Hello, sorry it's been so long since my last blog. This has been a combination of illness and the fact that the making of the replica has been the only real progress we've made on the hoard in the recent months. As to its actual conservation, we are still waiting on funding/permission issues to be resolved. I have however finished the replica which turned out, as ever, to be a bigger job than anticipated. The making of the moulds themselves went OK and they didn't need too much cleaning up before they could be used for the casting. Once again I began with the hoard top as this is a nice flat area. I mixed up a pourable epoxy resin in 200ml batches and painted it onto the silicone rubber mould with a 2" brush. I let a first thin coat harden before I applied a second. This time I stippled in strips of glass fibre to strengthen the cast. I repeated this process till there were generally about three layers of glass and a total epoxy thickness of between about 7-10mm. I did the sides in the same way but in the end I had to do it it more sections than I had originally planned. The problem I hadn't considered was gravity. Painting the liquid epoxy onto the silicone rubber curved mould meant it kept pooling at the bottom of the area I was doing. In the end I produced lengths of about one meter.
The epoxy cured quite slowly, strong the next morning but still flexible, only going totally rigid after a week or so. This proved useful as it meant I was able to cast each of the pieces and begin to join them up while they were still somewhat flexible.
The joining was trickier than I had anticipated. Once again I had not foreseen something, specifically that the removal of the top surface rubber mould dislodged some of the edge coins. This meant that when I moulded the abutting side sections those edge coins were no longer there so the two overlapping areas of the final replica sections weren't identical. In the end I cut the sections with a Dremel tool to get the best possible fit, then glued and filled the joins with the same epoxy resin. Finally I reinstated "missing" coins from the edges with epoxy resin copies I'd cast from elsewhere on the hoard, using high resolution images I previously taken to place them correctly. Written up in one paragraph this all sounds very controlled and well thought out but it was a tricky process and at one stage I was using every cramp, G clamp and length of rope I could get my hands on to hold the whole thing together while it set.
Once it was all together I went round the bottom edge, again with the Dremel to give it a flat bottom so that it would stand on a table etc. I was worried (unnecessarily as it turned out) that the whole thing would flex too much so I then filled its interior with expanded polyeurethane foam. Then came the fun bit, painting it. As with my test piece earlier I used Humbrol enamel colours. I airbrushed a brown base coat all over to replicate the soil between the coins. I then painted the green coins by hand. I referred to images of the hoard and replicated the correct appearance of the individual coins to a reasonable degree. I applied several different shades of green to replicate the varying corrosion types. I tried gold paint for the gold pieces but it looked flat and unrealistic so in the end I gilded those areas with 24Ct gold leaf which, as you might expect, looked much better. As a final touch I painted a very watery mix of mud from the original hoard over the whole cast and then wiped it off with a microfibre cloth. This give a very effective finish so I then sealed the whole surface with a satin finish lacquer which gave it a good "damp" finish.