5 replies to this topic

[Hipponater]

Edit: Shit, I forgot to test it the other way and it doesn't quite work. More at bottom

After seeing Split’s Hornet Shuttle Valve Mod, I wanted to make one, it's an amazing mod, however, at $10 apiece from McMaster, the shuttle valves are too pricey for me. I was looking around trying to find them cheaper when I ran across the picture here http://www.kepner.co...ttle_valves.htm and figured they could be made. The goop on mine are still drying, but they should be in a hornet tomorrow. I blew into them and it worked perfectly, but after the goop is finished drying, I’ll assemble it and see the real results.

Materials needed:
4” of 1/4” OD, .170” ID vinyl tubing
7/8” of 3/8” OD, 1/4” ID vinyl tubing
3/8” of 1/2” OD, 3/8” ID vinyl tubing (optional, but recommended)
BBs. (1 per)
1/4” dowel rod (5 or so inches)
Goop

Tools needed:
Your preferred cutters for tubing (X-acto knife, razor blade, etc)
Drill Press (preferred) or hand drill
1/4” drill bit

Start with your materials


Cut your 1/4” OD tubing into 3 parts, two will be the ends of the shuttle valve; the third will be the air exit. I cut all mine to about the same length.
Take the 1/2” OD tubing and slide it over the 3/8” OD tubing and center it. Like this:

This is slightly difficult, I took my vice, adjusted it to an opening of 3/8”- 1/2” and set the piece on it, then pushed the inner tube down while the edges of the vice held the outer tube from moving.

Once you have that centered, congratulations, you’ve finished the hardest part.

Now, slide in your 1/4” dowel to the two tube piece you just made.

The dowel will hold the tube so it does not collapse on itself while you drill. Drill a 1/4” hole (centered in the middle of the 1/2” tubing) through the 1/2" tube and through the 3/8” tube until you hit the dowel. Don’t drill through the other side of the tubing. Slide out the dowel. It should now look like this:


Now, put in one end of the input tubes, they form the top of the T shape. Put in the piece on the side and the bb. Make sure the side tubing does not protrude into the center, that will prevent the bb from moving and your valve won’t work.



And finally, add the other side.


Now, you can check it by blowing in one of the top parts of the T shape. The air should come out the side tube, but not the other end. If it all works, goop it up!




And you’re finished and ready to make a backpressure gun kick ass.
Hopefully it works, it seems to now, but we’ll find out when I put it in the hornet. Any tips/suggestions?

Edited to change spacing.

Edit2: Shit, I tested again by blowing in one output with the bottom plugged, it doesn't seal entirely with the other side, some air still leaks out. I'm working on fixing it by various means (changing from BB to 1/4" slingshot weight to other ball bearings) and funneling the edges of the tubes, anyone have any tips?

Edited by Hipponater, 26 July 2009 - 08:06 PM.

[Nerf Bros]

After seeing how proud Split was with his Hornet I thought he had found some cheap part to work with that would make a so-so gun great, but I didn't realize it would be $50(!) to do.
Congrats and thanks for making a good idea possible for those of us who work minimum wage. I might rebuild my hornet with some of these someday.

[Hipponater]

Shit. I forgot to check that it was air tight after pressure had been achieved. As of now, air can flow just fine, but when the tank is full, air will leak out of one side because it doesn't seal perfectly. I'm working on new fixes as outlined at the bottom of the first post. Any ideas?

Sorry for not checking it entirely, I forgot it had to hold the air after it was pressurized.

[Split]

I had already tried this. Mine seems to have been more successful than yours, but still finicky at best. Best of luck if you choose to continue exploring this route.

[Hipponater]

I had already tried this. Mine seems to have been more successful than yours, but still finicky at best. Best of luck if you choose to continue exploring this route.

What approach did you take?

On a new one, taking a knife and funneling out the sides of the 1/4" tube seems to be working, it's just a lot of fine tuning before it will be really ready. The seal is highly dependent on the straightness of the cut, if it's crooked, the bb cannot close off the tube as well and it will leak out.

I'll keep trying the funneling approach with the bb before I explore different ball blockers or maybe even another system.

[Split]

Similar to Zorn's check valves, mine were with ball bearings, and the "1/4” OD, .170” ID vinyl tubing, 3/8” OD, 1/4” ID vinyl tubing."
Specifically, parts 5233K561 and 9528K13, and the 1/8" was from Home Depot. The ball was in between the ends of the 1/8", all housed in the 1/4." The difference (besides the significantly larger ball) was primarily that the ball could only move about 1/32" either way. Simply sanded a hole in the side near that connection, and gooped on another piece of tubing. It sealed better (not perfectly, but bearably), but the valves wouldn't change input/output nearly fast enough, and I would get misfires. Not to mention it was a horrendous pain to make with such tight tolerances.

Another thing I noticed, mentioned in your last post. "funneling" the ends of the 1/8" tubing seem to have made mine not seal as well. Again, I'm using larger balls to seal though.