The first form that I was casting from.
You can see an early version of the vinyl tubing. The velcro is an attempt to develop a reusable casting form. The velcro performed well. It was attached to the vinyl only using the pressure sensitive backing. The vinyl sheeting was however not recoverable because of persistant folding problems.
Above I’ve sewn the tub structure into a solid sleeve form that is meant to be disposable. The sewing time fo each unit runs around 10 mins. Significant were this to be production block.
A simplified approach which reduces sewing time to three minutes is to make three simple tubes, with no joining moment. The tubes are twisted on themselves. When filled with plaster the smooth vinyl permits the “joining moment” to react to gravity. Once dry and removed from the wooden form they still remain integrally locked and support their own weight. This is the first successful cast of this concept. The final image above, the plan view, is driving the next phase in the study: