Building a hybrid, help

spanerman · Thu Apr 05, 2007 10:46 am

Hi im making a pvc hybrid i plan on running a 2xmix i will be using class E pipe which is rated to 217psi. I have plans for metering system, the ignition is sorted and the chamber plans are done. My only questions are about the burst disks and how to house them, im having a 3inch chamber and a 1.5inch barrel should i reduce down to the barrel diameter then have a short piece of pipe then the union? or have a bush with a thread on the inside and then have a union thread into it? Oh, and i do wish to have intechangable barrels 2inch and 1.5inch what size unioin should i use? and in what arrangment.

all the best, sam

frankrede · Thu Apr 05, 2007 11:06 am

What ever floats yoru boat man.
threaded connections chamber side allow versatility but are weak spots.
Solvent welded joints are stronger.

spanerman · Thu Apr 05, 2007 11:12 am

so for different barrels i would have different unions? say, for the 1.5inch barrel have a 1.5inch union and for the 2 have a 2?? does anyone have any picture of how the burs discs fit into the unions?? thanx , Sam

pyrogeek · Thu Apr 05, 2007 2:12 pm

Why not solvent weld one side of the union to the chamber, then have multiples of the other side with different barrels.

Thats kinda halfway between our Schedule 40 and 80 pipes, as far as the pressure rating goes. Could you get anything rated to a higher pressure.

spanerman · Thu Apr 05, 2007 3:25 pm

well i have changed my plans slightly i know have a 4inch chamber 2inch barrel, on the front of the chamber is a 4x2bush with a 2inch female thread on it then i have a 2inch nipple then a FF 2inch threaded union then the barrel, heres a diagram.

pyrogeek · Thu Apr 05, 2007 10:29 pm

Looks good, but as Frankrede said "threaded connections chamber side allow versatility but are weak spots.
Solvent welded joints are stronger."
If you go that route, just try to fire it remotely the first 10 shots or so.
Good luck, can't wait to see it when it's done.

spanerman · Fri Apr 06, 2007 5:14 am

well youl have to wait, this may be a long build, at least a couple of months

willarddaniels · Fri Apr 06, 2007 10:02 am

I would be concerned about the pressure rating, but if you don't oxidize or go above 2x, you "should" be fine. Your plans look like the makings of an excellent combustion / low-powered hybrid gun. Try to only drill through your chamber sidewall where it is double-thickness ie. at fittings. Good luck and check back with us throughout the construction.