Monday, 7 May 2012

Brewery Build #4: Fittings

The two 1/2inch threaded 4inch long thermowells (Ebay: mainlandvf) arrived from the USA last week.  They cost $14each, including shipping, which is not bad considering similar cost about $35-45 if purchased locally.  What I like about these is that while the thread that screws into the keg is 1/2 inch, it also has a 1/2 inch thread to fit a probe, most other thermowells are designed differently.

About half the 304 Stainless 1/2 inch weldless fittings arrived from (Ebay: dailyappliance2010) China today.  After checking the prices from four local vendors, two USA based websites, the Chinese Ebay fittings (which are probably exactly the same as all the others anyway) averaged out at about 20-40% cheaper.  The ball valves -3piece valves for kettle and mash tun, 2piece for HLT and pumps- were considerably cheaper from Ebay than I could find elsewhere.
I could not find 1/2 inch stainless or flat-silicon washers on Ebay so I grabbed a few at Keg King when I was there last week.  The small red silicon o-rings were purchased (costing just a few cents each) when I ordered my beer-taps from the USA, unfortunately the website had them listed incorrectly so they are not actually 1/2 inch in size and need to be forcibly squeezed over the fittings.

The fittings are all 1/2 inch NTP a U.S. standard for tapered threads, the theory behind the tapered thread is that it allows them to form a seal when torqued, unlike parallel thread fittings where the threads merely hold the pieces together and do not provide the seal.  This has advantages -sealed thread- and disadvantages -the fittings do not tighten snugly 'all the way up' like parallel threaded fittings do, so washers will be needed where the fittings pass through the wall of the kegs.

The difference between the two thread types is best shown in the photo below.  The tapered thread (1/2 inch stainless) fittings are shown on the right, notice that the male nipple does not fit all the way inside the female valve socket.  With the parallel thread (3/4 inch brass) fittings on the left, the male thread tightens all the way into the female valve socket, but it also relies on a rubber seal to ensure there is no leaks along the parallel thread.

Each of the tapered thread connections here are about as tight as they go.
The reason for using an U.S. standard thread is simply a cost one.  NTP fittings -purchased from the USA or China are generally significantly cheaper than similar local items that have a slightly different thread.  Luckily at 1/2 inch size, the only real difference is the thread-pitch so that my American-standard fittings should still fit with the local standard if I need to buy a few fittings locally.

When I purchased them last year (from Chi Company in the USA) the 'SnapLock' brand camlock fittings were about half the cost of similar local products.

Of course the major problem with using U.S. standard fittings is that it's hard to get just one or two more fittings without paying a significant delivery charge.  Which is why planning and working out exactly what I needed was something that took a fair bit of time.

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