The Forestry Forum

General Forestry => Drying and Processing => Topic started by: WoodenHead on April 27, 2012, 09:30:52 AM

Title: Newbee question: Solar Kiln or DH Kiln?
Post by: WoodenHead on April 27, 2012, 09:30:52 AM
I'm looking at potentially adding a kiln to my setup.   As a value added service, the intent is to dry some of the wood (pine and oak) that we mill.  I don't want to start out too big, but not too small either.  Woodmizer offers both a dehumidification kit or a solar kit and many of you come up with your own designs.  I was wondering if the solar kilns work well for commercial operations or are DH kilns better suited?  Or is "neither" the answer.

I have a brother-in-law who is a cabinet maker.  He buys red oak from a large wood distributor and pays a considerable price for his wood.  He has tried small local mills with DH kiln drying operations and found that the quality just wasn't there.  As soon as he began to work with it, the wood would warp, twist, bend.  The experience he had he did not want to repeat again, because it cost him in ruined cabinets.

Any kiln I would like setup must be able to produce high quality products.  Are solar kilns suitable for this?  Are DH kilns suitable?  Was the poor quality that my brother-in-law experienced likely due to improper use of the kiln?
Title: Re: Newbee question: Solar Kiln or DH Kiln?
Post by: pineywoods on April 27, 2012, 11:13:19 AM
newbe, 2 neighbor sawyers and myself run pineywoods solar/dh kilns. See the lengthy post by planman1954 in the drying and processing forum. This is a solar kiln with a de-humidifier to pull the moisture out of the saturated air in the kiln enclosure...

pros... cheap cheap, I have about $250 in mine..
           get plenty hot enough to kill bugs, 160 deg +
            will dry boards down to as low as 6 %
            mixed loads are no problem
            no controls or fancy monitoring, just load it, close the door and
            wait.
            lumber from these kilns is stable, just about ideal for furniture
            low power consumption, just fans and small room d-h unit
            loadable with a fork lift or fel, no carts, no stacking
            easy to build, if you can build a chicken coop, you can build a kiln

cons     Slow, can easily take a month or more
             no control over drying time or conditions
             inconsistent drying time, varies all over the place even with like
             loads
             location sensitive, needs as much direct sunlight as possible.
             probably will be slower in northern climates
             published drying schedules do NOT apply

We have used them for  oak flooring, cedar furniture, pine millwork, oak furniture,cypress furniture and cabinets, beech cabinets, and osage projects
No problem with any of it.

If you need to produce dry lumber quickly on a predictable schedule, don't even consider solar, go with a commercial unit. If speed is a problem, build 2 or 3 and stagger the loads...
Title: Re: Newbee question: Solar Kiln or DH Kiln?
Post by: jdonovan on April 28, 2012, 09:31:17 PM
I imagine the solar kiln performance might differ a bit from ON, vs LA.

I would think for a commercial operation you would want a DH kiln not a solar. You have much more control over the drying schedule and therefore can reduce drying defects. Also you have a MUCH more predictable time from green to dry, and don't have to rely on sunny days.

QuoteHe has tried small local mills with DH kiln drying operations and found that the quality just wasn't there

A kiln is a tool, it can be used poorly. I've got paint brushes in my shop, but I'm no Picasso.