Twice turned bowls in half the time…
Internet image shown above - similar to Bob's set up
From Bob Wolfe - The following is an article I wrote for our blog.
I do not profess to be a writer, but I was excited with the results so far.
I am not a patient person, so when I want to turn a bowl, I don’t want to wait 6 – 8 months before I can turn and finished it. I have relegated my bowl turning to smaller blanks that have been kiln dried. This is very expensive and limits the choices of wood I can turn.
I talked with Dennis Paullus and his take is that you must constantly harvest and first turn wet wood to have blanks available when you want to turn a finished bowl.
I did not like this answer so asked Larry Sefton if he had any other options that would be more palatable to my impatience. He suggested turning wet wood blanks, then boiling them to reduce the time for drying and improve the success rate for avoiding cracking and checking. So, I gave it a try. Larry sent me an article written by Stephen D. Russell who has developed a wood boiling protocol that he says “achieves the well-documented success rate of 96% or better” dried blanks in less than 50% of the time from non-boiled blanks.
The document is long and redundant, but I have tried this protocol and I’m a believer.
Obviously one successful drying makes me an expert………NOT! But I did get the results I was looking for and it looks very promising.
I have also boiled down (condensed) the protocol to “CLIFF NOTES” with nine easy to read and execute steps. The article by Stephen Russell is very informative and I have also included the link to this article.
I took a piece of Boxelder approximately 12” diameter and 7” deep and first-turned a bowl blank approx. 11” diameter, 5-1/2” deep with wall thickness 1”. The sides and bottom of the bowl are fairly uniform thickness with a tenon about 3/8” thick.
I followed the following protocol:
Boil the blank 1 hour (60 minutes) for every 1” thickness of wall or base (not including tenon).
If you boil for less than an hour per inch of thickness, you will not achieve the "well documented 96% or better" drying with no cracks or checks.
If you are boiling a batch of blanks, the boil time is to the thickest section of the largest piece in the batch.
Boiling longer does not help, but it also does not hurt the protocol.
Boiling time starts once the piece is in the water, completely submerged, and a medium boil exists - the medium boil should continue for the entire boiling time cycle.
The blank should not be left to air dry before boiling. Any cracks or checks that exist before the boiling will not be mended.
Once the boiling time is achieved, remove the blank from the water and protect the blank from rapid drying by wrapping in a heavy towel, no wood exposed.
The blank must be allowed to dry in the towel for three days. After the first day of drying with the top side up, the next day flip to the bottom side up, then back to the top side up at the beginning of the third day.
After three days, place the blank in a paper grocery bag (a cardboard box works if you don't have a paper grocery bag) to dry until it reaches an equilibrium moisture content. (When the blank quits losing moisture as measured by a scale)
<<See graph and photos below>>
Stephen D. Russell’s protocol article:
Weigh the blank in the bag (or box) after the 3 day towel wrap.
Keep weighing until the blank does not change weight after 2 or 3 days.
This is the Boxelder first-turned bowl after 43 days.
From the graph above you can see the moisture loss has all but stopped.
The bowl blank is dry and ready to second turn. The color in the wood is not affected by boiling, there are no cracks or checks, and the bark remained on the natural edge. I will let the blank dry another week before I second-turn it.
I am optimistic about the results and look forward to trying more boiled blanks.