  A comparative study has been performed on Resistive Plate Chambers (RPC) made
of two different grades of bakelite paper laminates, produced and commercially
available in India. The chambers, operated in the streamer mode using argon,
tetrafluroethane and isobutane in 34:59:7 mixing ratio, are tested for the
efficiency and the stability with cosmic rays. A particular grade of bakelite
(P-120, NEMA LI-1989 Grade XXX), used for high voltage insulation in humid
conditions, was found to give satisfactory performance with stable efficiency
of > 96% continuously for more than 130 days. A thin coating of silicone fluid
on the inner surfaces of the bakelite RPC is found to be necessary for
operation of the detector.
