Here are most of the required parts. You will need some tubing to nest around the pumps outlet. I used the outlet pipe from a UMB pump. You may want some 1/2" thinwall PVC to move the grip back.
First let's chop up the SSPB. We'll use various methods to keep debris out of the guts. A bit of foam works well for the pump inlet. I used grease for the valve this time. A little electrical tape keeps dust out of the trigger. Twist the barrel peg out with needle nose pliers. Stuff a piece of crumpled up, wet paper towel tightly down the barrel to protect the valve from debris on this rough cut. Pull the pump handle all the way out. Chop your SSPB here.
Clean all the debris away and add some white lithium grease to the valve area. Try to get it behind the cross or remove the cross with a razor knife. This will keep debris out. I also removed a support boss at this point. It will get in the way of the grip later.
Chop a little more to get past the cross without hurting the valve. Scoop out the debris and grease with any small tool. I also used a q-tip to clean the valve out thoroughly. If done carefully there should be no need to flush the tank.
Chop a coupler in half, just behind the ridge.
I chamfered the area around the valve a little just for experimentation's sake. Glue on the coupler. While it's drying we can build and fit the tank.
Now onto the tank expansion. I used a PVC stub for the larger tank. I'm not sure if there is a real performance difference. It's a bit trickier to shape than a CPVC stub. Both tanks use a 1/2" PVC elbow. The larger tank uses a PVC endcap instead of a nested CPVC one. Nest a small length of PVC inbetween the elbow and the endcap for the larger.
Dremel the area under the PVC stub until it's paper thin.
Carefully slice out the center. Sorry about the recycled pic.
Afterwards I melted the edges a bit with a wood burning tool. This is optional. It's easy to see that support boss that needs to be removed in this pic.
Test fit the tank. I kept everything close to the SSPB so I could glue it in a few places for strength. Solvent weld the tank together and let it dry. I affixed the tank to the SSPB with super glue but epoxy or solvent welding is a good choice too.
Ok let's move on to the pump. I used a fairly slim pump but a slimmer one would raise the pressure in the tank a bit more. This pump needed the 90 degree bend chopped off to fit of course. This is still to small to nest into the SSPB's pump tube so we'll need a small section of tubing to make up the difference. The outlet tube from an old UMB pump is perfect.
Here it is chopped up and test fitted. I used the tape as a guide to line up the pump with a mold seam on the bottom of the SSPB. Solvent weld everything in. I added a filet of superglue to the join later for extra strength. Now we can fit the pump support/grip handle.
Here it is glued up. Add some glue to the elbow (or thinwall spacer) and pump face when assembling, to support the back of the pump well.
Chop 2 slots down the elbow. The length of the slots can be manipulated to change the grip dimensions. I just twisted the waste material with needle nose to remove it. I needed to dremel away some material from inside the elbow on the shorter grip. I also needed to add a (notched) 1/2" thinwall spacer to the longer grip. Later we can add a length of PVC and a 1/2" endcap to the grip. I used thinwall for weight. Glue the elbow both to the pump and to the SSPB for strength.
Now let's make the pump work. I used a piece of 1/2" PVC (conduit) with a piece of CPVC whomped into it. Shave a portion of the PVC to fit inside your pump. The CPVC is whomped in and reamed out until the pump tube slides through it freely. I affixed this with electrical tape for easy maintenance. I added an additional piece of CPVC to the end of the pump to affix my elbow and pump handle.
Shot de Money.
The smaller expansion takes 3 pumps for 100' ranges. The larger works a homemade wye at the same ranges but takes 5-6 pumps.
Edited by iamthatcat, 06 April 2012 - 01:47 PM.