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Author Topic: Waterproofing a mahogany planked hull  (Read 6210 times)

coolbumble

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Waterproofing a mahogany planked hull
« on: January 09, 2015, 02:05:36 pm »

Hi NEW to this?
I purchased a mahogany planked hull awhile ago which I am need to waterproof. It is going to be painted ie undercoat and top coat on the outside  However should I seal it first say with a resin before I paint it if so which type ?
Advice appreciated.
Regards
Ian :-))
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jarvo

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Re: Waterproofing a mahogany planked hull
« Reply #1 on: January 09, 2015, 07:43:08 pm »

HI Ian


Welcolm to the forum, I had the same problem, I contacted Easycomposites, they have a big web site with a lot of how to videos,


The epoxy i got was AT30 with fast Hardener, they also do light weight glass cloth and all the tools and brushes, cleaner etc. Do mail order.


Another posibility is Delux adhesives, again a large web site with how to videos, much more expensive though, available through model shops.


Hope this gives you a start of where to look


Mark
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dreadnought72

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Re: Waterproofing a mahogany planked hull
« Reply #2 on: January 09, 2015, 07:59:31 pm »

Do you mean waterproofing?

I would not resin-and-glass this.

If the hull's structurally sound (i.e. there's enough wood in it to prevent flexing) then by all means plug any gaps if leaks are seen following a quick dip in the test tank. Wood shavings/chippings and glue are great for this.

If the hull's to be left immersed for months, then maybe resin is the answer - but beware osmosis.  %%

If, as with most models, the hull gets a dunking for an hour or two now and again, then resin is serious overkill. A decent quality undercoat and top coat will do the job.

Andy
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Time Bandit

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Re: Waterproofing a mahogany planked hull
« Reply #3 on: January 09, 2015, 08:48:31 pm »

Will you paint it with colour or should the mahogany be visible afterwards?

I glass all my wooden hulls due to bad experience in the past.
The wood will work over the years so some of my hulls started to get cracks and leaked a little bit over the time.
Especially if the inside of the hull is hot and the outside is cold (due to the water) this is going to happen pretty fast, I even heard one hull cracking around 5 mins after I put it in the water.
I glass my hulls with slow hardening epoxy (over 1h potlife) and 2 layers of 25g glass fabric, so I dont have to use too much filler and grinding afterwards.

For my Riva I followed these instructions here:
http://miniwerft.de/44.html
Maybe google translate will help

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regards

Tobias

vnkiwi

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Re: Waterproofing a mahogany planked hull
« Reply #4 on: January 09, 2015, 10:20:41 pm »

A brief note
the term "resin and glass", is a very vague expression, and can refer to a whole range of products.
The most common are
POLYESTER RESIN, which IS water soluble, hence osmosis in full size boats using it.
It has to be either painted or have a gel-coat to protect it from water and sunlight, and is usually brittle.
EPOXY RESIN, is water and vapour proof, retains usually a degree of flex, but needs a top coat, to protect from the UV component in sunlight.
There are other resins, and other clothes other than glass. All have their uses.
PERSONALLY MYSELF, i only ever use epoxy resin, and seal the whole hull, inside and out, with a light weight, or finishing matt reinforcing glass or other cloth. I use the same epoxy to 'glue' the hull and superstructure, sometimes tacking things together with a flexible instant glue gel.
Works for me, and cheap insurance after spending 100's of hours on ones pride and joy
 :-))
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derekwarner

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Re: Waterproofing a mahogany planked hull
« Reply #5 on: January 09, 2015, 10:29:33 pm »

..... ok2.....For my Riva I followed these instructions here: http://miniwerft.de/44.html Maybe google translate will help

Windows does it automatically  :-)) ... Derek

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vnkiwi

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Re: Waterproofing a mahogany planked hull
« Reply #6 on: January 09, 2015, 10:57:51 pm »

Very nice link Timebandit.

"For my Riva I followed these instructions here: http://miniwerft.de/44.html Maybe google translate will help"

Those instructions are clear and concise, and google translate does an acceptable job of translation.
Highly recommend to everyone wanting to seal and finish their pride and joy so it lasts as long as it deserves and you want it to.
 :-))
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coolbumble

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Re: Waterproofing a mahogany planked hull
« Reply #7 on: January 10, 2015, 12:21:57 am »

Hi
Many thanks for all your replies something for me to ponder.( No pun meant )! I will let you know how I get on and hopefully show you the result when finished.
Once again
Many thanks
Ian  :-))
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martno1fan

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Re: Waterproofing a mahogany planked hull
« Reply #8 on: January 14, 2015, 06:30:46 am »

Cpl coats of sanding sealer then undercoat and paint is fine,if you want the wood look then epoxy could be used but make sure you use very slow setting epoxy used in laminating not the glue type as its too thick.
Mart
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rickles23

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Re: Waterproofing a mahogany planked hull
« Reply #9 on: January 14, 2015, 07:27:49 am »

Hi,

Try some varnish poured inside the hull and shake it around.

Seals most wooden boats

Regards
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coolbumble

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Re: Waterproofing a mahogany planked hull
« Reply #10 on: February 14, 2015, 05:33:44 pm »

Hi all
Have pondered over all your advice and its now nearly done ! I applied inside and out an epoxy coating resin  purchased from easycomposites. Very helpful and very fast delivery. Dunked it in the water and had a small leak ! So upturned the boat and pushed it under bubbles telling me there were two very small holes either side of the keel so fixed that with milliput then applied another coat of epoxy resin.  To make sure I fibre glassed over the keel to one joint of the planking each side  and all OK. So its now been undercoated and one top coat needs a bit more tlc and one more coat. Being made of wood some grain shows but think that will do for me !
Regards and many thanks for your advice
Ian  :-))
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