What will grind away decayed wood?

[mjernigan]

I have some window sills that are decayed (courtesy of the previous owner's neglect), and I've been told the way to go is to cut away the decayed volume, build up with Bondo and reseal and paint. Seems like a decent way to go, but I'm at a loss for a good way to grind away the decayed portion.

Is there some tool sort of like a dentist's grinding ball that I could use to quickly and easily dig out the bad stuff, down to the good, or am I going to just have to chisel it away?

[crokett]

Chise is what I use. Also, as long as it is not too bad, Bondo makes a kit that includes something called rotted wood stabilizer. This seals the bad wood before you use the bondo. If you are doing this in warm weather, mix small batches. The Bondo will start to cure and become unworkable in only a few minutes.

[poolhound]

Depending on how much and how rotten I have used a variety of methods. Handheld wire brush, motorized wire brush on drill or angle grinder and of course chisels.

[cabinetman]

These rotary rasps work good in an electric drill and are more aggressive than a wire wheel in an electric drill.

As suggested, Bondo works good all by itself, and getting the mix right will give the most working time. Just make sure it's thoroughly mixed, and the grey Bondo with the red catalyst, should mix to a light pink color. Just don't mix too much at once. DAMHIKT. Try to prime and paint before it gets wet again.
.

[dbhost]

Depending on how bad the rot is, you may want to entirely remove the sill, and rebuild with entirely new wood...

Time to break out the saws and router!

[Sid]

I haven't used them, but I've heard good things about products that will penetrate and fill rotted wood:
http://www.hereandthere.org/oldhouse...cayed-wood.htm

Sid

[mjernigan]

That's why I love this place

Many thanks to those who responded... I think the rotary rasps are the ticket, and what I'd visualized without realizing they existed. Perhaps the special Bondo mix that seals previously rotted wood might be the appropriate method of build up.

Thank you all who responded... I'll consider all suggestions.

Cheers, all.

Mike

[kramer katt]

West Systems is well known in the boat building world but they also taylor a product for your exact situation. I have used it with good success to fix dry rot in doors. Check out all the info on the website. They use to have a small kit as a sample

http://www.westsystem.com/

Also some versions sold at Rockler

[jabe]

All of the tools mentioned to remove the rot will work. But after it's all removed, scorch the wood with a propane torch to kill the fungus/mold & whatever that caused the rot. It's more cost effective than buying the chemicals to seal the wood. Then proceed with the bondo. I learned the torch method from an old carpenter my late father in law.

[Mr__Bill]

All of the tools mentioned to remove the rot will work. But after it's all removed, scorch the wood with a propane torch to kill the fungus/mold & whatever that caused the rot.

I had forgotten about that trick. Just remember that if the rotten wood is dry it burns rather well. I have used a small sandblaster to get rid of the rotten part and then hit it with a torch. That was a boat so setting it afire would not put me out of house and home. Window sills have a lot of potential for flammable stuff just around them or inside the wall next to them. take care and have a garden hose available.

bill