I source as many resources as possible from the local natural environment of the Yorkshire Dales to make my own glazes. My Greywacke Gritstone dust comes from the Ribblesdale Dry Rigg Quarry, located a few miles down the road from where I live. I harvest the iron ochre from a roadside ditch/spring along the skirts of Whernside, the tallest peak in the Yorkshire Dales. I source my wood from local farmer friends, and I collect all of my plants-for-ashes locally. Glaze-making is an exciting, intriguing and sometimes frustrating process! ...But one that I have come to love and appreciate.
For those interested in the more technical side of things...
I source the greywacke gritstone dust that makes up some of my glazes from the local Dry Rigg Quarry near Horton-in-Ribblesdale. It is a waste product from the drilling process and would otherwise be washed away or disposed of. Gritstone has quite a high silica content, which is what makes up the 'glass' part of a glaze. It also has a balanced amount of alumina, flux and a good bit of iron, which means it produces an excellent glaze on its own, very dark and slightly metallic.
All of my wood is locally sourced from a young lad through our church, and most of the ash is harvested from my woodburner at home. Ted sources his pine from Ribblehead Forest and Beech from Giggleswick. Occasionally he will find a particularly interesting tree for me... the latest was an old Beech tree felled near Giggleswick Private School! Each wood produces a slightly different (or greatly different) colour of glaze, depending on what kind of minerals the tree is picking up from the soil. Wood ash tends to be high in flux, the component that makes the silica melt and creates the 'run' or fluidity in a glaze. Because wood ash is high in flux, a wood ash glaze is characteristically runny, producing beautiful pools of colour where it has collected.
Thistle ash makes a pale moss green glaze that sometimes 'bleeds' into other glazes. This effect works particularly well when paired with a teal blue under-slip, gritstone and wood ash (Wood and Thistle Blue glaze). They're easy to collect (with gloves!!) and, when dry, burn very very well.
Common Hogweed Ash
Due to their perfectly hollow large stems, folks often think of these as their childhood pea-shooters. In glaze-making, I prefer them when they're dried out and seeded. When combined with the gritstone and iron ochre, common hogweed produces a deep rich ruddy brown colour.
Docks are plentiful... often found along the roadside, footpaths, along dry stone walls. The leaves are used to relieve the sting if you've been bitten by a nettle! For me, they produce a beautiful coppery tone to a glaze, one of my favourite effects.
So not nice when you brush up against them, but otherwise I think nettles are brilliant! Really good for you (lots of vitamins), a fantastic remedy for respiratory colds... and they produce a gorgeous moss-green glaze. Best when collected during the winter though - less stings!
Rushes are prolific across many fields in the Yorkshire Dales, but also really unwanted by farmers as they can soon crowd out the rich grass needed for grazing sheep and cattle. A free natural resource for me, and a bit of a help to some farmer friends in cutting them out of the fields. When fired, however, their ash produces a rich speckled brown colour, brilliant in combination with other materials, or on its own. When mixed with a plain base glaze, rush ash produces a delicate pale purple glaze with brown flecks!
I collect iron ochre from a roadside ditch/spring in sight of Whernside summit... by the bucket! Layered under or over an ash glaze, it produces some stunning results. I also mix iron ochre with a homemade base glaze, producing a warm cream when fired in oxidation or a pale stone grey blue when fired in reduction