Monday, 18 April 2011

A ring is born

This is the story of Stoo's ring.  Stoo is one of The Boy's friends.  He saw the silver ring I made at my silver clay class last year and asked me to make him a thumb ring. That was a while ago.  It's not that I haven't wanted to make his ring.  I've just been putting it off because I only had one pack of silver clay and I didn't want to mess it up.

At the end of last week The Boy asked when I was going to make Stoo's ring & I figured I didn't really have any excuses so I should just get on with it.  The main reason for my reluctance is that there are so many standards for ring sizes.  I learned using Japanese sizes but only have UK & US ring gauges so I knew I was going to have to do some calculations to work out shrinkage before I started.

So I got out all the size conversion charts I'd downloaded and tried to work it out in UK sizes. Stoo's thumb is a size Y so what size do I need to make the unfired ring to allow for 8-9% shrinkage?  After checking & triple checking I convinced myself it needed to be Z+4, 5 whole sizes bigger.  I was a bit worried that the guidance for US sizes was to go 2 sizes bigger and for Japanese sizes to go 3 sizes bigger.  Then I realised that UK sizes are a lot closer together than US or Japanese and relaxed a bit.

First I decided to prepare my ring mandrel.  Challenge no. 1 - even the thick end of my mandrel was too small for size Z+4.  Solution - tape paper round the mandrel to pad it out:

Challenge no. 2 soon followed - the ring papers were just too small to join around the mandrel.  Solution - use a teeny piece of sellotape to stop the paper pinging off.

Now I was ready to get the clay out and make the ring.  It took a few attempts & some extra clay before I actually had enough to go around the mandrel enough to join it properly.  And that's when I found out that there was sellotape somewhere it shouldn't be and I couldn't move the paper.  The ring fell apart and that was that - back to the drawing board again.

Brainwave - I fetched the greaseproof paper from the kitchen and wrapped the mandrel again:

That helped so I was finally able to construct the ring on the mandrel.  I slid the whole lot down the mandrel slightly and left it all to dry overnight.  I checked it with the ring gauge to make sure it was was still sitting at size Z+4.  Here we have a not very good photo of the ring, all dried and ready to be sanded and filed and inspected:

There was a disappointing number of fine cracks in the pattern but I suppose that's only to be expected considering how many times I had to start over and that the clay seemed to dry out very quickly even though I was working it inside cling film as much as possible.  For the next few hours I kept coming back to check it under the magnifying light, carefully dabbing a teeny amount of water or slip on any cracks and leaving it to dry.

I took my time about sanding the edges and the inside and carefully bevelling the inside edge so that it wouldn't be sharp against Stoo's delicate skin. :o)

Finally I felt ready to fire it.  I laid it on a piece of firing blanket on top of the kiln shelf and cooked it at 650 degrees for 30 minutes.  I plunged it into cold water then took it away and gave it a first polish with a brass brush:

That doesn't look too bad does it?  I checked it with the ring gauge again it measures size Y - result!  My calculations were correct.  Just need Stoo to try it on his thumb now to be sure it fits.  Then I have to send it to the Assay Office to be hallmarked before he takes possession of it.

I've been going back to it now and then throughout the day with sand paper, the burnisher and polishing papers and I'm happy with how it looks.  I hope Stoo likes it too.

If making rings for boys is going to become a habit I need to buy a bigger mandrel.