Jovial_Monk said:

Was interested in the comment re the side arms needing to be an inch from the sides of the esky. got any more details on that GMK?

Jovial Monk

OK

I read up on mash tuns and manifolds - could habve been in Palmers how to brew book or there is an american book on how to make brewing gear - that it has to do with channeling and flows thru the grain bed.

As the sides are straight - you get good flow rates there. The trick is to try and make the run into the manifold the same.

If the manifold is an inch off the sides and there is 2 inches between all manifold pipes = a pretty even flow rate from every where. ie the channel coming down the centre of the grain bed does not have to travel further (eg 2 inches to reach the manifold than the side where it is travelling <1/2 inch.

I hope i am making this clear....

Hear is the link to how to brew...making manifolds

http://www.howtobrew.com/appendices/appendixD-1.html
Here is a quote of the summary of the chapter from the above link:

Here are the summary guidelines for designing efficient manifolds and lauter tuns:

Have the straight line distance to the drain be as short as possible. In other words, orient the pipes longitudinally with respect to the drain.

Deeper grainbeds have more uniform rinsing, all else being equal.

The closer the pipe spacing, the more uniform the flow, all else being equal. A spacing of 6 inches is the maximum in my opinion. A spacing of 2-4 inches is preferred.

The spacing of the pipes from the wall of the cooler should be S/2 or slightly greater to avoid preferential flow down the smooth walls"