Wednesday, 16 July 2008

cost of boiling out wax an interim stage of wax removal in the Feeding the Ducks batik:

Ten litres of cold water in the Burco took 23 minutes to reach boiling stage, and the (metre square) batik was submerged for a further 22 minutes with the power intermittently on. The total 45 minutes 'boiling out wax' activity used 1.4 kwh of electricity. Translating to 0.6 kg CO2.

Starting with warm or even room temperature water would have saved a little energy, but more would have been saved if the batik hadn't needed to boil for so long. Sometimes a few minutes dip is enough to melt and remove wax but other times the wax leaves a yellowish residue that takes longer to shift. It's often only visible when the batik is wet but can affect subsequent dyeings, such as had had happened with this last dyeing.

Experience suggests this happens when wax has been 'well cooked', turning brown, and where used has lost some ability to repel water/dye. In turn, being well cooked could mean the wax is being heated too high, ie where it touches the hottest part of the bowl it's getting hotter than ideal. But if I have the pot at lower temperature then the wax isn't hot enough for fast canting work.

I removed the 'old' wax, cleaned the pot and replenished it with new wax to the same recipe (100 g batik mix, 20 g white beeswax). This time I used half quantity, ie half filling the pot and heating at setting '5'. Always before I've filled the pot to ensure a consistently heated supply of wax, but my thinking now is that if there is less wax to start with then the pot needn't be set so high to get the ideal wax temperature. The wax is both less likely to be 'cooked' on the hot part and - importantly - used up by the time replenishment is needed!

I am truly shocked to find that of the 240 g of wax heated last time round, 145 g was removed too 'well-cooked', meaning only 95 g was used for the batik. I have been very very wasteful of resources and am determined to get this amended.

Another thought I had for saving energy with boiling out wax is to insulate the Burco boiler. Followed by hesitation from the likelihood of getting the insulation both very wet and coated by molten wax spluttering over the Burco top. And from remembering the hint from Paul Mobbs that beyond a certain depth (0.2m) loft insulation becomes carbon-uneffective (production etc cost outweighing savings). But, in my loft some old futon cotton-wool sheets are stored some of which might be adapted for this purpose.

This Ducks batik has already required three or four interim boilings out, and will need two or three more before the end. I don't usually work like this, believing it goes against the nature of batik if you can't go forward with the design in one go, with only one boiling out at the end. Somehow this design got too complex. I will be glad when it's finished!

images: top - over-cooked wax; middle - new wax pellets half filling wax pot; bottom - interim stage - Feeding the Ducks batik

1 comment:

Stephie said...

I think you should turn all this valuable research into a PhD!!