Tuesday 24 July 2007

sun and mud

I've been playing with solar power. Five or so years after first pondering it I have bought a Freeplay Ranger solar-powered and wind-up radio, and also a Freeloader portable solar charger for mobile and camera. I love them both!

Proof that "objects" are anything but... an hour after ordering the new radio I turned on the kitchen radio: hissssssssss.... Hmm. It was working at breakfast. Only a few hours later it had died. Over twenty years old I think, it worked brilliantly for most of that. And presumably held on faithfully until the last moment, right until knowing the next generation was safely on its way. Something like old and ill people who "hang on" until an occasion, a particular moment has been reached and then they die, presumably more at peace than before.

Unfortunately I had earmarked the new radio for the studio, but couldn't transfer the existing studio radio to kitchen because I play (music) tapes on it (especially while the CD player is out of action). I thought a second new radio would be needed but you know what's so great: having a portable radio again! I take it round with me to whichever room I'm in, and it's no effort! I hadn't realised just how lazy and consumerist wired appliances can make us, well, me anyway.

So far it's stayed playing just by being on window sills (after an initial 24 hour electric charge) but I am spending a lot of time maximising direct sun dose of both toys. Ideally they need to be outside in direct sunlight but unless I also am outside that's not so easy. They are trickle charging through the windows but several days of daylight and some sun-through-the-window didn't re-charge the Freeloader enough to fully charge the mobile; it took another 10 minutes on electric.

But what about charging a wax pot by solar, or rather charging a battery to provide power for the wax pot? It doesn't seem feasible at the moment – not just financially but also in terms of creating enough juice to fire the thing! None of the solar panels I've read about online will do more than run laptops, electric lawnmowers, TVs, lamps etc, certainly nothing hotter than a toaster. So definitely not wax pots or Burcos (I use the Burco to boil wax out). But solar thermal collectors for heating hot water (for boiling out) might work, though personally I use little hot water during our warmer months. Then there is the question of Cornwall's sunniness... plenty hot water in summer, warmish only in winter.

Carbon reduction through lower power consumption is the main reason for me investigating renewable-powered tools. But I also believe within a few years electricity will start being rationed, either by a number of off-hours per day or through personal allowance. There's a few studio-based essentials I feel handy to have around – radio for news, wind-up torch and an ability to charge the mobile and camera. But if I have to seriously curtail waxing time I need to find either an alternative way to heat wax (and water to remove it) or find a non-heat-requiring resist.

In Malaysia (where I first made batik) wax was heated in a wok over a naked flame, either from a gas stove or charcoal fire. In my current studio set-up with its low ceiling, neither sounds desirable especially in winter when window-opening is minimised. But I need to find out how carbon intensive these methods are – if they are carbon-practical alternatives then my workspace may need to change from an indoor one to... hmmm. Outdoor working is great but the cold, draughts, damp and everything else about the Great British Outdoors are not conducive to wax resist working.

I've been fascinated by mud resist since first hearing this is how Mali people decorate cloth. But their batik doesn't use mud to resist dye in the conventional sense, instead mud is applied to yellow-dyed cotton, with something (iron?) in the mud turning the yellow brown. Un-mudded areas are discharged with a caustic solution returning them to white. It would be great if china clay could be used in some way – but again I stumble with my lack of chemical knowledge. I do want to experiment with china clay, local river muds and natural dyes, but the potential size of the experiment seems overwhelming! Either I spend aeons on trial and error, or I seek help!

By chance a few weeks ago while visiting an artist/gardener in the next village she produced some decorative batik she'd made as a student. Which led into discussion of various techniques... as she had used mud resist! And then she produced her notebook full of recipes and samples – which I have on loan... It's a start!

Thursday 12 July 2007

ashes to soda ash

Bang goes my hypothetical reed bed plans... soda ash is toxic to aquatic life! Pretty obvious really, considering its multiple uses as cleaner. According to the Fine Chem Trading's MSDS the toxicity comes from "a damaging action due to shift in pH". So all dye rinse water that contains soda ash fix must go down the mains drain for treatment and not be used for watering the garden (OK, mine isn't an aquatic garden but it does rain-a-lot in Cornwall and, well, it might eventually filter through to the village stream.) Also, here on Bodmin Moor the soil is acidic - Ansac's MSDS indicates that soda ash can react violently with strong acids with, uh oh, none other than carbon dioxide (and heat) evolving. Maybe the moor isn't acidic enough for that, but I'll stick to the mains!

Na2CO3. Sodium carbonate. It was the chemistry that got me into researching soda ash. More specifically the carbon aspect. What does happen to it – errr, it doesn't go into the atmosphere hopefully? And, well, where does soda ash come from? Is it natural-ish or entirely man-made?

Before soda ash, potash (potassium carbonate) was the alkali equivalent. It was extracted from wood fire ash with water; later soda ash was found in the ashes of certain salt marsh plants, also in kelp ashes. This is really exciting news - I could make my own soda ash, maybe with strandline kelp! Ashes from a beach barbie kelp fire!

But, as it seems with everything, more questions emerge. Would producing my own kelp-derived (soda) ashes release more carbon into the environment than the commercially produced ones? Would the amount of strandline kelp I'd need deplete this mini-marine ecosystem faster than it could be replenished? Would the amount of calorific energy I'd need to get to (probably) Crackington Haven to gather kelp and stoke a fire outweigh the oil-based energy required to bulk manufacture and ship the soda ash from factory to my house via the supplier?

I'm not going to try to answer these! Just keep in mind that soda ash can be derived from kelp ashes. As an aside, I was once told Procion dyes' chemical structure is derived from kelp's.

Anyway plant-ash derived soda ash soon couldn't keep up with C17 European demand (or plant "replacement" couldn't?), and physicists began researching artificial production. Frenchman Fresnel discovered in 1811 that carbon dioxide bubbled through brine containing ammonia created sodium bicarbonate (NaHCO3) and from this sodium carbonate is derived. The process was commercialised in 1864 by Belgian Solvay. Using ammonia doesn't sound too pleasant but most is recovered and recycled. Carbon dioxide and water are also are recoverable and re-used. Calcium chloride, the main by-product, is sold as road salt (hold on... I thought mined rock salt provided that), and the only raw inputs are salt, limestone and some form of thermal energy.

The process involved:

CaCO3 goes to CO2 + CaO
calcium carbonate goes to carbon dioxide + calcium oxide

NaCl + CO2 + NH3 + H2O goes to NaHCO3 + NH4Cl
sodium chloride + carbon dioxide + ammonia + water goes to sodium bicarbonate plus ammonium chloride

2 NaHCO3 goes to Na2CO3 + H2O +CO2
2 sodium bicarbonate goes to sodium carbonate + water + carbon dioxide

2 NH4Cl + CaO goes to 2 NH3 + CaCl2 + H2O
2 ammonium chloride + calcium oxide goes to 2 ammonia + calcium chloride + water

The Solvay Process Wiki explains this chemistry more fully, and Solvay SA's soda ash website informs about all stages in the process. For instance, their salt is extracted from underground salt mines through solution mining; coke is used to fire the kilns that decompose mined limestone into lime and carbon dioxide; ammonia and carbon dioxide are recovered for re-use in a distillation process...

The Solvay process predominates production worldwide, except in North America where trona-derived production has replaced it - mainly because the production process is cheaper. Trona is a naturally-occurring mineral found in non-marine evaporated deposits. The US has the world's largest resource in Wyoming, with enough trona to supply the world for 1300 years. Apparently. A batik artist wouldn't use much of that but it's still a finite global resource if mined faster than replaced. The Wyoming trona was laid down 50 million years ago as a large lake in the Green River Basin evaporated.

Trona is Na3HCO3CO3.2H2O and needs a bit of work to bring it down to Na2CO3. The Solvay SA website explains the trona process well, clearly demonstrating the simpler procedure compared to the Solvay process.

I have to admit to being a bit bamboozled by all this chemistry... and what it means for me as a simple artist so am going to post this now and come back when I've dug and thought deeper.

Tuesday 3 July 2007

candles for the well

Getting back to practical matters (and away from philosophising), my boiled-out wax remnants and "well-cooked"-in-the-waxpot wax have been given a new purpose in life: candles! Vanda Inman is making and selling them to raise funds for St Clether's Holy Well and Chapel, and has incorporated my accumulated leftovers in some, saying it's worked a treat!

One of the earliest Celtic saints St Clether came to Cornwall from Wales in the fifth century, settling in the still beautiful and peaceful Inny Valley. His chapel and well has been restored a few times since then, but an aura remains leaving visitors with a wonderful feeling of wellbeing and calm. It really is a special place and I'm glad I can contribute, even in a small way, to its upkeep.

I've never attempted to re-use boiled-out wax... having heard water is trapped in it and might spit when heated (and yes, I did warn Vanda and apparently there was no problem). Now I feel I should try re-using it. It might be no good for fine canting work but may work with brushwork or stamping. Or it may work fine with cantings. Perhaps using 10% old in with the new... I will play around and see, soon. I do foresee problems remembering what's in the waxpot at any time – new, re-used or even multiple re-used!

Well-cooked wax I used to save and use again for crackle effect finding it cracked more easily and sharply than "fresh" wax, having lost its malleability. But as I rarely use crackle effect now in work I will continue giving old wax away.