How To Put Water Repellent On A Windscreen In Australia
There is no mystery to applying water repellent to a windscreen. Make sure the outside of the glass is spotless and bone dry, put on an even, thin coat and let it cure. Once you have buffed off any residue, the hydrophobic layer will do its job of making rainwater bead and run off the glass, at highway speeds in particular if done right.
Thomas Rourke here. I write from Melbourne and have put in my share of miles in all manner of weather, from a coastal drizzle to the kind of grey that has you wondering if the sun has given up, not to mention the odd downpour. In this guide I will cover what Australian drivers can do for themselves with windscreen water repellent, the cost of it and when to call in a pro, as well as the errors that result in streaky rather than clear glass.
The Way Water Repellent Works
It alters the behaviour of water on exterior glass. With a windscreen rain repellent in place the water does not make a flat, indistinct film but comes away in small droplets as you are driving.
A hydrophobic layer over clean glass is what the treatment provides. It will not stand in for good wiper blades, working washer fluid or sensible driving, but then again it can be of some assistance with your visibility when the weather gets rough as guts. See car window drying best practices for helpful guidance.
Beading Up
Do not be looking for miracles at low speed; the water is going to remain on the windscreen in suburban traffic. You will see the difference more at the sort of pace one keeps on the highway where the air will take the droplets up and out of your line of sight. The same goes for side windows and mirrors, though one product may not give the same results as another on different surfaces. Provided the glass is in order and the wipers are decent, it is worth having.
Preparation Is Key
You will need little more than a bit of preparation for a good DIY job, nothing to do with the packaging. Any old polish, road film or insect remains on the glass and the coating will not bond well, giving a patchy look.
Find yourself a spot out of the direct hot sun and in the shade with some airflow, and make sure the temperature is at least 3°C. There is no point putting the product on in the rain or when there is dust about the car like a minor sandstorm from inland.
Checklist
- For automotive glass you want a water repellent of the proper type.
- Have some fresh water on hand, low in minerals.
- A glass cleaner and clean microfibre cloths.
- A water-spot remover or glass polish if you need it.
- Disposable gloves and adequate lighting.
- A windscreen free of haze, grease and the like.
Hold off on household cleaners with ammonia unless the instructions say they will do no harm to your vehicle; a product that is fine for the bathroom mirror is not necessarily so for the car and can leave behind residues.
Application
Patience is called for even if the process is unremarkable. One is tempted to think more liquid equates to more protection and put on too much, which is a mistake and only means more buffing.
Heed the label on whatever you have bought. Formulations are not all the same and the time required for curing will be dictated by the method of application and the state of the weather.
Apply Thinly And Evenly
Put a little on the applicator, do not drench the glass, and go over the windscreen with horizontal and vertical overlapping strokes to get full coverage in one section at a time. Let it flash or dry as you are told to and then with a microfibre cloth make the surface clear. Change sides of the cloth now and then so as not to be smearing residue around.
Look at the windscreen from all sides. What you cannot see in the garage will be in your face at night from the headlights of an oncoming car. I was reminded of that after heading out in a light rain and finding “looks fine” was not a sufficient way to inspect one’s work.
Drying
If the glass is not properly dry and clean the rain treatment will not last. Oils and grime will get in the way of a consistent bond and any water under the coating will dilute it. Car window drying best practices are not to be treated as a formality. The application is something you will find in the humid of a coastal region or with Melbourne’s unpredictable weather.
Film And Residue Removal
Should the outside of the glass be caked with mud or dust, put the vehicle through a wash first. A cloth on the windscreen should not come into contact with grit that has not been rinsed off; do so and one is liable to put fine scratches on the surface.
Apply your glass cleaner with a cloth and follow up with a dry one to wipe it over. Put in the effort to make the glass uniform and smooth to the touch. Any contamination or an old treatment will show itself in the form of irregular patches of water instead of proper droplets.
Let the windscreen air-dry for a few minutes once you are done cleaning. Do not put the product on when the glass is anything but truly dry, even in the lower corners and under the wiper arms.
Options For The DIYer And The Professional
For the conscientious owner with the time and a clean area to work in, a DIY approach is well suited to the task. But if there is heavy contamination, damage to speak of or recalcitrant mineral deposits on the windscreen, then professional detailing is to be preferred.
A technician will see to the preparation, curing and application of a windscreen coating in a way that gives more even coverage. It is no substitute for new wiper blades and it will not render damaged glass safe.
Which Is The Right Option?
| Option | Best For | Typical Effort | Cost |
|---|---|---|---|
| DIY | Drivers at ease with a bit of buffing and cleaning | 30–60 min or so, prep permitting | Cloths and cleaner aside, this is generally the cheaper way to go |
| Professional | Where the glass is badly contaminated and consistency is wanted | 1–3 hours if any correction is in order | More labour is saved but the upfront cost is higher |
| Basic cleaning | For residue without the need of a coating | 15–30 minutes | No hydrophobic protection but least expensive |
In Australia one can expect to pay in the region of $15–$40 for a consumer grade water repellent, whereas a professional may charge anywhere from $80 to $250 for the treatment. These are working estimates as much as fixed tariffs; they will be influenced by the type of product, location and condition of the glass, to say nothing of any polishing.
The tendency is to compare on the price of the bottle alone which is a mistake. One has to ask if the glass requires some correcting beforehand. An expensive treatment on glass that has been properly readied will give better results than a cheap one put on top of oily or mineral stained surfaces.
Selecting A Product
Do not assume the strongest or priciest water repellent is the answer. There are products out there that are simply a spray for glass and others touting themselves as nanotechnology systems, the marketing of which can be overblown. What is required is clear guidance on how to apply and cure the product and remove residue, and a finish free of haze or glare that can stand up to Australian conditions. Make sure it is marked for automotive glass.
What The Label Will Tell You
See if the treatment is fit for laminated windscreens, mirrors and side windows. Note the minimum temperature for application and its durability and if it must be taken off prior to using certain washer fluids.
Shun any product that would have you believe wipers are no longer necessary. In slow traffic an effective hydrophobic coating has its limits, and road grime puts in an appearance fast enough.
How Long It Will Last
There is no set schedule for every vehicle in Australia. Durability is a function of the product, the climate, one’s washing and wiper habits and how the glass was prepared. Salt air, bushfire smoke and hard rain will cut into the life of the treatment, as will an automatic car wash or worn wipers.
When To Reapply
Pay attention to the water. If the windscreen is calling for more from the wipers, or night driving is marred by increased glare, the treatment could be on the wane. Clean the glass and if it appears cloudy, put down the product and look into it before putting another coat on. Old residue should be eliminated as best you can; a fresh layer on top of a failing one will be patchy.
Wiper Blades And Fluid
Even a treated windscreen calls for wiper blades in good order. Hardened or split blades will smear the water and make a fine treatment seem like it is not doing its job.
The reservoir should be filled with the sort of washer fluid made for vehicles. In a pinch one can put in plain water, but it will not have the cleaning and anti-freeze qualities of the real thing under every condition.
Keeping The View Clear
A damp cloth will do to see to the rubber wiper edges from time to time; put in new blades if they are chattering or putting down bands. And resist the temptation to put household detergent in the washer tank: on treated glass it is prone to foaming and leaving residue.
Should the windscreen get hard to see through, put some distance between you and the car in front and ease off the speed. One does not want to make an issue of driving safety over a coating, especially in a storm or when you are on an unknown part of the Stuart Highway or near a road train.
Common Errors And Safety
Water repellent is to assist your visibility, not give you leave to put on speed in bad weather. Be it heavy rain, a flooded road or the spray of a truck, any treatment has its limits so allow more room and modulate your speed.
In Victoria there is driver safety guidance from VicRoads for wet-weather driving. For the rest of Australia the local road authority is the place to look, in the event of severe weather, cyclone warnings or bushfire closures.
- Do not put the product on a windscreen that is hot, dusty or wet.
- A coating is no fix for chips and cracks.
- See that the final buffing is done with a clean cloth.
- Make sure there is no heavy residue in the way of the driver’s view.
- It is not the time to try out the treatment for the first time on a long night drive.
- An empty reservoir or substandard wipers should not be overlooked.
When you are applying the treatment the vehicle needs to be in a safe parking spot. A garage or driveway is preferable to the shoulder of the road, unless circumstances dictate otherwise and it is safe to do so.
Frequently Asked Questions
Drivers wanting better visibility without making of their windscreen a chemistry experiment put these questions to me. The answers are straightforward enough, though for the specifics of application the label is what counts.
What Can You Put On Your Windshield To Repel Water?
Nothing but an automotive or windscreen rain repellent designed for the purpose. Cooking oils and furniture polish or other household items are not to be used; they will cause smears and glare that are hazardous.
How Do You Apply Windshield Water Repellent?
After the exterior glass is dry and clean, put on a thin layer with overlapping strokes and let it haze up or cure per the instructions before using a microfibre cloth to buff. Best done in the shade and away from the elements.
What Is The Best Water Repellent For Windscreens?
One that is suited to where you are and has good instructions. Marketing is no substitute for properly prepared glass.
Is Water Repellent Good For Windshields?
Properly applied it will help with beading and seeing in the rain. It will not make heavy rain any less of a risk, nor is it a replacement for wiper blades. Consider it part of sensible maintenance.
How Much Does Professional Treatment Cost?
In Australia a professional job will run you $80 to $250 or so, a matter of the vehicle and where you are and how much prep is needed. Get a quote that covers decontamination, polishing and aftercare.
Clear Glass, Safer Driving
If the glass is in order, a water repellent is an easy DIY affair. Do not skimp on the preparation, use sparingly and have a good look at your work in proper light before the next downpour.
For a day’s work it makes sense to put your efforts into the windscreen, wipers and washer fluid as opposed to the side windows or mirrors. You will be well provided for in ordinary Australian driving, be it in Melbourne, the Top End in the wet or on the Gibb River Road.