SpudFiles

Hi there,

I'm planning about making a hybrid launcher from 50mm PN16 PVC, but I'm wondering about the max mix I could get from it?

Thanks, and sorry for my bad english =/

PN16 PVC is RATED to 16 bars, or 240 psi...That is equivalent if I am not mistaking to a 3x mix. each mix has a potential pressure peak of around 80 psi...correct me if I'm wrong. I'd say you'd be safe with a 3x mix, now do what you want but be aware of the risks...

sorry to disagree with you, but NO!

i wouldn't really care if it was rated to 500 PSI, its not the PSI itself that causes PVC in hybrids to explode, its the extremely rapid pressure spike- the PVC cannot handle it.

I believe every hybrid made out of PVC has exploded, even though it was rated to the pressure, it was the pressure SPIKE that did them in.

just go with a steel one, and keep things alot less dangerous

So even if I just use it with à 2x mix (that is approx 160PSI, if CpTn_lAw is right), it could explode because of the fast compression in the pipe?

Ok, so I'll try to see if I can found something else, like galvanized steel.

Thanks a lot!

I believe every hybrid made out of PVC has exploded, even though it was rated to the pressure, it was the pressure SPIKE that did them in.

BS.

SOME have exploded. Enough to consider them unsafe at least.

Also, Redaplle, You should probably try a couple basic combustions /pneumatics before you try a hybrid. You'll save yourself a lot of frustrations.

Don't worry about it, I have already made a combustion and few pneumatics (my last one shoots 10mm steel balls at 200m/s, using 35bar ).

ilovetoblowthingsup wrote: I believe every hybrid made out of PVC has exploded, even though it was rated to the pressure, it was the pressure SPIKE that did them in.

Brilliant observation, and completely false. Hybrid failures, while they can happen, are extremely rare.

So I can make my PN16 PVC hybrid without any problem if I don't use it at more than a 3x mix?

Dude just use steel. It's a little more expensive but you'll be able to use higher (funner) mixes. It might not fail if used in the cold the pvc is more brittle more likely to burst. I don't care what the pvc is rated to i wouldn't want to be near the thing when it fires.

Yep, but I wanted to use PVC because I have 6meters of 50mm PN16 PVC (I had this for about 20$)...

if its $20 bucks your worried about then a hybrid is probably not the best option.

A well built (and safe i might add) will cost you about $100 on the cheap-end using steel. My motto is build it right or don't build it at all. i am fortunate enough that my friend works at ace hardware and gets amazing discounts, but don't skimp when it comes to safety.

The pipe I use are really good. It's not because it's only 20$ that it's bad material. I also have good discounts.

I have already made plans for one in steel, and it should cost about 60$, but I don't want to spend 60$ on it. I prefer spend my cash for pneumatics

I never said it was bad material. its just that in the interest of self-preservation I recommend doing it correctly.

The price means nothing. $20 for what? How much of it did you get? What quality?

I don't want to be a downer on your hybrid-building parade but i do like to see things done right and the builder happy and safe in the end.

In the end its truly your call. Have fun and be safe

Simple explanation:
Hybrid cannons do not only produce more pressure, they also produce bigger shockwaves and pressure spikes.
PVC is a material which cannot withstand repeated shocks like that.

An PVC hybrid can never be considered safe: sooner or later, they simply start to form micro cracks and fail.

So I can make my PN16 PVC hybrid without any problem if I don't use it at more than a 3x mix?

No. You can't.

you guys over estimate this a load to much, a 2x mix in a PW chamber (in this case PN16) is about the same as setting of a combustion mix in a DWV chamber, the biggest problem you will have is heat. if you constict flow it WILL melt your chamber where it goes over to the smaller diameter.