Just out of curiosity, does anyone have an idea when spray painting was introduced on an industrial scale. A quick Google search shows "bottled" spray paint as early as the 1890's, but I'm just curious as to when brush marks in a paint job are appropriate and when they are not.

Thanks

Matt Bumgarner

Spraying with hand held pots with nozzles about in the 1920's, but not widespread until the later '30s, based on what I've read. Others mileage may vary. My guess is it didn't get common until after WWII. Given your mission - NC narrow gage shortlines - probably spray painting isn't in the picture at all.

dave

I was told years ago that one of the original paint spray devices, was based on a steam locomotive valve oil can and was called a "paint thrower".

Wikipedia says 1892 Columbian Exposition:

https://en.wikipedia.org/wiki/Paint_spraying

-Hudson

On one of my many visits to Nevada Historical Society I looked at a invoice book from the Eureka & Palisades. This is a record book into which paid invoices were pasted. As I recall in either 1898 or 1899 this little narrow gauge bought a spray paint rig from the Southern Pacific Sacramento shops. Probably to be used for painting the freight cars.

I recall an old carman (Milwaukee Road?) describing how they made a "spray nozzle" by flattening the end of a pipe and hosing the paint on freight cars. I have a notion this story dated to the 1930's. But it could have been done much earlier by anyone with a container of paint and air pressure.

Conversely, close inspection of the British Rail Intercity 125 trains in the 1980's showed they were brush painted. Probably a labor thing that went out with Thatcher.

Aarne Frobom
Horsehair, Michigan

Yeah, I would more be looking at the underlying paint layers and see what they look like.

You can't go by modern sensibilities. Today, we place great value on human time and less on supplies. Back then, the other way 'round.

Consider an early 20th century shop playing with spray for the first time. They will be aghast at the supplies consumption. You will use nearly twice the resin/pigment and four times the thinner. The extra winds up on the ground or on the superintendent's automobile. If you've got men lined up around the block waiting to work for 50 cents a day, that kind of wastage makes no sense.

And while there is great labor savings in application time, there's additional labor in masking, often more labor than in the spraying. Either way the prep is the same. And prep is the lion's share of the job.

So spraying is not an open and shut case. Hence it would not have been leapt upon without skepticism and careful consideration. I'm sure the railroad trade rags would tell the tale.

I actually think for railway preservation, the pendulum is swinging the other way. For several reasons.
FIRST is the new paints... we've suffered the loss of metal-oxide pigments, we damn well ought to gain the benefit of aliphatic polyurethane resins. These are hazardous to spray, but safe to brush/roller (and too expensive to waste!) SECOND is rollers, which are a postwar development. They give big production and combine very nicely with brush, the roller laying down volume while the brush swishes out stipple. Here http://www.youtube.com/watch?v=k-SGcSlN ... re=related Roll/tip works extremely well with a 2-man team (and a bigger roller). And the new poly's are designed for this. THIRD, you can get an inexperienced volunteer productive very quickly with a brush and roller, but your spray job requires a specialist. How many projects are sitting around waiting for an "Expert" painter?

Aarne and others, I have a hunch that the early improvised sprayers were merely the "roller" part of the roll/tip; their job was to apply large volumes quickly, which was then evened out and tipped out by the brush men who followed. The result would be a job that looked brushed.

I remember having this discussion with one of the ex-North Shore men, either Howard or Horachek, who made the flat statement that Highwood brush painted a lot of the cars. To prove the point, whoever it was took a little "nose oil" and started rubbing the oxidized finish on a nearby car with his fingers. Sure enough, the faint brush marks popped right out.

I remember reading an article in the period press (either Railway Review or Railway Mechanical Engineer, can't recall which) that concerned itself with a new car shop United Fruit Co. had built in Cuba. The article made a big deal about the spray equipment, making the statement that it, "had to work perfectly, for the painters would put it down and pick up their brushes at the slightest problem."

They may still be painting by brush.

Within the last 10-12 years I saw a article in The Railroad Magazine (a British rail enthusiast magazine that has been around 110+ years) that showed and talked about contemporary hand painting main-line locomotives. Seems it had to do with the release of volatiles.

Yeah, that makes perfect sense. Paint formulated for brush has far less volatiles. Spray takes a lot of thinner. It also takes more paint, since so much misses, and that extra paint takes more thinner still.

For instance here is the formula for mixing 1 gallon of Awlgrip G/H base with converter and reducer.
BRUSH: 1 gal. base + 1/2 gal. brush converter + 0.15 gal. brush reducer (thinner) = 1.65 gal.
SPRAY: 1 gal. base + 1 gal. spray converter + ~1/2 gal. spray reducer (thinner) = ~2.5 gal.
The difference is essentially VOC. Some paint misses the car, and that uses thinner too. A spray job could easily be 3-4 times (or more) VOC than a roll/tip job.

So if you're trying to get your shop under VOC numbers, roll/tip will get you there and retain some productivity.

The other reason a shop might do this is if your shop is too crowded to protect other workers from toxic overspray. That is precisely why marine paints must be brushable: some boats paint while underway.

It's interesting that we've seemed to have come a full circle here. Railroad equipment was traditionally brush painted. On passenger equipment this entailed multiple coats, rubbed out by hand to remove the brush marks between coats. The last several coats were clear varnish, to build depth of gloss the same way modern automobiles are clear-coated.

I have read references to the fact that Pullman "oiled" cars between full repaints. I take this to mean a rub-down with a polymerizing oil, such as linseed or tung oil, which would fill the micro cracks developing in the clear coat and restore its gloss.

Spray painting, as we know it, was really developed for the automotive industry during the twenties and thirties. Among other things, it made possible the use of nitrocellulose lacquers such as Duco. On the other hand, all of the traditional railroad colors in the Dulux line were, at one time, available in a brushable base. The base was denoted in the numerical prefix in the color code, and old Dulux catalogs from the fifties show several options that each color could be mixed into.

Those of us who were painting in the seventies found, if we wanted to use the old color formulations, that we had to learn to spray paint, since both Dulux and Ditzler had dropped the brushable bases when they concentrated their marketing on automotive refinishing. Believe me, compared to setting up to spray under the great "sky barn", giving half a dozen guys and gals brushes, rollers, and five gallons of Rustoleum was a walk in the park. And, we certainly did that often enough, depending on whether the level of surface prep warranted the extra work that went into an automotive finish. The problems with brush finishing at the time were 1) lack of color selection, and 2) lack of gloss retention. I have to admit, though, that some of the brush jobs at IRM don't look that bad after close to forty years. But, the Ditzler and Dulux jobs look better.

Now it appears that the scales have swung the opposite way, and the preferred coatings are again brushable. Which is good, since brushing is really more likely to be historically correct. I recall touring the Nevada State Railroad Museum in Carson City a few years ago. They have some amazing passenger cars, nicely restored, but the plastic look of the exterior finish just didn't do it for me.

When I last was in Australia, railway cars and transit coaches came from the factory spray painted. However when they were repainted later they were brushed. I was told it was because labor union contracts prohibited spray painting because it would have reduced the number of painters.

Actually, in 1892 for construction of the World's Columbian Exposition, the Chicago World's Fair of 1893. I have relatives who attended.

I sometimes use brush on things that were originally sprayed... for the reasons I outlined about 6 messages above, practicality.

However this is not your grandfather's paint. Awlgrip, and I assume its competitors, are designed to "look sprayed" if brushed well over a smooth surface. It has extremely good "flow out" which flattens out modest brush stipple. The trick is, they require a substrate of 2-part epoxy primer, and those don't flow out so well, and the topcoat will conform perfectly to any flaws in the primer, revealing them. This doesn't matter on a mottled surface like a rusted car or grained wood. On a smooth surface, you either want the brush marks, or spray the primer... or sand a lot.

As for gloss, it's as glossy as the yacht ads the moment it dries. No further work is required to maintain the gloss, in fact Awlgrip scolds people to NOT do anything. If you are going for that 'rubbed down' look, you're done. Some people say that's unnaturally glossy, I don't know, I've seen old photos of some mighty glossy boxcars fresh out of the paint shop and I'm pretty sure they don't rub those down. With a gloss modifier, the gloss can be adjusted all the way down to "flat flat", in fact I did just that on a railroad signal head and it came out fantastic.