8 replies to this topic

[NERF Downunder]

Hi, i am in the process of building a new homemade (it is still in planning stage, but i am not going to post design pictures, because people get flamed for that all the time) and it will be pump powered.
I am unsire as to how big my air tank should be, because i dont need too big a tank for big range, but i dont want too small an air tank that will make it underpowered ( i want to shoot 50-70 feet),i also dont want to to pump like crazy just for one shot.

The pump i am using is a small two way bike pump (it pumps when you pull as well as when you push)

Any help will be greatly appreciated.

Bazza

Ps. Hows my spelling and punctuation? i want to improve my post quality to keep the standards of the forum from sinking ( also, i dont think i would survive a big old flaming from one of the senior members ).

Edited by NERF Downunder, 27 July 2006 - 01:07 AM.

[Flaming Hilt]

[Edit -- sorry, but I have seen some harrassing going on about unfinished homemades]

Otherwise, I personally wouldn't worry about air tank size. The At2k has no more than 2 sq. inches in tubing, goo tube holding and extra space in the valve, and it gets 100 ft sometimes. Of course, a Titan with 10 sq. inches will go 150 ft... but then, you have to pump it 25 times.

I would say just build whatever is easiest, and as long as it's 2 square inches or larger (total), you should be fine. Chances are you don't even have to worry about an air tank because depending on what you're using for the valve, the extra space inside the valve will be enough to serve as an air tank.

As for spelling and punctuation, you can always copy and paste into a Mic. Word document and run spell check in there. I'm no mod, but it looks good enough not to get banned.

Edited by Flaming Hilt, 27 July 2006 - 10:52 PM.

[z80]

Flaming hilt, the homemade section can be for asking questions, maybe you should calm down.
Nerf downunder, as flaming said, msword can be good, or spellfox (extention for Firefox that checks spelling, search it in mozilla's website)
As for tank size, I would say just use your judgement. I would be more worried about leakyness. Try to make a good seal around the shreader, thats where my homemade died. Btw, does anyone know a better way to attach a pump? like glueing it directly to the airtank?

[Dr Nerf]

Btw, does anyone know a better way to attach a pump?

Use a real PVC check valve. Using only a schrader valve is the cheap way and is just asking for trouble.

Make a setup like this:


Using a real check valve also allows you to make attachments for air tools (including schrader valve). If you buy a correct size female adapter and a correct bushing to change the sizes, you can easily hook up a threaded schrader valve too. If you use teflon tape it should not leak.

As for the questions about tank size, it really does not matter as long as either the tank is large or the pressure is high. Using both would get the best performance, but don't expect great performance from a small low pressure tank.

[z80]

Where are these check valves located in, say, home depot? These would be great for a homemade pump setup.

[Dr Nerf]

Check valves are usually available in the plumbing section of home improvement stores like Home Depot and Lowes. They make both PVC and brass ones in many different sizes. Larger ones can cost quite a lot though (10 USD or more many times), but smaller ones should be fairly cheap.

[six-five-two]

For the nerf gun I made (went about 100 feet) I used 1 1/4" PVC, 12 inches long. I suggest 1 1/4" PVC at 10" long.

[NERF Downunder]

WOW, thankyou all for the replies, it is overwhelming how helpful the people on this forum are.

After doing a bit of research, i thought that i might try to make my own bladder, and use it as a tank. The gun i am making is aimed at having really good rate of rire and average power, with minimal pumps ( i will be hooking up a breech loading clip to the pump, so pumping loads a dart while filling the tank at the same time).

Considering the above, my tank needs to be small, but still pack a punch, and thats why i think a bladder might be a good idea.( having the added bonus of a tank that is trying to constrict itself to its original size might be an advantage over a solid tank)
I was wondering if anyone has ever made their own bladder for use in a homemade before? I was considering using a peice of bike tube, with pvc caps at each end, but i am unsure if this is a suitable material.

Once again thankyou all for the replies, the information has definatley helped.

[Doom]

Rubber bladders are only useful in a semi-auto type system with some sort of regulator to ensure that each shot gets the same amount of air. You'll have to make that regulation system or buy one. This is not an air regulator either, for it must be coupled with the trigger system to even work. Essentially all you will need to do is make a valve open for only a set amount of time with one trigger pull. The easiest way to do that would be to use an electrically actuated solenoid valve and do a little electronics work.

As for who's used rubber tubing, that would be myself and probably no one else. So far I've beaten everyone by two years in not only Nerf but also water guns.

Regardless, do a search for "bladder" in the homemade Nerf guns forum and look at the second link: http://nerfhaven.com...indpost&p=85560

If you want more power from a rubber bladder, you'll have to do some layering or order the tubing from elsewhere to get thicker tubing. It would be easier for most people to do what I'll mention next however.

Ideally however you will use a larger air tank and an air regulator. You can control the power and air consumption. You will also need a second air chamber to send a preset amount of air into the barrel with each shot. Not too hard, but this has only been done a handful of times. I've been considering making a Nerf gun like this for myself, but I'd first need to get money.

Hope this was helpful as well.

Edited by Doom, 28 July 2006 - 07:35 AM.