Sunday, 25 May 2025

Open Casket - lessons-learnt from first test with plaster, plus PVA-and-fabric covering experiment

So... Catching-up on a bunch of experiments I did for open casket... I've been busy in the evenings with the blog curation and with a job application, but during the day I have been able to do a bit more... Creepily dedicated readers will recall that in the last updated I did a full-body test using a damp sheet and got a pretty good impression. I decided to do a partial cast next: 

The impression came out quite well, although the dimpling from the polystyrene balls showed through. Some lessons learnt:

  • Although the fabric covered the entire width, it pulled back significantly from the edges due to the impression, so plenty of extra fabric will be required
  • I made up 0.25l water (0.5kg dry plaster) but this made too much plaster for pillowcase sizes piece so need less than you think!
  • Presoaking fabric in water prevented premature setting of the plaster when it came into contact with the dry sheet, allowing a much smoother covering of plaster
  • 30 mins was enough curing time to hold the impression when I climbed out
  • Getting out without swivelling is really hard
  • Even small pieces of plaster soaked fabric are hard to handle. Hard to avoid wrinkles. 
  • May be hard to smooth out (tends to stick to everything)
  • The polythene over the top of the plaster tends to stick, and tends to create off wrinkles

To give me more control, and to smooth out the shape rather, I decided to experiment in covering the plaster impression in a layer of fabric soaked in a 50:50 water:PVA mixture.

PVA cover test - want to have more control over shape and smooth out marks from polythene. I made a small beaker of each, and that was more than enough to soak another pillowcase-sized piece. Again I pre-dampened the fabric, although I suspect it would be less important since the PVA is very unlikely to cure on contact.

This definitely to smooth out the fabric and give a more 'fabric' impression, so I think I'll do this for the final run - it also means I can position the fabric as I wish.

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