+/-. I would much rather keep them available to all on my site free of charge.

I write these to help others not to profit though it would be nice to recoup some of my time and materials expenses. So for now, when it comes to making money, I have another job for that..

 

[Rich (P303)]

Maine Sail...

While I have you here. The stanchions on my boat, have a rubber and/or foam gasket under them. After I go thru the deck core epoxy process... I am assuming I wouldn't put the gaskets back (correct?). What sealant would I use under the stanchions? What sealant should I use around my portlights? A couple need to be rebedded... might as well do them all.

Thanks,
Rich