My overall objective with this was to make Lt. Stefan's PVAT more robust and easy to disassemble/reassemble.
First, I took a small piece of 1/2" SCH80 PVC and 3/8" ID PEX Tubing. I wrapped electrical tape around the SCH80 until it fit snugly in a 1" Threaded PVC Plug. I then wrapped electrical tape around the PEX until it fit snugly in the SCH80. This is to make the hole I drilled as centered and perpendicular as possible. I drilled down the PEX with a 3/8" Drill bit and continued through the plug.
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV1.jpg)
Once the hole is drilled, tap it with a 1/8-27 NPT Tapping Bit.
Next, I took a 1/8" NPT Nipple (the kind with the hex center) and a 1/8" NPT Nut. I applied Plumber's Goop to one end of the nipple and threaded it in to the PVC plug as far as it would go. I then used needle nosed pliers to thread the nut onto the nipple where it protruded into the inside of the plug.
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV5.jpg)
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV7.jpg)
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV6.jpg)
I proceeded to take a 1/8" NPT Cap and Drill a hole in the end of it slightly larger than 1/4". The inside of the cap is already dimpled where the center is so the drill bit should be guided fairly well by that.
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV3.jpg)
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV4.jpg)
Here's the new rear sealing set up. It is 2 3/16" ID 5/16" OD O-rings. There is a third one there (1/4" ID 3/8" OD) but I ended up not putting it on so ignore it. The idea is that the O-rings are sandwiched between the nipple and the cap so that they have nowhere to move but they can still be adjusted by taking apart the cap and nipple.
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV9.jpg)
Lube up the carriage bolt, but the cap on it, and put the O-rings on it (again, ignore the third O-ring). Put goop all around the O-rings and on the end of the nipple. Thread the cap and nipple together using two wrenches, thus sandwiching the O-rings between them.
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV10.jpg)
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV8.jpg)
Make sure the bolt can still slide through and it is not being glued in place as well. It should look like this
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV11.jpg)
While that is drying you can assemble all of the other internal parts. Mine is pretty much the same as Lt. Stefan's, but I added some nylon spacers because my spring wasn't quite long enough. The assembly goes Spacer-Spring-Spacer-Nut-Nut-Washer-Nut. The spacers are 1/4" ID 1/2" OD. The nuts are 1/4-20. The Waher is a 5/8L beveled faucet washer. The hole in the washer must be expanded with a 1/4" Drill Bit to fit on the bolt.
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV16.jpg)
Cut a 2 1/4" Piece of 1" PVC. I used thinwall, but I doubt it makes much of a difference. PVC cement this piece between a 1" Coupler and a 1" to Female Adapter. Also, cement a 1" to 1/2" Reducer into the other end of the 1" Coupler.
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV2.jpg)
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV15.jpg)
I needed a way to get air into the tank of course. I chose to use the method Whisper101 posted, but there are many other options. Drill a 3/8" Hole into the side of the adapter. Tap it with a 1/8-27" Tap.
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV13.jpg)
Now you can thread in whatever 1/8" NPT fitting you want. An example is a 1/8" NPT to 1/4" OD Quick Connect. I decided to go with a 1/8" NPT to 1/8" Hose Barb because I needed the other fitting for another project. I gooped in the adapter, but Teflon seal tape can keep it sealed fine as well.
![Posted Image](http://i549.photobucket.com/albums/ii361/venomm213/PV14.jpg)
Edited by venom213, 13 March 2011 - 02:39 PM.