I’ve heard that dish soaps can dull the fiberglass gel coat finish of an RV, precisely because it’s strong enough to cut grease, so a good car wash product should be used instead to clean RV sidewalls. What are your thoughts on this? —Gary, 2014 Forest River r•pod
I have been using dishwashing detergent to wash cars since 1973 and RVs since 1983. I have had no issue at all. Typically I use Dawn (blue), as it is environmentally friendly and does not contain any of the cleaning beads or particles you sometimes find in detergents. Remember, it was soft enough for the birds and wildlife after the oil spill in Alaska. More important is to use the proper micro towel, horse hair brush or other soft cleaning device.
Crane Composites, the company that makes Filon, Kemlite, and other fiberbglass FRP (fiberglass reinforced plastic) sidewall materials, also recommends a mild detergent and water. Keep in mind, the outermost component in your sidewall is a clear gelcoat that is not affected by the degreasing properties of the detergent as long as it does not have the “grit” of scrubbers in it.
However, I did some research with body shops and other paint experts. Most of them discourage using dish soap on an automotive finish as it can weaken the soft wax that is an aftermarket application. So, if you wax the sidewalls of your rig, could it deteriorate the protective wax covering? Maybe, but not right away. As I mentioned earlier, I have been using it for a long time. I worked in a full-service gas station all through high school and college, and even owned one for 3 years, and washed a ton of cars.
Detergent can dry out rubber and plastic
One other point that came up was detergent can dry out rubber and plastic. I had experienced that, so I have always been careful to treat the seals and any rubber/plastic components with 303 Protectant to reduce UV degradation.
I do find it ironic that the majority of posts and videos that state to NOT use dish detergent are companies that just so happen to sell a car washing product! One of the videos by Summit Racing stated that dish detergent is like liquid sandpaper. It said you can tell the difference between the gritty feeling on your fingers versus the smooth feel of the lubrications in their car wash foam. I was not able to find their product locally. However, I did purchase a car wash foam from the local parts store and I could not tell the difference between Dawn and their product. What I did notice is the Dawn seemed to be more concentrated and I needed less in my bucket to get a desired foam.
So, I go back to Crane Composites and their recommendation of a mild detergent. They even recommend Meguiar’s #56 Boat and RV Wax. So if you use a good wax, I doubt you will see any scratches or degradation in the finish.
Let’s see what our readers use for their rigs. I’m staying with Dawn (a Tony Orlando reference?).
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.
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