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.


  1. Might be worth noting that cartridge heaters are pretty inexpensive and completely sealed. Not sure what kind of output you'd be looking for but you'll probably get one for under $20. Grainger or McMaster Carr.

  2. Why did neither of those come up when I googled this? Weird. Anyway, there were some on those sites, but none of them quite fit what I wanted, the ones with the ability to protect themselves from low water levels were more expensive than I want, many of them were 120v, Australian mains is 240v, and there's also postage to factor in. I think that, given I already have a heater that's safe to use in an empty tank (it's designed to be used in air), all I need is a couple of plumbing supplies and some time with the blowtorch. For a first experiment with immersion heating, I think the glue gun is a better option, all things considered. Also, I don't have to wait for it to arrive in the mail, haha. That said, thank you for putting me on to them, I may well grab one at a later stage in the process.

  3. Also, they have a higher output than I need.