would this work for my spudgun?

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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spud-freak
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Fri Feb 04, 2011 6:40 am

does anybody understand a little bit german here? :-)
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jackssmirkingrevenge
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Fri Feb 04, 2011 6:58 am

spud-freak wrote:does anybody understand a little bit german here? :-)
Only if Till Lindemann is shouting it :D
hectmarr wrote:You have to make many weapons, because this field is long and short life
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The_Guerilla_Guy
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Fri Feb 04, 2011 9:17 am

does anybody understand a little bit german here? Smile
In fact, I do yes^^
There are so many assholes - and so few bullets
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Crna Legija
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Fri Feb 04, 2011 9:55 am

Jörgs does
'' To alcohol... The cause of, and solution to, all of life's problems.”
--Homer Simpson

Add me on ps3: wannafuk, 8/11/11 cant wait
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Technician1002
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Fri Feb 04, 2011 9:59 am

The problem with metering with a pressure gauge is the simple fact that screw on clean out caps don't reliably seal. If it leaks some, your mix will be way off. A volumetric meter can tolerate some chamber leakage and still be very close to the proper mix.
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spud-freak
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Fri Feb 04, 2011 12:54 pm

oukey i've testet it, but i can't so little set the propane-butane gas
because i don't have a little gauge for this mini pressures..

tomorrow i want to build a hybrid gun with steel pipes!
a 1x mix i not so efficiently, whitch mix do you need?
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Technician1002
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Fri Feb 04, 2011 4:01 pm

To find a very low pressure gauge, you want something used to monitor the pressure on air filters and such on commercial HVAC systems. Warning, they are not cheap.

I would recommend something from this page, but they are too sensitive for your application as many only measure up to 2 inch or 4 inch. You need one in the 20 inch WC range. You are looking to measure pressure in the 16 inch Water column range.
http://www.terrauniversal.com/measuring ... gauges.php

This one will work, but you will not like the price.
http://www.grainger.com/Grainger/MIDWES ... sure-3GVH6
metalmeltr
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Fri Feb 04, 2011 5:09 pm

No it wont those are designed to be mounted in a wall to measure pressure diferentilal between the two sides, th only way it would work would be to have a large flat area on the cannon to mount/seal it to.

This is a paint booth with a similar gauge installed to measure pressure in the booth.

Image
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saefroch
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Fri Feb 04, 2011 5:33 pm

cfb_rolley wrote:So, how come metering a mix by measuring chamber pressure rise isn't commonly suggested? To me, that seems like the most simple method of metering, because all you'd need is a sealed chamber, a propane bottle connected to the chamber and a pressure gauge?
That works great if you have a sealed chamber and can measure minuscule amounts of pressure, which most of us can't. Can you reliably measure 0.654psi?

If I were you, I'd go with JSR's suggestion and try syringe fueling. If you have a >351mL syringe, that is...
metalmeltr
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Fri Feb 04, 2011 5:49 pm

18.1 inches of water
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saefroch
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Fri Feb 04, 2011 6:32 pm

metalmeltr wrote:18.1 inches of water
I know that wasn't an answer to my question, but that leaves me horribly confused. Don't you need a given diameter for the cylinder?
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Technician1002
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Fri Feb 04, 2011 6:35 pm

Inches of water is the height the pressure will push water up a tube. Diameter doesn't matter.
metalmeltr
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Fri Feb 04, 2011 6:44 pm

presure per a given area ia pressure per a given area

psi
lbs per square inch

The basis of pascals principle.
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saefroch
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Fri Feb 04, 2011 7:37 pm

Oh duh wow. I'm amazed I possibly missed that. I thought the question sounded stupid when I posted it...

So I does the height of the column of water doesn't matter too?
metalmeltr
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Fri Feb 04, 2011 8:05 pm

I dont think so, but it may, I THINK it is just is the diference in height
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