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Vulcan Black Stoneware (Fine) 1200-1240C

  • Sku - 164-VUF
  • In Stock

Vulcan™ Black Stoneware (Fine) 164-VUF  |  Recommended firing 1200-1240C / Cone 5-6

See notes below regarding Vulcan recipe adjustment 2022/23

Vulcan Black Stoneware is unlike any other on the market, providing an unusual intense brown-black col…

kg Per kgs (Exc. VAT) Price (Exc. VAT) Quantity
1.00 £2.50 £2.50
12.50 £1.44* £18.05
25.00 £1.39* £34.72
50.00 £1.33* £66.66
100.00 £1.28* £127.76
250.00 £1.23* £308.02
500.00 £1.18* £588.27
1,000.00 £1.12* £1,120.99
kg Per kgs (Inc. VAT) Price (Inc. VAT) Quantity
1.00 £3.00 £3.00
12.50 £1.73* £21.66
25.00 £1.67* £41.66
50.00 £1.60* £79.99
100.00 £1.53* £153.31
250.00 £1.48* £369.62
500.00 £1.41* £705.92
1,000.00 £1.35* £1,345.19

* This price has been rounded to the nearest pence.

Please type the weight you require below or add pre-defined weights using the controls above.

Price kgs: £3.00 £2.50
Total Inc. VAT Total Exc. VAT
  • Description

    Vulcan Black Stoneware (Fine) 1200-1240C

    Vulcan™ Black Stoneware (Fine) 164-VUF  |  Recommended firing 1200-1240C / Cone 5-6

    See notes below regarding Vulcan recipe adjustment 2022/23

    Vulcan Black Stoneware is unlike any other on the market, providing an unusual intense brown-black colour when fired in an oxidising atmosphere. In a reducing atmosphere a metallic finish with shades of blue is obtained (Note: Too-heavy reduction will cause bloating).Containing 40% fine grog (up to 80 mesh), Vulcan Black Stoneware (Fine) has been formulated for artistic ceramics. It behaves excellently during drying/firing and its high plasticity makes it ideal for modelling. It is widely used for murals and sculpture and is ideal for detailed work. Supplied in a 12.5kg bag.

    Vulcan Black Stoneware (Fine) can be sensitive to too-fast cooling. It is recommended not to open the kiln until it has reached room temperature to avoid cooling breaks, especially in flat and thin pieces. Keep vent plugs in place during cooling. Do not open/crack open the kiln lid to rush the natural cooling process.

    Typical data:

    • Firing range: 1200-1240C / Cone 5-6 
    • Texture 1-2 on our indicative texture scale, smooth1, coarse 10.
    • Biscuit: Cone 06 (1855ºF)
    • Water content: 21%
    • Plasticity (IP Atterberg): 22
    • Carbonate content (CaCO3): 0%
    • Drying shrinkage: 7.0%
    • Firing shrinkage at Cone 6: 7.1%
    • Porosity (water absorption) at Cone 6: 1.3%
    • Dry bending strength: 4.6 N/mm2
    • Fired bending strength at Cone 6: 33.3 N/mm2
    • Thermal coefficient (a25-500ºC): 51.1x10-7ºC-1


    Recipe Adjustment for Vulcan Bodies 2022/23:

    From batch number 2322 (Production Week 23, 2022), due to unavailability of a raw material SIO-2 were forced to make an adjustment to the Vulcan recipe. This increased the sensitivity of the body to the thermal expansion of the glaze when fired at the upper end of the recommended range (for 164-VUF, 1240c/cone 6). However - from batch 2723 (Production Week 27, 2023) SIO-2 made a further adjustment with successful results under the same conditions where there were failures previously. For older batches between 2322 and 2723, SIO-2's primary advice continues to be to use glazes with a medium-high thermal expansion - further information in the technical notes below. Through our own tests here at Potclays, we recommend not to exceed Cone 6 with these batches, and if your controller will allow, it is beneficial to programme a controlled cooling segment <50c/hr from 200-50C.

    • Vulcan Black Stoneware (Fine) 164-VUF is suitable for tableware (food-safe), according to ISO 6486 when fired as recommended (less than 3% porosity).
    • Vulcan clay bodies are non-toxic according to European Rules (CLP) and also American Rules (ASTM D 4236). The manganese dioxide content in Vulcan bodies is lower than 5%: Under the CLP regulation, the manganese dioxide content required for classification as toxic must be greater than 25%. 
    • Vulcan Black Stoneware is no longer recommended for use in casting slips due to the high plasticity which makes it difficult to correctly deflocculate.

    When glazing:

    • Use zinc-free (Zn-free) glazes to prevent unexpected reactions such as bubbling or colour changes. Other elements that can react are zirconium (Zr) and tin (Sn). We have found that Mayco zinc-free clear glaze is suitable for use with Vulcan bodies and does not seem to suffer from the usual problems caused by outgassing from the high oxide levels in black bodies. Many ^6 commercial glazes such as Mayco perform well on Vulcan but trial-and-error is needed. Also see our potclaysglazes Instagram feed/highlights.
    • With older batches of 164-VUF and VUM mentioned above, SIO-2 warn against using glazes with a low coefficient of thermal expansion (a25-300ºC <60x10-7ºC-1). The Vulcan clay fired at high temperature has a high coefficient of thermal expansion in the range of 100 to 200ºC, which causes tensions between the glaze and the body, mainly in pieces glazed on one side only, which can cause breakage during cooling in the kiln or even later (for example, when pouring hot water inside). Check with your usual glaze supplier to ensure that you use glazes with a medium-high coefficient of thermal expansion (a25-300ºC >60x10-7ºC-1).

    To comply with RHA regulations concerning tail-lift deliveries (where there is no fork-lift truck available at the delivery point) the maximum net weight of clay we are now permitted to pack on standard pallet is 950kg (76 x 12.5kg bags of clay). To achieve the best price for your clay, please add the full 1000kg to your cart when checking out and we will make the necessary weight adjustment/refund when we receive the order.

  • Downloads

    Vulcan Black Stoneware (Fine) 1200-1240C downloads

    • ISO 6486 standard on food safety in ceramic ware

  • Delivery & Returns

    Delivery & Returns

    Full information at this link>


    Your carriage charge will be calculated at checkout based upon the volumetric weight of your order, and your location. If for any reason your delivery charge cannot be calculated at checkout, you will see a message explaining that our sales team will contact you with a quote. You will be under no obligation to accept this and have the right to cancel your order. 

    We deliver throughout the UK and overseas using a trusted third-party distribution network. Delivery is to kerbside or letterbox only.

    Due to exceptional demand, please allow up to 10 working days for deliveries. Our Nextday service is suspended. Collection from our Stoke-on-Trent warehouse is currently only possible by placing your order by phone +44(0)1782 219816. Although carriers will endeavour to deliver within the agreed timeframe, unexpected delays due to weather conditions, breakdowns, traffic and other factors may cause some disruption to schedules.


    We are bound by the terms and conditions of our carriers therefore we cannot pursue a claim if these instructions are not followed:- 

    Special Delivery Conditions: You must inform us at point of order of any special conditions such as restricted access or opening times, otherwise you will be liable for any consequential costs incurred.

    Damage/Missing Items: You must check your delivery carefully before providing a ‘clear’ signature to the driver. Outward signs of damage/disruption to packaging must be noted alongside your signature. You must notify Potclays of damage or missing items within 24 hours of delivery.


    Returned Goods (Non-faulty): Subject to our prior consent having been obtained, products can be returned to us in an unused condition within 30 days of invoice date.  An administrative charge will be levied of 10% of the nett value plus transport, but subject to a minimum charge of £ 2.00. 

    Returned Goods (Faulty): If merchandise is returned because of some defect or due to error on our part, full credit/refund will be given.  However, customers must contact us in advance so that making methods and user error can be ruled out. 

    Read more about returns >

If you have any questions contact us now

If you have any questions about our range of products, please do not hesitate to get in touch with Potclays. Our team of experts will be more than happy to answer any questions you may have.

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