Painting airstream red!

[Inland RV Center, In]

Paula.

Painting an Airstream trailer, metallic silver, based on my almost 40 years experience, does indeed have an effect on it's value.

The value substancially "increases", simply because if done properly and with first class materials, waxed once a year or so, the life expectancy is at least 20 years or more.

Many of my old paint jobs are still running around from over 20 years ago, that still look great.

Most Airstream owners know that plasticoat on the older coaches is good typically for 3 to 4 years, depending on a number of conditions. They then would be confronted with either replasticoating or polishing the trailer, which in itself becomes a headache, since it must be waxed very often.

If however, someone uses a far out paint design, or poor preparation or materials, then your correct that the value will more than likely decrease.

The latest plasticoat that the factory is using, seems to be holding up far superior to the older material.

However, time, as always, is the real test.

Andy

[Zeppelinium]

Originally Posted by malconium

When the weather improves around here I would be willing to do some more tests. I still have the panels and the temperature guage. I would love to hear from more people about whether or not they feel more tests are in order and what they would like to have tested. Perhaps those of us that are interested in this topic could colaborate a bit and come up with some testing scenarios?

Malcolm

Malcolm,

Wow, I never thought of the "inside of the car" greenhouse effect. Very possible, but it seems that would have heated the top panel, too. I need to think about how we'd design the unassailable experiment.

I think if I use my data logger to watch the temperature profile throughout the day, and build the box you mentioned but connect it tightly to the earth (cut out the bottom of the box and bury the edges a little--good thermal sink, the earth), we could infer quite a bit. Here's a full description:

1. Build said box (box to be insulated with 3/4" foam on all sides and painted white outside) and tie it to the earth-- provide suitable standard hole in top to fit the various panels. Provide temperature sensor in dirt, in the air inside the box, and two more for bottom and top temperatures of the panel. Provide a wind shield around the test site that doesn't shade the box.
2. Provide a "standard plate" that is black and is horizontal, on a pole next to box. Put a sensor on the plate and some small distance under the plate to get air ambient temp.
3. Record and graph the temperatures for 24 hours.
4. Install new panel and repeat.
5. Take a standard reading (24 hrs) on the box with a single sheet of unpolished aluminum to cover the "test hole."

I recognize that day-to-day ambient conditions won't be constant, but by graphing the results (and maybe doing this test for a week, then repeating for all panels) you will quickly see the delta temperatures. I think a lot can be inferred from that.

I will do all the above. Need to have someone else build and provide test panels. I suggest about 16" square--how big were the panels that Andy built? I'd like to see a panel with a rib in the middle. I think we ought to also see what happens if you make the panel sandwich without ribs (use foam and glue on the edges) and with ribs (one side, two sides, four sides) to get an idea of what the thermal conductivity of the ribs is compared to the larger area between the ribs.

Yo! This is a lot of little pesky panels!! I guess you'd only have to do the rib variations on one panel design, say with fiberglass batts as the standard, since that's what the standard AS comes with. We'll need to establish a standard size and thickness (1-1/2", right?) if there is a lot of interest.

[Rivka]

Wow Malcolm, this is great to see these tests!

i plan on doing some version of the foil insulation and was pondering coating the inside of the outer walls for extra barrier. i was thinking if the coating for waterproofing, sound dampening and condensation help. did not really occur to me that it would help heat also, makes sense though.

Please keep this testing up and if you need some help i would be happy to drop by. I live 2 hours north of you and am often down in oregon.

did another thread that was focused on this from the start ever get made? maybe we can get this one renamed? i would never have found it had it not been for a random link i saw and a love of t he color red that made me want to read it! haha

Rivka

[Rivka]

found the other thread, nevermind, thank you

[Zeppelinium]

I still intend to do the test. Seven weeks of summer got eaten up by a proposal, so I'm just now back home. Hmmm, how to generate the heat now that it's actually cold here in Colorado? Darn.

Zep

[Minnie's Mate]

Actually, to answer one of the OP questions, yes Airstream did indeed paint some of their trailers back in the '50's. Wally experimented with pastel or "Easter Egg" Airstreams and some fiberglass Airstreams painted to match the pastel cars being produced by the auto industry at the time...they were not popular and were short lived. I can see why. Why would you buy a trailer destined to last 20-30 years to match a new car you would get rid of in 3-4 years?

[w7toc]

Originally Posted by Inland RV Center, In

The results are in.

Tests #2 on 8-20 2004 noontime.

Ambient temperature about 80 degrees F.

From left to right the aluminum plates are.....

#1 far left. plain aluminum as used by Airstream.

#2 2nd from left. same aluminum, primered and painted white.

#3 3rd from left. same aluminum, primered and painted red.

#4 far right. plain aluminum with about a 1/16 inch thick rubberized sprayed on backing.

The temperatures of each panel as displayed on an infrared thermometer was:

#1 86 degrees
#2 109 degrees
#3 131 degrees
#4 89 degrees

The plates are setting on 2 inch thick fiberglass insulation, duplicating the Airstream construction.

Conclusions.

The best, seems to be leave it alone, again.

Andy

Dear Andy: Your test temperatures are not correct for the highly polished aluminum. The Raynger ST2 is set with a fixed emissivity of 0.95 (http://www.leadfar.com.tw/Product-2004517143525.html). The emissivity of highly polished aluminum is 0.039-0.057 (http://www.electro-optical.com/bb_ra...lemisivty.htm). The bottom line is that the Raynger ST2 is not calibrated to properly measure the temperature of highly polished aluminum. The next issue of highly polished aluminum is that the minute it gets dirty or oxidized it dramatically gets hotter. The good side is that as it gets oxidized its emissivity lowers (0.20-0.31) which means it reduces heat loss in cold temperatures. As to the base question of painting the roof white to reduce thermal load, white paint will lose up to 70 percent of its ability to lower surface temperatures in as little as three months of dirt buildup. The only product in government testing that was able to dramatically reduce temperatures and thermal load when covered with dirt is a technology called ENERCHRON V40 (test reports http://www.enerchron.com/testing_of_ENERCHRON.htm).The testing of thermal flow through building systems costs millions of dollars because of all of the parameters which must be monitored. With today’s high energy costs the last thing you need is for someone saying that you are liable for their utility costs because you were trying to do a nice thing.