Thread: Dry Rot in Redgum

Dry rot is a fungus that lives in timber that has been damp due to fresh water. If you have cleaned out all the visible rot, try treating the area with a fungicide and all should be OK.

"Dry rot" is one of those misconceptions that persist in the public imagination. There are many species of fungi which will happily chew up the structural material of wood, but they all have one thing in common - as living organisms, they need WATER. Different species can operate at different moisture contents, but so far, no fungus has evolved that can live on wood at the usual indoor moisture contents of less than 14% (depending on where you live and what season it is!).
As long as you keep your table dry, there will be no further progress.
Cheers,

IanW is absolutely correct, there is a great tendency to confuse "rotted areas that have dried and are now inert" with "dry rot".

True "dry rot" will actually attack dry timber PROVIDED it has a water source within cooee. The fungus actually "crawls" to wherever it needs to be, while keeping it's toes in the damp bit.

This is unlikely to happen on a table unless you live in a cave with a damp dirt floor.

On the other hand it is also quite possible that "rotted areas that have dried" will contain spores of the fungus, and will revive if moisture is reintroduced.

Cheers,

P

Does anyone know of a treatement for 'hardening' areas of dry rot. I mean just slightly spongy areas, known by some as 'dozy' wood. I have wire brushed out badly affected sections from some NSW roswewood I'm making a desk from, but a small area of harder but still affected timber remains. I read somewhere of an Amercian product made for just this purpose, and was wondering if similar was availabe in Australia. I assume it was something with good penetration that sets hard; I dont think it was a mould treatment as such. As mentioned above dry rot ceases to be active when the wood is dry, so I'm not worried about the affected area spreading or worsening.

a very thin slow set epoxy should do it.

JB, you're aware that whatever you use to harden the wood will probably greatly limit your chices of finish?

As a consequence if the "soft spot" is going to be visible then, IMHO, you'd be better off reassessing your cutting plans in the hope of swapping it for something more acceptable. I've actually improved some designs when reconsidering after similar problems.

If, on the other hand, 'tis concealed but you'd like hardening for structural reasons (eg. edge of a M&T) then almost any water-based glue will do, watered down and left to soak in. Adding a bit of fungicide wouldn't be a bad idea. I've also seen a slow-set CA that penetrated a few mm on redgum, I was impressed but didn't think at the time to actually write down the brand name. It's still on my shopping list though.

Thanks for the replies echid and skew. This desk will be lacquered (pre-cat); Don't envisage any problems with that finish over either epoxy or pva—am I wrong?

Good tip on changing design; might make an inlay. The base already has about 10!

Echidna is right. we use a slow set thin epoxy and warm it up with a heat gun, it goes down pretty deep.
Dont worry about the "dry rot" it won't go anywhere.
Polish with Precat or two pack.
No good for waxing though.

Sandgroper