Monday, March 29, 2010

Additions to the 'recycled' staircase.

While waiting for the treads & risers to return from the kiln, I built a series of curved shelves along the outside edge of the staircase. Since the wall is less than 3 feet tall, I was able to use a variety of short studs salvaged from other buildings, and scrap plywood pieces I saved just for this project. I also scored a pile of tongue & groove wainscotting removed from a friends turn-of-the-century garage (yes, I said garage- from back when construction was considered a 'craft').
I was able to salvage more than enough to complete the wall, so I may use the rest to build cabinet doors in the kitchen....
I hit it with the palm sander to remove the surface residue and gave it a seal coat of shellac, then my mom came over and put on several coats of our Bioshield clay paint and AFM Polyureseal to match the ceiling upstairs- nice! The top shelf will be a built-in storage cabinet. While researching lighting options, I stumbled across a really cool LED step light kit from somebody far more intelligent than me. The little LED bulbs are flush-mounted into holes drilled through the back of each step riser, and the whole system is motion activated by infared beams at the top and bottom steps. It only took me couple hours to install the whole system, and at night it looks something like this:
The lights automatically fade out one-by-one after about 20 seconds, then are reactivated whenever motion is detected. After playing with them every night for a week now, I'd say the lights are about 50% safety feature and 50% pure geek bling :)

Monday, March 22, 2010

Solar Sundays- Part II

The plumbing and controls parts arrived by the end of the week, so I was able to finish up the assembly yesterday. Before attaching the glazing, I installed a snap switch inside the collector- this will control the circulating pump as the collector's temperature changes.Here's the finished collector, with twinwall polycarbonate glazing fastened down.
I soldered together a pumping station and mounted the assembly to some home-made wood brackets. I was able to borrow the expansion tank from a friend, and I used the pressure relief valve off a spare water heater we have. The rest of the components (temp gauge, Taco pump, and fill/purge valving) were purchased new. The parts cost around $130, so together with the collector parts we are at about $250...a small price to pay for a lifetime of heat (and the satisfaction of watching the bottom fall out of Exxon stock someday).
Ready for installation next weekend!

Friday, March 19, 2010


It wasn't supposed to happen like this. I don't like failure, and I generally do an excessive amount of research and testing to make sure projects go as planned. So when I learned of a very new 'green' concrete counter top mix called Eccorok, I was excited, but cautious. This product consists of 98% fly ash (a byproduct of coal-fired power plants), which exhibits the same chemical properties of Portland cement. I was aware of fly ash being used as an additive to Portland-based cement (it makes for harder, stronger and more chemically-resistant concrete), but this new Eccorok product actually replaces all of the Portland cement in the mix. Since traditional Portland cement is extremely energy-intensive to produce, replacing it with an industrial waste product like fly ash is a double bonus for the environment...very exciting stuff.
I ordered a small quantity of the Eccorok and cast a couple of sample pieces to test the formula and develop the color tint that I was after. It seemed to be easier to work with, stronger, and more dense than Portland-based product I had used in the past, so I was sold! We purchased enough for casting the barn kitchen counter tops and back splashes, and I got started making the templates and forms. The forms were made at a friend's shop, on his steel casting table. The counters are formed face-down and the mix is contained by the melamine borders glued to the table. Since I couldn't fit all the forms on the table, I made one of them (shown in the foreground) on a base of our particleboard material coated with polyurethane, and let it overhang the edges of the casting table. Also shown is the steel rebar pieces that are suspended in the form to reinforce the concrete.
With the forms prepared, we were ready for 'casting day'. On the advice of the distributor, I made one little change to the mix formula by adding a set retarder this time- a product used to slow the rate at which the concrete hardens, thereby increasing the "work time" available. Seemed like a good idea, and the casting process went well, or so we thought.
But that seemingly innocent little additive was a BIG mistake! In the cool, low-humidity northern Minnesota conditions, the last thing we needed was a set retarder. Instead of 'curing' in the forms, the chemical hardening process was so much retarded by the additive that a reaction took place between the mix and the surfaces of the casting forms and table. When they were removed several days later, we had to forcefully pry the counter tops off the casting table, and parts of the counter tops literally delaminated in the process. Instead of the crisp edges and dense hard surfaces I was expecting, they were crumbly and porous. At first sight, I thought they were ruined and I'd be starting the whole process over the next day...not a good feeling.
Not wanting to toss them in the landfill and start over, I set out on a long process of damage control. The voids were filled with a 'slurry' paste of Eccorok and cenospheres (extremely small ceramic particles reclaimed as a by-product of coal-fired power plants), tinted to match the counter top color. The slurry was rubbed onto the surfaces, allowed to set up for a day or two, then wet-polished with a disc sander. But the counter tops were so soft, that the polishing process would just pull the 'grout' right off, leaving the same voids that I started with. This process was repeated several times with no success. As I dumped more time into the project, the situation improved little. Then a friend had the great idea of applying a densifying agent to the surface, which made all the difference in the world- the counter tops hardened up, the next slurry application held on better, and they began to smooth up. Shown below is the counter top after wet polishing (the wet surface makes it look shiny). The lighter brown areas are the grout-filled voids, while the darker brown is the original material. With the pieces looking hopeful, they were finally moved into the barn. Each section weighed several hundred pounds, so the process required some careful choreography and ample horsepower.
Here's the pieces set in place in their rough form.
Satisfied with the fit (and happy they didn't crack or break on moving day), I continued the slurry/grout process several more times, trying to fill the voids and get a smooth surface prior to sealing. Not able to wet polish inside the barn, I did my 'polishing' using a palm sander and a vacuum cleaner to contain the dust. It was still a mess!
After a total of 7 slurry applications over a several week span, I realized the counter tops were about as good as they were going to get- not at all what I had initially expected, but nevertheless good enough. The final step was to apply the sealer- in this case we went with a water-based zero-VOC epoxy called Eco-Tuff, which had held up pretty well to staining and water in my earlier sample testing. After one coat of the Eco-Tuff primer, and 3 coats of the epoxy, here is the finished product.
That's the end of my Eccorok experience for now. Start to finish, this project took around 2 months! Despite my troubles, I'd recommend the product to others and would definately use it again myself- but would omit the set retarder next time!

Monday, March 15, 2010

Solar Sundays- Part I

My interest in solar projects has been growing for a few years, and I've been researching solar water heating hoping to someday install our own system here at Green Gate. While the government tax rebates for solar projects sounded attractive, we found they would only cover a small system- basically enough for domestic hot water heating, but not for winter space heating. Purchasing a multi-panel solar thermal system would be cost prohibitive. So once again, I came to realize if you want to get something done, you have to learn to do it yourself! Having spent many a night perusing websites and solar forums all winter, I thought it was time to dive in and actually build something myself. With an enthusiastic 'okay' from my wonderful wife, I decided to start dedicating a day every week towards getting a 'prototype' system online and tested. Here is our first solar collector, inspired by designs on the Build it Solar website (one of my favorite resources for a variety of sustainability projects, by the way). Basically, I started by making a 4X8 'box of 2x6 lumber and a plywood bottom.
Then I added 1.5" of polyiso insulation over the plywood.
Next, I soldered together the copper piping that will carry water through the collector- basically 1/2" 'risers' connected to 3/4" manifolds, with an inlet on one end and outlet in the opposite corner. This copper is the expensive part of the project, but I managed to get a pile of tubing for less than scrap prices off Craigslist about a month ago! The photo shows the copper assembly as I was pressure testing it prior to the next step.
To make the 'fins', I took my leftover aluminum heat transfer plates (these are the ones I was using for the in-wall hydronic system installed in the bedrooms recently) and expanded them to 7/8" dia using a pipe, a simple wooden jig, and several blows from a sledgehammer. Good exercise. The fins were then clamped around the tubing using some special vice grip clamps made by a friend of ours for this project. With the clamps forcing the aluminum fins tightly around the copper, I put in several screws through to the plywood base to hold everything in place. This system seemed to work very well once I got the hang of it. Here's a close-up of the fins installed over the tubing.
Then I gave the assembly a coat of black paint.
and finally cut a piece of twinwall polycarbonate for glazing (this is the same stuff I used for our raised bed garden covers). Other than trim pieces over the glazing, it is basically weekend I'll work on the pump and controls.....

Saturday, March 13, 2010

Zone 3 and the heat is on!

The last area calling for heat is the soon-to-be master bathroom in the upper level of the silo. Before tiling the floor, I installed a serpentine of hydronic tubing over the subfloor- basically 1/2" pex tubing pressed into Thermofin-U heat transfer plates, surrounded by 'sleepers' of 3/4" plywood to keep the floor at a consistent level. Schluter Ditra (the orange colored uncoupling membrane) was mortared over the subfloor assembly, and then our local slate cleftstone was mortared over the Ditra. By nature, this slate is not perfectly flat like manufactured tiles, so there was some resulting variability in the pieces. I did my best to maintain smooth transitions from stone to stone. After setting the stones, I put down the last few planks in the entryway, scribing the final board to fit the curve of the stones. The stones still need to be cleaned, sealed and grouted once the mortar has fully cured, but you get the idea. In the boiler room, I connected the lines for the bedroom and bathroom hydronic loops and installed electronic zone valves so they can be regulated separately from the in-slab heat. I also extended the supply and return branches that will run outside to the solar thermal panels we'll be installing this summer. Everything went back together and I fired the system back up this morning without any leaks. The barn is now fully heated and solar-ready!