Experiment 38: Iron Thermite!

After years of anticipation, I finally succeeded in making iron thermite, the king of infernos!  I used the aluminum powder from Experiment 35: Ball Mill & Aluminum Powder for Thermite and the iron (III) oxide from Experiment 37: Making Iron (III) Oxide for Thermite mixed intimately in a 1:3 mass ratio.  The resulting mixture was a somewhat golden color and had the consistency of flour.  I placed the powder in a depression dug in a pan of sand and lit it with a 2" magnesium ribbon.  The reaction exceeded my wildest expectations - it was an utterly brilliant ball of orange flame, totally engulfing the pan with its furious power.  Check out the video below for footage of the event:

Also, I have now started a Summer of Thermite playlist on YouTube, so be sure to subscribe to my blog by email or to my channel via YouTube to keep up with these firey experiments.  I plan on doing many more reactions similar to this one.

After the slag cooled, I removed it from the sand and broke it into fine pieces using a hammer.  For the most part, it was bubble-filled glassy alumina that easily fractured.  In some pieces, I found small blobs of iron produced by the reaction.  I cleaned the black oxide off the pieces of iron using vinegar and then swished them around with sand to abrade off other surface contaminants.  After weight the resulting product, I was absolutely astonished to find out that I had only recovered 16 grams of iron from the reaction!  Without even calculating anything, that is a terrible yield, considering I converted over 200 grams of iron in my iron (III) oxid
e producttion.  But since I like chemistry, I did some simple stoichiometry to reveal that starting with 322 grams iron (III) oxide, the theoretical yield would be 225 grams iron metal, so I got a 7% yield.  I believe most of my iron flew up during the reaction and rained down to earth as tiny iron droplets.  Honestly, though, the yield is of little concern to me considering how exciting the reaction was.  :)

Experiment 37: Making Iron (III) Oxide for Thermite

In the last experiment, I made fine aluminum powder, with the intention of doing the thermite reaction.  The most common type of thermite is the iron thermite, and its second ingredient is iron oxide.  Both red and black iron oxide will work, but I used red (iron (III) oxide), because it was the most common and I saw good instructions on making it.  Basically, the process involves running electricity through iron electrodes in a brine electrolyte until one electrode is completely eroded away.  This produces rust from the iron.  I switched the polarity (+12V and ground) of my electrodes every 12 hours to even out the erosion and make the cell last longer.  After 36 hours, I drained the excess water and baked the sludge at 400°F for an hour.  I then ball milled the product to a fine powder.  I also made a video showing the system I developed of making red iron oxide in large amounts (it works quite well):

Update to Experiment 7: ATX Computer Power Supply Conversion

Although blowing up hydroxy-filled bags and creating shotgun-level bangs was fun, the end result of the last experiment was that I burnt out my lab power supply.  To remedy this situation, I acquired another ATX PSU from a friend and converted it, this time with some added flair.

Previously, I used two packs of overpriced binding posts from RadioShack.  Each pack had one red and one black, which meant that for three positive voltages I either had to buy even three packs or just use a black post where a red one should have gone.  I opted to use a black binding post where a red one should have gone in the +5V terminal.  That didn't look good, so this time around I found an online supplier and exactly what I needed.

I had also previously broken a blade of the fan on my lab power supply.  The fan was on top as there was no space left inside the unit.  However, I didn't have extra screws for the fan cover, so I left it off, and a fan blade got broken.  For my second lab power supply, I reused four screws from the broken unit to attach the fan cover, which gave the supply a nice shiny finish.

Lessons learned from destroying and rebuilding my lab PSU: 
  • Don't try to trick the overcurrent protection on an ATX PSU - it's there for a reason.
  • Source parts online - it's cheaper (sometimes free) and has better selection that RadioShack.
  • Using social connections to obtain unwanted (but useful) parts can pay off handsomely - the PSU I previously bought for $20 was free the second time around.

Experiment 36: Hydroxy Gas Fun

A very, very long time ago, I found a cool YouTube video (this is how everything starts, right?) showing a hydroxy torch melting stuff.  Hydroxy torches are pretty neat, because they burn H2 and O2 gas cleanly, only producing water and a whole lot of heat.  The heart of the hydroxy torch is a hydroxy generator, which electrolyzes water to split it into its constituent gases.  I tried making one with hot glue and some scrap metal, and it failed about as badly as the word "hot glue" signifies.  Hot glue is an inferior building material.

Years later, I was inspired to work on the project again when I saw a friend's hydroxy generator that he bought off eBay.  I used the same scrap metal from the first generator design, but this time I used some proper plastic rods with spacers to assemble my electrolysis plates.  This time, the design worked beautifully!  I demonstrated that the generator worked by filling various containers with the explosive hydroxy gas and igniting them with a remote match.  The video below has a compilation of some of the best explosions:
Regrettably, I seem to have burnt out my lab power supply (Experiment 7: ATX Computer Power Supply Conversion), so I'll have to make a new one and be more careful with my current consumption.  Perhaps after that, I will use the hydroxy gas for a torch, but as of now, I am extremely happy with my newfound source of earth-shattering explosions.  :)

Experiment 35: Ball Mill & Aluminum Powder for Thermite

Years and years ago, I decided I wanted to make thermite, so I tried to make a ball mill for producing aluminum powder, a key ingredient of most thermites.  A ball mill powderizes materials by crushing them with the continual falling action of hard milling balls (in my case steel ball bearings).  My first attempts to build a ball mill failed horribly.  They were slow, finnicky, and didn't work at all.  A couple months and a few YouTube videos later, I built one using a corded drill and some castor wheels, along with a metal container.  The attachment of the drill to the container lid was so stressful that I ripped a perfect circle out of the container lid.  I then switched to a plastic container with small bars on the inside to lift the balls up and send them crashing down on the aluminum foil inside.  This worked... until the drill melted.  No joke, the plastic on the drill melted and that was the end of the drill.  Oops.

A few more months went by, and then I got a free dryer off Craigslist.  The motor worked well, even though the first attempts to use it didn't.  One time the motor spun so fast the ball mill container flew off toward the ceiling!  I finally figured out a way to harness the speed of the motor with some belts and wheels to tame its ferocity.  However, the ball mill still had the small bars on the inside.  Most ball mills don't have these, for good reasons - they are loud and hard to clean (especially when attached with duct tape!).  So, I took them off, and the balls in the mill proceeded to slide, rather than tumble.  After a few more months of apathetically looking at the years-long failed project, I finally got the motivation to finish it and found a container that I hoped was the right size - the balls filled it approximately halfway up.  To my extreme surprise, the ball mill worked!  After years of dissapointment and failed prototypes, the mill jar finally opened to reveal ultra-fine aluminum powder!  This is how many things in the inventing/experimenting business go. They take perseverance and dedication to finish and might not be immediately rewarding, but they will pay off if you finish strong and pull through until the end.
This has been the too-long story of how I built the ball mill to finally fulfill my dream of thermite.  It takes about a week for it to turn foil shreds into fine powder.  The aluminum powder produced has been confirmed to work in thermite.  To sum up the mill's actual operation, I made the above video explaining how it works for milling aluminum... or anything else highly flammable.  :)

“I have not failed. I've just found 10,000 ways that won't work.”
― Thomas A. Edison

Experiment 34: DIY Metal Stamping

A while ago, I found myself wanting a good way to make metal stamps for stamping element symbols into the various pieces of metal I have, in order to identify them when the time came to melt them into new and interesting objects.  To accomplish this, I used a steel bolt and the electro-etching process to make a neat little stamp for hammering into metal.  I first sanded the head of a bolt so it was flat and almost mirror-like in finish.  Then, I applied masking tape and used a box cutter (along with a strong light) to painstakingly cut away the design, flipped in reverse.  Since it's reversed, it will stamp out in the right direction.  I then attached the bolt to my power supply's +12V and hooked another wire up to the ground terminal.  I then placed the ground wire in the bottom of a dish with about 1/2" of strong salt water and put a cotton ball on top of it's exposed metal strands.  I pressed the bolt head onto this lightly and waited about 10 minutes.  What happens is the electricity erodes the exposed areas of the positive anode, producing iron oxide.  This darkens the brine solution.  After about 10 minutes of etching, I rinsed off the bolt and peeled off the tape.  The places under the tape were still shiny, but the exposed areas had eroded away considerably and were deeper than the lettering, as seen above.

Finally, although it might not have been necessary, I hardened and tempered the stamp.  This will prevent undue wear of the stamp, since it will undergo a lot of force throughout its life.  I used a propane torch to heat the stamp head bright orange and then quickly dropped it in room-temperature water.  To relieve the stresses built up by the sudden change in temperature, I tempered the stamp by heating its entirety to a blue color and then letting it cool in air.  After testing on a strip of metal, I was quite pleased with the result.  Honestly, I didn't think it would turn out this well.