Solar kiln for hardwoods part deux

[Dfw245]

please read post number 1 it Describes how to putthe kiln together, it also says u shaped vents.. the vents are for the warm moistur laden air to excape and the fresh air come up from the bottom. You may see moisture the first few days.. after that you should be good as long as your venting enouth air. you need to check the temp of the kiln.. you want it like 140 degrees in there..

if you put it together correctly you will have no issues..

It's been a while, but we last spoke about this kiln building. Well, life got in the way what can I say. Well I know it's September and nearing October so most aren't considering this anymore. However here in the south...In TX, temps are still well over 90F. This entire week is actually mid to high 90s with temps in the mid 80s not slated to be our avg until late October or so. I still have a little time to do at least SOME seasoning. It's been in the heat all this time so I don't need alot. Maybe a month of seasoning left.

Now for my question, I'm putting the kiln together and was wondering if it can be feasible without the extra wood frame that peaks at the top. Is it necessary to have that wood frame? Or can I just use the wood racks?

 

[johneh]

As long as you vent the top to allow the hot moist air to escape you are good to go
Vents should be adjustable to allow for heating conditions. The hotter the kiln
gets the more you want them open the cooler a little less vent. You are trying to
control or maximize the amount of moisture you are pulling from the wood

 

[Dfw245]

As long as you vent the top to allow the hot moist air to escape you are good to go
Vents should be adjustable to allow for heating conditions. The hotter the kiln
gets the more you want them open the cooler a little less vent. You are trying to
control or maximize the amount of moisture you are pulling from the wood

I just know he mentioned something about not allowing the moisture to drop onto the wood. Maybe if I just did a flat clear square of tarp and vented the top and one on each end, I'd think that would do it.

 

[Woodsplitter67]

It's been a while, but we last spoke about this kiln building. Well, life got in the way what can I say. Well I know it's September and nearing October so most aren't considering this anymore. However here in the south...In TX, temps are still well over 90F. This entire week is actually mid to high 90s with temps in the mid 80s not slated to be our avg until late October or so. I still have a little time to do at least SOME seasoning. It's been in the heat all this time so I don't need alot. Maybe a month of seasoning left.

Now for my question, I'm putting the kiln together and was wondering if it can be feasible without the extra wood frame that peaks at the top. Is it necessary to have that wood frame? Or can I just use the wood racks?

If your talking abot the wood at the top.. its not mandatory to have, but it does make things alot easier.. 1 it helps shed the water and less gets into the kiln. . 2 It makes the kiln vent more evenly and the more evenly it vents the more constant the wood will be.drying in the kiln. Having that extra space at the top is a benefit. Its really not hard to make and really the whole kiln should take a couple hours to put together correctly..

 

[Dfw245]

If your talking abot the wood at the top.. its not mandatory to have, but it does make things alot easier.. 1 it helps shed the water and less gets into the kiln. . 2 It makes the kiln vent more evenly and the more evenly it vents the more constant the wood will be.drying in the kiln. Having that extra space at the top is a benefit. Its really not hard to make and really the whole kiln should take a couple hours to put together correctly..

Understandable. I'm just not a crafter/builder. I'll screw a couple things here and there but drilling or sawing is out of my scope. I dont even own a saw or a drill. (I have an impact driver) so if I can get away without it, I'll try it that way

 

[Woodsplitter67]

Understandable. I'm just not a crafter/builder. I'll screw a couple things here and there but drilling or sawing is out of my scope. I dont even own a saw or a drill. (I have an impact driver) so if I can get away without it, I'll try it that way

if it was earlier in the season maybe.. if your short on time and need the wood to get as dry as possible.. Id probably build the best kiln I can and skip cutting any corners.. if your going to do it.. why not try and get the best results as possible.. also the first builds are for learning.. so learn to cut wood and screw.. not that hard..

 

[PDutro]

I’m so glad to have been pointed to this thread by a member.

I’ve got between 1.5 and 2 cords of white oak that was cut into rounds and stacked in 2021.

I split it last weekend and the MC in the center was around 30-33% average. The outside ring is much drier, maybe 20-25%.

Included is a pic of the cheap stacking racks I’ve been using. I already bought materials to make two more of them, and am contemplating how I might make them work for a kiln.

My thought is to add a cross brace at each end between the two 2X4’s, possibly add another 2x4 in the center of the rack cut to the height of the arch cross brace, and run another 2X4 (or other long lumber) over the cross braces and over the end of the verticals center 2X4. Was that explanation clear enough?

Would love anyone’s thoughts.

 

[PDutro]

This will be my kiln, it's exactly like my other wood stacks, except it's oriented N/S and in a location that will receive full sun from about noon till sundown. I did build a taller 2x4 into the ends and allowed space in the middle for more, these will support my horizontal boards that my clear plastic will drape over. It's 24' long, and will hold about 2.4 cords. It's almost all red oak on the visible side, with white oak, maple, ash, black oak and hickory on the other.
View attachment 276244

This is basically exactly what I’m planning on doing. I also get sun from about noon to 5 or 6 with some shots of sun in the late morning. Hoping that will facilitate warming of the environment inside the kiln in the morning and build up of heat the last part of the day.

Anyway, how did this design work for you? Any pointers you’d offer someone planning to do an almost identical kiln?

 

[Woodsplitter67]

I’m so glad to have been pointed to this thread by a member.

I’ve got between 1.5 and 2 cords of white oak that was cut into rounds and stacked in 2021.

I split it last weekend and the MC in the center was around 30-33% average. The outside ring is much drier, maybe 20-25%.

Included is a pic of the cheap stacking racks I’ve been using. I already bought materials to make two more of them, and am contemplating how I might make them work for a kiln.

My thought is to add a cross brace at each end between the two 2X4’s, possibly add another 2x4 in the center of the rack cut to the height of the arch cross brace, and run another 2X4 (or other long lumber) over the cross braces and over the end of the verticals center 2X4. Was that explanation clear enough?

Would love anyone’s thoughts.

View attachment 313427

this looks ok.. id fill it up as much as I could.. results will be slow without alot of sun

 

[Poindexter]

I agree with @Woodsplitter67 that the results will show.

Local to me, I get my best (fastest) results when I limit the solar gain, temperature change, to about 40 dF. The rest is up to increased airflow. So if outdoor ambient is about 90 dF I don't see much point in letting the temp inside the kiln get above 130dF or so. Local to me, if my inside the kiln temp is more than 40 dF above outdoor ambient, I see that as an opportunity to allow more airflow, but I am seasoning white and black spruces. If you are into eastern hardwoods, @Woodsplitter67 is your best resource. If you are dealing with Douglas Fir in the PNW, meet @PDutro .

@BKVP I am now running a new design proven x3 years, improved by me 2023, and am drooling for the next "Best woodshed in Fairbanks" shootout.

 

[BKVP]

I'm heading to Shreveport this weekend and when I return, Fairbanks. So who knows, maybe I'll do a drive-by!

 

[PDutro]

I finished my kiln over the weekend. The spot is the best option for all day sun, so despite it being tucked up against the fence I’m hoping to see some decent drying between now and mid September.

 

[Woodsplitter67]

I finished my kiln over the weekend. The spot is the best option for all day sun, so despite it being tucked up against the fence I’m hoping to see some decent drying between now and mid September.

View attachment 313884 View attachment 313885 View attachment 313886 View attachment 313887 View attachment 313888

looks good Id say you see dry wood come fall. Where are the vents and how big are they. you probably could use a little pitch on the top portion to help shed the rain a little easier

 

[Woodsplitter67]

I wrapped my kilns on the 4th of july weekend. I moved the around in the yard yesterday.. The beech was 38% on the 4th when I measured it. We started off with good weather for seasoning. Since the 3rd week in june its been crappie her with the smoke from Canada and all the rain..

 

[PDutro]

looks good Id say you see dry wood come fall. Where are the vents and how big are they. you probably could use a little pitch on the top portion to help shed the rain a little easier

Thanks, I was relieved to get it done and pleased with how it came out.

There’s a slight pitch, with the high point down the center created by 1x2’s set about 6” above the top of the wood. Then I ran paracord across each side about two inches above the wood. The pitch is gentle, but I’m anticipating the slight dip created by the weight of the plastic ought to allow any rain to channel off at the low point of the dip at the sides.

If I observe a problem with rain pooling I’ll add 1x2’s to the center to creat a steeper pitch.

Vents are at either end, grapefruit sized. I’ll work on them some more to make it easier to adjust them open and closed, but for now Gorilla tape is working!