Anyone here run a small non-solar/dh Kiln?

[No_Dude]

Maybe I just suck at using the search feature, but for the life of me I can not for the life of me find any info around about non-solar or DH kilns. Anyone here run one and care to share?

[Southside]

Are you trying to find someone who runs a DH kiln or some other non solar type like a steam kiln? If it's a DH style there are many of us.  

[No_Dude]

Like steam or something of the sort. Everything I read on here seems to be on solar or DH, so looking for non-solar or NON-DH. Should have been a bit more clear in my initial post.

[Ianab]

I think the problem with small scale steam is the energy / steam source. 

With solar your drying energy comes from the sun, and the control system is simple. Cheap to set up and operate. Drying is slower, but energy cost is minimal. 

With DH technology, you basically have an industrial AC / heat pump. The system recovers much of the energy from the evaporating water as it condenses, which is then pumped back into the chamber to evaporate more water. So depending on the system, you might use 2kw of energy, but get 6 kw of drying? You can buy a "turn key" box that can be added to an old shipping container and off you go. Reliable drying that doesn't depend in the weather. 

Steam works if you have a steady source of cheap heat, like a big waste wood fired boiler. Some of the local mills have systems rated for 50mW, and if the mill isn't operating they can even sell power back into the national grid. But a setup like that costs $millions, and needs operators to keep it running etc. But if it runs your industrial size kilns and knocks $1mil off your power bill, then it makes sense.  Hard to set up on a small scale though. 

Then there are RF and Vacuum kilns, that can be done on a smaller scale. But NOT cheap, and beyond most mere mortals DIY skills. Mostly applicable to high value wood that's difficult to dry otherwise. 

[GeneWengert-WoodDoc]

There are also hot water kilns.  There are also hot oil kilns.  The difference is the energy source, as these, plus steam, "all use hot air that is heated and that have controlled humidity". In fact, DH is rather close to these as well, except it operates at a cooler temperature.  So, the difference is hardware and not the drying mechanism.

Therefore, a text like Drying Hardwood Lumber applies.  The main difference for a drying operation is the cost...energy cost.  Electricity with a DH kiln in a smaller scale operation, under 1 million BF per year, is almost always the least expensive.  Basically, the electric company generates the power, which is simpler than making your own power with wood or other fuel.  Making your own energy is likely expensive in the small scale...under 1 million bf annually.

[DR Buck]

Mark, member "GA Boy" use to run a hot water kiln that worked OK.   But man was it a lot of work keeping it up and running.   After seeing his setup I'm glad I went to the Nyle DH kiln.     Mark sold off everything and got out of the milling and drying business several years ago.   

[No_Dude]

I'll see if I cant find some of his stuff. How thick of stacks, or how deep of several stacks of lumber do y'all run? I've read that you can go up to 15 ft deep, then you start needing reversable fans, and I thought that sounded REALLY thick, seems like most folks only go 1 or 2 stacks wide somewhere around the tune of 3-4 ft thick each.

[K-Guy]

The problem with small steam or hot water kilns is nobody I know of offers a package setup for them. That means you have figure out what you need and purchase the parts separately. The price of the boiler, fans, controls, etc add up to more than a DH or solar kiln usually. Also it requires a good deal of research on your part to get the equipment sized properly.

I hope this helps.

[GeneWengert-WoodDoc]

You need reversing fans for green lumber at eight feet of air travel. For air dried, twelve feet. 

A few small commercial hot water kilns, turn key, have been mDe and sold. WoodMizer used to have one.  Hard to compete with DH price-wise. 

[mike_belben]

I built a drying shed for firewood that was wood fired and based on a rocket stove burning trash wood from my splitter.  Used a horizontal draft pipe underneath the wood to heat the space.  If you picture a pallet rack with a stove on one side, a vertical stack on the other and a piece of pipe connecting them across the ground, with a pallet rack ontop thats been enclosed, thats pretty much it. 

It would get to about 150 or 160 inside and dry green wood well enough to burn in two days.  But for lumber it could be a disaster.  Theres a thread on it somewhere in this subsection.   Hillbilly kiln or something like that i think.  It never burned down but once i got the combustion optimized it was right on the edge.  Red hot flue and all wood construction.  

[No_Dude]

lol yea red hot flues and wood not necessarily a great mix. I had been reading on waste oil burners and was wondering if that could be used, if it piped the exaust right out of the room, and pulled air from outside the kiln, to eliminate any possibility of soot and the sort getting on the wood. But I was concerned about the warm surfaces around all the wood.

[No_Dude]

Also I was wondering if you could set a pump to pump 1 second of oil every 5 seconds, or whatever the determined happy medium was for keeping your burner burning, but not torching the place

[mike_belben]

I put in a lot of time on pure oil burning, both WMO and WVO in various configurations.  It was dangerous and almost impossible to deal with the viscosity change at warmup.  You either let the fire die or it flooded and hopefully went out... Spilling onto the floor. Or worse, overfilled and ignited in a lava red runaway.  Smoke was an issue, soot was an issue, messes, clogs, filtration, runaways.. Constant babysitting.. Theres not a quittin bone in my body, but i stopped burning pure oil.  If you want to do it, use an old becket gun and just build a furnace and filter rig.  Lots of filtering.

  If you want to burn oil the easy way, mix it in sawdust to the saturation point and build a stove for that.  The key is turbulent draft.  only the top half inch of an oiled sawdust pile ever burns.  And all that really does is char as it releases the vaporized oil which is burning above the mound.  Turbulence and swirl is needed to blow this charred dust off and expose more.  It is very similar to a wick in candle wax.  The amount of heat output is a consequence of the pile area and its turbulence.   A stove built from a vertical 30 gallon drum with a basketball sized pile burning in bottom and a tangential, swirl inducing intake tube at ground level, to a 6 inch vertical stack will easily heat a shop and run at 800-1100F.  

Its a good way to get rid of sawdust and theres hardly any seasoning required.  Stores easily in drums outside unsheltered.  No splitting or heavy lifting.

[GeneWengert-WoodDoc]

Probably everyone's knows, so let me repeat...

A kiln for almost all hardwoods and some softwoods needs control of both humidity and temperature.  This means that the hot air going into a kiln cannot be excessively dry.  This dry air will happen if the hot glue gasses are pumped into the kiln.  So, instead the kiln air is recirculated and drier air only comes in when the interior RH is too high.  So, heating and venting are separate events.  Normally the humidity is kept high because of or by the moisture leaving the lumber...in a tight buiding without vents or DH, the RH will reach 100% RH.

A direct fired kiln putting hot gases into the interior, versus using a heating plenum like a household furnace, can be used for construction 2x4, 2x6, etc.

[No_Dude]

I put in a lot of time on pure oil burning, both WMO and WVO in various configurations.  It was dangerous and almost impossible to deal with the viscosity change at warmup.  You either let the fire die or it flooded and hopefully went out... Spilling onto the floor. Or worse, overfilled and ignited in a lava red runaway.  Smoke was an issue, soot was an issue, messes, clogs, filtration, runaways.. Constant babysitting.. Theres not a quittin bone in my body, but i stopped burning pure oil.  If you want to do it, use an old becket gun and just build a furnace and filter rig.  Lots of filtering.

 If you want to burn oil the easy way, mix it in sawdust to the saturation point and build a stove for that.  The key is turbulent draft.  only the top half inch of an oiled sawdust pile ever burns.  And all that really does is char as it releases the vaporized oil which is burning above the mound.  Turbulence and swirl is needed to blow this charred dust off and expose more.  It is very similar to a wick in candle wax.  The amount of heat output is a consequence of the pile area and its turbulence.   A stove built from a vertical 30 gallon drum with a basketball sized pile burning in bottom and a tangential, swirl inducing intake tube at ground level, to a 6 inch vertical stack will easily heat a shop and run at 800-1100F.  

Its a good way to get rid of sawdust and theres hardly any seasoning required.  Stores easily in drums outside unsheltered.  No splitting or heavy lifting.

Yea having done some math, it would have to be a pretty small burner, so I was wondering how small of a burner one could make and keep it burning, but not just squelch the chamber.

[mike_belben]

Pure oil?  

A drip burner inside a wood stove chamber could have a burner as small as a tuna fish can and sustain burning but it would hardly warm the stove.  I had a dog bowl for a burner and also a bread pan along with a few other similar sized contraptions.  The issues are the same as what i mentioned but they scale up in size.  Temps on any of those setups could range from maybe 200F to cherry red, as drip control is borderline out of control. 

 A babbington burner is probably a lot more consistent but i never tried.  Theyre like an oil and air fired salamander heater made from a doorknob or copper ball float.  But still, youre filtering oil.  I switched to sawdust so i could pour in the worst of my settled out shmeggy barrel bottoms for disposal.  Creamy chunky watery stuff that would be hard to deal with any other way.

[mike_belben]

You know.. A babbington for a kiln might be a great idea if you have sufficient supply of waste oil for your kiln demands.  It just shoots a flame into a pipe.  No reason that pipe cant be ducted through you heat exchanger.  More air and oil equals more heat.

[No_Dude]

I'll have to look into a babbington and see what they are about. I agree that drip by itself is wildly inconsistent, I think you'd have to run some kind of electronic, be it a solenoid to control the drip rate, or a itty bitty pump. 

[GeneWengert-WoodDoc]

Analogy:   You need colorcopies.  Should you buy a color copier or let someone else like the UPS Store do color copies?
Or
Your truck needs front end repairs.  Should you build a service facility and do it yourself, or let Don's Truck Service do it?

With a small kiln that needs energy, should you get an energy generator, or let the electric company do it?

Every kiln drying company has to draw the line.

[mike_belben]

For pure oil drip burner a metered injection quantity really is a necessity.  In winter, initial startup babysitting probably would be too until the air space is up to temp and the viscosity change is complete.. But for the most part a gear pump wont care if oil is thick or thin.  A needle valve cares a LOT. 

Becket oil burners have a small oil pump with a bleeder.  Theyre perfect for coupling to a slow variable speed motor and fitting a hose to the bleed port to feed oil to the drip line.  Depending on ones savy with motor controls, automation can and has been done.  An automotive wiper motor is perfect for this.  For the offgrid crowd especially, a basic 12v solar cabin kit and batteries, a PWM speed controller, wiper motor, becket pump and copper tube.  

My basic quickie oil filter for stove fuel was a cut in half,  upside down 2liter bottle screwed to a wall stud to make a funnel.  A pair of old but not holy boot socks inside each other rubber banded around the bottle neck.  A stainless pot underneath caught the clean oil, then it went on the stove for preheating before getting poured into the drip reservoir.  A soft copper line went from the reservoir, through a needle valve for control then more soft copper than made a few loops around the flue for preheat before dropping into stove top where it landed in a burner.  

The "MEN heater" was the original water heater based 1970s rig and im sure hundreds have been built.  Each one is a little different and youre kinda on your own with the fine details.  One little baffle can change EVERYTHING about combustiom dynamics in any stove.


Stoves i know pretty well, but kilns i do not.  Gene wrote the book on that.