A manifold or false bottom is a piece of equipment that sits on the bottom of the mash tun to prevent grain from getting into the boil, which causes tannin extraction. No matter what type of manifold you use, its essential function is to filter.
Copper manifolds are constructed by soldering standard copper tubing and fittings together in a rectangular or radial arrangement. Small slits are then cut on the underside to allow the wort to fill the tubing, and drain out one side of the manifold. (please expand this section).
Using Stainless Steel Braid as a Manifold
Stainless steel braid is used as a covering for plastic plumbing fixtures, because it is flexible and durable. The supply lines to sinks and toilets are usually made of soft plastic tubing wrapped in a stainless steel braided sheath that protects it from accidental damage.
Some brewers use a stainless steel braid as a manifold in a homemade mash tun. Proponents of the stainless steel braid argue that it's easier to build and more durable than a copper manifold, and that it clears the wort more quickly during the vorlauf.
Buying a braid
Braided tubing can be found in the plumbing section of most hardware stores in multiple lengths and widths and with a variety of fittings. Choose a length that makes sense for your mash tun and a width that will allow you to easily connect the braid to your outlet pipe. Don't worry about the fittings, since the first thing you will do is remove them.
Be certain that the braided pipe you are buying is stainless steel; nylon coverings are becoming more and more common.
Preparing the braid
To prepare the steel braid for use as a mainfold, you will need to remove the internal plastic tube.
First, cut the plumbing fittings off of each end of the braided plastic pipe. The easiest way to do this is probably with a rotary cutting tool such as a Dremel tool, but you can also use a hacksaw, strong tinsnips, a bolt cutter, or even a hatchet. To maintain the integrity of the braid, put masking tape over the ends and cut through the middle of the tape.
Once the ends have been removed, you should be able to work the inner plastic tube out of the stainless sheath.
Some brewers reinforce their braid, but most feel that this step is unnecessary, even with extremely large grain bills.
Attaching the braid to an outlet pipe
The braid can be connected to an outlet pipe with a hose clamp; simply slip the braid over a piece of appropriately sized copper tubing or other material and tighten.
For best drainage, a T connector can be used so that both ends of the braid are connected to the outlet. Otherwise, you will need to clamp or otherwise close up the open end of the braid to prevent the mash from flowing in and bypassing the manifold.