Making DaaB's False Bottom Mash Tun
 

This may be the option for the all grain brewer who has minimal space for equipment
 as it can be easily dismantled and used as a fermenter after the mashing is complete.
 It can also be stacked away with the other fermenters when not in use and is an alternative
 to the stainless steel braided manifold.

Its fairly quick and easy to make and basically starts off life as a standard fermenter with tap.

The next addition is a shallow plastic plate with a 20-21mm hole drilled
 in the centre and a matrix of 2mm holes drilled evenly over the plate.
 This sits in the bottom of the bucket and is used to sepperate the grain from the sweet wort.

The plate is then adapted using a modified brass tank connecter. This has been cut down...

...so that when this 15mm elbow with short extensions is fitted,
 it lines up with the existing hole in the fermenter and can be coupled to the tap.

Its fitted with the nut uppermost...

...so that the dogs on the other part of the connector act to prevent the plate
 from being squashed by the weight of the grain and water,
 shutting off the flow. Not all tanks connectors are designed like this
 so you may have to get file out and modify it a little.

The elbow is inserted into the connector (no need to solder) and the vertical leg of the elbow is cut to length so that its shy of the end of the dogs. This means if the plate is crushed, the wort can still flow into the pipe with the dogs holding it away from the bottom of the bucket.

Reinforced food grade tubing is attached to the elbow and secured with a stainless steel jubilee clip then forced into the back of the tap. 1/2" tubing is a slack fit so it needs to be expanded first. This can be done by boiling the end of the tube in water and inserting some 15mm copper tubing. It's then cooled using cold water and the copper tubing removed. This should then be a snug if in a WD lever tap. Other tubing may need to be found if a different tap is used.

The finished article, (almost) ready for use. Tests have shown that the mash tun will drain down leaving as little as 1/2 a pint of liquid. 

Now the mash tun needs to be insulated using an old sleeping bag or by throwing old blankets over the top, its low tech but very effective. They can be secured using bungee straps if required. Don't for get to insulate the underside to prevent the work surface conducting the heat away. This can be done by sitting it on a newspaper or better still a towel that will soak up any spillages.

This article courtesy of Chris at http://www.18000feet.com/