The table top is of aluminium, area 3.2 x 2 metres, thickness 8 mm. The heating chamber beneath, containing the electrical heating elements, is 15 cm deep. Air is blown through this chamber for cooling. Temperature is controlled thermostatically to ± 3°C on the surface. Heating to around 58°C takes 35 min., cooling to room temperature 48 min., the important fall occupying the first 10 mins. The three vacuum ports in the table-top are placed in a way to permit use of half the table, the whole table, or relining of a picture up to twice the table area. Standard relining takes place in three stages: (a) impregnation of original canvas, (b) impregnation of relining canvas, (c) adhesion of the two canvases under controlled atmospheric pressure.