Frequently Asked Questions
BLACK CLAYS – safe or not?
Quite rightly, concerns exist around the safety of black clays in the studio and on functional ware.
It is true that historically, some black bodies have been coloured with Manganese Oxide which is a toxin. Years ago, Decopot declined to purchase such bodies from an Asian supplier.
NIGRA 2002 sold under the Primo-Pro label is manufactured by a reputable European supplier and widely sold throughout Europe. We have our supplier’s absolute assurance that this body (pigmented with manufactured stains) is safe to use.
How can I prevent the glaze settling on the bottom?
The glaze composition is largely determined by the effects that characterise that glaze. Consequently, some glazes suspend easily in the bucket and others need help. The first rule is to avoid over-watering the glazes as there is no way that a very thin glaze will suspend well. Some glazes with very low clay content can be treated with bentonite and a flocculant to aid suspension. Our preferred flocculant is plaster of paris – it is cheap, most of us have some in the studio and the effect is long-lasting. Alternatives are Epsom salts and calcium chloride. Pre-disperse the flocculant in water and the resulting slurry gradually to the mixing glaze. As a rule of thumb, you might use one or two teaspoons of plaster per bucket of glaze. Adding bentonite(in similar quantities) can also contribute to improved suspension and better-bound glaze surfaces. Add the dry bentonite to water, blitz with a milkshake maker (or mix by hand and stand overnight) and also add gradually to the glaze until the right smooth creamy texture is observed. This sounds complicated but it becomes second nature after a while.
If your glaze has settled into a hard layer with clear water on top, first scoop off (and reserve) most of the clear water. The glaze can then be (manually) redispersed in the remaining water to the desired consistency. Add back as much of the reserved water as needed. Glazes that have settled like this will almost certainly need the bentonite/ plaster treatment to keep them suspended. They should have the consistency of yogurt when they have been allowed to stand for a few days but should be easy to redisperse with hand mixing.
How do I set up a brushable glaze using Universal medium?
This medium is the basis of all Abbots brush-on glazes.
Any dry glaze material can be dispersed in this medium(rather than in water) to produce a thixotropic gel suited to brush application. This enables multiple coats of glaze of one or more varieties to be applied without risk of peeling or blistering. The risk of crawling is lessened due the strong bond between glaze and body.
We suggest adding glaze to medium in a ratio of 1-1.3 parts glaze to 1 part medium (by weight). Vary these proportions or add a little water to achieve the density and brush-feel that works for you.
Disperse the glaze in the medium using a stick blender or power mixer. Sieve through an 80# sieve once or twice before using
How to use Universal Medium?
This medium is the basis of Abbots brush-on clear glaze.
Any glaze material can be dispersed in this medium (rather than in water) to produce a thixotropic gel suited to brush application. This enables multiple coats of glaze of one or more varieties to be applied without the risk of peeling or blistering. The risk of crawling is lessened due to the strong bond between glaze and body.
We suggest adding glaze to medium in a ratio of 1-1.3 parts glaze to 1 part medium (by weight).
Vary these proportions or add a little water to achieve the density and brush-feel that works for you.
Disperse the glaze in the medium using a stick blender or power mixer. Sieve through an 80# sieve before using.
Why does my glaze craze, and should I care?
Freight - Larger Shipments
SHIPPING WITHIN NEW ZEALAND ONLY.
For larger shipments savings can be achieved by accepting freight on a pallet, delivered by truck.
If you can safely receive freight and a vehicle of this type at your address and in person then you may wish to select this option.
Once you have received a tracking number we advise making contact with the carrier to discuss the details of your delivery.
Decopot bisque products are, by definition, fragile. They are fired to a temperature that develops some strength but not so high that porosity for glaze pickup is diminished. Decopot packers go to considerable lengths to pack bisque safely.
Breakage is rare when bisque is sent on freight pallets and is a more frequent occurrence with goods shipped by courier. Priority should be given to shipping on pallets and urgent orders sent by courier will carry higher risk of breakage.
All consignments travel under the insurance provided by the carrier. For claims to be considered the goods need to be inspected by the purchaser on receipt and breakage reported with evidence within 24 hours. In some instances, it may be practical to sign for goods as ‘received unchecked’.
Decopot will, at their discretion, consider claims for goods shipped on freight pallets where claims are submitted with 7 days of receipt with documentary evidence.