elevated temperature the temperatures encountered in use also are likely to be beyond the capability of latex if permanent elasticity is required in the sock a heat resistant material can be included in the thread from which the sock is woven for example a fine extruded cord of soft fluorocarbon elastomer preferably of about 60 ihrd may be used although the resulting sock would be harder to stretch over the mandrel then a comparable one containing latex fig6 is a flow chart for one embodiment of the method of producing a protector bag according to fig4 by compression moulding the embodiment presumes the use of two cores or mandrels stages 52 66 the bag on one being cured whilst the other is being laid up prepared uncured sheet rubber material of a tetrafluoroethylene propylene tfe p compound based on a blend of asahi glass 39 s aflas u00ae 150p and 100h polymers reinforced with carbon black and incorporating a peroxide cure system is calendered rolled to a uniform thickness of 1 to 1 2 mm at stage 54 it then is cut into strips 25 mm wide stage 56 one of the strips is wound helically around a pre heated mandrel or core stage 58 to cover its circumferential surface as required for the finished shape of the bag advantageously the mandrel can be rotated eg in the headstock of a lathe to facilitate this the pbo sock or tube having first been cut to length is pulled over the first layer of rubber stage 60 a second strip of rubber is then wound helically over the sock stage 62 it may be found advantageous for this layer to be wound to.