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| Rogue |
 Posted: 11/05/2007 11:21 AM Post subject: Problems with mini |
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Specialist
Joined: 03 Nov 2007
Posts: 42
73.61 Spud Bux
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Ok I just attempted to make a mini combustion with the pill bottle and pen tube method. Except my piezo thingy does not click anymore. 
But when i did get a spark in between the screws it would not light. So far i have used Axe and Bod. How much fuel do i put in there? Like a .5 second squirt or like a 1 second 1/2 half squirt?
Ahh help please |
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| psycix |
| Posted: 11/05/2007 11:28 AM Post subject: |
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Major General
Joined: 25 Jun 2007
Posts: 1581
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The big rule of thumb on combustion fuel problems:
You got too much fuel
The big rule of thumb on mini combustions:
You always have too much fuel!
Put in the smalles spray you can, wave it forth and back a few times and then close it.
Experiment with the amount of times waving it.
OR use a syringe to measure out fuel. |
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| Rogue |
| Posted: 11/05/2007 11:31 AM Post subject: |
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| CpTn_lAw |
| Posted: 11/05/2007 12:07 PM Post subject: |
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Colonel
Joined: 11 Sep 2005
Posts: 511
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| 4% of gaz is very small....you really need to shake it back and forth... |
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| Rogue |
| Posted: 11/05/2007 12:46 PM Post subject: |
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Specialist
Joined: 03 Nov 2007
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| now i switched over to a little butane thing from a lighter. how long should i depress that thing for(gas). then how many times should i wave it??? |
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| CpTn_lAw |
| Posted: 11/05/2007 13:00 PM Post subject: |
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Colonel
Joined: 11 Sep 2005
Posts: 511
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| that depends...i suggest you try to inject 1/2 second of gas, then a little more if it isn't enough...try by increment of 1/4 second. |
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| Rogue |
| Posted: 11/05/2007 13:05 PM Post subject: |
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Specialist
Joined: 03 Nov 2007
Posts: 42
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| when i move my screws back more i get a larger purplish spark. keep it like that or should i move them so they are very close together for a small bright blue spark? |
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| Tom |
| Posted: 11/05/2007 13:11 PM Post subject: |
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Sergeant Major
Joined: 24 Aug 2007
Posts: 186
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You can also use a long nosed lighter, take out the nozzle, fuel hose and the gas tank(including valev). Glue the nozzle in the barrel as close to the spark-gap  , connect the rubbe hose from the long-nosed lichter to the lichter itself and the nozzle that is glued in your combustion chamber . This wil have a result that you can put the feul in more accurate.
GR.Tom |
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| Rogue |
| Posted: 11/05/2007 13:15 PM Post subject: |
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Specialist
Joined: 03 Nov 2007
Posts: 42
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| i am going to move to a glue stic one. ty tom |
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| Rogue |
| Posted: 11/05/2007 13:53 PM Post subject: |
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Specialist
Joined: 03 Nov 2007
Posts: 42
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GRRRR... i made another one out of a glue stic and i got it to work the first 2 times, one bod one butane.
should i let the chamber vent?? |
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| Rogue |
| Posted: 11/05/2007 15:12 PM Post subject: |
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Specialist
Joined: 03 Nov 2007
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UPDATE!
got it working. needed more fuel.
thanks guys
roguE |
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| f.c |
| Posted: 11/05/2007 16:02 PM Post subject: |
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Captain
Joined: 08 Jul 2007
Posts: 342
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| try using metholyted spirits. just one drop should be ample for a decent and reliable shot. |
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| jimmy101 |
| Posted: 11/06/2007 10:49 AM Post subject: |
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Major General
Joined: 28 Mar 2007
Posts: 1567
6648.31 Spud Bux
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You can convert a standard disposable butane lighter to a more accurate metering system like this.
Even without a syringe, it'll work better than an un-mod'd lighter since you can get the small piece of tubing well up into the chamber.
One challenge with a mini is getting the fuel to mix well. Kind of hard to put a fan in a chamber that small. A couple of BBs can be added and then the chamber shaken to try to help mixing.
Another challenge with a mini is getting anywhere near a reasonable CB ratio. For 1/4" ID copper tubing as the barrel, and using a typical pill bottle that is what maybe 1"x2", you have a chamber volume of ~1.5 in3. For a 1:1 CB the barrel would have to be 30 inches long. A 6" barrel gives a CB of 5. The BIC pen body has an even smaller ID than 1/4" pipe so a BIC barrel would need to be even longer. A grossly too large chamber (CB too big) will significantly drop the performance of a gun.
The size of the spark doesn't make any difference, small spark, big spark, are all the same. |
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