Confused about pith!

Pith is bad... most of the time.

steve antonucci

>The pith is the least stable part of the wood. What does that mean? It means that if you turn something with pith in, you have a much higher probability of the piece checking radially from the pith.

Does this mean you can't turn pith in? Of course not. You might find with the smaller diameter logs (<12") that you need to use the pit, or all of your forms will be 3" tall. I have turned a few pith in HF's and the pith will certainly be the worst of it, but you can stabilize it to some extent with CA glue, or fill the cracks that develop with epoxy, or just do nothing and see what happens.

I also think it helps a lot to alcohol dry pieces with pith, since I just finished 3 cherry bowls that had pith at the top, and they dried without cracking and any significant warping (I thought they had already been retrued...)

Given the nature of green wood, it will always move. The pith is the "worst case scenario" in any straight grained normal wood. If your plan includes pith, I think careful management will result in some success (not always, but sometimes).

Steve

Re: Confused about pith!

Anthony Y

>My .02, pith is bad and will most likely crack.

Also, it seems that I'll have to use a last initial from now on

Anthony

Re: Confused about pith!

John Lucas

>Ken

The others have given some good answers. You have several options. If you turn a hollow vessel with the pith in the bottom here are some tips.

One option is to drill all the way through a hollow vessel so the pith is gone. Then after the turning dries and warps true up the hole and put a plug in.

Another option is to turn the vessel through the bottom. Upside down. You can drill or turn a hole in the bottom and then hollow the vessel through this hole. Then after it dries true up the hole and plug it.

Turn the vessel to an even thickness but leave the pith in. The area where the pith is needs to be around a 1/4" or so and it's just as important to have the rest of the vessel the same thickness. If the area where the pith is found is flat you have a greater chance of checking. If that same area is cone shaped you reduce the chances of checking considerably.

Slow down the drying time. Wrap it in paper or put it in a paper sack. Anything to slow the air movement. I dried a bunch of slices off a dogwood limb one time by putting them in zip lock bags and turning the bags inside out every day or so. I did this for months but everyone of them dried crack free. Flat sections of a limb such as these are the worst case scenario for splitting.