Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 63 users online :: 4 registered, 0 hidden and 59 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

What kind of tests

A place to ask general spud cannon related questions.
Sponsored 
  • Author
    Message

What kind of tests

Unread postAuthor: noname » Tue Mar 27, 2007 7:37 pm

What kinds of tests does everyone want to see? Soon, I'll be doing tests on vortex and cloud strafers of the same size and barrel length, seeing their power, ROF, and air consumption, at 10 psi increments going from 70-110 psi. I also might do tests on how long it takes for PVC cement to cure (not that you should go against the time on the can). Another test I might do would be pressurizing Sch 40 PVC, Sch 40 cell core PVC, and cell core ABS, small chambers of the same volume, and seeing if they can hold pressure.
Any suggestions, post 'em here.
  • 0

User avatar
noname
Lieutenant General
Lieutenant General
 
Posts: 2699
Joined: Mon Apr 10, 2006 9:19 pm
Location: Bay Area, CA
Country: United States (us)
Reputation: 9

Unread postAuthor: lukemc » Tue Mar 27, 2007 7:58 pm

how are you going to figure out rof for a bbmg??
  • 0

"Those who are different change the world. Those who are the same keep it that way"
User avatar
lukemc
Colonel
Colonel
 
Posts: 565
Joined: Sun Feb 25, 2007 8:48 am
Location: NY
Reputation: 0

Unread postAuthor: judgment_arms » Tue Mar 27, 2007 8:13 pm

I heard, more accurately read, somewhere that if you put a magnet near the breach of the barrel it will increase power, when using steel or other ferrous metal projectiles of course. That would be something for you to test.
  • 0

Call me "Judge", it's easier to type.

Spud gun safety rules
User avatar
judgment_arms
Major General
Major General
 
Posts: 1272
Joined: Tue Oct 17, 2006 8:49 pm
Location: Not so beautiful North Carolina, but at least it’s the U.S.A.!
Reputation: 0

Unread postAuthor: benstern » Tue Mar 27, 2007 8:30 pm

Clear chamber on cloud and film in slow-mo. That way if we see if there is anything to improve.

Same with vortex with clear block too.

OH! And Redo the gasoline effect on pvc test
  • 0

User avatar
benstern
Donating Member
Donating Member
 
Posts: 909
Joined: Wed Sep 21, 2005 8:24 pm
Reputation: 0

Unread postAuthor: frankrede » Tue Mar 27, 2007 8:58 pm

Test all-purpose abs-pvc cement on PVC with abs endcaps.
  • 0

Current project: Afghanistan deployment
User avatar
frankrede
Lieutenant General
Lieutenant General
 
Posts: 3220
Joined: Thu Jul 20, 2006 9:47 pm
Reputation: 0

Unread postAuthor: SpudBlaster15 » Tue Mar 27, 2007 9:45 pm

Test the integrity of a chamber constructed using an epoxy such as JB weld as opposed to PVC cement.
  • 0

User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

Re: What kind of tests

Unread postAuthor: clide » Tue Mar 27, 2007 9:48 pm

noname wrote:I also might do tests on how long it takes for PVC cement to cure (not that you should go against the time on the can). Another test I might do would be pressurizing Sch 40 PVC, Sch 40 cell core PVC, and cell core ABS, small chambers of the same volume, and seeing if they can hold pressure.
Any suggestions, post 'em here.


Those tests will only be useful for your specific pipe and circumstances. Chances are that the SCH40 pipe will hold up well over its pressure rating, the cell core pipe will probably hold a significant amount of pressure, and the glue will hold up to pressure well before the listed cure time. However, the recommendations for pressure are based on a statistical distribution of failure based on numerous tests and theoretical calculations. Where the "safe" limit is set depends on the chances of failure and cost of failure.

Say there is a 1 in 100 chance that a certain size of cell core pipe will burst 100 psi. You could do a ton of tests and still get no failure, but given that hundreds or possibly thousands of people make spud guns each year, and chances are a person will be standing right next to the pipe if it fails, is it really safe to use?
  • 0


clide
Donating Member
Donating Member
 
Posts: 785
Joined: Sun Mar 06, 2005 3:06 am
Location: Oklahoma, USA
Reputation: 0

Re: What kind of tests

Sponsored

Sponsor
 


Unread postAuthor: homedepotpro » Tue Mar 27, 2007 10:22 pm

SpudBlaster15 wrote:Test the integrity of a chamber constructed using an epoxy such as JB weld as opposed to PVC cement.

yeah i want to make a gun using JB weld and that would be useful
  • 0

User avatar
homedepotpro
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 443
Joined: Sun Nov 26, 2006 1:00 am
Reputation: 0

Unread postAuthor: MrCrowley » Tue Mar 27, 2007 10:37 pm

How much pressure a standard 1" sprinkler valve can handle before it starts to leak/fail. You could try the common green one or loads of different types.
  • 0

User avatar
MrCrowley
Moderator
Moderator
 
Posts: 10207
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Country: New Zealand (nz)
Reputation: 4

Unread postAuthor: noname » Tue Mar 27, 2007 10:43 pm

lukemc, I'd pour exactly 500 BBs and measure how long it takes to dump them all.
Judgment Arms, I could do that, give me some more details on how I'd set it up.
Benstern, I don't have a video camera or the funding for that, maybe someone else could do it. I'd provide the clear block, no problem.
Frankrede, it's possible.
SpudBlaster, sure, I'll try it.
Clide, "is it safe to use?" Those who read my tests and think it's safe might use it, those who still think it's unsafe won't.
Crowley replied as I was typing this one-fingered while eating a drumstick. I'll test that with a normal one, then with one of my soon to be seen "Modded Out the Ass" valves. This includes the valve's body, a custom metal diaphragm, a modded blowgun, and one of DR's valve lids.
  • 0

User avatar
noname
Lieutenant General
Lieutenant General
 
Posts: 2699
Joined: Mon Apr 10, 2006 9:19 pm
Location: Bay Area, CA
Country: United States (us)
Reputation: 9

Unread postAuthor: clide » Wed Mar 28, 2007 2:09 am

noname wrote:l\
Clide, "is it safe to use?" Those who read my tests and think it's safe might use it, those who still think it's unsafe won't.


The problem is that the "test" caters to the unsafe, and in all likelihood will only serve as justification for those who are ignorant to the reasoning behind pipe ratings to continue their unsafe practices and misinform others. Somebody who doesn't know better will say, " this guy pressurized his cell core chamber up to 300 psi and it didn't blow, so there is no way mine will blow up at 120 psi." Next thing they know they are waking up maimed in a hospital room ready to become the next media figure for how dangerous these unregulated weapons known as spud guns are.
  • 0


clide
Donating Member
Donating Member
 
Posts: 785
Joined: Sun Mar 06, 2005 3:06 am
Location: Oklahoma, USA
Reputation: 0

Unread postAuthor: Fnord » Wed Mar 28, 2007 7:30 am

For a ROF test on a bbmg couldnt you just get a large sheet of paper, burst fire for 1 second, and count the holes?
  • 0

User avatar
Fnord
Major General
Major General
 
Posts: 2244
Joined: Tue Feb 13, 2007 9:20 pm
Location: Pripyat
Reputation: 7

Unread postAuthor: CpTn_lAw » Wed Mar 28, 2007 8:21 am

it would be a little long....my ancient cloud BBmg shot a hundred BB's a second. (measured.)
  • 0

"J'mets mes pieds où j'veux, et c'est souvent dans la gueule."
User avatar
CpTn_lAw
Brigadier General
Brigadier General
 
Posts: 987
Joined: Sun Sep 11, 2005 9:10 am
Location: France
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Wed Mar 28, 2007 9:56 am

SpudBlaster15 wrote:Test the integrity of a chamber constructed using an epoxy such as JB weld as opposed to PVC cement.


Using marine epoxy resin and PVC (properly mixed with the PVC suitable roughened to ensure proper adhesion) I've taken my designs to 400psi without failure, indeed the PVC will split before the epoxy will.

For a ROF test on a bbmg couldnt you just get a large sheet of paper, burst fire for 1 second, and count the holes?


Er... as opposed to just counting the amount of BBs in your chamber before you pulled the trigger compared to the amount of BBs after you let go of it? :roll:
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: judgment_arms » Wed Mar 28, 2007 1:31 pm

They say a picture’s worth a thousand words:
  • 0

Attachments
Magnets_on_BBMGs.PNG
Can you see it?
Magnets_on_BBMGs.PNG (13.96 KiB) Viewed 271 times
Call me "Judge", it's easier to type.

Spud gun safety rules
User avatar
judgment_arms
Major General
Major General
 
Posts: 1272
Joined: Tue Oct 17, 2006 8:49 pm
Location: Not so beautiful North Carolina, but at least it’s the U.S.A.!
Reputation: 0

Next

Return to General Spud Cannon Related

Who is online

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], Yahoo [Bot]

Reputation System ©'