A very hard and strong plaster called FGR 95 is mixed up. This is incredibly strong stuff- used alot to make hollywood sets (building frontages) I’ve heard. The damp burlap is lowered into the pan of mixed plaster and dragged through the creamy mix so both sides are liberally coated. The burlap is removed and gently squeezed or wrung out over the pan- usually it is squeezed by being pulled through a hole created by the index finger touching the thumb tip.
The “bandage” is put on the toilet papered specimen and starting at the middle, the bandage pressed down into the specimen, adhering to its contours and any air underneath is pushed out to the edges if necessary. Then another bandage is put next to the first one with a good bit of overlap. Three thick FGR 95 and burlap layers (with heavy overlap) were put on the Gorgosaurus. A final coat of thick FGR 95 was put on top of that and as it cured, it was smoothed out by hand, which was frequently dipped into a pan of clean water. Plaster and burlaping took about 1 hour.
Once done the just made support jacket was allowed to sit, cure and dry. The jacket gets quite warm as the chemical reaction in the plaster occurs. Alowed to sit and dry, much water evaporates out reducing the weight of the specimen. The final picture shows the new support jacket finished; scale bar = 10 cm.