Forge Update

So finally after months of idleness Matt and I have got back to work on the forge.  Last time I posted we had simply stacked the bricks and a lot of propane was leaking out between the cracks. At that point we were planning on buying a 55lb bag of refractory cement and only using a very small portion for this project. Since then we found small containers of pre-mixed fireplace mortar which seems to be working for now:



Now that most of the flame is contained inside the forge we were able to get some 12 gauge copper wire heated to "red hot" which is about 650 degrees C or 1200 degrees F. Not nearly the 1080 or so degrees C needed to melt copper, but a good start.

It seems like the next hurtle will be coming up with a better "burner" as our "sidewalk torch" is producing too much turbulence inside the furnace. So much turbulence that increasing the propane above a certain point actually lowers the temperature inside.

For now more pictures:

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Building Moisture Sensors

This weekend we built a couple of resistive moisture sensors. While I cannot claim to have come up with the idea, I am nonetheless proud of building these moisture sensors from scratch. The basic principle is simple, embed two electrodes (wires) in Plaster of Paris which drys solid but porous. When dry the sensor will have infinite resistance (i.e an open circuit) but when placed in damp soil the plaster will absorb some of the water and the resistance will drop down into the 100 kilo-ohm level. By applying a voltage to the sensor and measuring the voltage drop across it you can get a pretty good idea of how moist it is.

Here is a series of pictures showing the construction process (which I will describe below)

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We had some 20 gauge uninsulated wire laying around which we decide would make decent electrodes for these sensors. If I were to do it again I would try to find some insulated wire so that I would only need to strip the ends instead of heat-shrinking most of the wire.

The first step was to modify some electronic header material for use as spacers. We broke four two pin sections off of the header and pulled out all of the pins. Next we enlarged the holes for our 20 gauge wires. If I do this again I will also try to find 22 or 24 gauge wire so I don't need to enlarge the holes in the spacers.

Once the wires were inserted into the spacers and bent to hold the spacers in place, we added two types of heat-shrink a small diameter tube around each of the wires and a larger diameter to hold the two wires together.

Next we taped one end of our straw sections closed and filled them with Plaster of Paris. Into this mess we inserted the bare wires and spacer construction.

Then wait... and three hours later sensors are ready. I used an exacto knife to cut off the straws and then let the sensors dry for a couple more hours.

Ta-Da cheap moisture sensor.

Experiments in Metallurgy

So we built a small forge this weekend. It still needs some refactory cement to fill the gaps between the bricks but with any luck we should be mealting down copper for lost wax casting soon. We also designed and build the table its sitting on. All in an afternoon of mad sciency doom.

The forge will be fairly inexpensive when its done. The bricks we got second hand off craigs list for 2.50 a brick. Which is pretty cheap for firebrick. So a dozzen bricks cost us only $30. The refactroy cement will cost us something like $60 for a 55lb. bag.  Our heat source is a "sidewalk torch" that we got from Harbor Freight for under $20, they have soo many cheap tools. So not counting time and energy the forge itself will cost just over $100 which in not bad at all for a small forge.

Good weekend.

Mad Science Runs in The Family

I was going through some pictures I took back in 2006 when I was in Germany, and I found some neat ones I want to share. You see, it turns out my great grandfather was somewhat of a pioneer in early photography. I wish I could remember the model of camera in these pictures but the important thing to know is that it was very early in the history of Photography.  The camera below was built before the advent of a shutter. Pictures were exposed by first covering the lense with a hankerchief or hat then removing said hat for a few seconds and then replacing it. My great grandfather got fed up with the lack of control of this process and added a custom shutter to his camera.

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In these pictures you can see, the camera from the front, the shuter in the open position, the shutter in the closed position, and the handbrake from a motorad (motorcycle) that great gramps used to control the shutter.

Ten does not a study make!

So I've been keeping up on wind turbine news the best I can since they look like a pretty good renewable energy source. Today I saw this article on a wind turbine health scare. It was publised by the Houstan Cronicle and it complete bullshit. The article opens with a sob story about some idiots who are afraid that wind turbines near their home will make them sick. Other than that emotional fuzz the article referneces one study of 10 families living near wind turbines. TEN !!!! for the love of TFSM thats not a study! Its barely qualifies for peliminary reasearch into forming a hypothesis. Even if it turns out wind turbines are bad for people's health ten is not a large enough number to come up with any conclusions. I cannot belive the Dr. Pierpont has the gal to call her ten family investigation a study. And then the Houston Chronicle has the balls to publish it as news! They got one thing right, this qualifies for a scare but only because the Houston Chronicle published it as news. This is BULLSHIT not science or news.

Gold Fish in a Deep Fryer

I had to see this one to believe it. Its basically a fish tank under a deep fryer. The video is narrated in Japanese but the science is pretty easy to follow.  This method has several advantages over conventional fryers.

1. No fillter nessicary. The fish eat any bits of food that fall into the oil.


2. No danger of splash-back if you spill water into the fryer, the bottom layer is already water.


3. This fryer definitely earns points on the madness scale.

Check out the video:


The only downside I can see is maintaining the fish. Its great that they eat what would normally get caught in the grease trap, but that diet can't be great and gold fish arn't famous for their long life in any case. So how do you remove the ones that inevitably end up "belly up"?  Maybe they float up to the oil and become fried fish food for their brothers and sisters.Even if you ignore the fish canibalism, there a bunch of fish poo to wory about. Fish tanks need a good scrubbing every once in a while last time I checked. So its probably not a practical invention but oh so cool.

Upside-down Tomatoes (Part 3)

A few more weeks have gone by and the results of growing upside down tomatoes have been mixed. One of the pants has put on fruit and like I originally guessed, started growing down with the weight of the fruit. Another has ignored the pull of gravity and grown up, around the side of the basket and continues to grow up towards the sun. This is not altogether unexpected either, it is a plant after all. The third plant is somewhere in between with larger fruit it cannot grow up too much but that has not stopped it from trying. I'll keep monitoring their progress though, they still have a lot of growing to do and with more weight from both the plants and their fruit I expect the plants will start trending downwards. We will see. For now check out my latest pictures to see what I'm talking about.