another challenge

[Den Socling]

A couple years ago I dried some elm blocks for an artist in NYC. He carves them but I have never seen a finished carving. He has been hounding me for about a year to dry more. I finally agreed and the wood was delivered today. Luckily for me, it looks like it has had lots of air time. It's going to be tough to handle, though.


 



 

Those big pieces are 10" thick and 24" wide.

[Deese]

 

[Den Socling]

I forgot to mention that it was delivered in the back of a van! If that driver had hit anything, he would be history. And his accent was Russian. That's two Russian truck drivers in two weeks.

[bkaimwood]

I'm wondering if the van was black...

[rjwoelk]

And vas his name boris,  I vonder

[Den Socling]

No, the van was white and I'll have to ask Patti what his name was.   :D   She did the talking.

[Den Socling]

Here I go crowing again. I didn't get to the elm yet but look at this 18/4 White Oak. It was loaded dead green and was in the kiln for 19 days. It's mixed with locust which is dry and I'll give the oak another couple days to equalize.
The first two pictures are locust.


 



 

These are White Oak.


 



 



 

What do you think? Probably the first time anywhere in the world where 4-1/2" White Oak has been dried?

[scsmith42]

Wow....

[Darrel]

Wow....

X2

[Den Socling]

Well I crowed too soon. We finally took the time to pull that load of 4.5" White Oak out and it isn't as good as I hoped. Some were 7% but some others were as high as 23". Some had zero cracks, some had cracks around knots but some had cracks in good wood. Here are a few pictures.


 


 


  

 

[Gearbox]

Den I wish you could get a reading in the center of one to see if it got dry all the way in . that is nice wood .

[Den Socling]

I would bet that the ones reading 7% are dry to the core. I would also bet that any that read 23% are soaking wet in the core. I talked to the guy who sent them today. He says he already has an order for hundreds of those 4.5" x 4.5" x 6' White Oak post. Also said they were going to Australia. And he wasn't too concerned by the surface checks. I sent him a lot more pictures than the 4 here. He made them a half inch oversize because he thought they would bow. He thinks they will come clean out of a molder.
So, I'm going to Arizona for two weeks and when I get back, I'll reload anything over 10%. In the old RF/V days, we called these "rebakes".  ;D

[Den Socling]

I would add, Gearbox, that my drying schedules are nothing like conventional drying. In a conventional kiln, you need to blow warm air over the wood to heat it. The air has to be dry enough to have the capacity to carry away water. You have to go very slow to give water time to migrate to the surface. With my kilns, I heat the water to increase a property called vapor pressure. Then when I decrease the chamber pressure to the same value as the vapor pressure, water boils out of the wood from below the surface. Also, I kept the humidity around 80% until I decided to equalize. I have found cores at lower MC than shells.

[serg]

Dan, Your work is good! The question is, how do the guys think with England? The forest they dried in a vacuum kiln?
Sergey

[Den Socling]

Thanks Sergey but my work has to do better.

What were you asking about England? I couldn't follow that.

[GeneWengert-WoodDoc]

When drying a square with conventional drying, if they are spaced apart, we have over 50% more surface To volume as we have when drying lumber.  For example, an 8/4 x 10" x 12" piece of lumber is 288 square inches of surface area and 240 cubic inches of wood; this is a ratio of 1.2.  For an 8/4 square x 12", we have 96 square inches for 48 cubic inches, a ratio of 2.0.  This means that at the same temperature, humidity and air flow, we will get over 50% faster drying of a square than we get for lumber.  With oak, this faster drying can mean checking and honeycomb.  With vacuum drying, the surface area helps move water without the shrinkage gradients we see in conventional, so square drying is more easily done, although the rate might be slowed slightly to be safe.  Getting back to conventional drying, this surface area to volume ratio is why it is good to not space squares apart (or even narrower pieces of lumber), and not good to mix squares and lumber unless the schedule is modified.

[serg]

Den. On the forum there was a post. The boys from England did a vacuum chamber drying from the tank, they dry forest in the vacuum contact method?

[Den Socling]

It's a sad story, Sergey. They kept trying to dry the same load of White Oak after making modifications to the kiln. They ended up in disagreement and separated ways. The last time I heard from John, he was in South America and the kiln was in England collecting dust. It's a real shame after those young men did all of that extraordinary work.

[Gearbox]

Den when I worked as a millwright we had a vacuum oil drier . that thing was cool . Hook it up turn it on and watch the water run out of the oil . Free water was a problem you would get boil overs . I could dry 150 gal of milk colored oil in 8 Hrs.

[serg]

Dan, the sad story of the beautiful young guys. I know a lot of stories, when the company goes in the direction from each other. First North, second South.

[Sawmill Man]

Den is it possible that the thermal transfer between the plates and squares could have been different because of slight variations in size of the squares themselves ?

[Den Socling]

No, because another technique that I use negates the required contact. Almost 20 years ago when I built my first kilns, the company had a sloppy head saw. Size would vary by a quarter inch. In those days, we were drying squares and when the operator thought they were dry, he would bleed vac and pull samples. Guess what they always pulled. The under-size that had no contact with the plate above and were easy to get out. And they would be dry.

[Den Socling]

Well the guy who sent the test load of 4.5" x 4.5" x 6' White Oak ran them through a moulder and then talked me into drying 600 more. 200 showed up this morning.



 



 



 

If he wants any more, he is going to buy his own DanG vac kiln.