I have made of the cheapest and most effevtice mash tun.
buy a plastic food grade bucket that holds approx 20lts..at least 40ltrs is better.
Can go to to a bee keeper and get on of there buckets or use one that they sell to put bags of flour in.
Buy a seperate extra lid...cut off the downside of the lip leaving the upside...the extra lid will later become the false bottom.
This up lip part will create a nice tight fight...next comes the fun part...drill lots..i means lots of 1.5mm holes in the former lid..took 4 days and than i had to use a 1.5mm thick nail to nicely round the drill holes.
1.5mm diameter holes as recommended by the men of malt craft.
Buy a SS valve...drill hole to fit..use a fibre fasher on the inside.
As this plastic bucket will loose alot of heat...add some thermal foam with the foil towards the plastic..use contact cement to stick it down.
Alternatively, buy the plastic Phills bottom...smaller holes than the metal. if you want the proper SS mesh that has 1mm holes on a 1.5mm centre..e-mail me...i had a price on some off cuts but very expensive..enough to do 4...but no else wanted one at the time.
I had the bucket and extra lid..
Got the SS gate valve for $10.00..i can get you one..let me know..they are $40.00 from Blackwoods for ss gate valve od similar size ..
Thermal foam to cover outside surface area and lid ...$14.00.
Contact cement...already had.
Not as good at keeping the temp constant as an esky or round willow cooler.
Will need a minimum of 20 ltr round willow cooler (to use a false bottom..best way to go) 38 - 40 ltr better.
I personally dont like the square eskys...too much trouble with the manifold.
Better to go round and use a false bottom..once done..so much easier..
Might have a picture of mine later.
Hope this helps.
E-mail me if you need more info...
What efficiency to you get from your mash tun designs?
Jazman, check out www.howtobrew.com - there is a detailed section there on how to make an efficient mash tun from a cooler. I put one together based on these designs, total cost was less than $50, and a couple of hours effort (and I am no handyman).