Hey guys, I did a "search" and got 88 results, none of which seemed to have anything to do with my question, so, I'm wondering if it's safe to use Rain-X on our face shields. I went to their web site, but didn't find an answer, so I was wondering if some brave soul here, has tried it, and how it worked. I know that it does beautifully for car windshields, but I'm hesitant to try it on my face shield. Thanks in advance!
Dislaimer: I make Raincoat and Fogtech, so I have a dog in this hunt.
But I have studied this quite a bit, so bear with me.
Your question really has two parts. First, is RainX safe to use on face shields and wind shields? Second, does RainX repel water off plastic face shields and wind shields and make my vision better?
First question:
RainX has a small percentage of alcohol in it. Alcohols are generally safe to use on polycarbonate (PC) plastics. Our face shields and some windshields are made of polycarbonate and on those you can safely use RainX without fear of checking or haziness. Won't happen on PC.
But most motorcycle windshields are made of acrylic plastic (Plexiglas). And alcohols can leach out the plasticizers in acyrlics and that causes microcracks to appear as haziness. This does not happen immediately but can occur overtime.
Second question:
I have tested RainX on my visor and on other plastics and have found little effect on water beading. I know there are those who swear by it (even on this thread) but other than a very short effect, there is little benefit to applying RainX. And this makes sense. RainX is designed to work on glass. The chemistry at the molecular level is very different between glass and plastics. RainX works very well on glass and lasts for months.
So to settle this, I contacted a very reputable company Rame-Hart who makes instruments to measure water beading (costing about $30K!!). Just by luck the top guy there started riding again. So he tested the effects of many common approaches riders have used to repel water off their shields. These include RainX, Lemon Pledge, Plexus, Raincoat and others.
His conclusion is that RainX does nothing and Raincoat kicks serious butt. Click on the table to get the full article.
Another suggestion was to try a product called Raincoat®, made by MotoSolutions. We obtained a sample of the paste version as well as a spray-on version from the manufacturer and replicated the testing we did last month with (6) other surface treatment products.
We were surprised to see an an increase in contact angle (BA Delta) of over 21° after applying the paste treatment to an untreated Lexan surface. The spray version of the coating improved the contact angle by nearly 25°. After the 5-minute rinse, the paste coating actually improved slightly while the spray-on coating lost some of its hydrophobicity. See BR Delta in the chart below which is the difference between the original contact angle and then the contact angle after treatment and rinse. Overall, the Raincoat® performed better than any of the previously tested products.