Dealing with non-structural rot

[Gordonmc]

Advice sought.
A week ago I found a patch of discoloured mahogany on the saloon coaming. It is clear that rainwater has permeated into a corner joint through damaged canvas on the coachroof. /forums/images/graemlins/frown.gif since repaired.
The varnish (deks) came away with a fingernail and water exuded.
Last weekend was fairly dry and I was able to sand quite a bit of the discolouration off, but the wood still felt wet, but solid. There is about an inch x four inches of fibrous wood.
I realise the advice would normally be... cut out the rot and replace, but this is on a piece of solid mahogany 2 foot by five. There is no sign of damage inside the cabin.
What would be the best way to eliminate any spores before refinishing?
I now have the area covered to dry it out completely... one suggestion was to use wood hardener.
Comments welcome.

 

[LittleShip]

Have a look here

http://boatbuilding.com/content/rot.html

Tom

 

[Casey]

I have had a similar problem on my boat with the ends of an oak beam becoming very soft. This only became apparent when I removed a piece of decorative mahogany which had become very discoloured. The soft patches have now been removed and the area left to dry thoroughly. I intend to fill the holes with epoxy putty. If the holes had been very deep I would have scarfed in new pieces of oak and glued them with epoxy.

Before deciding that your piece of Mahogany is rotten let it dry our completely. Mahogany that is soaked will tend to fray away when rubbed and can give the illusion of being rotten. That was a tip from an old shipwright.

One other thing, make sure that the moisture can escape to atmosphere - if you have already repaired the canvas covering you may trap moisture in the timbers and start the whole problem again. A hot air gun can be used if you are very careful.

 

[Gordonmc]

Thanks both to Littleship - the item on Boatbuilder.com was interesting. I am encouraged by Casey's tip that "fraying" mahogany might not be rotten.
I will source some glycol antifreeze, but will try it on a bit of scrap wood first... I am suspicious about the claim the dye is weak. I don't want pink or livid green patches!
For the moment I have the area protected from the weather and I will put a fan heater on for a few hours to (gently) dry the area.
Any more comments?

 

[fishermantwo]

Further reading can be found at www.rotdoctor.com . I have used the glycol concentrate method. It does soak in and presumably does the job. Copper nathalate or however its spelt, soaks in much better but will leave a green stain.

 

[chippie]

Is International's 'everdure' available where you are? It is an epoxy product that preserves and protects wood. It is very runny and is painted on until the wood wont take any more, and then left to harden. Though quite expensive if doing a whole boat,the use of small quantities seems economically viable.

I have had similar success with epoxy resin thinned substantially with methylated spirits and applied in the same way. Once the thinned epoxy has hardened but is still sticky, paint with unthinned epoxy. This can be applied over the glycol treatment.
If you have doubts, try it on a piece of scrap first.

Good luck.

 

[fishermantwo]

[ QUOTE ]
Is International's 'everdure' available where you are? It is an epoxy product that preserves and protects wood. Good luck.

[/ QUOTE ]

Chippie,
Actually its an Epicraft product, originally a New Zealand company. First class product though, there are several other brands about now as good. Everdure has a fungicide in it too.

 

[chippie]

Epicraft products seem to be owned by International over here now. They all have the propellor on the can. Do you get International's free newsletter 'waterline? toll free Australia 1800 251 431 www.yachtpaint.com