By D.D. ROBERTSON.
At the Master Car-Painters' Convention, D.D. Robertson, of the Michigan
Central, read the following paper on the best method of testing varnishes
to secure the most satisfactory results as to their durability, giving
practical suggestions as to the time a car may safely remain in the
service before being taken in for revarnishing:
The subject which the association has assigned to me for this convention
has always been regarded as important. There is no branch of the business
which gives the painter more anxiety than the varnishing department. It is
more susceptible to an endless variety of difficulties, and therefore
needs more close and careful attention, than all other branches put
together, and even with all the research and practical experience which
has been given to the subject we are yet far from coming to a definite
conclusion as to the causes of many of the unfavorable results.
Beauty and durability are what we aim at in the paint shop, and from my
experience in varnish work we may have beauty without durability, but we
have rarely durability without beauty, so that the fewer defects of any
kind in our work caused by inferior material, inferior workmanship, or any
other cause, it is more likely to be durable, and ought, therefore, to
possess beauty. There are certain qualifications absolutely necessary to
durability in varnish. The material of which it is made must be of the
proper kind, pure and unadulterated; the manipulation in manufacturing
must be correct as to time, quantities, temperature, handling, etc., and
age is also necessary. The want of durability arising from the quality of
the materials, or from the manner of manufacturing, the painter has no
control over; but let me say here, that frequently a first-class varnish
has been used upon a car, and after being in service for a short time it
deadens, checks, cracks, chips, or flakes, and therefore shows a very poor
record. The varnish is condemned, when in reality, had the varnish been
applied under different circumstances and over different work, the result
would have been good and the durability satisfactory.
I am satisfied that in many cases first-class varnish has to bear the
odium, when the root of the evil is to be found nearer the foundation. The
leading varnish manufacturers of this country have expended large fortunes
to secure the best skill and appliances, and, indeed, to do everything to
bring their goods to perfection. Their standing and respectability put
them beyond suspicion, and their reputation is of too much value for them
knowingly to put into the hands of large consumers an inferior article;
and even when we have just cause to complain of the varnish, we ought to
be charitable enough to attribute the mistake to circumstances beyond
their control (for every kettleful is subjected to such circumstances),
and not to charge them with using cheap or inferior material for the sake
of gain.
If the question which has been given me means to give some method of
testing before using, I confess my inability to answer. For varnish to be
pronounced "durable" must be composed of the materials to make it so, and
to ascertain this, chemistry must be called in to test it. Comparatively
few painters understand chemistry sufficiently to analyze, and if they
did, and found the material all that is necessary, the manipulation may
have been defective, so as to injure its wearing qualities, and therefore
I cannot suggest any way of pronouncing varnish durable before using it.
As to the common custom of hanging out boards prepared and varnished to
the exposure of the sun and weather for months does not seem to me to be
the correct way of testing durability. It is true we may by this mode get
some idea of wearing properties, but the most thorough and correct way is
to put the varnish to the same exposure, the tear and wear, that it would
have in the regular service on the road on which it is to run. Cars while
running are exposed to circumstances which boards on the wall are not
subjected to. The cars under my charge run through two different countries
and three different States, and therefore subjected to such a variety of
climate and soil that the testing by stationary boards would completely
fail to give the correct result. For example: I have placed two sample
boards, prepared and varnished, and exposed them to all kinds of weather
and to the constant and steady rays of the sun for an equal length of
time, and both gave favorable results; and I have also put the same
varnishes on a car and found very different results. One of the varnishes
having some properties adapted to resist the friction caused by cinders,
sand, and dust, and consequently not so liable to cut the surface, and
therefore much more durable.
The system which I adopted long ago, and to which I still adhere (not on
account of "old fogyism," but for want of better), is as follows: I have
two varnishes which I want to put into competition to test their relative
merits. With varnish No. 1, I do the south half of the east end of the car
and the east half of the south side of the car, the north half of the west
end, and also the west end of the north side; this is also done with the
same varnish. On the other half of the car varnish No. 2 is put.
Thus you will see it is so placed that, should the car be turned at any
time, both varnishes on each side will have the same exposure and
circumstances to contend with. This I regard as the best method to test
the durability of varnish. And again let me say that it would be wrong for
me to argue that because the varnish which I use gives me the best
results, therefore I would regard it the best for all to use. This would
be wrong, inasmuch as we have a diversity of climates between Maine and
California, and between the extreme northern and southern States. The
varnish which has failed to give me satisfaction may be most suitable for
other parts of the Union.
As to the second part of my subject, "What length of time may a car safely
remain in service before being taken in for revarnishing?" this must be
regulated by the nature of the run and general treatment of the car while
in service. Through cars are frequently continuously on the road, and
little or no opportunity can be had to attend to them while in service.
Such cars should be called in earlier than those which make shorter runs,
and where ample time is allowed at both ends of the journey to be kept in
order. And again, cars which are run nearest the engine cannot make so
large a running record as those less exposed. Some roads, for a variety of
reasons which might be given, can run cars for 14 months with less wear
than others can run 12 months. So that I hold that the master painter on
every road should keep a complete and correct record of his cars, and have
an opportunity to examine these at intervals and report their condition,
in order to have them called in before they are too far gone for
revarnishing. If this system was more frequently adopted, the rolling
stock of our roads would be more attractive, and the companies would be
the gainers.
I cannot lay down a standard rule as to the exact time a car should remain
in service before being called in for revarnishing, but I find as a
general rule with the cars on the Michigan Central Railroad that they
should not exceed 12 months' service, and new cars, or those painted from
the foundation, should not be allowed to run over 10 months the first
year. By thus allowing a shorter period the first year the car will look
better and wear longer by this mode of treatment. Cars treated in this way
can be kept running for six and seven years without repainting.
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