Groninger Communion cup

Below is a series of photos of the making of a communion cup.

A round silver disk is sawn in the desired diameter
from a square silver sheet of 0.925 dz silver (sterling).
This sheet is annealed over a big round flame at 650º C and quickly quenched in water.
Next it is pickled in sulphuric acid.
Now I start forging, starting in the centre, and working my way outwards in a spiral.
This is done over an iron stake (anvil), using a raising hammer.

This method of forging is repeated up to six times without annealing,
until the tension in the silver can be felt.
Shaping becomes really difficult now and it seems as if the silver starts to yield
and becomes resistant to hammering.

After six rounds of hammering it is time to anneal the silver again.
Annealing causes the silver to oxidise.
This oxidation is removed by pickling the silver in sulphuric acid,
after which the cup-in-the-making is rinsed.

More forging...

...and the silver takes even more shape...
Next it is time for more annealing.
This process is repeated a number of times until...


...it starts to look like a cup or vase.
The spirals in which I forge the silver are now closer together.
First the space between the coils was ± 3 cm, now it is 1 cm.

I am nearing completion, but there are still a lot of hammer marks visible.
The photo below shows a close-up of denting the silver.
The right hand side has been pressed together as far as possible,
the left hand side still needs work.

After that the cup is annealed one more time.


Now it is time to planish the cup. This is done over a stake. I use a 200 gr. planishing hammer.
Every new hammer blow covers three quarters of the previous one.
Planishing requires a lot of patience and precision. The silver has to be hammered flat,
but not made thinner, or it will mushroom all over the place and take on a shape you do not want.


Now the cup is as good as ready.

After completion of the base, the cup is finished.
The base is made of tapered silver threads, which are welded together and blackened with liver of sulphur.

And voilà, one finished cup on a blackened silver base.


The Groninger Communion cup and other bowls are shown in Large Silverwork .


International modelright applies to all pieces shown here.

Photos: Willem Tredgett ©