TURNING SPALTED WOOD
Whatever techniques you choose to spalt wood, assuming you fulfilled the basic
requirements, here is a tip: stack the log you wish to spalt on its end, not on its side. Spalting
seems to begin on the dependent portion of the wood. If the log is on its side the end result
will be assymetric rotting thus causing the block of wood to be unbalaced when turning.
If the log spalts while standing on its end the fungus attacks the wood evenly and proceds
throughout the log. This will give the most attractive arrangement of the zone lines.
A log is selected and cut into appropriate sections. I turn the spalted stock between a spur
drive and live tail center being careful to make an appropriate tenon. Even though I cut with a
razor sharp spindle gouge, soft spots (white rot) will either fall out or cause the knife to dig in.
So care is required when making the inital shape.
Once the shape has been made Elmers Rotted Wood Stabilizer is spread, in liberal amounts,
over the entire outside surface, including the tenon. the stock is removed from the lathe and
set aside for 24 hours.
The stock is put back on the lathe and secured with the four jaw chuck. It is then wrapped with
blue, painters tape. On top of this a single layer of duct tape is applied. Two inch, clear, plastic
wrapping tape will also work.
Spalted wood will not only explode, fall apart, or sections will blow out; even the tenon will
separate. So, for safety purposes the tapes are applied.
If the duct tape is applied on the bare wood, adhesive of the tape will combine with the Elmers
Rotted Wood Stabilizer and produce a sticky, gum like substance which cannot be sanded
away. The clear, plastic wrap will solve this problem. Re-turning the stock is not a good option
so apply the painter’s tape (3/4”) first.
The second reason for applying the tape is to prevent any “stabilizer”, applied to cavity of the
stock, from leaking through the vessel wall and showering the lathe, the turner, and the shop.
After applying the tape hollowing of the stock is done. Wall of the stock can be made very thin,
from 1/4 to 1/8 inch, but the white rot will blow through the wall if not supported by the tape.
If the vessel being made is cylindrical and the wall is parallel to axis of the lathe, Wipe On Poly,
(about 10 cc and sometimes much more) thinned a bit with paint thinner is poured inside. It’s a
good idea to make a tape baffle over open edge of the vessel to prevent the varnish from flying
around the shop. Insertion of the varnish is done with the lathe turning at about 25-30 rpm. An
attempt to evenly distribute the varnish is made.
Use a wide mouth container over the mouth of the vessel to catch any varnish that wants to
come out when the lathe is reved up to high speed (2000-3000 rpm). Centrifugal force will
cause the thinned varnish to penetrate the wall of the vessel. If there is considerable white rot
present the varnish will be sucked up like a blotter. Many times the varnish will bleed through
the wall and be caught by the tape. At this high speed the tenon may separate.
If the inside wall is variable and not parallel with axis of the lathe then, when hollowing by
increments (outside to center approach), application of the varnish is also done by
increments -- but it is difficult to force even distribution of the varnish.
Once the vessel wall has been thoroughly soaked with the varnish, remove it from the lathe
and set it aside for at least a week. This will alow time for the varnish to harden.
A week later reattach the stock to the four jaw chuck. Remove the tape. Use progressive grits
to sand the surface --- all the way up to 600 grit. Rub a stick of red (jewelers) rouge on a strip of
(piano turner’s) wool and finish polishing surface of the vessel. When this is done clear Deft is
applied. Any other varnish will darken the wood.
Part off the tenon and seal base of the vessel inside and outside. Monogramming and dating
the turning (for me) detracts from freedom of the zone lines, so just attach a label with a string.
Commercially spalted wood can be purchased for turning and, in this case more conventional
techniques are used for turning.
The wood I use comes from a pile of well rotted wood so there is considerable loss and the
process can be dangerous.