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2 weeksish until I'm home!

Ok, so here's my thoughts. Rather than freeze or remove a check valve I want to replace it with one that kicks in at a higher PSI. A "medium k mod" if you will. This way I can put more balloons on a CPS bladder and yet still have a safety mechanism to prevent cracks form forming or ruptures from occurring.

I imagine I could do this 1 of 2 ways. First, replace the spring in the check valve with a stronger spring. This would require cutting open the check valve and resealing it. I could also replace it with a new check valve. There are a few questions that, if answered, would help us understand the process better, and thus might help us achieve superior results. Do we know at what PSI certain check valves kick in at? Or is it unrelated to that? If you're making your own check valve how can you figure out at what PSI it would kick in at? I imagine I may have to do a lot of experimenting and trouble shooting.

Could be gr8. I might do this to my CX once I get parts...

I seem to remember GJiv doing this at one point. (of course of anyone it was him ) On his 1500 perhaps? I do not remember what he did though. He hasn't been around much lately, but a PM might get his attention.

If you replaced the check valve, what would you replace it with? A valve from McMaster? They probably have something that would work, but then there is the question of getting in in place. Larami didn't help us out with that 90 degree bend and tiny little valve.

They do have small nylon check valves connected via barbs on Mcmaster.

might be worse. But worth a try.

I have done a check valve replacement to a Vaporizer I sold. It was getting ridiculously hard to shoot, and I had 2 others that worked fine, so I cracked it open and got to work. Like you said, just cut open the part with the spring, replace the spring with a weaker/stronger one, close it back up and glue it really well. I might have some pictures, but it's more the concept part is viable than anything. I believe that replacing the valve entirely would be harder; unless both ends were about the same size and could be glued together well. I should note that the Vaporizer was probably under a lower pressure. Also, I am fairly certain that the pressure of a CPS chamber/pipes when pumping is almost constant; when the chamber physically can't expand anymore, that makes the pressure skyrocket and the check valve/s open. That is why you should always pump a repaired PC to over-maximum, to make sure that it can handle the force when the check valve is about to open. On certain XP blasters with them, the check valves are "tuned" for a certain pressure rating. Although for the most part, you just pump air blasters until you can't pump anymore. Nowhere near constant pressure!

Also, I am fairly certain that the pressure of a CPS chamber/pipes when pumping is almost constant; when the chamber physically can't expand anymore, that makes the pressure skyrocket and the check valve/s open.

Except that the PRV can open well before this point, entirely preventing the bladder from ever hitting the walls. A light K-mod on an MK2 2100 or 1200 sometimes provokes the PRV into kicking at just 5 balloons. It could obviously expand more, as an MK3 2100 with 95 balloons on it takes 9 pumps to hit the PC walls with a disabled PRV. The strain on the pipes of a CPS gun also cannot possibly be constant. If you pump a heavily K-modded gun up once, it's not very dangerous. If you pump it up 14 times, a pipe can explode.

CPS valves are kind of hard to get at. Replacing the spring requires some of the same things as disabling the valve, with the same problems regarding leaks. I would do this if I had a cutting wheel and a dremel. With my current tool set, definitely not.

Duxburian wrote:

The strain on the pipes of a CPS gun also cannot possibly be constant. If you pump a heavily K-modded gun up once, it's not very dangerous. If you pump it up 14 times, a pipe can explode.

Could this be due to the fact that one pump is not able to push a pipe far enough or it to fail? Explosive failure is just as much about amount of energy stored as it is about pressure. This is why water rocket builders will pressure test a vessel by first filling it with water, then pumping in air. Since the water stores almost no energy, the failure is much safer to be around.