SAND LIME BRICKS

Taranaki Daily News, Volume LII, Issue 81, 1 May 1909, Page 5

SAND LIME BRICKS

MANUFACTURED FROJI TARAXAM BLACK SAXD AND TOKO J.I ME.

A sample of sand lime bricks containing New Plymouth black sand mixed with a small propi.ni,,;, 0 f Toko lime, n now on exhibition at Mr. Xewion King's premises, Devon Street, where tuey are open for public inspection. The bricks contain no other ingredients. I'hc materials haying been mixed together, slightly moistened ami pressed into sinipe under tremendous pressure, they wore piled on trucks and subjected to steam at a pressure „f 12011, ,„.,• square j.,,.), for a [icriod of ton hours. An examination of these will no doubt satisfy as to their quality. It may In- of interest to know something of their ability to withstand weather conditions. To do this it. is necessary to give a little hformation regarding the origin of this class of building material. Sand bricks were tirst mamitactured in Europe, (iennany being the tirst to : introduce them. Afterwards thev were I made in France and England., America took the matter up some eight or nine years ago, and they are now used in immense numbers there. Over fortv years ago the bricks were iirst useii, but were then moulded in the ordinary brick mould's and were allowed to 'harden by exposure to the atmosphere. By this method the bricks, alter being moulded, had to lie for many months before they were hard enough to handle. Still, the atmosphere brought about the desired effect, namely, causing the two ingredients to unite, in forming a bond due to the formation of a hydro-silicate of lime. It was impossible by tluis method to turn the enterprise into a profitable one, on account of the length of time the bricks had to lie in stock before being marketable. After many

experiments it was found that in the presence* of moist heat the hardening process became much accelerated. Hits moist heat could be obtained by steam from a boiler entering a closed vessel, into which the newly-moulded saint bricks had been placed. The results from this were satisfactory. But at that time boilers could not be built to withstand a high pressure, and consequently the bricks had to remain under steam a much longer time than is the case today. The bricks can now be hardened and ready for laying on the wall in from nine to ten hours after being moulded. •The method of manufacturing the bricks is a simple matter nowadays with the greatly improved machinery. The brick is subjected to an enormous pressurel in order to obtain the required density. It will readily be seen that with the improved conditions a better brick can be turned out in twenty-four hours to-day than could be formerly in many months. Under weather conditions the bricks continue to harden and improve with age, not being affected either by frost or rain, other than beneficially. As everyone is aware, the climate of Europe and North America is severe and extreme compared with our New Zealand climate. Jbirae and sand as a building material can be seen to advantage in England and Scotland, where it has been exposed to the weather for many centuries. Often, where the brick or stone lias been eaten away the lime joint ean be seen to protrude audi to be hard and tough. j

Sand bricks have been manufactured at Invercargill for three years, and the local architects are satisfied as to t/hc ability of these to harden with age. Over four millions have been built in and around Invercargill since the factory started, having been used by the (.Jovernment in the construction of a new gaol, also for railway work, together with many public buiidings. I

The following are extracts from two Invercargill architects' letters:—

Mr. Charles Roberts, architect, writes as follows: "Regarding your inquiry as to my opinion of your sand bricks, I think the fact, of which you are wel \ aware, that I have used more of your sand; bricks than any architect here is proof that I am well'pleased with them. You are aware that I used the first lot of bricks that were sent out of your works' two and a half years ago. I have used them continually ever since, nnd am still using them.' I find the bricks become harder with age. They are of good even size, shape, and quality. They can be laid faster than clap bricks and require less mortar, which enables a bricklayer to make finer joints. I have studied' sand brick manufacture' for several years, and consider they are much preferable to clay bricks, where neat strong work is to be considered. Bricklayers tell me they cost at least 10s per 1000 less to lay than the local clay brick. You may make what use you like of these remarks, which might be of use to you if you intend manufacturing elsewhere, especially as 1 am not interested in any way with your brick eompauv." Mr. J. Urotlcrick, architect, Invercargill, writes as follows: " In reply to vour inquiry re my opinion of the sand bricks vour company has been making here during the last'three years, 1 have pleasure in stating that I have used them largely in the erection of bot'.i public and private buildings here, with even- satisfaction to myself and clients. Their principal characteristic being regularity of shape, uniformity of size, rectangular faces and freedom from Haws ■of any description, enables a very solid, substantial and uniform wall to be built. With regard to the durability of trie brick, I have found they are hardening with age, as their composition suggested they would. I have every confidence in their future." A meeting will lie duly announced, where a proposition will be laid before the business men here by Mr. Todd, who is lierc in connection with this matter, of starting a factory in lor near N«w Plymouth'for the manufacture of these sand lime bricks.