Looks as though carlbelcher beat me to the punch!
But instead of offering yet another tutorial, why not go one step further, and eliminate the fuss altogether?
Modifying the Lid on an OrbitWaterMaster<sup>Ã‚Â®</sup> was (more often than not), an aggravating process. You have to worry about drilling your hole "dead-center"... You have to worry about tapping through less than 1/4" of material (about 5mm), and keep the tap straight while doing so.
<center><a href="http://img.villagephotos.com/p/2003-9/398596/DR2010.jpg"><img src="http://thumbs.villagephotos.com/17411315.jpg"></a></center>
Even if you manage to get through both of these processes with no mistakes, you still have to go through the messy process of epoxying the solenoid mounting hole and its port.
The Lid Sub-assembly was taken off of an Orbit WaterMaster<sup>Ã‚Â®</sup> 57100 Series valve, and modified by completely eliminating the Solenoid hole and its port. A mold was made of the original, and the new part was cast with a glass-filled polyurethane.
<center> <a href="http://img.villagephotos.com/p/2003-9/398596/DR2005.jpg"><img src="http://thumbs.villagephotos.com/17411314.jpg"></a> <a href="http://img.villagephotos.com/p/2003-9/398596/DR2012.jpg"><img src="http://thumbs.villagephotos.com/17413730.jpg"></a></center>
The next picture shows how the solenoid port tube was eliminated, while still maintaining a "boss" to align the diaphragm;
<center><a href="http://img.villagephotos.com/p/2003-9/398596/solenoidporttube.JPG"><img src="http://thumbs.villagephotos.com/17414012.jpg"></a></center>
The thickness of the Lid center was increased, so that a 1/4" NPT fitting could be screwed in all the way, without hitting the "little plastic dome on the diaphragm assy;
The tapped hole on the re-designed Lid is now approximately 300% deeper than the original. (about 15mm)
<a href="http://img.villagephotos.com/p/2003-9/398596/DR2013.jpg"><img src="http://thumbs.villagephotos.com/17413731.jpg"></a> <a href="http://img.villagephotos.com/p/2003-9/398596/DR2003.jpg"><img src="http://thumbs.villagephotos.com/17411313.jpg"></a></center>
The material of the re-designed Lid is said to be 50% stronger than the original.
I've been testing one of these of a launcher that I slapped together from spare parts, and have cycled the valve well over 100 times now, at 120psig.
This new part was just a protoype design... And although I have only two of them, I plan on making many more. Being able to cast custom parts opens a whole new realm to the world of spudgunning.
Pistons, manifolds, sleeved barrels, handles, saddles... What was impractical will now be easily achieved. What was impossible will now be plausible.
I've got so many ideas going through my head, that it's hard to concentrate on just one. - What I plan to do next, is to custom-cast either pre-threaded plugs for the Cloud BBMG, or custom cast vortex blocks...
Either one will directly accept a 1/4" Brake line, with the hard-to-find 7/16-24 thread already molded into the block and the bottom will directly accept either an 1/8" or 1/4" NPT fitting.