What to do when wet bulb reading is too low to kick on compressor?

[doc henderson]

sounds like you got this! 

[TBrown99]

As an update, my neighbor who does furniture making brought over 30 steam bent lamp posts in black walnut and white oak about 8' long 4x1 yesterday, which he needs to re-dry post-steaming. Results after 24-hrs are good though I lowered temps to 110 overnight (from 120). He's telling me this would be a regular request and he wants to ramp up his product. He normally let's them air dry 2 weeks in his shop, taking up a lot of room.

It seems that with temps now reaching 70 F outdoors, overheating and exhaust fan activation is occurring regularly, so I'm trying to figure out how to manage the auxiliary heat (which is required because unit heater can't maintain 120). The options involve adjusting the flow rate and temperature of hydronic system to radiant fins... but directing all flow from 3 system areas to only the drying room and adjusting flow level at the valve to this one location. Guess testing will show what works best.

Is it best to mount the powered exhaust fan low? Is this where it's meant to be positioned.

Waiting to proceed with adding insulation as warmer outdoors temps begin.

Still preparing white pine 5th charge test in the kiln room. Should be interesting with the new Lignomat system. With this system, it seems to be working fine though I've not evaluated the EMC wafer system, only the three temperature probes. It seems like a great system though the manual isn't entirely current as far as wiring requirements go.   

My big question now is how critical is it to minimize the exhaust fan coming on. I understand that maintaining a certain moisture level in the kiln works best and frequestion activation of exhaust makes this harder to maintain. I expect that like cooking food in an oven, it will just take some practice regulating the heat. But I'm still trying to figure out how "bad" it is to dry by allowing moisture / heat escape via the exhaust fan -- whether it's activate or just though slow loss when it's off via the poor seal in this area.

Finally, while I've know this for a while, the other 2/3 of this side shed would work very well as a pre-drying area... so I need to start looking at configuring this area for drying. Same applies to our 25'x30' back shed area.

[K-Guy]

When drying hardwoods in a DH kiln the idea is that you have better control of the drying when you don't vent but this is only a concern if the wood is over 25% as you can over dry it then and cause defects. Below 25% it is not a concern.

[TBrown99]

Thanks Stan. It's good to know that the 25% level applies to hardwoods too. (I'm preparing to do my first load of hardwood with a black cherry that came down in the woodland recently. But first another load of white pine.)

I'm still wondering if, before I add insulation, whether I should move the exhaust fan low.

The Lignomat remote pin system worked very well on my first "commercial" load: Redrying steam bent walnut and oak. 1.5 days drying. Pins helped me track it the whole way down vs. wondering what's going on in there.... I still need to bone up on the EMC monitor which I also have with the system. I say commercial but I didn't charge, as I'm still learning the ropes (and I don't know what's actually fair... and I'm thinking by time is easier than by board foot. )

I attended the annual Vermont Forestry Products Expo in Essex last week. Actually, the "Northeastern Forest Products Equipment Exposition, otherwise known as the Loggers' Expo, is the premier forest products industry trade show in the Northeastern US." It was interesting however there were not actually hardly any forest products, nevermind products from Vermont. There was one interesting company from Quebec selling finished red and white cedar shingles. The big hitters were based around logging equipment dominating the exhibits. That and tools and gear to support those machines. Perhaps that's the problem with the decline in the industry: Lack of local producers of actual products made from logs. But it's beyond me. What did make me stop and think was the conversation I had with the iDry representative, who from what I could tell was the only booth in the whole place with an old-fashioned salesperson actually getting up on a soap box and promoting their product no matter who might be listening. The gentleman there Mr Grenier is a true evangelist for the local products market arguing that it's time for small time producers to take on big boxes -- and he's ready to help get it started with their vacuum and conventional style lumber kilns. Very interesting. And it makes me proud that Vermont features this innovative company. Seeking to learn more. Though he said that it's possible to case harden softwoods by improper drying techniques, though I didn't specify the 25% rule.

Thanks!

[TBrown99]

FYI, I am considering an iDry vacuum system.

Paul at iDry claims that DH systems can't dry 2". (Perhaps he'd say they can but it takes too long.)

True?

[K-Guy]

Of course we can dry 2" material, it is just a matter of time as you can't force the wood too much depending on species.

[blackhawk]

FYI, I am considering an iDry vacuum system.

Paul at iDry claims that DH systems can't dry 2". (Perhaps he'd say they can but it takes too long.)

True?

I have dried 2-1/2" walnut, cherry, and white oak slabs with my Nyle L53.  Just like Stan said, it just takes time.  I always air dry first.

I know a full-time professional sawmiller/woodworker about 30 miles from me.  He bought an I-dry and hated it.  He ended selling it and going back to drying everything in his Nyle DH kilns.  He does a lot of slabs.  My info is 2nd hand, but heard that he had trouble with the quality of the lumber coming out of the I-dry.  That is just one person and I-dry sells a lot of kilns, but I would do a lot of investigation before pulling the trigger on that expensive of an item.  The thing that about the I-dry is that it is not built to set outside especially in a northern climate.  So, you will need a building large enough for it.  It also requires a clean water source to cool the vacuum pump.

[TBrown99]

Thank you for the feedback Stan & Blackhawk on i-Dry. 

I need to focus on fully utilizing my L53 before I even consider expansions. (STOP!!!) 

What got me thinking is that I have a 1700 sq. ft. 3-unit efficiency apartment building on the homestead that needs renovation bad though one end unit is okay, so crunching numbers on reno costs vs. potential income, it's very possible I could do much better with the building just drying lumber. Adding a new roof and side shed for the i-dry would be fairly easy compared to full renovation. Has heat & water already. Paul at i-Dry seems very helpful and knowledgeable. They try to help with marketing for you. He believes a local retailer would likely use service out of the gate.

[TBrown99]

For updates, I've realized that the remaining area of my side shed where my l53 is housed as well as my back "loose housing" (25'x30') -- with the main barn area 30'x50' with insulated ceiling, offer perhaps ideal pre-drying spaces -- as they both receive passive warm air flow via the barn attic space. I put two good fans in the attic space and closed up the side shed -- which has open soffits to the attic (unlike the two other sides which are fully blocked with the back loose housing being open yet facing prevailing wind direction)... and with warmer temps outside and sunshine was able to get the side shed up to 100+ degrees. With a few fans in there, it seems like a quite good pre-drying area. The back housing would require a large door facing outside. Though perhaps only for the Summer/warmer months.

My barrier is my inability at construction/building as I need to make small storage units to clear out these spaces for better lumber stacking. I have help from builder friends but still other work calls, so progress is slow.

[logbyr]

Through my job i visit a lot of different sawmills and quite a few of them are using vac kilns.
All of them say maple is a home run as wood is bright and flat when dried in vac kiln.  Quality is consistently good in thick stock and 4/4.  One has dried 11/4 green curly red maple for me in a week.  It came out wonderful.
They all say that walnut and wo are species that require a learning curve.  Neither species can be put in green off the saw.    They all tell me walnut will turn a greenish color when put in dead green.  If air dried it does fine.    Wo thick stock causes problems for all of them.    I hear of people who say they can do it but the guys i talk with say they can't get it to work
I've dried 2" walnut successfully in my nyle kiln.  It went in well air dried at 15%MC.