screw verses spark plug, I'd check the spark plug for resistance. Your bbq lighter may not have enough juice to make a good spark.

jjjd wrote:iv tried all that can it be going through the abs?

abs doesnt conduct electricity, its plastic.
what kind of screws are you using certin low grade metals dont conduct elec very well.
Try some different screws

I used stainless steel reinforced sch80 for all of my threaded conections, and the rest is sch80. I have a test area I have set up at my parents acrage. Cement filled cinder block walls ect. We'll see how well the sch80 holds up. If it doesnt I can get stainless pipe and fittings and weld it all. Ca...

all ready though of that, I'm using an oxygen and propane set

If I creat a vacuum in my combustion chamber before I fuel my chamber. would I get enough fuel to make a difference? I've built a launcher that has a full port spring check on the barrel( just after the reducer. Trying to get as much power as possible without using all the vales and burst dics in a ...

search sprears part # 436015

I can get a ful port spring check that would take care of the orfice problem. Still cant figure out the math end of things. Its been a few years scince I've been in school.

the gasket is attached to a 1/4" thick puck and slides up and down on a stainless shaft ( spring loaded of course). The entier unit will be sch 80, except the spring check, it is bass. Not sure how to figure out how much pressure will be built in this unit. Or how fast the projectile will be moving....

I'm building another spud gun, but this time I'm going to put a 5lb spring check after the reducer so I can use fuel ( propane and oxygen) under pressure aprox 4lb. Anthing I should concider in doing this? Has anyone tried this before?

the pressure rating is 25.5 bar (roughly 350 psi) on the aqutherm.However it does change with outside tempeture and internal tempeture,But not as much as the pvc.
And it is availible in the States.

Anyone tried using Aquatherm? Look like it has a good pressure rating.

www.aquatherm.de

did some checking around, the fan may have two speeds or directions. Black should be negitive, red should be postive ( high speed or forwards ) yellow should be positive ( low speed or reverse ). Youll just have to try it too find out. Or you can search for the manufacture and look up the modle and ...

what voltage is it? ac or dc? ect

you could just use lexguard, at 3" thick it will stop a direct hit from a morter. Should work for your purposes.

MrCrowley wrote:some guy said that before on another thread didnt they?

yah I did, but I'm not arduing with anyone. Not worth my time.