Way back in the early Seventies, I visited Colorado/New Mexico for the first
time,
specifically for watching and researching trains, primarily the D&RGW & RGS.

At that time, there were a number of D&RGW Narrow Gauge Stock Cars that
had been deposited behind the roundhouse at Chama, NM. Actually, they
were sitting on the lead track of the old sheep dipping plant. For those not
modeling Colorado Narrow Gauge, most, if not all of the Rio Grande's
stock cars, narrow & broad gauges, were painted black -- the whole car.

I was just learning about the little nit-picking type stuff, like how/why the
corners of the stock car roofs were carefully cut at a 45 degree angle, etc.

I climbed up the rungs on the "B" end of one of the stock cars, as the grab
irons
on this car seemed to be the safest (least rotted) of the lot -- you could
still
do that then without being yelled at by an employee! <G>

Unfortunately, due to the condition of the grab irons, I did not take my
camera
up to the roof with me, something I've regretted for over 30 years.

What I saw was this ---

The roof walk boards were still a dull black -- with a bit of a grainy
finish.

At the time I didn't know that there was such a thing as roof cement. I just
assumed that the paint had been applied "extra heavy" on the roof walks.

The rest of the boards that made up the wood roof were totally devoid
of paint and most had "cupped" significantly. Apparently, these were
not treated the same as the roof walks.

Another interesting observation, was that some of the cars had
somewhat rectangular areas of the "roof cement" painted on the
ends of the roof, about two feet wide, adjacent to the center roof
walk. My guess was/is that the painter(s) put a little roof
cement on the roof boards in case the "brakie" slipped while on
the regular roof walk.

Several of the cars had this extra application. Several did not.

I climbed down and checked the "Paint Date Stars" on the cars.

Cars with the extra application had been painted in the late forties,
while the "untreated" cars had paint dates in the early fifties.

At that time the "oldest" paint jobs were only 25 to 30 years old.

What I later learned to be "roof cement" had really stuck to the areas
it was applied to. Obviously, on the Rio Grande "narrer gauge" the whole
roof, at least on these cars, had not been fully treated with "cement".

The way I represented this on my HOn3 stock cars, was to paint the whole
car Floquil Engine Black, then use Floquil Grimy Black, with a little Engine
Black added to visually blend the colors, and painted the roof walk areas
that had "cement" applied with that.

The slight color and texture variation remains visible through moderate
weathering, too.

'Hope this helps,

John





John Hitzeman
President/Owner
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The normal car cement was itself black.

Probably what Ed wants to know is, does the application of
car cement guarantee that a surface remained black? The answer clearly
is "no." The other side of Ed's questions is, does a black roof or end
mean it was necessarily unpainted car cement? Again, the answer is
"no."

Tony Thompson Editor, Signature Press, Berkeley, CA

Hi Gang:

Would someone be able to define the difference in properties or composition between paint and car cement?

What are the attributes of car cement vs. use of paint?

In HO scale, would black car cement appear different from black paint?

Thanks
Tim Costello

Hi:

Hi Gang:

Would someone be able to define the difference in properties or
composition between paint and car cement?

What are the attributes of car cement vs. use of paint?

In HO scale, would black car cement appear different from black paint?

It appears to this newbie that car cement is essentially a bituminous coating used for sealing while paint is, er, paint. Probably the biggest visible difference is that the thickness of a layer of paint is a few thousands of an inch while the thickness of a layer of car cement is a few 32nds of an inch.

In 1/35 (my other modeling scale) bituminous coating or similar items like Bostik Sealant and asbestos grease are replicated by brushing on a thick model paint vs. airbrushing for regular paint. With HO being about 1/3 this size, even this might be too much difference. If the car cement was sprayed, I doubt that you could detect a difference in texture at 1/87. Black paint might tend to weather toward gray while bituminous coatings often go toward brown.

KL

My knowledge of car cement is limited to a few box cars I used to walk
by almost everyday. The ends had car cement on them, although I didn't
know that at the time, the ends were black. The cars were all
refurbished and received solid bcr color paint, but you could still
see the texture of the cement on the ends. The best way to describe
the stuff is to say it was like roofing tar or more like `Black Jack'.
I doubt if the texture would be worth modeling in HO. Of course, I
don't add rivets or add up those itty bitty numbers :)
Clark Propst

Kurt Laughlin wrote:

It appears to this newbie that car cement is essentially a bituminous coating used for sealing while paint is, er, paint. Probably the biggest visible difference is that the thickness of a layer of paint is a few thousands of an inch while the thickness of a layer of car cement is a few 32nds of an inch.
In 1/35 (my other modeling scale) bituminous coating or similar items like Bostik Sealant and asbestos grease are replicated by brushing on a thick model paint vs. airbrushing for regular paint.

I'd agree with Kurt on both points: it's a tarry material which I have seen being applied with a mop in one photo. Santa Fe, as well as PFE and others, blew slate granules onto it while wet to provide a less-slick surface. Hand-brushing model paint does provide a bit of texture, compared to the very uniform paint applied by an airbrush, and one can perceive this slight difference on a model.

Tony Thompson Editor, Signature Press, Berkeley, CA
2906 Forest Ave., Berkeley, CA 94705 www.signaturepress.com
(510) 540-6538; fax, (510) 540-1937; e-mail, thompson@...
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