gas leakage

[adama]

Has any one had problems with fumes leaking out the back of the gun when they ram the projectile down?

I built a BBQ igniter into a cap for my gun and sealed the holes for the wires and such with RTV. When I ram a foam plug down the barrel there is a hissing noise and the plug goes down way too easy. Then it doesnt fire. Im 99% sure Im pushing the fumes out the holes that are supposedly sealed with RTV

Any thoughts and suggestions are greatly appreciated

[djt]

does the cap screw on? if it does then just put the foam in the barrel first then put fuel in and screw the cap on

[spudshot]

you are just asking for a frogboy situation by ramming a spud down the barrel of a gun that has the ignitor in the cap, and is already fueled!

get a new cap, use the electrode method of installing an ignitor, and put the potato in BEFORE you fuel it.

[adama]

Sorry, i didnt explain my self well enough.

1.First I put the plug in the end but i dont ram it.
2.Then I put the fuel in and screw the cap on.
3.Then I ram the plug down (I had heard theis compresses every thing and makes it work much better, on my first gun i always did this with out problems so i think im correct in doning it with the one in question). Here is where my problem is: when i ram the plug down, with the cap on and fuel inside i push most of the fumes out the cap instead of compressing them. The plug is a good tight fit so i know that the gas isnt leaking around the plug as i ram it down. i also know its not leaking out the threads or any joints. I was just wondering if any had had gas leak where the igniter was attached and how they fixed it

[sgort87]

Ram before fueling and that will solve all your problems. Combustions with threaded fittings that arent teflon-taped will allow the pressure you speak of to equalize with the atmosphere rendering your entire process useless and your fuel wasted.

Cut, ram, fuel, cap, spark, smile deviously, vent, repeat.

[Benny]

i had this real nice teflon tape roll that doesnt melt when my combustion fires, it was like 6 bucks tho.

[adama]

how easy is the cap to remove with teflon tape on the threads?

right now i can take the cap off with my hands and i dont need a wrench, will i need a wrench with teflon?

[drac]

Teflon will make it easier. it is a sealant and a friction reducer.

[sgort87]

How about installing a 2" ball valve for venting? It works very well for me. I never need to remove the cap except for switching it between launchers.

[Andrew52]

yah i bet that would also be nice for fueling if using the spray n pray method