Materials
Ivory Stoneware: £8 for a bag
Bag used for 4 pieces around a 1/6th of a bag
Underglaze: £12.15 for 59ml
Drill: £3.69
Rolling Pin: £3
Rolling pin guides: £3.47
Time
Assembly for 4 pieces: 7 hours
Time taken to get to these specific pieces has been 28 hours
Packaging:
Bubble Wrap: £1.50
Boxes for 4: £15 for 25 (0.60 per piece)
Postage: £6.49 maximum for these four pieces
Photography, Editing and Website
£9.98/month – Photoshop, Lightroom and Portfolio
Kiln
For bisque firing you can use this equation for cost of firing
Kiln KWatt x Firing Hours x Duty Cycle x Cost per KWH
Smaller kilns are 1.5 – 18 kilowatts so I’ll use 1.8 here
Firing Hours is 43 hours using the example from the workshop
Duty Cycle for bisque firing is 65%
Cost per KWH is 0.34 p - https://www.edfenergy.com/energywise/what-is-kwh-guide#:~:text=According%20to%20the%20Energy%20Saving,of%20electricity%20is%20%C2%A30.34.
1.8 x 43 x 0.65 x 0.34 = £17.11 per firing
This would be plus the cost of the kiln and other materials for the upkeep of the kiln.
https://www.lakesidepottery.com/HTML%20Text/Tips/estimating-electric-kiln-firing-costs.htm#:~:text=Cost%20per%20firing%20is%20therefore,w%2Flabor)%20per%20firing.&text=If%20all%20variables%20are%20added,per%20glaze%20firing%20is%20%2413.48.
Some kiln rental spaces cost £4 a kilo so estimating that 6 lots of 4 will end up being less than 2 kilograms I would rent the space at £8 a firing – if I had to pay the cost of the kiln it would be an extra £17.11
Kiln = 8 + 17.11 = 15.11
Firings per week = 3
Cost per week = £45.33
Overheads = 120.82
Hours making the nets and the build-up to the final pieces = 28 hours
Overheads per week – 120.82
120.82/21 = 5.76 an hour
Costing the items
6 sets of 4
Hours taken to create and work up to the set of 4 = 21 hours
Set of 4 takes 7 hours
Time 21 + (7x6) = 63 hours
Materials 8 + 12.15 = £20.15
To make a set of 4
Time 10.5 x 15 = 157.50
Materials = 3.36
= 160.86
+ 20% Profit = 193.04
Cost = £194 for a set of 4