Archive for 24th January 2014

Another Elegant Cadence Sensor Magnet Option

I’m apparently on a quest to find ideal neodymium magnets for triggering the cadence side of ANT+ speed/cadence sensors such as the Garmin GSC-10 and Wahoo Cycling Speed/Cadence Sensor. I’d previously tried wide/thin (10mm wide, various thickness) magnets such as the one seen here on the Salsa El Mariachi Ti which sit on the end of the pedal spindle. This works well on the El Mariachi Ti where the crank boot supports it from the side, but on bare cranks it’s not difficult to knock the magnet off. My friend Jeremy has lost at least one magnet this way.

A few days ago I received some 8mm x 10mm (diameter x height) neodymium magnet cylinders via eBay and these seem like an even better solution. On Crank Brothers pedals with 8mm hex sockets in the end of the spindle, these magnets slide snugly into the 8mm hole, with a bit over 2mm poking out. This works great for triggering the reed switch inside the cadence sensor, and unlike other magnets which simply stuck to the end of the spindle, roughly 75% of the magnet is inside of the pedal so it won’t be possible to knock this one off.

Removing the magnet as needed is pretty easy, too. Because there is no flat surface at the bottom of the hex socket the magnet is relatively easy to remove. It can easily be pulled out with another magnet, by sticking a flat piece of steel to the top, or grasped firmly (say, with pliers or some strong finger tips) and slid out. While getting to this fastener outside of a shop isn’t usually needed, it’s good to have the option.

Well Seasoned Cast Iron Pans: Flaxseed Oil

Our house has a couple pieces of cast iron cookware, but it wasn’t seasoned very well and Danielle and I both wanted to change that. After some separate but overlapping research we both found that using flaxseed oil is best for seasoning cast iron cookware due to the high quantities of α-Linolenic acid (ALA) that it contains, as this will polymerize nicely during the seasoning process.

Sheryl Canter’s post Chemistry of Cast Iron Seasoning : A Science-Based How-To was the basis of much of the information used, but I disagree with some of her techniques (eg: applying very thin layers of oil then wiping them off until no longer visible, starting with a cool oven) as being overwrought. Starting with a clean, dry pan (scrubbing to get food residue off and putting in the oven at 200°F to facilitate drying) I instead did the following, using some food-grade refrigerated flaxseed oil purchased at Whole Foods:

  1. Using a piece of a synthetic fabric sock (a square about 2″ x 3″), spread a layer of oil on all surfaces of the pan. It should look oily, but not have any drips, sags, or pools. Be sure it is an even coat. Paper towel (which I tried at first) left lint residue that’d burn into the oil and get stuck in the coating.
  2. Put the pan in your oven and set to 550°F or so. The temperature needs to be above the smoke point of the oil, because during this smoking the ALA will polymerize and thus the cast iron becomes seasoned.
  3. Once the oven indicates it’s at temperature, set a timer for an hour. During this hour the cast iron should reach the oil’s smoke point, which’ll release a bunch of somewhat unpleasant smoke. Vent the house if you can.
  4. After an hour has elapsed, or once the oil is done smoking (you’ll get a better feel for this as you repeat the process) turn off the oven, open it up, and slide out the racks so the cast iron can cool.
  5. When the cast iron has reached a temperature that it can be handled with bare hands, repeat these steps as many times as desired.

To season our cast iron cookware I used seven repetitions of this process. Each took a couple of hours, but most of that time was waiting for the oil to smoke or the cast iron to cool down. The result on one of the pans, a Lodge Wedge Pan that Danielle received for Christmas from my parents, can be seen above. Prior to the flaxseed oil seasoning it had a factory season on it, which was a dull, thin-looking surface that only seemed sufficient to prevent corrosion during shipping. After receiving a proper season the pan was not unlike a used PTFE non-stick surface and quite pleasant to use.

Post-seasoning the cast iron can be easily cleaned with water, a plastic bristled scrub brush, and a gentle plastic scrub pad / sponge that’s safe for non-stick pans. This has easily removed everything we’ve had stuck to the pans and left the season intact.

† While flaxseed oil and linseed oil are the same thing, products labeled as linseed oil are commonly for wood finishing and usually contain drying agents and other things that you probably don’t want in contact with your food. Thus, it’s best to just suck up the seemly-high price of buying food-grade flaxseed oil at a local store knowing that it’ll be safe. Don’t worry, one bottle will last you for a long time; this process does not go through it very quickly.

Other oils could be used, but flaxseed oil will be the most efficient readily available oil due to it’s high ALA content. This portion of the Wikipedia article on α-Linolenic acid listing the ALA content for a number of different oils, showing that flaxseed is around 55%, while canola and soybean (both frequently branded as vegetable oil) are 8% and 10%. If a lower ALA content oil is used, it’ll take longer to build up a thick coating of seasoning (polymerized ALA).