Most of the plumbing is 1/2" rigid copper. The kind you would plumb a house with. The valves are soldered in brass valves from a home improvement store. Much of the plumbing has been insulated with foam pipe insulation to help prevent heat losses.
Here is a picture of my recirculation manifold. It is a simple "H" pattern with 45 degree elbows on the ends. It is made from 1/2" rigid copper and soldered fittings. The ends are not capped and there are no holes drilled on the bottom side of this manifold. The size of the manifold was calculated to gently deposit the recirculation flow approximately in the center of each quadrant of the mashtun.
Here are a couple pictures of my sparge manifold. It is being held by my faithful brewing helper and 11 year old (then 7) son, Alex (I've gotta get a new picture). I used to use the octagon shaped sparge manifold (below) for all my recirculating and sparging. I found that the little (1/8") holes in the sparge manifold would become plugged with the slightest fragments of grain. I use this manifold when recirculating the mash and during temperature raises. When the mashing is done and it's time to sparge the grain bed I swap manifolds to the sparge manifold below. In the pic on the left, he is holding onto the tube that connects the recirc line to the manifold. I have several of these tubes of varying lengths to place either of the two manifolds just above the grain bed in the tun to help prevent hot side aeration and foaming. My general opinion about HSA is that it isn't a problem for me. I've never tasted a problem with my beers that I can attribute to HSA. But, I'm not going to tempt fate either. I do try to keep foaming to a minimum by putting the bottom of the manifold at the liquid level in the mashtun. The bottom side of the manifold has been drilled with several 1/8" holes that fairly evenly distribute the sparge water over the top of the grain bed.
