The ApiBioxal leaflet, link below, suggests the 280-290C final temperature. I've not done extensive testing, just used the Varrox but essentially you're heating a pile of oxalic in an open pan. You need a fair energy input to get the heating element, the pan and the oxalic up to sublimation temperature and get it out of the pan, leaving very little, if any, residue. Sublimation in an open pan is not going to see the oxalic heated much higher than it takes to leave the pan, just as it takes confinement and pressure to get water over 100C. The exact final temperature will vary with previous use, any water left from previous cooling, ambient temperature, any wind or draught, size of box, the mesh it rests on, state of charge of the battery and other factors. So you needa safety margin. If you're making your own, you'll need to experiment because the current, the amount of metalwork and shape of your device will determine how heat accumulates and disperses over the 2 or 3 minutes connected. I'm guessing that the final temperature is what the Varrox and/or Apibioxal makers were seeing experimentally when heated for long enough to sublimate the crystals plus what they considered as a safety margin.
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It was a very small space, and light wasn't a good option...
Oh yeah ... Just try doing that yourself, before recommending such an unsuitable device to others.
Would you care to upload pictures of OA vapourisers that you've made yourself and have worked ?
I fail to understand why people are continually trying to use novel heating devices, when some of us have already spent many fruitless hours playing with such things, and are more than willing to advise others in order to save them from wasting both their time and money.
For example - I once tried to use the ceramic elements from 50W soldering irons - only to discover that one wasn't enough, so I started on a vapouriser design which would incorporate two. :
That's as far as it ever got, for while making this I 'discovered' diesel pre-heater glow plugs - and now I wouldn't even consider using anything else, as they are PERFECT for the job.
So why not take advantage of the experiences of others ?
Only two forms of viable DIY OA evaporators have thus far emerged from countless hours of experimentation: the copper tube & gas torch method, and the use of Diesel pre-heater glow-plugs. Just 'do a Google' to check this.
Anyone playing with anything else is almost guaranteed to be wasting their time.
LJ
