10 replies to this topic

[The Crackerjack Man]

Okay well this is my first homemade, its going to be made out of pvc pipe and shoot with an air compressor or a bike/ball pump. Would like some Suggestions on design. Also should i glue it while building or glue after done with final job?

Edited by The_Crackerjack_Man, 09 November 2006 - 11:10 PM.

[Carbon]

A few thoughts...the way I see it, your trigger system is going to give you problems, for a few reasons.

One, your trigger doesn't look like it'll have enough travel to fully open your ball valve. If it did, I doubt you'd have the leverage to properly open it, as ball valves are somewhat stiff to turn (but it might work if you rotate the handle 90 degrees so the cable is directly pulling on it |--- ...otherwise, you're wasting pulling energy in a direction that doesn't cause movement =--- .).

Two, even if you had enough travel and enough leverage, string or fishing line is way too weak and elastic...you'll need to use steel aircraft cable...nothing heavy, but it'll get you away from the stretch.

As far as gluing, probably the best way to do it is cut all your parts to size, assemble it and make sure they fit together, then take it apart, prime it and glue it.

It'd be cool to see some different takes on a ball valve trigger...good luck with it.

[six-five-two]

If you can make this ball valve trigger, I would like to do it for my unfinished walloper... I think a solenoid valve may be better though.

[The Crackerjack Man]

If you can make this ball valve trigger, I would like to do it for my unfinished walloper... I think a solenoid valve may be better though.

Sorry but, I dont know what a Solenoid valve is can some one explain?

[Carbon]

Sorry but, I dont know what a Solenoid valve is can some one explain?

When someone says solenoid here, they're talking about a solenoid sprinkler valve, an irrigation valve that is usually electrically powered. They can be operated by three 9 vollt batteries, but the best way to run them is to modify them to operate via air pressure (they open faster that way).

They've been discussed at length....do a search for them, or check the homemades section for CX's BAMF.

[SHADOW HUNTER ALPHA]

I don't have any experience with solenoid valves, but that ball valve is definitely going to cause some problems. I should hope you all know this, but a ball valve opens from one direction, meaning that if you can't get it completely open before the dart leaves the barrel, then the pressure and force behind the dart is going to fluccuate. This is not as big a deal with a longer barrel where the pressure has time to equalize behind the dart before it leaves the barrel, but barrels under 1' are going to have trouble with this. Since the pressure is released from one side first, the dart has a lot of potential to slice to either side or rise/dive out of the barrel. Tha faster and smoother the valve is opened, the better your accuracy and range. (Although in theory opening the valve so that the bottom opens first could create a hop-up effect that counters gravity for a short while, similar to that of an airsoft gun. I'll have to experiment there.)

[Carbon]

I don't have any experience with solenoid valves, but that ball valve is definitely going to cause some problems. I should hope you all know this, but a ball valve opens from one direction, meaning that if you can't get it completely open before the dart leaves the barrel, then the pressure and force behind the dart is going to fluccuate. This is not as big a deal with a longer barrel where the pressure has time to equalize behind the dart before it leaves the barrel, but barrels under 1' are going to have trouble with this. Since the pressure is released from one side first, the dart has a lot of potential to slice to either side or rise/dive out of the barrel. Tha faster and smoother the valve is opened, the better your accuracy and range. (Although in theory opening the valve so that the bottom opens first could create a hop-up effect that counters gravity for a short while, similar to that of an airsoft gun. I'll have to experiment there.)

Sort of. The biggest problem with ball valves is the speed in which they open. The problem isn't that the pressure fluctuates (goes up and down), but that it isn't completely vented before the dart leaves the barrel. You want all the air in the tank to leave instantly: since the a ball valve has a hole which gradually gets bigger as it's opened to the barrel, pressure will be gradually released. If the valve is opened too slowly, it is possible for the dart to have completely left the barrel before all pressure is used. Like you were saying, that's where a longer barrel comes into play, giving more time for all the pressure to exit the tank and act upon the dart.

However, the side that the air is released from doesn't matter at all. Pressure is pressure, and it equalizes near instantly. The effect you're talking about might come into play if you were actually blowing a dart down a very loose barrel, but guns such as these use a tight fit and air pressure (not velocity) to expel the dart.

Hop up in an airsoft or paintball gun isn't caused by the airstream behind it, but by spin intruduced in the barrel. Since darts are cylindrical, "hop up" really isn't possible.

Edited by Carbon, 10 November 2006 - 07:36 PM.

[The Crackerjack Man]

Just a quick questoin.... If you get ball valve and put some kind of lubricant on will it open faster?

[z80]

Just a quick questoin.... If you get ball valve and put some kind of lubricant on will it open faster?

Yes, dish washing detergent works actually really well. Another valve you should consider is getting one for a hose. They are shaped like gun handles already, and are fairly fast opening and cheap (4$ approximately)

[blinkycc13]

If he got a hose handle, then he would have to change the layout of the gun. Hose handles are good though. If you get one make sure it's metal. Plastics break to easy (I have experience with them).

[The Crackerjack Man]

Today I tried out the design that I had. No luck, even with the detergent it wouldnt open fast enough for the dart to get a decent distance. But I did find another design that will have a solenoid valve on it. After finished with the new design I will post pictures.