jonesy42 wrote:
When did i describe "HPA" as being under 300psi?... I used the word HPA in the title
so people know i'm not trying to make a combustion cannon!
Thanks for answering anyway.
It was assumed that you would be using pressures under 300PSI as it would be far from intelligent to put more than that in a plastic container like the one you found without first putting it through a rigorous safety test (multiple hydrotests at above the pressure you plan on using it at).
If you want people to think you're not making a combustion, say pneumatic and not HPA. HPA stands for high pressure air and, IIRC, is also a term used widely in paintball and airsoft where it refers to a more specific high pressure fill/storage device.
jonesy42 wrote:
Don't forget that the bottle in the picture has 3 times the wall thickness of a "soda bottle" and i was never planning to use a "soda bottle" in this project anyway.... Just using wyz's creation as an example
![Wink :wink:](./images/smilies/icon_e_wink.png)
Is it even the same material as a soda bottle? I know little about the chemical and mechanical properties of materials but I would assume that doubling the thickness does not double the pressure rating for all materials and that changes in container design (shape, length, diameter) would significantly effect the structural properties of said container.
I would do more research in to the type of material used and what kind of pressure people pump weed sprayers to. I doubt the bottle will have been tested at over 100PSI by the manufacturers but it probably can take 150PSI without trouble. I would recommend that you perform some tests beforehand, though.
jonesy42 wrote:
What is the diameter? Have you seen a golf ball before?
Bends? Can you see any bends in the photo?
There are no flow restrictions, the bottle screws in to one end
of the valve, and the barrel the other.
Don't be a dick. I'm not sure if Tech saw the attached photo or not but it is possible that he is browsing on a device that doesn't load photos (save bandwidth/increase speed).
I can't tell what size everything is from the photos but it looks as if your valve will be a flow restriction.
As for your original questions:
What pressure is needed to throw a golf ball at a descent FPS?
How much pressure could you "safely" fill this 2 litre weed sprayer bottle too?
How long should the pvc barrel be roughly?
1. How long is a piece of string?
40-50 psi?, it would dribble out the end of the barrel lol, we are talking golf balls here remember?
As others have said, 50PSI will shoot a golf ball.
2. Find out. That's your job, not ours. You haven't given us much info about the bottle and I'm sure that any info on what kind of pressures these things can take is probably on Google. I imagine most people here can only guess, like I did, as to what is a safe pressure. Don't take our word for it; fill it with water and pump it up.
3. GGDT. A very kind person spent a lot of time making that program, it would be a shame if it didn't get used. We also have a GGDT request thread if your computer can't run the program.
If I were you, I would just make a chamber from PVC/ABS. There are times when it is good to improvise and use materials for tasks that they were originally not intended for but I don't think this is one of those times.