Friday, July 29, 2011

Riving Green Wood

Riving, or splitting, is an excellent way to process large pieces of wood into blanks or billets for spoons.  With enough wedges you can turn a 5 ft diameter log into a passel of future spoons in no time.  One good advantage to riven wood as opposed to sawn is the grain will be continuous along the whole length of the spoon, adding great strength.   It is not hard to do but you need to know a little bit about the properties of a log.

To start with you'll need a log of suitable spoon wood.  The fruit woods are all good and split easily when green. Maple, Sycamore, Dogwood, Walnut, Mesquite, Osage Orange, White Oak, and Perssimon are all good choices.  If you live in the East then Tulip Tree is an excellent choice Also.  The wood is the color of split pea soup but it turns a nice shade of brown upon exposure to air and light.  Older trees often have lots black and purple streaks in the heartwood that add a lot of interest to the spoon.

So you've found a suitable tree.  Wait for a moonless night and be sure your neighbor doesn't have a dog.  Be careful climbing over the fence.  Just kidding.  You won't need to do any clandestine logging.  There are plenty of sources of wood even in the city.  I'll tell you where to look in a later post.

Woods to avoid.  Pine, to me is not a wood for spoons.  Ditto with Red Oak.  It has all those large open pores. Stay away from Hickory and Pecan as well.  They tend to warp when they get wet.  Beech also is unstable and cracks in use.  Red Gum is terrible as well.

The very best in my experience are Cherry, Sugar Maple, Mesquite and Apple.  By all means experiment with your local woods.  There is an invasive species up in Minnesota That I have heard good things about called European Buckthorn.  Apparently it is really taking over in some areas and is crowding out the native trees.  The wood is an attractive yellow or orange with red heartwood.  I have seen some beautiful spoons maee out of it.  Now on to how to rive.

You'll want a piece 18 to 24 inches in length without too many knots or branches.  The ends of your blanks are going to split or check on the ends so you are going to lose about 2 inches on each end.  Coating the ends   helps a lot but they will still crack a little.

I'll be using a green piece of Mesquite for this example.  Its best to start your first split right on the pith center of the log.  This is the first rings in the center of the log.  It may not always be centered, especially in limbs.  If there are any big cracks started already use the biggest one to start.  In the above picture I have marked out the way I want to proceed.  The pith is off center so I will get a thicker piece on the right if I orient my first split as it is marked.  This can be a ladle or a bent handled spatula.  Mesquite usually has a lot of cracks or heart checks radiating out from the pith for up to a third of the diameter.  I have drawn a circle to outline the cracked area which will be waste. With most other woods this area will only extend a half inch or so from the pith and should be avoided like the plague.  If incorporated into your spoon it will crack.  

Start your split with a hatchet head.  Its easier if the handle is attached but all of mine need to be replaced at the moment.  You may need additional wedges to finish the split.

If there are no major knots or crotches your piece will split right down the pitch, however many logs will have a twist to them.  This one split pretty good.

Here I am splitting the smaller half again.  Its best to divide your piece in half as much as possible with each half being the same size. The split will run straight.

Here I am splitting off the inner part of the tree containing the pith and the heart checks.

The piece on the left will be my spoon blank and the waste piece will go into the fireplace or be used for barbecuing.  Now I'm ready for the shaving horse.  See my earlier post on this most wonderful of Human inventions.

Smooth off the split edges with a sharp draw knife.  Then shave off the bark.

And here is my blank all ready.  They won't all be this straight.  Usually they will be all manner of curvy but that is a good thing.  I like to work with the natural shape of the billet.  Let each individual piece give you ideas.  You can either put it up to dry or start carving on it right away.  I'll go over carving spoons from green wood in the next post.  There are a few tricks of the trade for dealing with green wood.  If you're going to let your wood dry first then you'll want to coat the ends.  There are all kinds of special coatings out there to prevent the ends of the wood from checking but the best thing I have found is Shellac.  Get a can of Zinser's 3 lb. cut Shellac at the hardware store and dip the ends.  Shellac dries hard, is an excellent moisture barrier and is environmentally friendly.  Plus it won't gum up your tools when you go to carve your spoon.  Out here in Colorado this piece would be dry enough to carve on in about 6 weeks.  It might take longer in humid areas.  I prefer working the wood dry

  I don't want to be a nanny but make sure you wear safety goggles when doing this.  I have had shards of metal fly off the wedge or the hammer and hit me in the face doing this and as I always tell my kids its a long way to get stitches and eyes don't grow back.