Knowledge You Can Build On — Est. 1998
Punky Wood
Doug Reynolds
I have some beautiful spalted big leaf maple but, some sections is a little punky in that I can leave a finger nail mark if I press a little hard. I don't know how it will respond to my tools. I'm concerned that I may be courting disaster/injury and, am looking for your advice. Thanks in advance, Doug Reynolds
Re: Punky Wood *LINK*
Dave Paine
It is not unusual for spalted wood to have soft spots. Some softer than others.
The punky areas are not a problem for the tools per se, just for the turner.
The punky areas will tend to tear rather than cut. Also when sanding the abrasive will remove more of the punky wood than the surrounding wood.
You can try applying dewaxed shellac or lacquer to the punky areas to reduce the tearout.
One dewaxed shellac product is Zinsser SealCoat. Now sold as Rustoleum BIN in big letters. Have to look close to see Zinsser name. It will say "wax free" rather than dewaxed.
If you want to strengthen the wood, you may need to apply epoxy. A low viscosity epoxy will soak into the wood. It adds strength, but at the expense of not allowing the wood to take a stain since the pores will be sealed.
I use an epoxy from Smooth-On, the 690 resin. I cannot link to the product just to the page. 5 hour pot life. I apply hot glue around the area so I have a shallow dam to hold the resin while it cures. Needs an accurate weigh scale since mixed by weight not volume.
You can also use CA glue, this works well, but it very expensive for large areas.
Some folks "stabilize" punky wood. This is different resin which needs vacuum or pressure to force into the wood, then heat to cure the wood. Expensive equipment for a one-time project.
http://www.smooth-on.com/Castable-Epoxy-Res/c1295/index.html
Three Articles
Doc Green
Here is a link to the first of three articles dealing with spalted and degraded wood.
http://www.docgreenwoodturner.com/spalted1.html
Sharp tools and shearing cuts will often produce an acceptable surface where conventional cuts do not. Have fun!
~Doc
Re: Punky Wood
John K Jordan
I like to soak it with thin CA glue. (might get hot) (watch out for eye-irritating fumes) I let it set up, make my cuts, resoaking as needed.
Last time I used this was on a three-corner bowl cut from a cube of spongy punky spalted yellow poplar using this method. The end surface was hard and smooth as glass.
The CA will change appearance of the wood some, just like applying oil or another penetrating finish.
JKJ
