hpr-knowledge-base/hpr_transcripts/hpr0037.txt

Episode: 37
Title: HPR0037: This Old Hack Part 5
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr0037/hpr0037.mp3
Transcribed: 2025-10-07 10:38:51

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You
I'm working on a very special project today, I'm getting ready to go to Shmookon here.
I'd like to thank Larry Pesci from Paul.com for giving me a ticket to go to the conference,
otherwise I wouldn't be going to the conference, I'd just be going up to a party for a night
and sleep in my van and drive home the next day.
So what I'm doing is I'm trying to create a Shmooball Cannon, now a Shmooball is a stress-releaf
ball, one of those foam ones, and they use them at the conference when a speaker is talking.
You can throw the Shmooball at the speaker to interrupt the speaker in order to ask a question
or if you don't agree with what they're saying.
Now I know last year somebody made a Shmoob Cannon that was a modified leaf blower.
I've done some research on the internet and I see that people have made a ball launcher
out of PVC using one piece as a pressure rise chamber and then a sprinkler switch, a sprinkler valve
for, I suppose it's for landscaping purposes, a sprinkler valve to release the pressure
and so pretty much you pressurize your PVC with a pressure tank or some CO2 and then you
get one shot at about 40 to 80 psi which will launch a weighted tennis ball, something
like a 100 to 200 feet and a good height and they do this, it's called a pneumatic antenna
launcher.
You can research that they use the ball, they put a fishing reel type set up on the end
of the launcher and attach fishing line to the ball, shoot the ball over the top of
trees and then they get the ball and lower it so they can get a hold of it and then you
string an antenna up into the tree tops using air pressure and a valve to release the
pressure suddenly.
Now if anybody knows about making a potato gun, potato gun is PVC without a chamber on
the end but instead of building up the pressure and releasing it with a valve you have a larger
end with a screw-in cap, you spray some like a clampable gas in there like hair spray
or something and you have an ignition switch from a camp stove, you flip the switch, it
lights the gas and it sends the potato launching from the explosion from the compressed gas.
I've decided I had a moment of inspiration, came up with something almost completely different
and I'm not going to go, I don't want to go into all the details of the actual propellant
quite yet.
I'd like to leave that as a surprise for after the conference, but I have already been
to the store, picked up a few little things that I'm going to need to build the launcher
and it's very simple, designs, much like a regular potato gun, ever had a schmoo ball
before.
So I had to ask Larry what the size of a schmoo ball was and he says it's about two
and three quarters of a niche, so he was using three-inch PVC pipe, so I went ahead and
got myself a piece of three-inch PVC pipe, a coupler and a clean-out cap which if you
were doing plumbing then you could have this outside of your plumbing system, so if you
had a drain clog, you could take a cap off and run out of snake, which a snake is a
plumbing cleaning device that you unwind into your plumbing system and it kind of breaks
up the clog.
So I got a cap screw in, clean out cap, I got a coupler and I got two cans of stuff
here and one of them is the purple primer.
Now if you're doing PVC you have to get primer, which usually is purple, they do make
clear primer, but it's a little more expensive and there's regular PVC cement, now you're
not actually gluing it as well, you're not gluing it like you think it might be.
PVC, when you use the cement it actually bonds the two pieces together physically, not
just by just making them sticky, making them stick together, it actually takes the two
pieces and bonds them together.
I'm getting ready to do, so I've got my work area here and I've laid a bunch of newspaper
down so I don't get purple primer because it will stain permanently and I'm going to
clean the PVC, then it's already cleaned, it's already dry and I'm going to just use the
dremel here to kind of take the edge off of the pipe, which I'm going to be inserting
into the coupler.
I think I'd better put a safety goggles on to keep plastic shrapnel out of my eyes and
I will also put on a dust mask here to keep from inhaling, particularly matter, because
who wants to breathe in, you have PVC stuck in their eye, okay so all I've done is created
a rounded leading edge on the PVC pipe here, that way when I insert it into the coupler
it will not scrape the cement off of the edges of the wall so much and hopefully create
a better fit because I did a little dry fire testing yesterday without it even glued
together using my method of propulsion and I was, let's see, I was using a closed 12-ounce
beer bottle with about an ounce or two ounces of liquid still in the bottom of it as my
projectile and I had the cannon propped up against the well house kind of like a mortar
at a very steep angle, I mean like it wasn't quite vertical, you know, it was maybe ten
degrees off of vertical, something like that and I test fired two or three shots with
the longest shot being about a little over a hundred feet with a height of about, I'd
say you know another 50-75 feet shooting it horizontally, I'm fairly certain I could
launch a glass beer bottle about 200-250 feet or so, so I've got the leading edge trimmed
up and so now I think I'm just about ready to prime and prepare to glue my coupler and
my end cap here, do some sections, actually I'm going to go ahead and I'm going to round
off the end cap as well which fits into the coupler so that way I can just go ahead
and glue everything all at once, I think I mentioned I was using a Dremel to do my sanding
for me, it's a Dremel Lithium Ion cordless, it's 10.8 volts, 5,000 to 35,000 RPM model 800
and I've got to tell you it's my wife got it for me for Christmas, she's the last year
of the year before, the battery holds a charge for a really long time, it's got a little
metal hook, a metal ring on the bottom so if you wanted to hang it up you could hang it
up and use the shaft attachment if you're doing some detail work which I really recommend
if you're doing some kind of artistic carving because it takes the weight of the Dremel
out of your hand and lets you just use the tip kind of like a stylus or a pen so you
can more accurately do your creative endeavors, so first thing I'm going to do is I'm going
to do the primer here and the top is, oh they're pretty good, I found that sometimes
you have to get a little creative getting the tops off of these things because they tend
to go in there pretty good, go figure considering it's a volatile substance and you don't want
to accidentally spill it, so now I've got to find some wrench, some sort, I guess I can
get your I can hit it, try to wrench, vice grips, chisel that might work, just something
to loosen the cap up, just a little bit, I'm sure plumbers that are using it usually
have some sort of plumbing wrench available, so if they won't open up they can figure
something, okay, wrench is just a little wrench isn't going to work, needle nose pliers
are going to work, so I'm going to pick a cap up here, chisel, see if I can get it loosened
up here, that doesn't work, I'll find, I'll add some vice grips but I used them on my
last project, I don't exactly remember what I did with them when I was done, which is
always a cherished thing to do, I think I kept the chisel just right because it's got
curves around it and I could get it turned, all the reason I'm using a chisel by the way
is because it was the first thing I found and it's probably not the best thing to use but
you know I was going to use a flathead screwdriver but I said it was the first thing I found,
chisel are actually generally pretty freaking sharp, but I used this one when we were fitting
in the house, doing the floor, and so I'm pretty sure it's not, the sharp is too
in the shed, okay, well windy tonight, but I have found my trusty and only slightly rusty
vice grips, which I will definitely be able to remove the top of this cannon primer, okay,
now I'll take one second, get the right tool for the job, okay now you want to prime the
whole thing, the whole area where you'll be fitting the piece together, I'm going to do
this in sections, so first I'm going to prime one side for the clean out, for the end cap
screw on, now it slides into the coupler and purple stuff is kind of messy so that's
why I've got all clothes on here, I'm holding the fitting upside down and the primer doesn't
have to be wet, it can dry, so if you happen to make a mess you can take a second to grab
a paper towel and clean up a little bit of the excess if you want it to kind of look
like a nice, well if you want it to look nice you can either get the clear primer or you
can mask off areas of the PVC that you don't want stained, so I've got my PVC cement here,
got the area to prime, the most important part of the seam is the bottom two-thirds because
the sticking action is going to happen, so be sure to use plenty of cement and I'm just
going to take my end cap and slide it in with a twist, make sure I get a good tight seal on it
and that's that part there, I guess I'm going to take a screw out just in case I make a mistake,
I wouldn't want my end cap to stick in place, I'm going to do the same thing to the other side of my
coupling, again I'm holding it angled down, applying a liberal amount of primer to the inside of the
coupler, make sure it's evenly good and purple, I guess it's a good thing about it being colored is that
you can see the evenness of the application, okay, I'm done with the primer, so I'm going to go ahead
put the top back on that and get ready to attach the coupler to the end of the PVC tube here,
go ahead and kind of brush it off, make sure there's no loose PVC flakes on there to interfere with the
weld and then just apply PVC cement over the primer, be sure I get the whole area coated, all right,
nice and good there, nice and even, wipe off these little drips, my paper towel, just slide it on with the twist,
yeah, so I dried fire it, I didn't dry fire it, I fired it live yesterday, after I bought the parts,
just to see how well I thought it was going to work, and truly impressed with the results,
one particular test, with a large amount, not a large amount, but I use a different method of charge, I use a
different type of charge to launch the projectile, and the amount of pressure it created actually blew the
unglued end cap off of the PVC pipe, and so it gave me a little idea as to the actual, you know,
amount of pressure being created, another thing I noticed was, another thing I tried to launch,
was an empty beer can, and when I went to retrieve the beer can, why I didn't find as far as the
bottle, which had more mass, so I guess it traveled farther, but I didn't notice that the can,
it had been partially crushed by the force of the charge, and I thought that was pretty interesting,
so that glue's got to sit, but read the instructions here, that it's set for 24-48 hours,
before applying pressure, well that sounds about right, it'll probably be another day or so before
I actually get to test it anymore, now that it's glued up, and I've got a three-foot length here,
which is pretty big, and I've read that I can go down to about 19 inches, and I'll still have optimal
range, apparently the projectile actually gets the pressure built up in front of it,
and it slows the rate of the launch, so what I'd like to do is reduce the barrel length,
and use the smallest charge possible, because it's really loud as hell, and one of the tests I did
yesterday, it pretty much sounded like I was shooting off some kind of fire alarm, now I know
what a shotgun sounds like in a 22, and it's somewhere in between a shotgun in a 22, and I'm
planning on taking this to Washington DC, so what I essentially have here is half of a pipe bomb,
that I'm planning on taking to the nation's capital, which that's a dumb idea, especially since I
spent a week before I built it, googling around on how to build my bombs, so since I know that they
have the ability to unnecessarily monitor my surfing habits, which of course, you know,
Google monitors, everything you do, but all I would take would be to put two and two together and
come to the wrong conclusion that I was trying to, you know, do something that I'm not, and okay,
so I went to the store to get the pipe, and they had like a sheet, it must have been like a 10,
15 foot piece of three inch PVC, I mean this thing was huge, and I was like yeah,
I'll just take the whole thing, and then I got it up to the counter, I was like you know,
I really don't need all this pipe, and so the guy offered to just cut me off a section, and so
I guess he didn't feel like saw it all the way to it or something, because when he came back,
he had, he'd just like broken three feet off of the end of the pipe, I mean it was all jagged,
there was a point on it, it looked like he'd kill somebody with it, I mean, so first thing I did
before I used it to launch was I cut off the jagged piece, and it's still, I still didn't get
a really straight cut on it, because I left, I kind of left the hacksaw sitting out from the
last project, and he got rained on, kind of rusty, and think about a rusty saw, is it's kind of hard
to cut with it first, but after you get going, it just, the rust works off the blade, and it cuts
fine again, and so it took me a minute or so to get it going, but once I got the blade cleaned off,
and it started cutting, and it cut pretty straight, there's just a little lip here, so all I'm
going to do now is, I'm going to just kind of round off the, the leading edge for aesthetic purposes,
in case I decide to just leave it a three-foot mortar, and I don't do anything else to it.
All right, that's a lot better, and I'm still using my safety goggles and my dust mask to prevent
inhalation of PVC, and get it in the eyes, wash my hands, I've got powdered plastic on my hands now,
and since this is not a Chinese cooking show, I won't be serving plastic. I will talk a little bit
about the type of charge that I'm using, I'm not going to go into detail, like I said, I don't really
want to spoil the mystery, as it were, pretty much what I'm doing, is I've experimented with
using both plastic and glass bottles. Well, it turns out that the chemical reaction that I create
get really freaking hot. I mean, one of the ingredients is water, and everything's got
fucking water in it, right? So, the reaction is between water and one of the other elements,
and it's catalyzed by a third element, so it's really a trinary compound creating a large
amount of pressure in a small space, which if you know anything about explosives, an explosion
is expansion plus compression, like say you take gunpowder and put it in a dish, it's just going
to make a flash. If you take gunpowder and put it in a metal casing and prevent it from
expanding rapidly, it will make an explosion. So, what I'm doing is I'm creating a quite
somewhat volatile chemical reaction in a enclosed space. In this case, I'm using 12-ounce
Mickey's beer bottles, which they're called Mickey's Grenade. They have a white mouth and they
have a screw on cap, which is perfect, because I put the ingredients into the bottle and I can
screw the cap back on, and the expansive forces created will cause the top to pop off. The bottle
doesn't explode because the cap is the weak link in the chain there. So, what I do is I put the
ingredients into the bottle and drop them down the tube, and I've got like maybe 30 seconds to a
minute, depending on how much water I add before the pressure inside the bottle is large enough
to blow the top off. So, after I put the charge, the charge would be the bottle with the
ingredients. I drop the charge down in the tube, and then I drop my projectile on top of it,
so that's the process there. So, now the only thing left to do is wait, I've got to wait 24 hours,
which I won't wait 24 hours. If the weather's okay tomorrow, I will go out and do a test
fire tomorrow that should be pretty nice. I will be able to get an idea of the size of the charge
I need. Then, for the conference, I will pre-mix the ingredients. Well, since once you mix them together,
they become volatile. What I'll do is I can mix two of the ingredients together and they don't
interact. They, you know, it's stable. And the third ingredient, I'll keep separate, and so when
it's time to do a launch, then I will add the ingredients together and create explosion.
All right, welcome back day two of the Schmoo Launcher project. I'm just getting set up here.
A couple of beers. And the first thing I'm going to do is set up my camera, have a launching
line, and then I'll pace off from this line so I can get a consistent reading of the actual
range of the gun, the cannon, 73 paces, which that's something like, well, I'll get to take measure
out now. Actually measure off how far one pace is from my heel to my toe, and so I can get an
accurate idea of the actual range. So now I'm going to take a lighter to my firing area,
so I can figure out how to best set up the shot here. I'm more interested in the range
than the actual firing of the device, but pay the camera set up and go do a trial shot just to make
sure everything looks okay, and then I will set up my mixing station and prepare to do it for real.
Hopefully I won't blow up and get the PVC shrapnel in me because PVC doesn't show up on
show up on X-ray, so I think I can fake it. I really don't love how I'm going to put it on my shoulder
or hold it down at my hip. I don't know if I'd rather get probably a shrapnel in the hip
than in the neck. Okay, I took a little test video there. I'm just going to review it.
Now, okay, well, video looks good. I'm going to drink beer.
If you're ready to mix me up a batch to charge my machine here, let's see, I've got
done. I know I've got enough for two, maybe three total launches. I'll go check around and see
what other kind of stuff I have because I don't want to boil. I'm going to get a little creative
here today. I might have some RPG action going on, but it just depends on how well things work.
Okay, what I'm going to do now is I'm almost ready for the final phase of the testing project here.
All I've got left to do is prepare my concoction and add some water and other stuff to it,
and it will be good to go. I'm showing it down. I've got enough bottles here
to where I can do at least one appropriate launch. I can play around and I like you do two more,
just depends on the quality of my caps because I know I don't know how recycling them is going to do.
Once they've been fired, cold beer, actually they're not cold, they're room temperature suitable.
Tonight I'm, once again, drinking warm walkies best ice. I think what I've decided to do is
I'm just going to do a little shot from the hip model horizontally and I don't know what to expect
from it, exactly. I will court him and make my 15 minutes fame here, just a hand at the solution
to the bottle. Shake it up real good. I'll drop it in the tube. Drop it in the tube.
Well, that was different. I'm not sure exactly what happened. It seems that
the bottle got hung up in the tube. Not quite sure what happened, but I've got to do one more
test here. That was a miserable failure. I don't know. I must have used too much water. I'm not
really not really sure. I'm trying to do it. Well, at this don't do it. I'm pretty likely to
blow my freaking hand off this time. Don't really know what happened. We went off.
Seems like it had a decent amount of pressure. The projectile just didn't just didn't fly.
Maybe my set of this camera shot. I gotta do it. So I'm going to do it again. It's time to bless
this water. Let me see. I can't really imagine what went wrong. The car in the world.
Shoot the car. It looks like a star. So I'm just going to try this experiment again.
Well, I almost killed myself at that time. The small amount of water just happened to make
thing go off a little too soon. So now it's going on to the even more risky, dangerous
trial attempt. The time now out of my bottles, which I planned on using, and worked so well
in the initial testing. I'm not really sure. Well, that last cap had been used once before. So
I'm fairly certain that that has something to do with it. Now I know we have to use one of these
bottles again. So I'm going to take it back over here. This should be a dosage. And for the first
try, I'm not even going to hold it in my hand. I'm just going to record it because it's a good
chance that something could really explode. I don't want to be that guy that gets blown up.
I mentioned that I've been choosing 12 ounce makies. I won't liquor beer bottles because they don't
melt. The top just blows off once it builds up pressure. But with the case of soda bottles,
they get hot. So I am going to use more water to prevent the explosion from happening prematurely.
In other words, before I can get the fuck out of the way. This should work. Now I only got a
limited amount of stuff left. So this is going to have to be the official grand finale. I've got to
make this work. I'm going to go all RPG areas. This one. I'm going to keep talking this and see
just how crazy it is. And a little less water and it's not going to work at all.
We would work about this in the glass bottles. So with the plastic bottle, it starts to expand
right before it explodes. So if the first bottle doesn't blow up before the second bottle starts
expanding, then I'm just going to have a double explosion in my chamber, which is probably just
going to get hard to clean them with a fucker out. So on that note, I will not be
making the RPG using two plastic bottles today. If I do plan on making a grenade,
then I will be using a glass bottle for the grenade as well. So I am almost ready here. Of course,
this is a part of my great one. Getting ready to achieve greatness. This should be good.
I wind up the shot. My spear box target. Best I can.
Wait for the traffic to go by. Getting everything ready here. Might have used too much water at
time. You can usually hear the plastic one before they're about to go off. It kind of makes
groaning sound. I must use way too much water. Nope, here we go. Here we go. So I'm just going to
have to know. Fizzled out again. That's the problem with the plastic bottles is that, like I said,
it's hot. They don't melt rather than explode. Okay, well, what to do now? Because I could try a glass
bottle with a used top one more time. Plenty of water in it and hope for the best.
A little more air. Plenty of freaking water. So I want to have plenty of time to get the hell out of
the way. I know that's way too much water. Okay, well, this is going to be it. I'm sure I'm
even going to hold it. Be a man. Hold it. As I shoot. Just like I planned on. Now edit this whole
thing out and act like I'm not retarded. This would bring you a future note to not take your face
directly in front of the barrel of a mortar. No matter how safe you think, oh, this is not going
to work at all. That cap is fucked. This is going to work very well. Very disappointing. Here we go.
In my explosion. Again, toxic fuel. This has been a pretty big waste of time so far, but I did
say that my shot wasn't going to work. The cap wouldn't go on just right. So now I'm going to have
to get more water. I'm trying to shoot a whole more time. Bunch of water. I think it's a problem I've
seen when I first tried this. I did it at a near vertical, near vertical. So I'm going to try to
put shit down the water. I mean, I'm going to fill it just about all the way up. I don't know.
When I had it vertical, it just compressed out the top and made explosion happen. But since it's
at such a horizontal angle, I'm not certain that it's even going to work with the plastic bottles.
I know I have a more making bottle. So what I'm going to do after this is this doesn't work.
I go to town, I go to town tomorrow, and if this doesn't work, then I will get some more bottles
that work because I only had one. I think I must have had some kind of issue with the projectile.
So I'll be starting with fresh materials. This is a part of the learning process. It's really,
you know, it's like you don't want to go into something not really knowing what to expect.
A little more propeller. Shake it up. Re-e-e-e-e-e-e.
Oh, cool. This stuff seems to be happening.
Learning up the target. Raise the elevation slightly.
Okay, check. So there's about to happen. Probably nothing. Here we go. This is it. It's a car coming
to. It's not working. This is about again. I'm going to manage to make a big mess.
Well, that almost worked. See, by looking at the bottle, that it banded properly, but it still
got so hot that it melted to the plastic before it had a chance to, before it had a chance to fire.
So, I guess I'm going to clean it with a mess and edit this down. Let's try it again.
Disappointing, but not discouraged.
How the hell are you? How the hell are you? This is Fox Fire, and I'm coming back to you once again
to recreate the original testing of my Canon mortar device after a series of failures in the last
attempt. I have decided to come back once again, revitalized with the audio quality sounds a
little better. That's because it is. I've got a new cheapo headset. This time it's not a ear clip.
It's a behind the head, and that's got some kind of big fancy name that I can't pronounce,
but that's not important. So I'm ready to do my proof of concept. Once again, this time I'm going
to set it up in mortar mode. I've got just about everything ready to go here, and I'm going to
get it set up. So all I have to do is add water, turn on the camera, and set my charge, and run
away. So that's what I'm going to do now. So I'm going to go set the camera, and there will be
some video of this available somewhere. If you know me, I've probably shared it with you.
If I haven't shared it with you, then you might see when the camera is recording, adding water.
That should be plenty.
Charge is set. Safety goggles on. I'm going to step back and wait for the boom.
Then kind of a fun day. Yesterday we had a 65 mile an hour winds. There wasn't any storm,
just some hellacious wind. So I had to spend a good part of the afternoon cleaning up the yard,
and currently violating the burn band. I actually surprised the fire department didn't show up,
because I burnt a foam mattress cover. You know when I was thinking, okay, it'll
just got a small burn smoke, and that thing might turn into a fucking mushroom cloud like the
second I threw it on the fire. It was insane. Okay, I'm expecting something to happen here.
I might not have used enough solution, but that's the part of a trial and error.
If it looks like I need to add about twice the amount of solution, then I added this time.
It's kind of hard. I mean, I should have started out with accurate measurements and done it all.
Scientific methods, fabulous. Then I would know exactly how much of X, how much of Y,
and how much of C would have needed. But it's more fun to experiment, I think, to do it this way.
I had our monomy of when I was in high school, my chemistry teacher actually let me make
gunpowder. Lacking the ancient Chinese formulas, I had to guess the appropriate mixture of
salt, Peter, charcoal, and sulfur. Okay, this is going to go hot quick.
Okay.
Check. Oh, shit. It's aimed straight up. There we go. That should work pretty good.
See if I'm going to scare the neighbors.
God damn. That was a fucking hang time. That thing was in the air for a good couple of seconds.
Well, I think we are well on the way to success here. So since I put a unscrupulous bottom,
I should be able to extract the charge without dumping it. That bottle is long gone, long freaking
gone. Okay, so I do know I just, since I have measured out for the most part what I'm using,
I now know pretty much exactly how much stuff I need to mix together. Now it's pretty nice.
Now it could be that with the change in angle, see it worked really well at a vertical angle. I mean,
I didn't even see where the fucking thing went. I mean, the bottle must have been like,
must have gone up like 40 feet or something. Shit, I don't even know. I mean,
I thought it had misfired because I didn't hear the thing. I didn't see the thing anywhere.
So it must have gone up over the trees and landed like 150 feet into the woods because I didn't
even see it here. All I did was hear a thunk out there somewhere and I have no idea where. I've
been the habit now of pre-preparing that way it doesn't take so long to record the show here.
So I've got most of my stuff ready to go. Ready to just add water. Oh, systems check.
One charge, one projectile, one tube. Okay, everything is just about ready to go. Just
get a camera and head water. It should be that easy. But I found nothing is ever
ever easy. Yeah, we got a hell of a windstorm.
Half the counties in the state have some kind of fire in them. The governor declared a state
of emergency and called out the National Guard to help out. Okay, here we go. Check
there for water. Check. I kept it and go on. That's not going to work. That one's going to be a dud.
The cap got cross threaded. Like I said, what can go wrong? Well now we know. Now we know what can
go wrong. So try again. New charge. It's going to pop. It's going to pop. It's going to pop.
No, not. It's probably just going to steam a whole lot. One of these people looking. Oh, great.
The lady next door is. Oh, now I've got an audience. Trim into not glass, not glass, not glass.
Well, it's time I'm going to be more careful when I put the top on. Okay. Top of something good.
Charges in. Second charge is in lightly. First, I'm going to do from the hip. Any second now.
Here comes the car. Great. Nice. Success. We have explosive. Listen to that.
Poisonous toxic chemical reaction. Hi. Okay. Well, they did not go quite as far as I had expected. Let's
see. Let me stop the camera. And that will be the end of demo. Number one. Successfully completed.
Thank you for listening to Haftler Public Radio. HPR is sponsored by caro.net. So head on over to