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Gillespie Borate

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  • Sku - 3418-04
  • In Stock

Gillespie Borate™ is a blended borate mineral for use in glaze formulas replacing Gerstley Borate on a pound-for-pound basis.

Features:

Consistency -- Manufactured from high purity refined raw materials, Gillespie Borate™ is highly consistent from batch to batch. Oxide Match -- Virtually identical to Gerstley Borate, this produc…
kg Per kgs (Exc. VAT) Price (Exc. VAT) Quantity
0.50 £13.74 £6.87
2.50 £11.27 £28.18
5.00 £9.84* £49.21
10.00 £8.48* £84.76
25.00 £7.25* £181.15
kg Per kgs (Inc. VAT) Price (Inc. VAT) Quantity
0.50 £16.49* £8.24
2.50 £13.53* £33.82
5.00 £11.81 £59.05
10.00 £10.17* £101.71
25.00 £8.70* £217.38

* 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.

Weight:
Price kg: £16.49 £13.74
Total Inc. VAT Total Exc. VAT
  • Description

    Gillespie Borate

    Gillespie Borate™ is a blended borate mineral for use in glaze formulas replacing Gerstley Borate on a pound-for-pound basis.

    Features:

    • Consistency -- Manufactured from high purity refined raw materials, Gillespie Borate™ is highly consistent from batch to batch.
    • Oxide Match -- Virtually identical to Gerstley Borate, this product requires no adjustment to formula and no extra additives are needed.
    • Mineral Match -- Gillespie Borate™ provides the same minerals to the glaze as Gerstley Borate, thus imparting the same glaze activity, texture and effects.
    • Particle Size Match -- As a -200 mesh material, Gillespie Borate™ combines well with other glaze raw materials.
    • Plasticity Match -- A high colloid and clay content gives the plasticity necessary for many applications.
    • Reduced Glaze Defects -- Our laboratory studies indicate that Gillespie Borate™ gives increased glaze surface smoothness and a reduction in crawling and pinhole defects.
    • Lower In Off-Color Impurities -- As a refined blended material, Gillespie Borate™ contains few impurities and produces brighter glazes and colors.

    Applications:

    • Raku, Earthenware, Stoneware and Porcelain -- Excellent over a wide temperature range from below cone 06 to cone 10
    • Special Effects -- Excellent glaze texture and activity for specialty glazes.
    • Colored Glazes -- GB works well with most pigments and has an exceptionally wide color palette.


    Finding a replacement for Gerstley Borate

    Gerstley borate is a complex ore but a major benefit of the unrefined naturally formed combination of minerals is its ability to produce variegated surfaces in glazes. Potter’s firing electric kilns which have oxidation atmospheres often produce flat static glaze effects much like bathroom tile colors. Carbon based fueled kilns, such as natural gas, propane or wood have the capacity to fire in oxidation, neutral, and reduction atmospheres which can introduce varied glaze colors and surfaces. If it wasn’t for this unique characteristic of Gerstley borate it would have been abandoned when the first series of its faults appeared. Gerstley borate’s wide swings in chemical composition are a factor in finding a direct substitute. It’s like trying to hit a moving target when deciding on what chemical formula to use when developing a substitute. However, Gillespie borate, a product produced by Hammill & Gillespie of New Jersey, has proven to be a reliable one-for-one substitute. In many instances it is difficult to arrive at such a close match as many raw materials are not mineralogically pure when removed from the earth. Any potential substitute has to match on many points and produce the same results in fired glazes.

    Recommendations for using Gillespie borate:

    • Do not use excess water in mixing the glaze.
    • Store the wet glaze in an airtight container.
    • When using any substitute material always test it in a small batch of glaze.
    • Test the glaze on the same clay body you will use in production.
    • After applying the glaze to several vertical test tiles place them throughout the kiln.

    NB The exact chemical composition of Gillespie borate is proprietary to Hammill & Gillespie. Gillespie borate is a mixture of ulexite (Na2O.2CaO.5B2O3.16H2O) with various clay minerals (aluminum silicates), alkaline earth carbonates and silicates. This material contains approximately 25% B2O3, 23% CaO, 4% total alkali and 31% loss on ignition.

  • Delivery & Returns

    Delivery & Returns

    Full information at this link>

    DELIVERY

    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.

    Please allow up to 10 working days for standard delivery. Our Nextday service is suspended due to the impact of COVID-19. 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.


    IMPORTANT INFORMATION

    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.


    RETURNS

    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. 

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