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Title: C-VAB 2.0
Post by: Nerf Doctor on August 16, 2011, 06:40:04 pm
 (http://www.youtube.com/watch?v=_2lRMiLFMEA)
Here is a video of the construction of the C-VAB 2.0. I will post the regular writeup later, seeing as there are about 30 pics to sort.


Title: Re: C-VAB 2.0
Post by: Nerf Doctor on August 16, 2011, 08:10:55 pm
This will be the actual writeup post. First off, the reason there is a 2.0 is due to the valve. When using the 1.5" valve, I discovered that it took great force to push the valve in pressures over about 30 psi. When thinking about this, I realized, the smaller the valve, the less pressure increase when trying to push the valve in, and therefore, less force required. Anyway, enough physics lesson.
First though, a word on safety. When working with PVC for pressure applications, it is important to prime and glue it properly. If your PVC cement is globbity, and comes out it lumps, DO NOT USE IT. It will no longer melt the PVC together like it should, and you will most likely get PVC shooting all over. Also, whenever using a dremel, you should wear safety glasses. Now, to the writeup.
What you'll need
(http://i46.servimg.com/u/f46/15/46/29/71/p8150011.jpg) (http://www.servimg.com/image_preview.php?i=166&u=15462971)
Top to bottom: 1/2" CPVC, 1.2" Conduit, 3/4" PVC, 3/4" check-valve, 3/4" coupler, 3/4" T, (2) 3/4" to 1/2" slip reducer bushings(already in T in picture), 3/4" to 1/2" threads reducer bushing(inside coupler in picture), Teflon tape, 1/4" brass pipe nipple, 1/4 brass T, 1/4" brass schrader valve(depends on pump connection), 1/4" to 1/2" reducer bushing(nylon in picture, cheaper than brass), 1/4" gauge, barrel setup of choice(my string arrow barrel shown).
Take the schrader valve, brass T, gauge, pipe nipple, and 1/2 to 1/4" bushing, and assemble like so
(http://i46.servimg.com/u/f46/15/46/29/71/p8150013.jpg) (http://www.servimg.com/image_preview.php?i=168&u=15462971)
Use the teflon tape on all brass to brass connections
Next, bring those pieces to a vice, and tighten into place
(http://i46.servimg.com/u/f46/15/46/29/71/p8150015.jpg) (http://www.servimg.com/image_preview.php?i=170&u=15462971)
Having wrenches that fit each piece is important. Also, be careful when tightening the brass into the nylon.
Then, tighten the nylon bushing(with brass attached)into the threaded PVC bushing
(http://i46.servimg.com/u/f46/15/46/29/71/p8150017.jpg) (http://www.servimg.com/image_preview.php?i=172&u=15462971)
Tighten until the hex head part of the nylon is flat against the PVC.
Now, cut a piece of 3/4" PVC about 7" long, and clean the ends with a dremel or knife
(http://i46.servimg.com/u/f46/15/46/29/71/p8150018.jpg) (http://www.servimg.com/image_preview.php?i=173&u=15462971)
Sorry for blurryness, was getting quite late when this was happening.
Get your PVC primer and glue out
(http://i46.servimg.com/u/f46/15/46/29/71/p8150021.jpg) (http://www.servimg.com/image_preview.php?i=176&u=15462971)
Stand the 3/4" PVC up in the vice. Coat the PVC that will be glued with the primer. Then apply a even coat of glue on the PVC, not the coupler. Firmly push the coupler on while twisting about 1/4 of a turn
(http://i46.servimg.com/u/f46/15/46/29/71/p8150022.jpg) (http://www.servimg.com/image_preview.php?i=177&u=15462971)
Hold there for about 10 seconds to prevent the coupler from pushing out due to the glue expanding.
Next, apply primer/glue to the reducer bushing with brass, and push into the coupler
(http://i46.servimg.com/u/f46/15/46/29/71/p8150023.jpg) (http://www.servimg.com/image_preview.php?i=178&u=15462971)
Again hold there for 10 seconds.
Next, cut a piece of 3/4" PVC about 2.5" long
(http://i46.servimg.com/u/f46/15/46/29/71/p8150025.jpg) (http://www.servimg.com/image_preview.php?i=180&u=15462971)
Push this firmly into the end of the check-valve that the arrow is NOT pointing to
(http://i46.servimg.com/u/f46/15/46/29/71/p8150026.jpg) (http://www.servimg.com/image_preview.php?i=181&u=15462971)
(http://i46.servimg.com/u/f46/15/46/29/71/p8150027.jpg) (http://www.servimg.com/image_preview.php?i=182&u=15462971)
Now, firmly push the T onto the 3/4" PVC piece
(http://i46.servimg.com/u/f46/15/46/29/71/p8150028.jpg) (http://www.servimg.com/image_preview.php?i=183&u=15462971)
The other PVC bushings should already be in the top and one of the side ports of the T.
Next, cut a short piece of the 1/2" conduit
(http://i46.servimg.com/u/f46/15/46/29/71/p8150029.jpg) (http://www.servimg.com/image_preview.php?i=184&u=15462971)
Push it into the bushing in the side port of the T, and sand flat to the bushing
(http://i46.servimg.com/u/f46/15/46/29/71/p8150030.jpg) (http://www.servimg.com/image_preview.php?i=185&u=15462971)
Now, dremel it out until your CPVC slides through smoothly.
Next, push the CPVC into the conduit until it touches the check-valve
(http://i46.servimg.com/u/f46/15/46/29/71/p8150031.jpg) (http://www.servimg.com/image_preview.php?i=186&u=15462971)
Mark on the CPVC along the conduit. Cut the CPVC above that mark. The distance is determined by comfort.
Next, twist the check-valve off of the PVC holding it to the T, and glue it to the PVC with the brass
(http://i46.servimg.com/u/f46/15/46/29/71/p8150034.jpg) (http://www.servimg.com/image_preview.php?i=189&u=15462971)
You remove the check-valve from the T so that you can push it in while the glue is curing to release any pressure.
Now, take your CPVC piece, and fill one end with hot glue
(http://i46.servimg.com/u/f46/15/46/29/71/p8150038.jpg) (http://www.servimg.com/image_preview.php?i=193&u=15462971)
This will keep air from going out the CPVC.
Once the glue has cure on the valve, firmly push it back onto the PVC with the T
(http://i46.servimg.com/u/f46/15/46/29/71/p8150036.jpg) (http://www.servimg.com/image_preview.php?i=191&u=15462971)
2.0 is on top, 1.1 is on bottom.

This gets round about the same ranges as the 1.1, seeing as the smaller valve allows higher pressure before being unable to shoot.
The gauge is purely to allow for testing at different pressures.

Remember: Globbity with lumps is bad.

Edit: Just realized, I posted the ranges from the 1.1 in the 2.0 video.
With a single 1/2" Conduit barrel, the 2.2(current version)shoots slingshot-weight-and-glue-dome megas about 150'. Flat. Yep.