WASHINGTON PAINT TESTS
The new vehicle test fence at Washington is fully described in the
writer's paper[31] as presented before the American Society for Testing
Materials, as follows:
[31] The Practical Testing of Drying and Semi-Drying Paint Oils, by
Henry A. Gardner. Paper presented at Fourteenth Annual Meeting,
Amer. Soc. for Test. Mater., Atlantic City, N.J., June, 1911.
"The high price attained by linseed oil during the past two years of
over a dollar a gallon, together with the unusual scarcity of this
valuable oil, has led many investigators into the field of research,
with a view of discovering some mixture of other oils to partly replace
linseed oil. Many valuable contributions to oil technology have
resulted, but the makers and users of paints have wisely demanded
specific and authoritative information as to the practical value of
proposed mixtures before adopting them. The Institute of Industrial
Research, at the request of the Paint Manufacturers' Association of the
United States, has recently started a series of practical paint vehicle
tests designed to decide the question at issue.
"Forty-eight white-pine panels have been placed upon a test frame on the
grounds of the new laboratory building of the Institute, at Washington,
D. C. They are painted with a standard white pigment formula reduced
with a different oil formula for every panel. White-pine panels were
selected for the test on account of the good painting surface which this
type of lumber presents; the grade selected was free from knots or pitch
pockets--defects which often ruin a paint test. Each panel was
constructed of four tongued-and-grooved planed boards, 22 inches long, 1
inch thick, and 9 inches wide. The boards were leaded together and
capped at the sides with weather strips, making the finished panels
about 2 feet wide and 3 feet high. The fence upon which the panels were
placed was constructed of 4-inch squared yellow pine with open
framework, allowing the panels a resting place upon which they were
finally secured with sherardized screws.
"Before erecting the panels, they were carefully painted in a paint
laboratory especially fitted out for the tests. The work was done during
the months of April and May, the temperature averaging from 60 degrees
to 90 degrees Fahrenheit. This precaution was taken in order that the
paint in each case might become thoroughly dry and hard before exposure,
so that there would be no accumulation of dust or effect from exposure
during the drying period. The actual painting of each panel was done
personally by Mr. Charles Macnichol, master painter, of Washington, D.
C., who has had a wide experience in the practical application and
testing of paints.
[Illustration: View of Panels on Washington Test Fence]
"The viscous nature of several of the oils tested precluded the
possibility of grinding each oil formula with the white pigment base
selected; great heating of the paint mills and a paste of insufficient
fineness was the result of an early attempt at this method. It was
decided, therefore, to grind the standard pigment formula to a thick
paste in the minimum amount of raw linseed oil. Subsequently a weighed
amount of the white pigment base was thinned with the oil formula to be
tested, to a standard viscosity, judged by the experienced master
painter in charge of the practical application of the formulas as
sufficiently heavy for third-coat work. When making the reductions with
oil mixtures, an allowance was made for the amount of linseed oil
already contained in the ground white pigment base.
"During the application of the first coat an equal amount of turpentine
was added to each formula, in the proportion of one-half pint to a
gallon of paint; in the application of the second coat there was added
to each formula a like amount of an equal mixture of turpentine and the
oil formula under test. The third coat was applied without the addition
of thinners of any kind.
"It is well known that the time of drying and the condition of the dried
film of any oil or mixture of drying or semi-drying oils will vary
widely. It is for the purpose of causing oils to set up to a hard film
in a short time that metallic driers in the form of salts of manganese
and lead, soluble in oil, are added to a paint. Some oils require a
large amount of drier, while others require only a very small amount.
Those which require a large amount are apt, upon exposure, to be burned
up by the drier, resulting in the formation of a powdered and
disintegrated film. To add various types of drier or even differing
amounts of a drier to the oils under test, seemed very unfair from every
standpoint, and it was therefore decided to eliminate the drier question
entirely, so as not to vitiate the results by bringing in a factor of
this nature. The plan of omitting driers proved successful in the
Atlantic City steel-panel paint tests, erected three years ago by the
writer under the supervision of Committee A-5 of this Society.
"The systematic methods which are necessary when making paint tests were
carefully followed. A standard weighed amount of white pigment paste was
placed in a clean paint cup and thinned to the proper consistency with a
weighed amount of the oil under test. Proper reductions were made, as
before stated. Weighings of the paint, cup, and brush were made before
and after application to the panel, in order to determine the quantity
of paint used and the spreading power. A period of fifteen days was
allowed between the application of successive coats, in order to give
each formula sufficient time to dry thoroughly. Although several of the
formulas remained tacky for over a week, all dried thoroughly in the
time allotted. (Oils which when used alone have slow drying properties,
have been found to yield good firm films when used with drying pigments
such as lead and zinc.) The backs and edges of each panel were painted
with two coats of the paint used on the face of the panel, so as to
prevent the admission of moisture. After erection, the panels were
numbered with aluminum figures pressed into the surface. Frequent
inspections will be made, and at the proper time reports will be issued
giving the results of the tests.
"During the painting of the panels considerable interesting data were
collected, of which the following is a brief resume:
"The hiding power of a paint is one of its most important requisites. It
was found in the tests that some oils had the effect of lessening, while
others had the effect of increasing the hiding power of the standard
pigment formula. This may be due in part to the varying refractive
indices of the oils used, as well as to the difference in the quantity
of oil required in each test. Some oils were very viscous, while others
were very light.
"The stiff working of heavy-bodied, blown, or heat-oxidized oils,
produced films which in some cases gave a very glossy surface, even on
the priming coat. Some of these resembled varnished work when finished.
It will be of importance to watch these tests carefully for any signs of
early breakdown, which might come from too thick a film. The treated
Chinese wood oil paints worked rather stiff but produced very smooth
films. The rosin oil paints became slightly lumpy on standing, but
worked out to a smooth finish somewhat yellowish in color. The marine
animal oils, especially the menhaden oil mixtures, dried to a film
slightly flatter than straight linseed oil. Any odor which was present
in the paints made from the animal oils seemed to disappear a few hours
after application. The cotton seed and corn oil mixtures made the
slowest drying paints, but at the end of the second week of the drying
period they set up rapidly to firm films. Soya bean and perilla oils
behaved like straight linseed oil, the former being a little slower and
the latter slightly more rapid in drying properties. The perilla oil was
made from one of the first importations into this country, and was dark
in appearance. It made, however, a very easy-working and hard-drying
paint.
"The oils used in the tests were obtained from reliable sources. After
they were received, they were carefully analyzed. The results of the
analyses appear in Table 1.
TABLE 1. ANALYSES OF OILS USED IN THE VEHICLE TESTS
===================================+=========+=========+========+========
|Specific |Saponifi-|Iodine | Acid
|Gravity | cation |Number |Number
| | Number | |
-----------------------------------+---------+---------+--------+--------
Raw linseed oil |0.931 | 188 | 186 | 2.0
Boiled linseed oil (linoleate type)|0.941 | 187 | 172 | 2.7
Boiled linseed oil (resinate type) |0.930 | 186 | 176 | 2.2
Blown linseed oil |0.968 | 189 | 133 | 2.8
Lithographic linseed oil |0.970 | 199 | 102 | 2.7
Soya bean oil |0.924 | 189 | 129 | 2.3
Menhaden oil |0.932 | 187 | 158 | 3.9
Perilla oil |0.94 | 188 | 180 | 2.0
Chinese wood oil (raw) |0.944 | 183 | 166 | 3.8
Chinese wood oil (treated)[32] |0.898[32]| 128[32]| 104[32]| 6.8[32]
Corn oil |0.925 | 191 | 118 | 9.5
Cottonseed oil |0.921 | 193 | 105 | 3.6
Rosin oil |0.966 | 27 | 41 |16.7
Whale oil |0.924 | 191 | 148 | --
Neutral petroleum oil[33] |0.916 | 6 | 12 | --
===================================+=========+=========+========+========
[32] Low constants due to presence of over 40% of volatile matter,
largely petroleum spirits.
[33] This oil contained over 20% of petroleum spirits.
"The pigment formula selected for the tests had the following
composition:
Basic carbonate-white lead 20%
Sublimed white lead 30%
Zinc oxide 35%
Magnesium silicate 10%
Barytes 5%
100 lbs. of pigment base ground to a stiff paste in 16 lbs. of linseed
oil.
"While this pigment formula was not selected as being superior to
certain other formulas, it is of a type that has given very fair service
in paint tests throughout the country, and will no doubt serve admirably
for the purpose designed in these tests.
"The vehicle formulas in the finished paints are as follows:
No. 1
Raw linseed oil 100%
No. 2[34]
Soya bean oil 100%
[34] Dry pigment formula in soya bean oil.
No. 3[35]
Menhaden oil 100%
[35] Dry pigment formula in menhaden oil.
No. 4
Raw linseed oil 25%
Boiled linseed oil (resinate) 75%
No. 5
Raw linseed oil 25%
Boiled linseed oil (linoleate) 75%
No. 6
Raw linseed oil 50%
Boiled linseed oil (resinate) 50%
No. 7
Raw linseed oil 50%
Boiled linseed oil (linoleate) 50%
No. 8
Raw linseed oil 50%
Blown linseed oil 50%
No. 9
Raw linseed oil 50%
Litho. linseed oil 50%
No. 10
Raw linseed oil 50%
Soya bean oil 50%
No. 11
Raw linseed oil 50%
Menhaden oil 50%
No. 12
Raw linseed oil 50%
Perilla oil 50%
No. 13
Raw linseed oil 50%
Treated wood oil 50%
No. 14
Raw linseed oil 50%
Corn oil 50%
No. 15
Raw linseed oil 50%
Cottonseed oil 50%
No. 16
Raw linseed oil 50%
Rosin oil 50%
No. 17
Raw linseed oil 50%
Whale oil 50%
No. 18
Raw linseed oil 75%
Soya bean oil 25%
No. 19
Raw linseed oil 75%
Menhaden oil 25%
No. 20
Raw linseed oil 75%
Perilla oil 25%
No. 21
Raw linseed oil 75%
Treated wood oil 25%
No. 22
Raw linseed oil 75%
Corn oil 25%
No. 23
Raw linseed oil 75%
Cottonseed oil 25%
No. 24
Raw linseed oil 75%
Rosin oil 25%
No. 25
Raw linseed oil 50%
Soya bean oil 25%
Menhaden oil 25%
No. 26
Raw linseed oil 50%
Soya bean oil 25%
Treated wood oil 25%
No. 27
Blown linseed oil 50%
Soya bean oil 50%
No. 28
Raw linseed oil 25%
Soya bean oil 25%
Menhaden oil 25%
Treated wood oil 25%
No. 29
Raw linseed oil 25%
Soya bean oil 25%
Menhaden oil 25%
Corn oil 25%
No. 30
Raw linseed oil 25%
Soya bean oil 25%
Menhaden oil 25%
Cottonseed oil 25%
No. 31
Raw linseed oil 25%
Soya bean oil 25%
Menhaden oil 25%
Rosin oil 25%
No. 32
Raw linseed oil 25%
Soya bean oil 25%
Treated wood oil 25%
Rosin oil 25%
No. 33
Raw linseed oil 20%
Soya bean oil 20%
Treated wood oil 20%
Menhaden oil 20%
Cottonseed oil 20%
No. 34
Raw linseed oil 20%
Soya bean oil 20%
Treated wood oil 20%
Menhaden oil 20%
Rosin oil 20%
No. 35
Raw linseed oil 40%
Soya bean oil 20%
Corn oil 20%
Cottonseed oil 20%
No. 36
Whale oil 33%
Treated wood oil 33%
Raw linseed oil 33%
No. 37
Raw linseed oil 25%
L. O.[36] 75%
No. 38
Raw linseed oil 50%
Raw Chinese wood oil 50%
No. 39
Raw linseed oil 75%
Reducing oil[37] 25%
No. 40
Raw linseed oil 50%
Soya bean oil 35%
Neutral petroleum oil 15%
No. 41
Raw linseed oil 50%
Soya bean oil 25%
Neutral petroleum oil 15%
Tungate drier 10%
No. 42
Linseed oil 25%
Soya bean oil 37%
Neutral petroleum oil 23%
Tungate drier 15%
No. 43
Raw linseed oil 25%
Soya bean oil 37%
Whale oil 19%
Tungate drier 19%
[36] Mixture of boiled tung and soya bean oil, thinned with petroleum
and turpentine.
[37] 25% raw linseed oil. 73% petroleum oil. 2% drier--lead and
manganese linoleate."
No. 44
Special test on white base of the following composition, in pure linseed
oil:
Asbestine 10%
Corroded white lead 20%
Sublimed white lead 30%
Zinc oxide 40%
Upper board of panel reduced with straight turpentine on priming coat.
Second board of panel reduced with wood turpentine on priming coat.
Third board of panel reduced with pine oil on priming coat. Bottom board
of panel reduced with petroleum spirits on priming coat.
No. 45
Same pigment formula as No. 44, reduced with:
Pine oil 50%
Linseed oil 50%
No. 46
Special test of white base of the following composition, in pure linseed
oil:
Corroded white lead 20%
Sublimed white lead 30%
Zinc oxide 35%
Asbestine 15%
No. 47
Cypress panel unpainted.
No. 48
Cypress panel painted with formula No. 1, thinned with benzol on the
priming coat.