reaction. When the surplus water evaporates, numerous microscopic voids are left in the cast and these affect its strength and hardness. The be gypsum strength of cast increased if setting can be brought about without the introduction of voids.
can
A method of doing this at low cost has been developed by Mr. M.J. Ridge of the Australian Common- wealth Scientific and Industrial Re- search Organisation (CSIRO) Divi- sion of Building Research.
In the method he recommends, small quantities of gum arabic and lime are added with the water. These additives disperse the particles very effectively, and the amount of water required for good workability is considerably reduced.
Cast gypsum with a compressive strength of 6000 lb. per sq. in. com- parable with that of good quality concrete, can be produced without difficulty.
VIBRATOR
Use in Precast Concrete Panel Making
A VIBRATING trowel made by the American Branford Co. is designed to promote more rapid densification of low slump concrete.
Particularly useful in the manu- facture of precast concrete panels, the trowel has an 8in. by 14in. blade which enables the operator to
Branford vibrating trowel spread the concrete within the form more quickly and uniformly. The alloy steel vibrator is pneumatically operated.
Further details are available from The Branford Co., New Britain, Connecticut, USA.
WASHBASIN
Rear Section is Built
Into Solid Wall
MADE OF ceramic-glazed fireclay, in a choice of white or eight colours, the Insette washbasin has been de- signed for use in locations where space is restricted. It is also claim- ed to stand up well to rough treat- ment in public places.
sec-
The integrally-moulded rear tion measures 18 in. wide by 12 in. high by 4 in. deep; both the bowl and the soap alcove extend about
74
2 in. back into this section so that, when it is built into a solid wall, the basin itself projects only 7 in. into the room.
The makers are John Slater (Stoke), Ltd., Berry Hill, Stoke-on- Trent, UK. Their agents are: Borneo - Malaya Representatives, Ltd., Singapore; and Tyler Bros. (Eastern) Ltd., 91 Regent Street, London, W.1, for Thailand and Hong Kong.
ARC WELDER
170 Amp Unit can be Carried by One Man
MCCULLOCH INTERNATIONAL of Los Angeles and Hong Kong, are now offering a 170 amp lightweight, petrol driven arc welder which can be carried by one man and quickly set up for immediate use.
McCulloch portable arc welder
Weighing only 55 lb., the unit. measures 14in. wide, 18in. long and 15in. high. It is powered by a 6.3 cu.in. two cycle, air cooled petrol engine that can operate the welder under a full load for 30 to 40 minutes. The welder will handle a full range of rod sizes of all types up to and including 5/32 in. for welding light and heavy guage metals.
The 170 amperes of alternating current is developed at a frequency of 2,880 cycles. A rectifier can be easily adapted to the unit to make possible direct current operation. The rectifier weighs 14 lb.
Die cast aluminium alloy with a precision honed cast iron liner is used for the cylinder and the crank- case is a high pressure aluminium alloy die casting.
DRILLS
Cheap Way of Installing Rawlbolts
FOR the builder with a small num- ber of Rawlbolts to install, The Rawlplug Co., Ltd., Cromwell Road, London, S.W.7, have introduced cheap drills which may be used for ten or a dozen holes in masonry and then discarded.
These Speedbore drills can be fit- ted in a variety of power hammers. Their patent form and the special process by which they are hardened
Rawlplug Speedbore drill give quick cutting and rapid debris removal. Freedom from jamming is assured by the scraper slots along the full length of each drill.
Ralwplug agents are: Innes and Riddle (China) Ltd., Hong Kong: Warner, Barnes and Co., Ltd., Manila; Bells' Asbestos and Eng- ineering (Malaya) Ltd., Singapore: and Mahajakyontr, Ltd., Bangkok.
WASTE PIPES
Marley to Market Terrain Vinyl Fittings
AN arrangement has been made between The Marley Tile Co., Ltd., Sevenoaks, Kent, U.K., and A.B. Plastics, Ltd. under which Marley are to market through their agents the Terrain brand waste pipes and fittings.
Unplasticised p.v.c. is used in the manufacture of the fittings.
Terrain fittings and
pipework
This
does not soften under load below 75 to 85 degrees centrigrade and is Satisfactory for use in soil or waste systems where continuous full bore discharges of effluent at temperatures of up to 70 degrees occur.
All the fittings are either injection moulded or machined from solid extruded p.v.c. rod. The dimensions of the pipe and fittings conform to the I.S.O. Inch Series Table which is designed to provide nominal clear bore sizes of 14 in., 14 in. and 2 in.
Marley agents include: Dreyer and Co., Ltd., Hong Kong; Loxley (Bangkok) Ltd.; Theo H. Davies and Co. (Far East) Ltd., Manila; Messrs. Hecla, Kuala Lumpur; and The Borneo Co., Ltd., Kuching.
Far East Architect & Builder March, 1965