First charge loaded in the portable solar kiln.

[Delawhere Jack]

The portable kiln is finally getting a trial run. I offered complimentary use of the kiln to a client I've milled for several times. I figured a test run was in order to see if I'd overlooked anything major. We loaded 620 bf of 5/4 walnut that has been air drying for about two years. The stack had not been covered, so the MC was a bit higher than I expected. MC varied from 19% on some of the lower boards on the outside of the stack to 30% in the top boards. If it was my material, I certainly would have shelled out $50 for some corrugated tin to cover several thousand dollars worth of walnut.... but what do I know?  :

The only problem we encounter was that I had cut the tarp too short. It was 12' x 16', but I cut it to 8' x 16'. I had planned to use the 4' cutoff piece to lay lengthwise over the stack to create a better guide around the wood, and then drape the rest from the plenum to close it off. Turns out the 8' dimension was too short to reach the floor. The client chipped in $40 for me to buy a new tarp.

BTW, the client recently built a woodworking shop at the back of his property that would make anyone here on the FF drool! Among other gems, he's got an old 24" American joiner that he's restored to like new!





 

[GeneWengert-WoodDoc]

With air dried, the spacing from the edge of the pile to the back and front walls is not critical, but for green, you need at least 12".

[Delawhere Jack]

We left one foot front and back.

[tmbrcruiser]

From the southern end of the State congratulations on the build and first run.

[fishpharmer]

Looks good Jack!

[Delawhere Jack]

From the southern end of the State congratulations on the build and first run.

Thanks Cruiser. I need to swing by some time and check out you operation. Looks real good from the photos.

[thecfarm]

I hope all goes well.

[Delawhere Jack]

Day 12. Average MC for the three samples is now 24%, down from 30.3% on day one. It's been mostly cool and overcast the whole time with a few good hours of mid-day sun here and there. Temp and humidity inside the kiln is pretty good considering the weather. Today -- 45deg and 40%hum outside, 70deg and 51%hum inside.

Since the wood is below FSP I've closed the vents from 1/4 down to 1/8 open. Hoping to build more heat.

At what point do you other guys close the vents completely?

[GeneWengert-WoodDoc]

With vents closed fairly far, you will keep the hot air in the kiln so it will get hotter.  At the same time, however, the humidity will increase as the wood dried. This high humidity slows drying more than the heat increases the speed- - roughly above 12% MC, but it depends on thickness and species.

[YellowHammer]

I never close the vents completly, the moist air must be vented from the kiln.  However, I like to close them as much as possible to reach max temps.  It's kind of hard to describe, but if I open the doors in the heat of the day, and the kiln air is hot and moist, them I open the vents some more.

[Delawhere Jack]

Unloaded the kiln today. Average mc just below 10%. Yellow Hammer, I understand what you meant now. After the first week or so I closed the vents to were you could just stick a pencil in the gap. Enough to allow air to exchange, but tight enough to build heat. It took 7 weeks to go from about 30% to 10%. No drying defects found. There were some existing checks that opened some more, but the client was aware that would happen. He will Anchorseal any would we mill in the future.

We had to trim one of the smaller boards down just a bit to fit through his 12" planer since his 18" planer was not hooked up. ;D



  

  

  

 

[YellowHammer]

That's some nice looking wood and a great run.  You should be proud of yourself.  Congratulations.  8)

[Glenn1]

I agree with Yellowhammer.  To have minimal defects is quite an achievement on your first run!  Way to go.    8)

[Delawhere Jack]

I couldn't have done it without all the guidance you guys have offered here on the FF. Thank you.

[WDH]

Now you are up and running.  If you pre-air dry your wood, drying is pretty simple.  I try to only put air dried wood below 20% moisture content in my kiln, that way, I can run it wide open and maximize the amount of wood in the kiln while minimizing the drying time.  Your walnut looks great.

[123maxbars]

Nice looking walnut, great job!

[Delawhere Jack]

Now you are and and running.  If you pre-air dry your wood, drying is pretty simple.  I try to only put air dried wood below 20% moisture content in my kiln, that way, I can run it wide open and maximize the amount of wood in the kiln while minimizing the drying time.  Your walnut looks great.

Thanks Danny. I thought that this wood would be in the 15-20% range already. It's been about 2 years since we milled it. I didn't know that the client had left his stacks uncovered.

I wish it was my walnut....

[WDH]

Me too (mine)  ;D.