o.t. Homemade windshield rain repellant

[AK]

Does anyone have a homemade windshield rain repellant recipe?

I am looking for something equivalent to the RainX that you apply directly to your windshield. And buff it off.

I have been using Turtle Hard Shell wax.

I did a search, but all the recipes use a variation of rubbing alcohol and water.

Thanks, Andy

[Marilyn Manson]

Not homemade, but it doesn't get much easier than this:

I've been using the 2-in-1 for decades. Fill and spray, renew as needed.

[AK]

It does not last as long as the rub in RainX.

Andy

[AK]

I make my own windshied wiper fluid.

1/2 cup ammonia 1 cup rubbing alcohol 1 teaspoon liquid dish detergent Add water to make 1 gallon of window cleaner

[rbowman]

In the summer I use white vinegar. The water here has all the essential minerals you'll ever need. Overspray from lawn sprinklers leaves water spots that ammonia won't touch. There wouldn't be much danger in adding vinegar to your recipe unlike some household cleaner mixtures but you'd wind up with ammonium acetate and pretty much negate both.

[AK]

There must be some things in that overspray besides water.

I use my recipe and it removes water spots.

Andy

[rbowman]

Water in this valley tests out at over 10 grains per gallon, principally calcium carbonate, with other calcium and magnesium compounds. Anything over 5 gpg is considered hard. Removing calcium carbonate (limescale) requires an acid of some sort. Hydrochloric can be used but requires care. The coffee pot descalers use lactic, citric, or sulfamic acid. Phosphoric acid also works. That's the basis for using Coke for rust removal though I suppose it would work on calcium carbonate.

There are many car specific water spot removers, again mostly some sort of acid. If you're really brave you can use wheel acid although some of the brands contain hydrofluoric which is rather nasty. That's what is used for glass etching.

However white vinegar is cheap, effective, and doesn't eat your skin. It's not a coffee maker so a vinegary smell isn't a problem.

I do use ammonia inside where it's effective on removing the scum that's mostly plasticizers cooking out of the trim (the new car smell). Since the jug of ammonia was sitting there that was my first attempt to remove the calcium. No go. I don't drive the car much in the summer so it had had several applications of sprinkler spray that baked on in the heat.

[AK]

I am a retired chemist.

Thanks for the vinegar tip.

And I used to use hydroflouric acid.

Using it in a water spot remover is crazy.

HF acid dissolves glass. :-)

Andy

[rbowman]

No, the HF is used in some of the wheel cleaners. Meguiar's Wheel Brightener, for example contains 5-10% ammonium bifluoride according to the data sheet. There are videos that suggest wheel acid for removing water spots but they often aren't specific which product they used.

The video is about water spots on the finish, not on the windshield. Personally I just wanted to get the scum off the windows and I'm not into detailing. At 8 minutes he gets to the acid. While he doesn't mention a brand he warns not to get it on the glass. He's also wearing gloves and after a little coughing says he should have been wearing a respirator too. Short of compounding, that's the product that really works so you know some people are going to jump right in, ignore the caveats, and wonder why they have cloudy glass.

I prefer to give HF a wide berth. That includes wheel cleaners and those glass etching kits. That's the acid that keeps on giving as the fluoride ions dig in.

[AK]

There may be some legitimate use for dilute HF.

I know that full strength does dissolve glass. That is why full strength is kept in special containers.

I used it for years in breaking down substances containing silicates etc. in order to analyze the amount and type of elements present in my samples.

Andy

[rbowman]

The semiconductor industry uses a lot of it. Oxidize the silicon wafer, apply a etch-resist mask, and etch away the exposed silicon dioxide areas. Japan and South Korea are still fighting WWII which led to Japan cutting off the HF supply.

Samsung immediately stepped up recycling attempts as well as domestic production. Currently TSMC (Taiwan Semiconductor Manufacturing Co.) produces more than 50% of the semiconductors world wide and only they and Samsung have 5nm technology currently.

In a world of sanctions and counter-sanctions there a lot of fragility. TSMC is recycling HF into cryolite which is fine if you're running an aluminum smelter but not very helpful for semicon production.

Interesting times.