Wednesday, May 30, 2012

Geodesic Dome Greenhouse - Part 12 - THE END

This is the final video about construction the aquaponic geodesic dome greenhouse. Don't worry, there are still more videos about the aquaponic system and other projects we're working on!

Hi Everyone.  I’m Rob Torcellini from Bigelow Brook Farm.  This is the last video on the series on building the geodesic dome.  I wanted to thank you for watching all of these.  I’ve had a great time of the last year building this.  Learned a lot, made a few mistakes along the way, but overall, it came out pretty good!

I’m planning on do a short series of videos about how I set up the aquaponics system inside the dome.

I also had this camera shoot about 1500 photos of the entire project that will be in a time-lapsed video.

Again, thanks for watching and we’ll see you soon!

It’s starting to get a bit warm in here so it’s time to add some vents.  I started by building frames that would fit loosely inside various areas around the dome.  There will be a total of five vents and each section will be able to swing open and closed.

Next I removed the existing polycarbonate glazing and then attached the new frame to the dome with a couple of standard door hinges.  In order to get the glazing to fit back into its spot properly, I had to cut it down a bit so that it wouldn’t hit against the hinges or the surrounding polycarbonate when the vent was closed.

I simply held the polycarbonate into the new frame and screwed it into place with the washer-backed screws and the vent was done.  The remaining 4 vents installed the same way, but just a bit trickier for 2 of them since they were 15 feet off the ground.

All of the exterior joints needed to be sealed to help prevent the rain from leaking in between each joint.  I used a clear polyurethane tape which is used as a protective tape on the edge of aircraft wings and wind turbines.  If it’s good enough to hold on to a wing at 500 miles per hour in the rain, it just may be good enough on the dome.  It was easy to apply by just removing the backing and pressing it down with a j-roller.  Once it bonds with the polycarbonate, it’s basically impossible to remove.  After covering each joint I drove a washer backed screw through the tape and polycarbonate.

Wherever there is a vent opening, I applied the tape to the polycarbonate and cedar which created a channel for the water to drain from.  I’m not sure how well the tape will bond to the wood…only time will tell.

Applying the tape on the upper areas of the dome proved to be a bit trickier. I found it to be unnerving being up there with the risk of sliding over the side or dropping through a section of polycarbonate.  I’m happy to say there were no trips to the hospital for this project!

I wanted to use some of the logs that I cut down last year from the site in a couple of areas of the dome and for grow beds for the aquaponic system.  My neighbor stopped by with his WoodMeiser saw mill and milled roughly 1500 feet of white pine into 1 inch and half inch thick boards.  It was a great way to save some money instead of buying lumber and we got to use some logs that would have gone to waste.

Inside the dome I covered the walls with some of the half-inch pine boards.  Each piece is roughly fitted, measured for the proper angle, and cut to size.  Sometimes the pieces had to be cut a few times to fit properly.  It was a very tedious process cutting all the angles, but the end result looks great!

In the shed area, I only filled the walls with one inch of foam to save a little money.  The rest of the wall cavities are filled with regular fiberglass insulation.  The boards on these walls installed much quicker since there are long and have square cuts!

The ice and water shield held up well through the winter but it was time to shingle the roof.  A friend of mine volunteered his crew to help out which was much appreciated.  Even for a professional builder, there was a lot of pondering on how to lay the shingles on the dome area.

On the south side of the greenhouse, I leveled and planted timothy grass.  Eventually, this area will used as a small orchard.  A local arborist was more than happy to get rid of their wood chips so I was able to spread this on the remaining areas that didn’t have any top soil.

The shed area and dome knee-wall is sided with cedar shakes.  They require little maintenance and they help to give a contemporary building a little New England feel.  I also added a small awning over the main entrance to make the building less….boring.

That’s about it.  There will still be more videos in the future.  If you have questions or comments, please leave them in the comments section below and I’ll try to address them in future videos.  Thanks for watching!

Monday, May 14, 2012

The Better Bell Siphon

This is an explanation of how a traditional bell siphon operates. It goes into some of the physics of how the auto siphon gets started and stops. One of the biggest problems I've run into is getting them to stop properly on large grow beds. I've solved this problem with one simple little piece! It's so simple, I'm kicking myself for not figuring it out years ago!

This grow bed is using 3/4" pipe for the drain and standpipe with a 2" bell. The fill rate is LESS than 1/2 liter per minute and the siphon still starts with no problem. It's been running for about a week without any problems.