Epoxy treatment to stabalise old wood

[alan006]

re roly-voya,
I agree the whole structure has to be considered. I discussed it with a friend of mine ( who is a marine surveyor) and we agreed that to stiffen the hull in isolation would be unwise. I have renewed all the stringers and rebuilt the decks using epoxy and laminated marine ply to stiffen the whole structure.The keel was really the last part of the jigsaw.
Its been really encouraging to find other people thinking along the same lines.

 

[alan006]

Thank you to everyone for there constructive input.
alan

 

[alan006]

I'm going to try to post some pics of the old girl to show you chaps what I've been rambling on about. Hope I can understand how to load them up.
Here's a pic of one side

I think its working!!!
here's another

here's another

 

[oldfrank]

Don't do it! However good your epoxy coating, water will get into the wood. The epoxy stops it getting out again and will quickly rot the wood. Better to let the water in and out -unless you wanted to make a new keel anyway! OF

 

[Arbitus]

I know of the Epoxy you are reffering to. I have seen it on a TV show here in North America called "This Old House." It is used mainly in historic restorations and preservations.

There are four forms of it.

The first is a flexible epoxy consilidant for non-structural uses. This is mainly used when you have a structure that has say dry rot or rotten wood in a non-structural member. They'll clean out all dry and loose wood from the area. Make sure it is dry and then apply the epoxy to consolidate the remaining wood. From my understanding it comes in both dyed as well as clear form depending on the brand. It has the consistency of vegetable oil at a temperature around 23 Deg C.

The second form is a flexible epoxy patch for again non-structural applications. It is similar in characteristics and uses to the first one but has the consistency of Mayonaise at 23 Deg C.

The third form is Structural Epoxy Repair, specifically it is mostly used to repair wooden timbers. This was the product they used on the television show. In that case they were repairing the sill beam of a historic house and could not remove the damaged beam because it would have caused too much damage to the building's structure. So instead the restorationists removed all rotten matterial, replaced a larger section of timber that was all rotted out and easily removeable, and then created a form and injected this epoxy in to fill the voids. Once curred they removed the forms and worked the surface removing any overflow etc.. They then applied a sealent to the rest of the wood and replaced the buildings exterior sheathing.

The last form of this epoxy is what they refer to as a Fiberglass Rebar using a combination of the epoxy with fiberglass sheet applied to the surface of the structure. I am not too too familiar with this version of the product past the fact it is used in load bearing situations.

Now as far as I have seen I do not know of any case where these products have been used in a Marine application. Let alone how they would fair in a salt water environment. As well from the above pictures you have damage to the planking/plywood and I don't really think these products were made for application to anything but large(r) timbers or frames.

As for oldfrank's comment before this about water inside the product specifcally warns not to use if the dryness of the wood is over 20% moisture content by weight which is better then most kiln dried woods. But again if your job sealing with the epoxy was to be at all imperfect you'd just end up rotting out the rest of the remaining wood.

So I would have to suggest like he did, spend the extra expense and have it repaired in the correct traditional manner. Though if cost is a problem I guess you could use the first version of the epoxy to stabilize the wood in place and stop any further decay until you could afford to have the proper repairs completed.

Here is one a url to one of the manufacturers of the epoxy I am referring to:

http://www.conservepoxy.com/

 

[alan006]

There seems to be several common points emerging from all this information which is making me reconsider how I tackle this. I had assumed that the epoxy system would be relatively easy to use in such a way that I could be certain of achieving complete saturation/ penetration. This does not seem to be the case. Some of the comments have said that the penetration is only a few millimetres. This would be very unwise as as soon as this layer was penetrated the wood would be very liable to rot out quickly. A point made by several people and with which I totally agree.
So, I can approach this from a different angle and engineer a seal between the hull and the keel which will allow this natural movement to occur but make a watertight seal. This is a safer approach and been suggested by several people.

 

[alb40]

Hi Alan

Looks like you been cracking on alot recently.

As you have reconstructed most of the hull anyway, then you could sheath the keel in epoxy and a few layers of matting to afford it some protection. Alternatively, you could fill the join between old and new with sikaflex in order to give a flexible seal, and apply a conventional paint system to the keel.

As you might be aware, Seona May is sheathed in epoxy and matting upto the waterline. This was done at least 10 years ago now, and I havent found any nasties so far. She never takes on any water at all (through the bottom at least!)

I do not believe the comments about wood rotting because water is getting in. Seen as though the wood is below the waterline anyway, surely it would be rather wet regardless?

Good luck with this one

Alex.

 

[alan006]

Hi Alex,
Thanks for the comments, you are right I have pushed the old girl along recently and weather permitting I plan to do the bulk of the port hull this summer. I think the safest system is to accept there will be natural movement in the keel and use a flexible sealing approach between the hull and the keel.
So the keel will end up being protected by a non-epoxy conventional paint system.
alan