The manifold is made up of 1/2" copper tubing, along with tees, endcaps, and elbow fittings. It looks sort of like a tree branch; a main stem with arms coming off of it, alternating left and right. One end of the stem is capped, the other end leads to an elbow that angles up 90 degrees to a standpipe. Here's an ASCII pic I hope will make it clear:
_ end cap
|
tee +---------] cap
|
[--------+
|
+---------]
|
[--------+
|
elbow \
90 deg up --------------->==========
standpipe siphon hose
(this would be coming out of the screen)
The length of the stem and the length and number of arms can be adjusted
to fit whatever kettle or cooler you use. The manifold should fit
exactly in the the bottom of the vessel when you're done.
The arms of the manifold each have a number of slots cut in them, spaced a couple of centimeters apart, not quite halfway through the tube (I used a hacksaw to make them). You can also use a hacksaw to cut all the other pieces of tubing, but buying a $5 tubing cutter will make life a lot easier. The tees, caps, and elbow fitting will already fit very neatly, so you don't even have to solder anything together.
When assembled, the slots will face down to the bottom of the vessel. This is to keep the grain from clogging them, and so you don't leave a half inch of wort in the bottom. The standpipe should come up the side of the vessel to just below the rim, so you can put the lid on.
You will need to come up with some way to connect your siphon hose the the 1/2 inch standpipe. We found a 1/2" to 3/8" ID reducer fitting and a short piece of 3/8" OD tubing will connect nicely to a standard vinyl siphon hose:
-----===
| \__ 3/8" _______
1/2 inch copper |redu |------|siphon hose
| cer_|------|______
| /
-----===
Also, the reducer and 3/8" OD copper need to be soldered so they don't
suck in air, since they're the only fittings that sit above the liquid
level. [Note: soldering copper is easy; it requires a few cents worth
of plumbing-safe solder and flux and a $15 propane torch. Ask the
friendly folks at your local hardware store.]
As you might have guessed by now, you don't need a drain hole in your vessel at all; just have the standpipe up the side of the kettle and siphon from there. You could somehow attach the manifold to a drain, but I don't think it's worth the trouble.
The manifold rests right on the bottom of the vessel, and my "spigot" is simply a hose clamp at the end of the siphon hose. Buy one of the plastic hose clamps that has variable click-stops.
Clean the manifold with hot water. Since it isn't soldered, you can just disassemble it when your done. You can clean it with a small bottle brush if you like, and if you're worried, you can soak the pieces in a metal-safe sanitizer like ChemPro. Whatever you do, *don't* try to clean it with bleach. Bleach and copper don't get along very well. And clean the manifold thoroughly with soap and hot water before using it for the first time to remove oils and such used while manufacturing the tubing.
Here's how the thing works: assemble the manifold and place it in the vessel, slots down. Add your mash water and grain on top of it. When the mash is done, attach the siphon hose to the standpipe and start the siphon going into another vessel. As the level of the mash water drops, add your sparge water so the water level stays an inch or two above the grain bed. When you run out of sparge water, or decide to stop adding water, let the siphon run until all the water has been siphoned out. You'll be amazed, this system gets almost every single drop!
This manifold system has a number of advantages: