Did a bit more on the HLT today - I've still got to mark the sight tube and test boil, and perhaps make a lid, but I think everything else is done
This is how it looks from the outside (still very green!). You can see that I've fitted the element, tap and polycarbonate sight tube (EDIT: I later swapped the compression fitting on the sight tube for push fit - see later in this thread):
You can't see it but I removed the thermostat from the element and connected the live direct to the element's brown wire with an electrical terminal block. The cable used is the heat resistant stuff of the type they specify for use with immersion heaters (used in their more traditional central heating role).
There was a slight change of plan here; I'd intended to use the old upper coil hole for a temperature probe, but realised it was too high for smaller batches. Also I'd intended to use the former lower coil hole for the sight tube, but decided it would be awkward having the sight tube on the opposite side to the tap. So I put the temperature probe's pipe in the lower coil hole and added a new 15mm tank connector for the sight tube, at a more handy location. This left a spare hole, and I decided to use it for an overflow:
Here's a closer view of the outlet and tube for the temperature probe. You can see I made a small dip tube so that the syphon effect would drain below the tap's hole - it leaves less than a pint in, not bad for something thats probably around 100l with so little dead space, so quite chuffed with that. The temperature probe tube is really just because I had a spare hole - I could probably have held a probe against the outside of the wall instead, really. The temp tube is a bit low down, which is good for small batches or for when nearing the end of the sparge, but I'll either have to stir or else compensate mathematically for the water changing temperature between bottom and top of the cylinder.
I tested it for water tightness and I'm glad because it leaked from the flange slightly - it was a real bu@@er to tighten enough, actually, in the end I managed it with the cylinder full of water to give it weight and used both hands on an enormous wrench. I was quite impressed with some aspects of the flange though - once you got it to a certain tightness the inside of the flange gripped the copper and so there was no need to hold it both inside and out - which is good as I'm not sure I could have done that at the same time. Another issue I had was that the flange is a bit thicker than the solder-in ones, which meant that the hole it makes (beyond the threads) is marginally smaller. The first three elements I tried didn't go in - the bent-over end of the element itself was bent at too big a radius to go through it.
I then cleaned the HLT by soaking for half an hour with a bleach solution (thanks are due to Chris-x1 for preventing me from soaking it for far too long!) and its come up really rather well.
I did consider building a barrel-type cladding affair around it, but in the end decided that would cost too much time and effort, and I like the honest functional look anyway - getting quite attached to the green beast actually. I think it may work well for a HLT if left largely in situe and just drained and filled etc. and it has no problem at all taking the volume/weight of water, even with no top. But were I going to use it for a boiler which would be moved around and turned upside down for cleaning then it would either need great care or some reinforcing. The rim isn't very robust and also the wall bends very easily if the pipes sticking out are bumped.
I'll think about bothering with a lid or not, and following a suggestion from aleman I could brighten up the inside witha vineagr solution, as there are a couple of green spots - generally though the naturally formed coating is reasonably uniform so I've no particular concerns about sanitation.
Next the test boil!
Cheers
kev
