Help with assembly

Build a homemade water gun or water balloon launcher and tell us about it.
thwei64
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Joined: Mon Mar 15, 2010 2:36 pm

Help with assembly

Post by thwei64 » Mon Mar 15, 2010 2:44 pm

Hi im a new member here and im recently on a school's project to build a projectile launcher so my idea was to build a compressed air bottle using a soft drink bottle , a schrader valve and a ball valve.

However i have some problems regarding the assembly. My ball valve does not fit the opening of the bottle nicely and my schrader valve have no threads so i have to wrap alot of teflon tape to fit the ball valve in and the schrader valve into the back. When i tried to pump air into the bottle it leaks at first but after a few tries i manage to secure it tightly but it managed to work twice only and then the ball valve shot out of the bottle.

Can i have some help with the assembly like places to buy ball valves that fit nicely into the coke bottle and threaded schrader valves coz im in singapore and we dun really have shops to sell schrader valve with threads

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zeda.beta
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Re: Help with assembly

Post by zeda.beta » Mon Mar 15, 2010 3:05 pm

I would use PVC for the body, soda bottles are too weak to use for any kind of pressure, and otherwise it could end up blowing up instead of just having the ball valve shoot out. If you cannot find any PVC in your area, then look for some copper pipe, from 2-3 inches wide, or 5-8 cm wide. Then you are going to want to look for some more pipe/PVC for your barrel, bring your projectile with you to check the sizes on the pipe/PVC. Then you will probably need a ball valve around the size of your barrel and PC, otherwise you will have to deal with converters and parts becoming very expensive. I would try to model it after one of the water balloon launchers in our homemades section.
-Zeda
Edit: Oh, and yay 200 posts! *Applause* :D
Last edited by zeda.beta on Mon Mar 15, 2010 10:26 pm, edited 1 time in total.
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thwei64
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Re: Help with assembly

Post by thwei64 » Mon Mar 15, 2010 3:15 pm

oh u mean finding something like a container made of pvc? ermm where can i get tat ? coz my project only requires to shoot a projectile at a oscillating target at a 3m distance so i dun need very high pressure i tink? ><

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soakernerd
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Re: Help with assembly

Post by soakernerd » Mon Mar 15, 2010 3:16 pm

You may also want to look into a Nerf style homemade. they are generally smaller and more usable, since they are firing smaller projectiles.

thwei64
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Re: Help with assembly

Post by thwei64 » Mon Mar 15, 2010 3:19 pm

wads a nerf style homemade pardon my lack of knowledge ><

where can i find pvc body for the chamber coz it would be nice as ball valves can fit into pvc openings perfectly so i dun need to spent more money to buy

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soakernerd
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Re: Help with assembly

Post by soakernerd » Mon Mar 15, 2010 3:37 pm

They are basically scaled down water Balloon Launchers. They are designed to launch small foam darts. They can be found on man nerf sites. You might consider joining one.

Lowes and Home Depot usually have a good supply of PVC.
What are you launching?
To grasp the concept, I would make the following:
|=============(ball valve)========

that is an endcap, followed by PVC, followed by a ball valve, and then a barrel.
to get air into the chamber, I usually use one of these.
All the info is available in that thread. (scroll down to post 6 for the best valves available)

thwei64
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Re: Help with assembly

Post by thwei64 » Mon Mar 15, 2010 3:39 pm

problem is im not in the US and so there isnt a need for a large size chamber? all i need is a long pvc tube to get engh pressure and volume to shoot?

im tinking of shooting maybe ping pong ball or anything tat can fit a pvc pipe

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soakernerd
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Re: Help with assembly

Post by soakernerd » Mon Mar 15, 2010 3:42 pm

depending on what you are shooting, 5 inches of 1/2" PVC can launch nerfs up to 90 feet. it should be noted that it is a VERY BAD idea to shoot these at people within 20 feet.
the valves are available at your average auto store. they usually cost $8 for 2.

thwei64
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Joined: Mon Mar 15, 2010 2:36 pm

Re: Help with assembly

Post by thwei64 » Mon Mar 15, 2010 3:46 pm

wow tats nice i can try building tat so the end cap i have to drill holes for the schrader valve?

how do i secure all the stuffs tgt? do pvc pipe have threads on them for the ball valve? and how do i secure the end cap?

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soakernerd
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Re: Help with assembly

Post by soakernerd » Mon Mar 15, 2010 4:53 pm

yes you have to drill a hole in the endcap for the valve.
use PVC cement to attach PVC.
some have threads, but they are more expensive. PVC cement is generally better.
Last edited by soakernerd on Mon Mar 15, 2010 6:38 pm, edited 1 time in total.

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C-A_99
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Re: Help with assembly

Post by C-A_99 » Mon Mar 15, 2010 6:32 pm

There is a guide on PVC basics on the site, though I don't have time to find the link right now. It overviews PVC assembly and explains how to put things together. As far as I know, you can't simply buy a PVC container; you have to make one yourself with pipe and fittings. (be sure the pipe is designed to handle pressure)

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martianshark
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Re: Help with assembly

Post by martianshark » Mon Mar 15, 2010 7:58 pm

The link is here: http://www.sscentral.org/homemade/aph/pvc-basics.html

This is part of the guide on building an APH, but it also shows how to work with PVC pipe and use PVC cement.

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zeda.beta
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Re: Help with assembly

Post by zeda.beta » Mon Mar 15, 2010 10:25 pm

If you don't have a need for something that can fire over 100 feet, then you could probably use a 1 foot long 1 inch pressure chamber, with a 1 inch endcap, and then a 1 inch ball valve. Then you would attatch a barrel that is the correct diameter for your projectile, probably 1.5-2 inches. If you use a barrel bigger then 1 inch diameter, you will need a converter from 1 inch to whatever your diameter is. To learn how to put it all together, go to the link that Martinshark provided.
-Zeda
I reject your reality and substitute my own.
Quack damn you.

thwei64
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Joined: Mon Mar 15, 2010 2:36 pm

Re: Help with assembly

Post by thwei64 » Tue Mar 16, 2010 4:45 am

thx alot guys i will try and buy the parts :D

EDIT: argh the website says this Warning! Never use PVC fittings and pipe with compressed air or gas.
Last edited by thwei64 on Tue Mar 16, 2010 4:57 am, edited 1 time in total.

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martianshark
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Re: Help with assembly

Post by martianshark » Tue Mar 16, 2010 7:44 pm

Maybe the pipe you were buying isn't pressure rated. If it's marked '150 PSI' or or more, it should be fine.

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