Wednesday, August 25, 2010

PEX to the rescue

The week got off to a bumbling start for me as I let myself get sucked-in by a plumbing job on Sunday afternoon. I had to declare a draw at 8pm that evening an take a half day of vacation on Monday afternoon to get it done. The only uplifting part of the process was my discovery of pex which is the successor of PVC in the universe of plumbing. It's cool stuff. It makes much of the task as easy as tinker toys. It's like PVC without the glue.

I've been recovering from that for the last two days.

Tomorrow I have the privilege of filling in for the dean at an event honoring one of our faculty in Joplin. I am looking forward to it.

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Location:W 1st St,Pittsburg,United States

Saturday, August 21, 2010

Potato cannons: warning with regard to variations on design

Because of considerations concerning noise and neighborly relations, I have downsized the design from a potato cannon to a Q-tip pistol. This entails using the outer cylinder of a ballpoint pen as a barrel and a vitamin D bottle as a combustion chamber.

Being the creative individual that I am, I have been exploring different configurations. Today, I thought I would explore the possibilities of using baby bottle as the combustion chamber. It has more volume than the vitamin bottle so it would have just a bit more power. My first trial was a roaring success as I used a half-inch piece of plastic pipe for the barrel.

Encouraged by this success, I decided to try a model with a pen for a barrel. I sprayed in the fuel, pressed the button, and lost a nipple. Fortunately the nipple was from the bottle and not from me, but it was badly enough mangled to cause me concern.

I believe the problem is in using too small of a barrel for the size of the combustion chamber.

Once again I warn the reader these are not toys.

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Location:W 1st St,Pittsburg,United States

Tuesday, August 17, 2010

Jaws theme music

Having moved back into Grubbs, denial that the new semester is just around the corner becomes more difficult.

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Location:W 1st St,Pittsburg,United States

Monday, August 16, 2010

Moving day

Today was spent moving my office back to Grubbs Hall from Whitesitt Hall. We'd been in our temporary digs since mid-May. There were new international students being oriented today. They were being toured around the Oval in little groups.

The local traffic also shows signs of returning students as there is a noticeable increase in flow and more drivers who don't seem to know where they are going.

Still, I had no appointments today. As Gandalf remarked, it is the deep breath before the plunge.

- Posted using BlogPress from my iPhone

Location:W 1st St,Pittsburg,United States

Sunday, August 15, 2010

Potato cannon part 3

After yesterday's incident wherein I inadvertently fired my potato cannon using only the residue of the PVC priming agent as fuel, it occurred to me that a potato cannon could be considered a firearm. There are laws against discharging firearms within the city limits, so that sort of slowed down the testing process, that and the fact that Jean doesn't use Aquanet.

You see Aquanet is the Hoyle-recommended fuel for potato cannons. As you may have noticed, the creation of these devices is very much in the spirit of McGyver. You make use of the materials available. Aquanet is just an aerosol hairspray. As with many aerosols, the propellant is flammable, and that is what makes it useful as a fuel for the potato cannon.

In my desire to test my potato cannon, I was required to do some deep thinking and make some fine distinctions. Putting the potato in the end of it was out of the question. That would make it a firearm. However, if the potato is not in the end, it is not a firearm; it's just a fire starter because it is not propelling anything. With no potato it is a fire starter, with a potato it is a firearm, and with a cap on the end it is a fire bomb.

I tried using Jean's sprayable Pam. It didn't work, and I wondered if, perhaps, sprayable Pam uses nonflammable CO2 as propellant.

It then occurred to me that it might not be necessary to use an aerosol. Given the fact that the primer worked and it wasn't an aerosol, this seemed plausible. I looked for isopropyl alcohol, but we didn't have any. I did have rum left over from Christmas 2 or 3 or 4 years ago. I soaked a piece of cotton wool in it and rubbed it on the inside of the combustion chamber. I couldn't get that to work. Maybe the concentration of alcohol in the rum was too small or maybe I just couldn't convince myself to use enough.

I put it aside for the evening after that. I resolved that I would get Aquanet when I bought donuts on my way to Opolis for church this morning. Then, on my way out the door this morning, I noticed a can of windshield de-icer on a bookshelf in my office. I went outside, sprayed the inside of my combustion chamber briefly, closed the lid, and clicked the button.

It didn't make the boom of the day before, but rather the sound of a Coleman stove lighting. I felt warmth coming from the end and it dawned on me the thing was on fire. I smothered out the flame, loaded up the cannon, the spray, and a potato into my car, and headed to Opolis. There I conferred with Perry who is learned in the lore of the potato cannon. He was able to offer me sound advice.

Later this morning I was able to test the cannon with potato in place. The projectile went 100 feet and it sounded like a 22-rifle going off. This is not a toy. This is not for inside the city limits.

Saturday, August 14, 2010

This is me

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The Potato Cannon, Part 2

The last 24 hours have been quite instructive.

Ordinarily in my adventures, I proceed without doing research. I push the project in the manner I naively think it should go, and only when I get to a point from which I cannot proceed do I seek help. (I've been told I need to seek help anyway, but that is neither here nor there.) This time, as there are explosions involved, I decided to read up on the matter first. Before I proceed any further, let me tell you that the phrase "potato cannon plans" will open up a whole new world to you whether it is typed into the Google search engine or the YouTube search engine. For those of you who are carrying the Y-chromosome let me recommend this link.

I found numerous sources and used the one at this location. It gives a parts list and instructions. In that which follows, I will try to gloss a few things in order to give the reader a firmer understanding of the process.

I did my shopping to fill the parts list at Home Depot on Thursday on my way home from work. On Friday, I discovered I didn't have the size of drill bits I needed. (They're around here SOMEWHERE!) I went to Ace and discovered their selection of PVC accoutrement is better. In any case, I had all of the materials assembled by 3PM Friday afternoon. The one part that had bothered me in the entire process was the igniter. I worried about what it was, how to get it, and how to install it.

I will share the first two parts now and save talking about installation until the appropriate time. I am using a replacement igniter for a gas grill. These only cost about $4. They are by the gas grills in Home Depot. The young man in the store didn't know what I was talking about and sent me over to welding supplies. Catch him gone and look around until you find it yourself like I did. (You don't have to wait long.)

The theory behind the potato cannon is simple. A spark ignites fuel. The heat from the burning fuel causes air to expand. As the combustion takes place in a chamber that is closed in all directions but one, the expanding air is forced out of the chamber in one direction. In the potato cannon, the chamber is made of PVC. It is closed on one end by a clean-out cap. The open end of the chamber goes into a bushing that reduces the pipe diameter. In the case of the instructions I've shown you, it reduces from four inches to one-and-a-half inches. It is then directed into the barrel where the expanding pressure will force out the projective, the eponymous potato.

You can see how the spark is key. If there is no spark, then there is no combustion, no heat, no expanding air. It looked to me as if the igniter should be installed first so that care could be taken that it worked correctly as the addition of subsequent parts would make it harder to get to the igniter. Therefore I ignored the directions and installed it first, making sure that it sparked. It was as I was putting the rest of it together that it occurred to me that this was a safety measure. You see, in order to put the PVC pipe together, you use something called primer which is largely alcohol. This gives off fumes. I noticed this as the work was progressing and the question occurred to me about what might happen if my igniter accidently sparked.

I then told each of my daughters whenever they entered the dining room where I was working on this (Yes, it should have been done outside. It was 105 degrees Fahrenheit.) not to push the button, and they immediately began to tease me by pretending they were going to press the button. Once it was done, I immediately took it outside. This morning I took my walk. When I got back home, Jean was outside watering. I helped her for a few minutes and then I showed her my new toy.

"This is the igniter," I said as I clicked the button. The sound of a click was followed by the sound of a boom.

The spark had ignited the residual fumes from the primer in the combustion chamber.

I've gained in respect for this device. I respected it before but more so now. I will not put a finer point on it lest I should open up pathways that would get young people hurt, but let me say it would be very easy for someone to hurt or kill himself with one of these things if he decided to push boundaries.

Friday, August 13, 2010

The potato cannon, part 1

I've always been a quiet contemplative sort, even as a child. I was never rowdy or noisy. When Mrs. Vestal had us play the quiet game in class, I wanted to win it even if Arnita Madron did beat me out most of the time. I've always played it safe. I've only received two speeding tickets in the thirty-two years I've been driving.

I've never engaged in those high adrenaline activities that so many men are drawn to. I don't even like roller-coasters.

But then I was stricken by a mania, an obsession. I was briefly flipping through channels the other day when I passed the Discovery Channel where some respectable-looking middle aged men were running around with devices that appeared to be made of PVC pipe. Along the side was a decal that read "DIKTATER." (I will leave it to smaller minds to give a Freudian reading to that decal.)

One man used the end of the PVC pipe to cut a hunk out of a piece of potato. He then used a piece of dowel rod to tamp it deeper into the barrel, like a Minute Man might do with a musket. He then turned his attention to the other end of his device which was somewhat larger in diameter. Into that end, he briefly sprayed an aerosol can. He closed off end with a cap, hoisted the device upon his shoulder, and pressed a button.

At the pressing of the button a piece of potato was hurled from the other end.

A man the briefly explained that all that was required to do this was PVC pipe, hairspray, and an ignition switch from a barbecue grill.

It was upon learning of the simplicity of the thing that I was fully hooked. I decided that I had to make one.