Transporting a Free solar kiln

[scsmith42]

Back in 2011 a local woodworker sent me a PM asking me if I had seen the posting on the Raleigh Craigslist for a free solar kiln. Nope, I hadn't seen it (it was about 2 hours old when I received his PM), so I checked out the listing and was intrigued. The solar kiln pictured was the standard Virginia Tech design (one of the best and most popular designs), and the posting didn't say much about it other than that it was free, tall (14' tall), and that it would be suitable as a solar kiln or perhaps a greenhouse, but that it may need to be cut down for transportation. The posting also stated that insurance would be required from whomever moved it.

I have been thinking about building some solar kilns to augment my Nyle dehumidification kiln, and dedicate at least one of them for drying 8/4 quartersawn oak (it takes almost 4 months to kiln dry 8/4 oak from green in an L200). So the opportunity to get a jump start on this project was of real interest.

No phone number was listed in the posting, just the standard response via Craigslist, so I fired off a short response indicating my interest. A couple of days go by with no response, so I sent another e-mail response but from a different e-mail address, thinking that maybe my first mail was blocked by a spam filter or something. In my second mail, I kept it simple and stated my interest, the fact that I had the equipment necessary to move it, and that I could provide the required certificates of insurance.

The next day I receive a phone call from one of the asset managers at SAS in Cary. Turns out that they built a new building in 2009 - 2010, and wanted it to be LEEDS certified. So they recycled a lot of the timber from the building site into wood for interior use, and built the solar kiln to dry it. Since the project was complete, they no longer needed the kiln and wanted it to go to a good home (they had previously offered it to a museum, NC state University, and another sawmill but to no avail. Hence the craigslist posting before they sent it to the dump.

Their contact told me that they had received several hundred responses to his posting, and that my original response probably got buried in his inbox.  He was frustrated with the amount of time that he had spent talking to woodworkers, gardeners, etc;, primarily all elderly and retirees, and none of them had a clue about how to move it (and he sounded pretty frustrated).  He told me that I was the first person that he had spoken with that sounded like I knew what I was doing (had him fooled - ) and he told me that it was mine if I wanted it.

A couple of days later I went over to look at it, and this is what I found:



 


Of the two VA Tech designs, this was the larger model (about 18' long), and originally designed for about 1,600 - 2000 bd ft of 4/4 oak. SAS had tacked on an addition to one end in order to accommodate the lengths of their lumber.

During the next few weeks I provided the requested insurance certificates, and waited for their Risk Management folks to draft up a legal agreement between us. I also spent some time figuring out how best to move the kiln. We then signed all of the agreements, and I stopped by DMV to pick up an oversize load permit.  Finally moving day came and we arrived on site bright and early to prep the kiln for moving and to load it.

Because of the height (turned out that it was 12' 6" overall), I could not load it upright onto my trailer, as it would be too tall to fit underneath the highway overpasses (the peak would have been 15' above grade). So my plan was to brace it internally, bolt some skids to one side, and then pivot it onto my trailer by hinging the skids to one side of the trailer.  This would provide me with a maximum transport height of under 11', and  width of under 13', which would work for my transportation route back to the farm.

We took the backhoe from the farm with us in order to handle the loading.

Here we are arriving at the SAS campus, preparing to unload the backhoe:




 


After unloading, we removed the extension scabbed onto the end, and installed the temporary internal bracing:




 


The next step was to install the 6 x 6 skids on the door side, and to install some plates across the top of the skids so that the backhoe forks could support the side of the building:



 


Next step was to measure and determine our hinge location, so that the kiln would be properly centered on the trailer after we pivoted it over. Because the weight was not concentric, I opted to stagger the kiln about a foot to one side of the trailer so that we did not have too much weight hanging off one side. After measuring and installing the hinges, we jacked up the side of the kiln so that we could place the trailer right up against it, and then lower the hinge pins into the rub rail of the trailer:




 




 



After I got the front of the trailer right up against the skids, I took the backhoe and picked up / skidded the back end of the trailer up against the kiln, and we lowered the hinges into position.

The next step was to attach a safety chain to the backhoe fork carriage, along with a come-a-long, and raise the forks up to the top of the building. The plan was to start pivoting the kiln onto the trailer by using the come-a-long, until we had the top plate where it would intersect the first foot of the forks. This would give us ample clearance for the fork carriage not to damage the roof as we pivoted the kiln over. It worked perfectly (and I'm still surprised!).

Starting the pivot with the come-a-long:




 


Continuing the pivot by using the forks:




 


Attached to the trailer and ready to depart:




 


Instead of strapping the kiln to the trailer and risking damaging it, we lag bolted timbers directly to the trailer deck and then lag bolted the timbers to the skids. Worked like a champ!

After an uneventful trip back to the farm, I used a 25 ton crane to unload the kiln, basically reversing the pivot and hinging it back over the side and onto the ground. We had placed steel chokers on the ground before pivoting it off the trailer, so all we had to do was hook them up and get everything balanced:




 


Next step was to pick it and swing it over to the foundation that we built earlier this week. This is an interesting photo that I took through the cab on the crane as I was swinging the building over:




 


At the end of the day today, it looked like this:



 




 


In the pix above, we rebuilt the left side where we removed the addition, reworked the internal baffles and fan system, and re-sealed the entire unit.

The following day I went back to SAS to retrieve my backhoe. All in all the project went off without a hitch.  I have subsequently built three more solar kilns based upon a modified version of the VT design, and I've been pleased with them.

It's interesting to note the differences between the SAS kiln and the three that I built.  The SAS followed the VT designs pretty closely, using EPS foam board for insulation inside the kiln and single pane greenhouse poly carb for the collector.  Due to the depth and height, if I want to max out the capacity we have to hand load the SAS kiln using 5' deep stacks with special stickers. In the three that I built, I modified the design to make them less deep, yet taller so that I could use my standard kiln stack (40" deep and 6' tall) without sacrificing drying rate or capacity in the kiln.  We fork our standard stacks in and out of the three new solar kilns, and in the cooler months place them in the Nyle for sterilization after the solar KD cycle is complete.  The three I built differ also by the use of close celled spray foam throughout, and double pane polycarb greenhouse glass.  

In the winter months I'll see a 35 degree (or thereabouts) difference between the SAS kiln and the ones that I built, with mine running much warmer than the SAS in the cold months.  They operate around the same in the summer time.

Although this project took place 11 years ago, I'm posting it now in response to BradBB's thread about making a solar kiln transportable.

Scott

[Southside]

So what happened during the 11 years between the email and the move?  ;D

[scsmith42]

So what happened during the 11 years between the email and the move?  ;D

Many, many loads of lumber have happened in the ensuing 11 years!  .  I'm posting this now in response to BradBB's posting about making a solar kiln that is transportable.

[caveman]

Thanks for sharing, Scott.  I am interested in seeing pictures of the doors and the hinge arrangement used on your solar kilns (no rush, just some time when you are out there).  Our solar kiln does a good job of drying lumber but the installation of the center panel between the doors on ours is a cumbersome exercise.  When we build our next one, I would like to do some things different/smarter.

[Brad_bb]

For Scott, that was a tricky and well executed endeavor for sure.  My thinking was having in the design the top triangular portion of the kiln removable.  Removable to the extent that sure, you'd have to undo some of the solar collector, the doors, and have plates of the two separate pieces that mate up.  This would allow a straight drag onto a low boy or a somewhat trickier lift on to a flat bed.   This is so that you'd not end up with an over-sized load, and loading would be more straight forward with more disassembly required of course.  It doesn't appear anyone has done this.  My thinking is if I use them for 10 years or whatever and then decide I don't need them anymore, It would make it easier to move them for another sawyer.

[Ljohnsaw]

After an uneventful trip back to the farm, this morning I used a 25 ton crane to unload the kiln

Just happen to have one sitting around! :D  Pretty clever way to move it.  As I was reading along, I was thinking you should have put the kiln up front and then have room for your backhoe that you're gonna need to unload it!  But then, 'just use the 25 ton crane'.

[scsmith42]

Thanks for sharing, Scott.  I am interested in seeing pictures of the doors and the hinge arrangement used on your solar kilns (no rush, just some time when you are out there).  Our solar kiln does a good job of drying lumber but the installation of the center panel between the doors on ours is a cumbersome exercise.  When we build our next one, I would like to do some things different/smarter.

My largest one is 20' wide, with two 10' wide doors made of a simple 2x4 frame with a diagonal cable turnbuckle for adjusting.
No center panel.
What I did was basically design a parallel chord truss to span the entire length of the door opening.  It's around 4' tall, with a triple 2x12 header lag bolted to the bottom of it, and a plywood shear wall installed on the outside.  I wanted the wide opening to not have any sag - pinching the doors and creating problems.  This design has worked well with no issues in the past 8 years.






Here is a close up of the doors.  They have a cable and turnbuckle running across them to help manage the sag.  The outer plywood skins are glued and screwed on to the 2x4's, and the closed cell spray foam provides a lot of rigidity.  These doors are 10' wide and 8' tall.  I made sure that the kilns were leveled in all  planes and that the doors were adjusted correctly before the spray foam was installed; otherwise I might not have been able to adjust them afterward.  Typically I would construct a door with a lot of diagonal members to support the weight, but in this instance I felt that a lightweight door with a plywood shear wall and the spray foam would provide a better, long term end result.  So far I have not been disappointed.



 



Door hinges are simply heavy duty gate and shed hinges.

[scsmith42]

After an uneventful trip back to the farm, this morning I used a 25 ton crane to unload the kiln

Just happen to have one sitting around! :D  Pretty clever way to move it.  As I was reading along, I was thinking you should have put the kiln up front and then have room for your backhoe that you're gonna need to unload it!  But then, 'just use the 25 ton crane

Unfortunately, not enough trailer (weight capacity or length)!

[Peter Drouin]

 smiley_clapping Good job

[aigheadish]

Well done with your rigging and the move! I haven't done anything like this but rigging stuff up can be a very interesting (and kind of fun) puzzle to figure out. 

Thanks for sharing!

[Nebraska]

That was an interesting post  thanks for sharing.