I've had a set of Bosch flexible wiper blades on my car for a little over a year now, and they've always worked great. Recently, I washed my car, wiped down the blades, and applied Rain-ex to the windshield. I have also been using the Rain-ex windshield washer fluid.

When I next used my windshield wipers, they were clattering and slipping like crazy across the glass, to the point where I was afraid they would damage my car! I tried wiping the blades down with some isopropyl alcohol, which left heavy black streaks on the cloth, but it didn't seem to resolve the clattering.

Is it possible that the Rain-ex has (chemically) damaged the blades? I've used Rain-ex before on my windshield, and I've never had this problem. I am fairly sure (but not 100%) that I followed Rain-ex's product instructions - which involves wiping and polishing the windshield to remove any residue after application. I imagine that Rain-ex contains a number of solvents, and that letting the wipers touch the Rain-ex before it dries could damage the rubber. Could this be my problem?

I've read through a number of other forums, most of which seem to degenerate into the "Rain-ex will ruin your car and make you sterile" people versus the "I never have any problems, you must be doing something wrong" people. Until today, I would have been one of the latter.

Is it possible that the problem is simply a matter of being absolutely, 100% sure not to allow any liquid Rain-ex to come into contact with your wiper blades?

I was able to find a list of the ingredients in Rain-ex original formula. My wiper blades are made from a proprietary rubber blend called "FX dual rubber compound".

It's also worth mentioning that the Bosch blades are the new flexible kind, so they do not have the rigid metal backing that would push them firmly against the glass.

  • 3
    How is this opinion based? It's a matter of chemistry.
    – alexw
    Aug 13 '16 at 23:42
  • 1
    @alexw As an aside, not really related to your question, but FYI another good way to find the list of ingredients in things is to search for their MSDS, e.g. rainx.com.au/msds. Also, I wonder what FX dual rubber is, they're very secretive about it.
    – Jason C
    Aug 14 '16 at 0:19
  • 1
    I sent an email to Bosch maybe they'll tell us what kind of rubber it is. I see that most of the rain-x products are acetone and various alcohols. mossrubber.com/pdfs/Chem_Res.pdf may also be of use. Urethane rubbers don't look too great in the alcohol category, but even without looking at that chart I'd put acetone as the primary risk. Silicone isn't uncommon for wiper blades and it definitely doesn't fare well with acetone (I mean, you use acetone to clean up silicone caulk, and also, mykin.com/rubber-chemical-resistance-chart). But we need to know what FX dual rubber is.
    – Jason C
    Aug 14 '16 at 3:11
  • 1
    The windshield wiper fluid additive looks pretty harmless, though. Also, we can only really conjecture anyways, because unless somebody did a study about this, it'll be hard for us to answer the real question here which is: Even if rain-ex contains a solvent that isn't compatible with icon wiper blade rubber, is the pattern of the blade's exposure to a windshield coating really enough to damage the blade?
    – Jason C
    Aug 14 '16 at 3:16
  • 1
    So you're saying, time to buy new blades ;-)
    – alexw
    Aug 16 '16 at 14:27

Drawing from years of experience with many glass treatments, if anything, RainX increases the wiper blade life when used properly. This could either be due reduced use of the wipers or the added lubrication between glass and blade.

You say:

I've had a set of Bosch flexible wiper blades on my car for a little over a year now, and they've always worked great. Recently, I washed my car, wiped down the blades, and applied Rain-ex to the windshield. I have also been using the Rain-ex windshield washer fluid.

About one year of use from a set of wiper blades is acceptable (depending on the environment), I think its the end of their effective life.

I'm not sure if how a 1 year old wiper blade would react if it were exposed to liquid RainX but it is a valid theory that this sent them on their way.


Rain-X, like any chemical that sticks around, has a residual film which can attract dust and debris. When you used your wipers on this chemical it allowed everything that has been accumulating on your wiper blades to clump up and cause poor performance. The alcohol you cleaned them with dried the rubber up severely, so it may be too late for those blades now.

Only one trick I've ever learned can restore a blade once it gets dried out (as long as it's not not dry-rotted). Use some car wax (preferably a hydrophobic polymer blend synthetic wax) and wax the windshield same as you would the car. Once the wax dries, buff it off and immediately turn your wipers on so the finest layer of the remaining wax will coat the blades and smooth them out. It also doesn't hurt to spray a little water on there while they're wiping. Rubbing a small amount of non-greasy leather conditioner on the blades couldn't hurt either.

In normal circumstances, you only need to wet an old wash rag and, lifting each blade up, grab and squeeze just the rubber blade itself and swipe all the way across it. Look at the rag now. It most likely left a black streak on it. If so, repeat with a clean portion of the rag until it wipes clean.

In my experience, the quality of the blades depends on the quality of the rubber or Teflon from which they are made. A softer material removes water better but catches debris better too. Repeat that cleansing trick every few months to keep them working like new.

Tip: If you do end up having to replace them this time, try to find TRICO NEOFORMS. They're the only ones I've ever dealt with that will hold up to literally anything, because instead of traditional rubber they use patented Dupont brand Teflon. I personally haven't found any blade that will outperform or outlast them - even the more expensive can't compete.

They're around the same price as you're BOSCH Icons were. You'll also notice that waxing your windshield works better at beading rain away than Rain-X ever could. The Rain-X anti-fog formula is the only one I'd even consider using, and only because it goes on the inside of the windows.

  • Since the OP has already tried to clean the blades, are you saying they need further cleaning?
    – Zaid
    Aug 14 '16 at 10:51
  • 1
    Yes, If they wasn't cleaned fully or properly. I've worked in a few parts stores in the past and was required to learn all the differences between wiper blades and I've tried them all so I have my preferences of course, but I further learned that most people are ready to change them out after only a few months and I would inspect the blades and wouldn't be dry rotted or anything so I cleaned them very well and worked like new every time. Any wiper blade that costs more than $15 or $ 20 per blade should last at least 3 yrs, but will need to be cleaned about every 6 months.
    – TRIGGA
    Aug 14 '16 at 11:41
  • But alcohol shouldn't dry out e.g. silicone wiper blades, right? Silicone is extremely chemically resistant to all types of alcohol. If we knew what the Bosch blades were though, we could say for sure.
    – Jason C
    Aug 14 '16 at 16:34
  • I've used alcohol to clean my blades before, without any problems.
    – alexw
    Aug 19 '16 at 20:04

Your windshield was not cleaned properly before applying the Rain-X Original. Your wipers are perfectly fine, there’s lingering dirt and grime on your windshield, it’s hardly ever the wipers unless they’re torn. The RainX in the tall spray bottle is crap, you want the RainX in the little 3.5oz cardboard box. It’s just better somehow. Now You need to deep clean your windshield to remove all dirt and debris that glass cleaner won’t remove. You need RainX Xtreme clean and a pack of new microfiber towels. Walmart sells all this for really cheap. You really need to scrub at the window for awhile until the glass feels slick and smooth when rubbing the XtremeClean on the glass. The glass should not feel rough in spots, if it does, scrub more. Deep clean with Xtreme clean and then spray SprayWay glass cleaner on it and clean the windshield. Do tiny bursts with the glass cleaner on the windshield and use a new dry towel to buff until streak less. You can stop here if you don’t want any hazing when the wipers swoosh back and fourth. Then get the rain x and a microfiber APPLICATOR PAD (the pad is important) and wipe the rain x on in HORIZONTAL MOTIONS, do not move the pad up or down when wiping or it will make the wipers streak if you apply in up and down motions. Wipe horizontally one way, then bring it back, pick up the pad, move down, rinse and repeat. Your wipers will not streak or chatter this way. Then let it haze slightly and pour water from the top of the windshield and let it drip down, then get a new microfiber and do the same horizontal motion like you did to apply the rain x to remove the water and the rain x. Presto! You’re done! Thank me later :)

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