Feel the inside of the fabric behind the dark spots. Does it feel wet? If so (and you’re sure it’s not just sweat), it may be that the water is soaking and your jacket or pants need a new application of DWR.
Note on wetting after heavy rain: Even new, hard jackets can get wet after prolonged, very heavy rain. So if you see dark, wet spots after a long time in a storm, it doesn’t mandatory means you need new DWR coverage. Do a little detective work to find out for sure. Once you take the garment home and it has a chance to dry, spray it with a spray bottle filled with water to see if the moisture has risen. If it gets wet again, it’s time for more DWR.
Clean the clothes first
Wash your clothes before waterproofing them again to remove body fat and old dirt. This will help the new DWR coating adhere better to the fabric. Buy a cleaning product made specifically for outdoor technical clothing, such as Nikwax Tech Wash, although you can use a small amount of ordinary laundry detergent instead.
You will want to wash them separately from your usual clothes, which are not outdoors. You are then ready to apply the DWR treatment. Here you have two options: spraying or washing.
How to apply DWR spray-on
Gear Aid ReviveX spray, Grangers Performance Repel Plus spray and Nikwax TX.Direct Spray are available for spraying options.
Whatever you choose, take it outside to apply – it’s not good to inhale these things. Just hang your garment on an outdoor hanger, zip up the front and close the pockets and spray the outside of the jacket or pants.
One spray is enough to re-waterproof a garment – which means a jacket and a pair of pants. In my experience, however, there is barely enough, so don’t waste it by spraying a certain spot on your clothes for too long. If you have any left after you finish, apply it to areas that see a lot of abrasions, such as the shoulders, armpits, and crotch / upper thigh area.
How to apply Wash-In DWR
You will usually want to use DWR treatment when washing or in a washing machine with top or front loading, set to hot water, gentle cycle, but consult the bottle of the product you are using. Your best options are Gear Aid ReviveX Wash-In, Grangers Repel Wash-In and Nikwax TX.Direct Wash-In.
If you do not have a washing machine on hand, you can apply the product by hand with a sink or bucket of warm water and a few gloves. Some DWR treatments instruct you to follow by tossing clothes in a low-heat cycle dryer to seal the coating. Just first check the bottle instructions with the things you use.
How long will it last
Re-administration of DWR does not last as long as the factory-applied treatment. There’s no way around it: you’ll just have to get used to checking your rain gear before traveling and re-applying DWR if necessary. Areas with a strong impact, such as the shoulders and armpits, are exposed to more abrasion and these areas tend to lose their waterproof coating earlier than others.
DWR treatments have long used long-chain perfluorocarbons (PFCs), which create toxic by-products during production and spread to the environment when the product wears out. The DWR treatments we recommend – ReviveX, Grangers and Nikwax – use carbon-free formulas. Although you may object to the idea of introducing more synthetic chemicals into your outfit, these treatments extend the life of your clothes several times, creating less waste over time.
The more you use the garment, the faster the DWR coating will wear out. But there is no limit to how many times you can re-apply DWR. As long as the clothing is in good shape, you can continue to waterproof it over and over again for years and save yourself from having to change your raincoat for a few hundred dollars.
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