SpudFiles

What type of pipe should i use for my combustion? ABS or PVC?

That depends on what is available.

Either solid wall (pressure rated or DWV) ABS pipe, or pressure rated PVC should be fine. DWV ABS can absorb pressure spikes better than PVC, and won't significantly weaken if dropped. Pressure rated PVC is actually designed for pressure, but is more fragile, and often more expensive and difficult to find than ABS.

I would recommend against cellular core plastic pipe of any kind.

ABS is usually more expensive in my area.
But ya thats just me.

I've been using cellular core ABS for quite a while, with propane, starting fluid, acetylene, and various other fuels, and I haven't had a problem yet. It's also cheaper than PVC (in the Bay Area, at least), and you can buy it in 1-5 foot sections, whereas you need to get a whole 20 foot length for PVC.

I've been using cellular core ABS for quite a while, with propane, starting fluid, acetylene, and various other fuels, and I haven't had a problem yet. It's also cheaper than PVC (in the Bay Area, at least), and you can buy it in 1-5 foot sections, whereas you need to get a whole 20 foot length for PVC.

ABS+acetylene= bad idea. It might work for a noise making gun, but I wouldn't trust it when a projectile is involved. The chances of dying are slim, but your ears won't benefit from the experience.

As for which pipe you should use, it really depends on personal taste. I prefer abs because it is light-weight, and doesn't crack easily. You can make a very large gun with abs and still have it under 5 pounds, whereas pvc would be kinda heavy.

ABS+ acetylene may be a bad idea, but it sure is fun!
I always make sure I'm wearing hearing protection and standing at least 15 feet away, so it's pretty safe. ABS's flexibility makes it capable of handling the shockwave caused by acetylene.