Wednesday, July 27, 2011

Wetsuits and cartridge heaters

Following the advice of Anonymous, I have bought a cartridge heater, found on ebay for under AU$8. It's 220VAC, 400W, which is more than I need, but not way too much, It will probably take at least a fortnight to arrive, and so I'm going to make the glue gun heater anyway, especially considering that I will need two heaters eventually anyway, as I brew in both a small 5L jar and a big 30L vat, sometimes simultaneously. Also, I have a small brew going at the moment, into which I would like to place a heater as soon as possible.

Insulation: I want thermal insulation for my vats, as I think I mentioned. I called up ACT foam and rubber and Clarke Rubber to ask after various foams for this purpose. I was quoted $39.90 p/sm for some stuff called 'form fit', which sounded quite good, or $120 for 2 square metres of neoprene. Being a cheapskate, I decided to find another source of neoprene for my insulating jackets. Wetsuits.

So, today on my way home from uni I stopped in at some op shops and picked up two absolutely hideous wetsuits, one for $15 and one for $20. The leg from one wetsuit provided me with an almost ready-made jacket for my 5L jar, and the trunk of the other, plus a strip from the trunk of the first, make up a jacket for the 30L vat.

I'll post some pictures soon.

Monday, July 25, 2011

Immersion heater plans and ideas

After struggling for a long time to find an immersion heating solution that was
a) affordable
b) relatively small
c) easy to immerse without contaminating the brew
I gave up and built a light box for my vat to sit on. This works well enough, but takes up space and has a light bulb in it, which is prone to breaking.

The other day, I was working on a vacuum box and needed to make a hole behind the electronics panel airtight. I did the obvious thing and filled the hole with hot glue. The problem being that my hot glue gun has a broken trigger mechanism, meaning that I have to manually push the glue sticks through. In the process of trying to quickly fill the hole up, I pushed ab it too hard, and shot the heating mechanism out the front end of the gun.

So no I'm down one glue gun. On the plus side, I got a small heating element that runs directly from mains power. Untouched, it measured about 10cm by about 2.5cm in height, and consisted of a stainless steel tube with the familiar conical nozzle at one end, with a stainless steel block mounted underneath, from which a pair of wires protruded. Guessing, based on the thickness of the walls on the stainless steel tube, that the heating element itself was confined to the block under the tube, I promptly cut the tube off to make the whole thing smaller. My guess was correct, so I now have a stainless steel heating element about 15mm diameter, 50mm long.

My next step will be to mount it in a brass or copper tube filled with mineral oil, this will allow me to mount it firmly throught the top of the vat, preventing it from touching the sides. It will also prevent the brew from conducting the 240 volts that are running to the element. There are two reasons for putting the mineral oil in there. Firstly, it is non-conductive, so the wires will be safe in there. Secondly, is removes air from the vessel, which is a poor conductor of heat, the oil will transfer the heat from the element to the brew more efficiently.

At the end, I hope to have a completely sealed unit about 200mm in length that I can easily mount, and easily swap between brewing vessels.

I'll post pictures and further information as I go.

Homebrew experiments.

As my previous post may imply, I've been playing around with homebrewing beer and with controlling the various processes involved in this. From now on, I plan to post my various prototypes, ideas, plans, and findings here. At the moment my list of things to integrate into my system includes:

-Improved thermostatic control, possibly using a PID system
-Immersion heater for direct heating of the brew, this also saves space
-Electronic hydrometer to tell me the specific gravity of the brew, the alcohol content, and when it is time to bottle
-A convenient, inexpensive, and space efficient method of thermally insulating the brewing vat.

I guess while I'm at it I'll also post the results and recipes of my more experimental brewing attempts.