I X D C S T H I S L A5U IWGINEERING CHEMISTRY
158
Although oils BIKIdriers mix well witli the paints, there advsutigc to lie rained from tlieir usc. (4) As in tlie case of orditiary paints, baking hardens tlic film. (Si Both air-dried and baked films show mod adhesion to most metallic and other surfaces. This adl&sion persists at temperatarcs as low as -51" C. (6) Direct ~xposurcto weather and sunlight reveals a pre-
(3)
is
\-,
vailing tendericy toward chalking, occasional checking, and
some rusting in spots. (7) Exposure to acid and alkali and to salt spray indicates
that thermoprene has exceptional protective properties.
Small-Scale Commercial Tests
The laboratory and roof experiments were siippleniented by a series of semicommercixl test.s tending to sliow the type of service for which the paint is best adapted. For example, there tias always been a great deal of trouble in obtaining a pairit which would protert the metal in a salt works. Several test panels and test sections of metal work in such a factory showed that the thermoprene paint stood up much better than commercial paints that had been used before. In R a t e I1 two panels are shown that had been exposed for
A Modified Weighing Pipet' Graham Edgar E r x n G ~ s o ~ rCOXPORAIION. r;~ 25 ~ R O * D W I Y , NEWYORZ,N. Y .
frequent,ly desirttble analytical work that aiiaiyscs Iand'I'beISinmade upon a nearly coristmt qimitity of material, the case of corrosive liquids or other liquids not iii
readily ineasurablc in ordinary volumetric apparatus, this procediire may be inconveiiieiit. There bas been devised in this laboratory a modified Lunge weighing pipet wliich ba,s proved very useful, and it is described here as being of possible interest to other laboratories where routine analyses are carried out. The apparatus, illustrated in the accompanying sketch, consists essentially of a Lunge pipet containing three bulbs I
Received December 28, 1927
Vol. 20, No. 2
five months. I'and 7 was covered with a lead ;and oil paint, and is complet,ely rusted. There are a few small rust spots on panel 6, wliich was protected by a thermoprene paint. These rust spots are due to pigment aggLmerates, which have now beeii eliiniiialed by improsixl methods of manufacture. The effect oS salt spray is fiirther brought out iii Plate 111. These panels were cut from a 4 by 12 inch (10 by 30 cm.) panel and tlre edges are raw. Tlie edges were left this way purposely to sliow how well the films would prevent rustspreading. There is practically 110 spread of ruet from tlre edge of the tbennoprene paint panels 72 and 5'3. In a cooling tower where the spray of steam and cooling water from tire vulcanizers was hloaii against. a series of louvres in a fine spray, a t the end of nixie niont,lis the commercial paints were practically a11 destroyed, while a few thernroprene paints OS a particular composition were in good condition at, the end OS sixteen months. Tlirse preliminary development tests are now being augmented by paintiiig tests iir chcmical plants.
of iiefiiiit,e voluiiie with gradua t i o n marks between them. 'The base is flattened and is of s u ~ l diiriensiorrs i tbat the pipet will ,stand comfortably on tlre ordiiinry balnnce pan. By tlie use of this pipet duplicate or triplicate n,eighiiigs of nearly bho same quant,ity of material may be conveniently mndc. The apparatus may be made with two bulbs instead of three a n d t h e dimensions of the bulbs may be changed to suit individual needs. Tlie pipet has been made by the Yonkers Laboratory Supply Co., 549 West 132nd St., New York, N. Y.
