Old trigger valve repair option?

Repairs to water guns. Please put repair topics in this forum so that people do not have to sort through so many topics when looking for a repair. If a fix is included in the topic, please add (Fixed) before the topic title to indicate so.
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CROC
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Old trigger valve repair option?

Post by CROC » Sat Jun 05, 2010 7:20 pm

Wow, It's been a while since I posted here, but I just thought of something after recently noting something that could fix the problem of the old trigger valves not closing entirely.

As some of you may know, when modifying a modern Nerf gun (based on the recon CS6), electrical tape is occasionally wrapped around the plunger tube such that the spring sits on that as opposed to the plastic. That is where I got this idea from.

My CPS 2000 had a faulty trigger, so I would up using a rubber band. However, due to constant wear and tear, the rubber band gave way. So I took apart the CPS 2000 trigger valve and wrapped electrical tape around the part of the valve that is the actuator (not sure what exactly to call it). So far from what I've been seeing this is working well. However, I still need to test it, which will happen most likely some time this weekend. I'll post results once I get a chance to test it.
-Croc
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C-A_99
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Re: Old trigger valve repair option?

Post by C-A_99 » Sat Jun 05, 2010 10:41 pm

So basically, you used electrical tape instead of rubber bands to hold the valve closed? I don't see that lasting very long; rubber bands last somewhat longer. Springs are the best as they last the longest (particularly stainless steel) but in most cases you have to assemble something behind the valve's pin in order to hold the spring in place. Often, it's not worth it when you can simply use rubber bands, but sometimes, the spring is a better option if there aren't any good places for the rubber bands to go.

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soakernerd
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Re: Old trigger valve repair option?

Post by soakernerd » Sat Jun 05, 2010 10:46 pm

no, he is wrapping electrical tap around the metal rod, so the spring holding the valve shut is precompressed, resulting in more spring tension.

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C-A_99
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Re: Old trigger valve repair option?

Post by C-A_99 » Sat Jun 05, 2010 11:17 pm

You'd have to wrap the tape inside to get that to work. Wrapping it on the outside will just cause the smaller spring that sits on the outside to push the whole pin back. The end result is that the valve will likely be left half open.

You'd probably have to do this from the inside, adding material to "assist" the internal spring in compression. However, this may also wear on the internal spring which is what causes pull valve problems in the first place.

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CROC
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Re: Old trigger valve repair option?

Post by CROC » Sun Jun 06, 2010 3:40 am

Sorry for the plausible lack of clarity there C-A 99, but that is what I am doing. Wrapping the electrical tape around the internal part of the trigger valve which controls the firing. I'll probably wind up just hunting down a new compression spring in the near future but currently I think this should work fine. Still awaiting testing because it is currently raining and I need to prepare for exams next week.
-Croc
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CROC
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Re: Old trigger valve repair option?

Post by CROC » Sun Jun 06, 2010 11:35 pm

So here's an update:
The gun held pressure fine, but I think since I replaced my PC due to it breaking, it seems to shoot a slow burst at the start then as the PC loses some water the range picks up, as does output. I'll collossus it once I open it up again and maybe attach a rubber band or something to ensure linear pressurization ( I had to cut the back half of the original piece so I need to improvise something). I am considering finding an endcap that will fit inside the PC case and contact cementing or securing that to the end of my PC.
-Croc
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soakernerd
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Re: Old trigger valve repair option?

Post by soakernerd » Mon Jun 07, 2010 1:08 am

For nerf guns, pen springs work well as catch replacement springs. Could they be used as spring replacements here?

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CROC
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Re: Old trigger valve repair option?

Post by CROC » Mon Jun 07, 2010 3:23 am

No, not really. There is no "catch", but the springs in pens are ridiculously small in comparison to the spring in the valve. Unless the ink cartridge has a massive diameter, I don't think that's feasible. Howeer you can run out to a Canadian Tire and get springs for pretty cheap, so I might do that after I am finished exams.

My attempt to fix this so it looks like the valve has always worked in the first place has been successful, but I would almost rather find a spring of similar strength such that I can just replace the old one. I can forsee the spring wearing down again, but since I compressed it a fair way, I don't see it happening in the near future. Now to work on that linear LRT problem....
-Croc
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zeda.beta
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Re: Old trigger valve repair option?

Post by zeda.beta » Mon Jun 07, 2010 6:20 pm

I might try this with one of my guns, it has the same problem.
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Quack damn you.

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CROC
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Re: Old trigger valve repair option?

Post by CROC » Tue Jun 08, 2010 4:08 am

Zelda - what is happening with your gun, and what gun is it? The only reason I did the repair this way was because I had the ability to take apart the valve to get to the inner workings. From what I saw on my CPS 1200 it is not as easy to access.

Just a random thought, but I don't think super soaker patented their old pull triggers. Once I go off to university I might try to fabricate a water gun taking advantage of the 3D printer and rapid prototyping machines there. I have about 8 inches of cps2000 bladder replacement LRT to play with, and could make my own valves and such. I could also attempt a homemade valve but that would probably be really crude and inefficient (I'm talking like 2 inch endcap sized, with maybe a 3/4 inch nozzle width, a NPT for LRT and another one for the water input. I've just got to plan how I could make the actual trigger part of it without water leaking. I have ideas but I may go with something on a nail.

See, now that I know I'm going into engineering, I can consider some of these options and possibly apply them to all of these fun applications.
-Croc
It's been a while guys, and its good to be back

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