March 24, 2015

Best garden tool for 2014: Austrian Scythe

My favorite new garden tool from 2014 is an Austrian style scythe from Scythe Supply. Over the winter I read The Scythe Book and watched some internet scythe videos, of scythe wielders beating men with gas powered trimmers in competition, barefoot young ladies elegantly and speedily mowing meadows, and the like. So I ordered myself a scythe outfit, mostly for cutting the grass in the front of my house which is unpleasant to do with a normal lawn mower. The kids thought this was awesome and were really excited to try it out.

March 10, 2015

Making LED Grow Lights

I want to grow leeks and alpine strawberries this year, and would like to try tomatoes and a few other things from seeds rather than seedlings. The only convenient place to start seeds at my house would be the basement. It is dank and dim, so some grow lights were in order.

To begin, I cleaned off a shelf and got some flat trays, lids, and seedling warming mats. I could possibly fit four flats on the shelf, but I started off with two.

There are plenty of nice looking LED grow lights on the internet, but the good ones are pretty expensive (like several hundred $ each). Some of the cheaper ones had low light output or were the wrong form factor for the shelf I had available.

I think these expensive LED lights are mainly targeted at the pot growing market, so people can justify shelling out some serious cash for equipment. People starting veggies inside mostly use flourescent tube fixtures. But this is 2015 and the LED lighting revolution is in progress, so I felt like I ought to take advantage of that. And for lights that will be on 14 hours a day, the energy saving aspect of LED was appealing.

Unlike the commercially made LED grow lights, LED strip is amazingly cheap these days on a lumens/$ basis. One could hack something together with scraps and so on to run LED strip, but I wanted these lights to be useful as general purpose fixtures when they are not in service for seed starting. I really like high CRI lighting, like halogens. At work I built some electronics work benches and put high CRI T5 high output tube fixtures on them, fitted up with high CRI bulbs. These are pleasant to work under.

So I ordered a 5 meter reel of "high CRI" white LEDs from ebay. Coming from China, they took a few weeks to arrive.

A number of times through this project I found myself thinking "really? did I really need to make my own lights?? Get a grip!". But what's done is done. I tell myself it was educational for the kids. And that 23 cents of electricity I'll save for the year when compared with fluorescent tubes.

I had in mind to mount the strip inside an aluminum channel which could also accommodate the drivers, a switch, and a diffuser/cover. The strip actually generates a fair bit of heat (input power is ~40W per fixture), which the aluminum helps to dissipate. Not finding a ready-to-use extrusion readily available, I ordered rectangle tube from OnlineMetals, chopped to length

then cut the top off (leaving a flange for screwing down the lid).

The bandsaw and a file served to make some mounting wings on the end of each channel.

Acrylic scraps from work made up the covers and end pieces.

I did this machine work in about half hour chunks during the occasional lunch break at work over a period of a couple weeks.

The flanges were tapped for M3 screws. The tap I used was munged so it ruined a few holes before I realized it, which I had to go back and helicoil to fix.

After getting all the screws in to hold the channels, covers, and endpieces together, I orbital sanded the lot, then hand finished with a nonwoven abrasive pad. I also added holes in the sides for electrical features.

The channels were selected to hold two Meanwell LPC-20-700 20W drivers I got for $10 each on ebay. In reality, the fit was a bit tight, so I sanded the sides of the drivers slightly to make them fit.

Each is held down with a pair of M4 screws.

AC power comes in through a 120V plug

through a plastic cord grip

and into the enclosure

to a toggle switch, then the drivers

neutral went from the service cord to a wire nut, then to the two drivers.

I had to do a little thinking about how to set up the circuit on the output side. Putting three lines of LED strip in the channel would provide about the right load for the two 20W drivers.

But the strip was 12V and the driver output 24V. So I divided the middle of the three strips in two and attached each half to an adjacent full strip, such that I had two sections of strip, each 1.5 lengths. These two sections could then go in series to allow them to run from the 24V drivers. Of course things would be easier if I had 24V strip and two 12V drivers, but this is what was cheap and available on ebay that fit my desired specs.

How to combine the outputs of the drivers? These guys had output voltage to spare, and I expected them to run out of current before running out of voltage. So I just put a 1A diode in series with the positive output of each driver, then wired them together at the input to the strips.

One issue I ran into was that soldering wires to the strips seemed to sometimes burn through the adhesive on the back of the strip and make contact to the aluminum channel. Or maybe the minus side of the strip is supposed to contact the substrate. In any case, the two strip sections worked fine when run separately, but shorted out the two were put in series. The solution was to put kapton tape strips under the places where wires were soldered on. The kids were impressed with the kapton tape because it was colored "golden".

Child 1 and Child 2 were happy to get a chance to do some more soldering, which they are always up for.

The covers were installed

and we were ready to go

Grow Center
These lights are pretty bright (about 3000 lumens per fixture), though I'm not sure the CRI rating is entirely reliable since the quality of the light seems yuckier than other high CRI lighting I've experienced. A 500W halogen worklight puts out about 10k lumens, for comparison. I'm not trying to grow actual big plants inside, I just want to make seedlings for transplanting.

The lights were mounted to the shelves, and I set up the warming mats with my all purpose temp controller box and a thermocouples for feedback.

I set the controllers for 22C, though mostly the warming mats are not quite able to acheive that. So probably I didn't really need the controller. One of the controllers didn't seem to actually work either. I did dig these out of the trash, so that could explain such a condition. Likely the output relay is blown; it is only rated for 3A. So both mats are attached to the output of one controller, with one thermocouple for feedback.

An appliance timer was used to switch both the lights and the heat mats.

We have a garden store nearby which specializes in hydroponic and indoor gardening (i.e. marijuana). While I don't grow that particular crop, it is a useful resource. I stopped in one day on the way home from work to buy coarse vermiculite, worm castings, and compressed cocoa fiber.

Child 3 and I rehydrated a brick of cocoa fiber

I decided to put in a little EM-1 microbe mix. Mostly the advice is to use sterile medium for seed starting. But I thought if any microbes are going to get in there, the best thing might be to pre-colonize the medium with beneficial bugs instead of waiting for pernicious ones to show up. I think we put a capful of EM-1 into the hydration water. No idea if that was a good or bad move, or if will make no difference.

Dang that cocoa fiber really expands. Must have blown up by about 7x!.

We mixed 1/3 each of cocoa fiber, vermiculite, and castings.

Child 1 and Child 3 were all over mixing by hand.

We added some water until it seemed well hydrated but not wet, then distributed to a 36 cell pack which I bought from Johnny's.

Then we sprinkled on seeds from Alexandria, Mignonette, and Yellow Wonder alpine strawberries, all from Annie's.

and barely scuffled the potting mix about the seeds.

We made sure the seed and upper part of the soil was moist.

We also made up a 36 cell tray with King Richard and Megaton leek seeds, from Fedco. Then we put the covers on and put them on the warming mats under the lights.

The seeds were started on Valentine's Day (2/14/2015). A little less than a month later, the leeks are doing fine. I've thinned them once already but should do so again I suppose.

And the strawberries are all germinated excepting one cell.

March 3, 2015

Felt Legion Cap

One day last fall, I could not find my felt gnome hat I made a few years ago. With cold weather closing in and no silly looking home made felt hat to wear, I urgently set to work to make a replacement. 

I like the angular lines and short brims of some military uniform style caps from 50-100 years ago. My plaster head cast was brought out for a bout of millinery, and I pulled a cheerios box from the recycling to cut up for a pattern. Child 2 and I messed around with the pattern for a while. We started with this:

Then I cut some slits in from the top and overlapped the cuts, to create a lightly tapered abbreviated cylinder.

This got trimmed at the top and bottom. Traced around the top to get a top piece, then traced around for the beginning of a brim.

Child 2 wanted to try it out at every stage.

After fooling with the cardboard and blue tape for a while, I had something that looked good enough for a first draft. 

I cut the paper mock up apart with scissors and an xacto. The brim was designed not as a perfect match to the oval shape of the cap edge. Instead, it was drafted to spread out a bit more such that when it was joined to the cap it would be given a light curve and downward slope. At least that was the idea.

Here is a photo of the pattern on my fabric cutting mat which has squares in the quaint old-fashioned units of inches (1 per square). The bottom edge of the cap part measures 56.5cm in length laying the tape along it's curve, while my actual head measures 56cm with a tape.

I did a quick sketch in Inkscape of something close to the pattern, bitmap shown below. If you want the PDF or SVG files, they are on my google drive for download. You could try measuring the circumference of your head, adding 1cm or so, then scaling the vector drawing up or down and printing it out on multiple sheets of paper. Or you could just draft a paper pattern using measurements and a square.

Remembering my experience with my last hat, I cut enough gray wool blend felt for two layers to make the new hat. I wanted it to be somewhat stiff and hold its edges so I also cut a layer of nonwoven sew-in interfacing to go between the two layers of felt. The interfacing was cut to not extend all the way to the seams, in order to make the corners and edges less bulky. The brim was made with the same construction. I now wish the brim was stiffer; perhaps next time I'll find a stiffer material to use for the interfacing in the brim. 

The treadle machine was used to laminate the interfacing layer to the inner felt pieces. 

Then I started sewing up two copies of the hat by hand. There isn't that much seam to sew, and the dexterity of hand sewing was useful for putting things together. 

I started by sewing the top oval piece to the strip which forms the main part of the cap, then joining the edges of the main part at the center back. I quickly found the hat was going to be too tight. Maybe my head mold shrunk during the curing of the plaster? Maybe because I used two layers, or I needed more than 5mm wearing ease? Becky says she has little doubt my head has gotten fatter in the fourteen years or so since I made that plaster cast. In any case, I cut a triangular wedge to patch in to the center back seam on both layers, bigger on the outer layer.

Of course the outer layer needed to be a little longer than the inner layer, which I didn't account for in cutting the pieces, figuring I could stretch and shrink the two layers with steam to match. That became impossible on the inner layer once I stitched on the interfacing. 

After finishing the cap section, I stitched on the brim.

Once the I had two caps, I put them together, did a little trimming with embroidery scissors to get the edges matched, 

then sewed around the lower edge and steam pressed to make one hat.

One of my favorite things about my old hat was the big red felt flower on the side. I recreated one to put on this hat, originally intending it to go in the front center of the cap section. But once I could try it on and experiment with placement of the flower, I found I preferred it to be offset on one side. 

This hat is pretty great. Comfortable and reasonably warm, for a bald guy. I wore it to California this last December to attend my sister Annesly's wedding. 

 I received several compliments on it during the trip. I'm used to a certain percentage of people in public giving me a double take when wearing my wood shoes or my gnome hat. This was also the case on this trip, but the quality of the looks seemed subtly different, like "that guy looks weird. But good" rather than just "that guys looks weird." Naturally I was also rocking my homemade high waisted wool pants, suspenders, and white shirt.

Last two pictures courtesy of Mary Gates.

I'd like to experiment with some 100% wool felt in a single, thicker layer. Might be less work to make the hat instead of dealing with three layers.

Here I am wearing the hat at the chinese new year's party put on by the chinese school the girls and I attend on Sunday afternoons. The kids are doing a game which my class organized where you can eat however many M&Ms as you can transfer to a cup in 30 seconds with chopsticks.

Photo courtesy Jean Newman

As you can see, anytime I need to appear in public and look nice, its either my home made black formal suit or the wool pants outfit. The only other clothes I still have that I can wear out of the house are four worksuits which are getting increasingly worn out.

Just the other week, my old hat turned up. It had been stuffed in the crack of a chair cushion in the living room. That's ok though, now I have two silly looking homemade felt hats!

I think almost anyone could manage to make a hat like this. Depending on your skills, it might take a few drafts and some time, but it is quite straightforward. Developing the pattern with paper and tape is a good method; you can just work on your own head with a mirror if you don't happen to have a plaster copy of your anatomy around.