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Large Circular Drop Out Mould 8031 (28cm outer, 17.5cm inner)

Price £22.31 Inc VAT (£18.59 ex VAT)

 Go Back to Circular Moulds 

All prices include VAT.

Stock Status: More than 10 in stock
We Also Recommend for Large Circular Drop Out Mould 8031 (28cm outer, 17.5cm inner):
Product Information
Large Circular Drop Out Ring  

Create many different types of vessel from one mould!  Drop out moulds allow you to control the depth of your bowls and vases. Experiment with different glass designs to discover the beautiful patterns which can be created by the dropping glass.

Fits in the HotStart Pro kiln. Also available in Small and Medium sizes, as well as in a square format.


Measurements: outside diameter: 28cm, inside diameter: 17.5cm. 

Will this mould fit in my glass kiln?

Examples of work using drop out rings, from one of our Amanda Simmons Masterclass courses:


Firing Schedule:

Please Read: This firing recommendation has been calculated using Bullseye Glass with a thickness of 6 mm in a Paragon GL24 kiln, and is courtesy of Bullseye Glass Co. This schedule is for making a shallow plate where the mould is placed directly on the kiln shelf rather than elevated.

Segment Rate (C/hr) Temp. Hold
1 167C 677C 1:30*
2 999 482C 1:00
3 56C 371C :00

*A visual check of the kiln should be made during this point. As soon as the drop out has lowered to the desired point, crash cool the kiln to approximately 600°C and continue the schedule as per segment 2 above.


  • Small kilns may require the process temperature reducing. In the Hobbyfuser and HotStart Pro, reduce the top temperature from 677C to 654C. In the Firebox 14, reduce the top temperature from 677C to 634C. All kilns vary, as does glass viscosity. Testing is necessary.

  • Side firing kilns may require more time in the first ramp than top firing kilns.

  • Bubbles in slumping are caused by firing too high or holding too long at process temperature.

  • Cracked moulds or cracked glass is caused by firing too fast in the first ramp or cooling too fast.

  • Devitrification on the outside of a slumped piece is caused by firing too high or holding too long at process temperature.

  • The blank should cover the outside edge of the mould but not hang over the edge

  • For drops under 10cm the optimum thickness of the blank is 6mm to 9mm

  • For drops over 10cm the optimum thickness of the blank is 9mm to 12mm 

  • Fire the blank on a basic full fuse and anneal correctly for the thickness of the glass

  • Use Bullseye shelf primer on the dropout mould and also 1mm fibre, cut 3mm back from the mould edge

  • The optimum top temperature is 650C to 700C depending on your kiln, glass thickness and how much you want to drop

  • In plugin kilns remove the shelf for longer drops but remember to protect the base of the kiln with fibre paper

Please note that all our moulds are hand-made and therefore the dimensions may vary slightly from those shown. Mould manufacturers allow a tolerance of up to 2cm. We strongly recommend cutting the glass to the size measured from the actual mould rather than relying solely on the dimensions shown.

All our moulds are designed for multiple use and with care should last for many firings.

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