Episode 42 - We Need A Bigger Cannon... and a VersaLaser! [Discussion]

[travislopes]

300 yard tennis ball hucks? No problem. Your questions about calculating barrel to air chamber ratios, finding fittings and what exactly Schedule 40 is? No problem. David's new Versalaser? Problem: he's out sick!

Watch and download here (http://revision3.com/systm/spud/)

[will_stutler]

is it just me or do they like to over complicate things

[nextgenxbox]

That's the systm way!!

[xplorer]

And how it should have been in the last one!

This was a MUCH improved episode, more info, less repetition. Pat looked so much more prepared, and it really helps the show. I know it seems like I am constantly bitching about things, but I really want the show to work!

Congrats guys, this is THE winning formula.

Can't wait for the next episode!

[justin316a]

I loved the look of "i'm so screwed" on Pat's face when he talked about the coil gun.

[minion4hire]

Too much bitching when things go wrong, yet not enough love when it's right.

As xplorer said, this is how episodes are supposed to flow. Well prepped, no major repetition like the last one. The only thing I would've liked to see is a bit more footage playing around with the "BFG 9000", although if you're going to play around with a dual-tank setup I'm sure there will be more time for that. Perhaps even a demonstration of its accuracy?

Anyway, great show Patrick. Hopefully Dave doesn't kill anyone! :)

[zipper]

Great job, keep up the good work.Even when you have projects that I have no interest in I always learn something.

[mikec]

Just wondering, was the audio on this episode lower then normal to anyone else? Other podcasts, from Revision3 and others, seem to be "normal" this Systm seemed low.

[benrev3]

is it 2.5 or 3?

thanks
-ben

[pmpsta]

Just wondering, was the audio on this episode lower then normal to anyone else? Other podcasts, from Revision3 and others, seem to be "normal" this Systm seemed low.

Yeah, it seemed lower to me too, I just finished watching Little Internet Superstar and had to crank up the volume to be able to hear.

[lordbyron]

it was low to me also but it was no big deal just turned it up some thats all....simple.

I liked it because the ads and the music were the same volume as the speech. In the past I would turn it up a bit to hear the speech better and would be blown away by the music and ads.

[marklar]

Heres a little demo of my simple yet effective cannon.

http://www.youtube.com/watch?v=y5OiYD_dxLE

[serafina]

Heres a little demo of my simple yet effective cannon.

http://www.youtube.com/watch?v=y5OiYD_dxLE

Cool!! I'll pass it on to Pat & Dave.

[ha3rvey]

I'm really interested in the idea of a gauss gun/rail gun/mag gun:

http://www.projects.clanscripts.us/index.php?topic=2.0

[flame500]

ha3rvey:
Wow, you actually beat me to posting my own project!

I do think that this design should appeal to Patrick/Dave since its more scientific and less well... deadly.

[mikexhibits]

great show, but please do not build a coil gun. I think that although it would be interesting, things that inflict actual damage (be it on things or people) and mimic real weaponry are the exact opposite of the lighthearted tinkering that (I feel) the show does really well.

[flame500]

A coil gun doesn't have to be dangerous or look like a real gun. Please follow the link that ha3rvey posted.
They can be quite fun to build but there is a substantial degree of sophistication involved in constructing one.
And something tells me Dave will like this use of a PLC.

[mmmlinux]

Did i notice that when the cannon was shot using the modified sprinkler valve, It didn't make that whining noise? or was i mistaken?

[greyhat]

Those cannons looked fun to build, but I must say I am disappointed that with all the emphasis on safety you guys missed the most important factor. PVC is not designed or safe for pressurized air! Compressed air stores a lot more energy than a liquid flowing, and when a pipe fails with water in it, it may leak, but when it fails with compressed air it becomes a grenade, launching shrapnel! While I realize you did state that if you drop it or see any stress markings in the pipe, it is unsuitable, that is not enough. The ASTM's position is that PVC should not be used for compressed gasses. Other types of plastic pipes like ABS air piping and others are designed for such uses, but PVC is not. I believe in some states it is illegal to run compressed air through PVC, and in many cases it is an OSHA violation to do so.

"Since PVC material does not possess shatter resistant property, and since it is very clear from the industry's recognized practice that PVC pipes are prohibited for above ground transportation of compressed air and gases (unless the pipelines are encased in shatter resistant material), any such use by the employers, where employees may be exposed to hazards, will be in violation of Section 5(a)(1) of the OSH Act. Therefore, employers who are found to violate the above described conditions or manufacturer's recommendations, during an OSHA inspection, shall be issued a 5(a)(1) citation." -- OSHA
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=20202

ASTM:
http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D1785.htm?E+mystore

Another memo on PVC w/ compressed air:
http://torque1st.clubfte.com/OSHA_PVC_Pipe.htm

:(

[lordbyron]

PVC is not designed or safe for pressurized air!

PSI(pounds per square inch) is the same in a gas or liquid

Compressed air stores a lot more energy than a liquid flowing

Not at all times is liquid flowing in PVC what happens when you turn the faucet off? The liquid stops.

and when a pipe fails with water in it, it may leak, but when it fails with compressed air it becomes a grenade, launching shrapnel!

Almost always PVC fails at a joint. Bad preparation is usually the cause. The reason why is seems it failures seem so much more dramatic with air vs. water is because most water pressures are about 9 - 17 PSI (most city pressures) and with air it is 90 - 120 PSI. If you pressurize water up to those pressures the failures would be about the same.

I believe in some states it is illegal to run compressed air through PVC, and in many cases it is an OSHA violation to do so.

If it is a violation in OSHA then it would be in all 50 states since OSHA is federal. Each individual state creates even tighter regulations to the OSHA code. Here in Illinois it is referred to as IOSHA.

You have to keep in mind that OSHA is Occupational Health and Safety Administration, and since this is for personal use OSHA laws do not apply. Although it is a good practice to follow OSHA code in your projects.

I do have training in OSHA:
10 hours Industry and Maintenance
10 hours Construction and Building
30 Hour Course

Bottom Line is if I was running piping for an compressed air system through out a factory I would not even consider using pvc pipe. But for this project I would only use pvc because I think black pipe would be impractical to use.

All comments in the post are my opinion only.

[catavarie]

For the flammable ignition fuel, aka Hair spray, style cannons this most volatile fuel to use is not Right guard as Pat mentioned but engine starter fluid. A quick spritz into the chamber followed by a good 5 seconds to let air into the chamber before capping will give you a seriously impressive amount of power. And what ever you do, don't open the chamber and look into it while pulling the igniter if it does not go off initially unless you want to burn off your eye brow as a friend of mine did twice, in the same day. :D

[gfree]

I like how it's light outside at the start of the episode, then progressively fades to night over the rest of the episode. Goes to show just how long a single 23 min ep can take. :)

[serafina]

I like how it's light outside at the start of the episode, then progressively fades to night over the rest of the episode. Goes to show just how long a single 23 min ep can take. :)

Hahaha, I was wondering if anyone would notice that...

[tkrabec]

Has anyone tried keeping the diaphragm open longer to avoid the howl? Since the pressure would be much lower, after an additional second or so.

-- Tim Krabec

[tokenuser]

The next obvious progresssion on the show is a full zombie defense canon.

What would be more effective against a zombie horde? A tennis ball or potato?

[kickarse]

Depends on if you put match heads inside the tennis ball and then drench it in lighter fluid, have a lighter at the end of the barrel so it just catches and lights as it comes out. Flaming exploding ball of doom!

[computoman]

Said I would never build one but having a powderless shotgun never hurts.It is not finished or even glued together yet. Just wanted to make sure I had all the plastic pieces. Have to take it apart to paint and then redo it.

http://img691.imageshack.us/img691/2091/pcdv0103.jpg