Psst!! Cm’ere! Want to learn how to properly waterproof anything? Obviously not anything – you can’t waterproof dust, or air, or things like that, but cycling coats, cycling shoes, panniers, tarps, tents, or even jeans? Those you certainly can waterproof! So, you ready to learn how? And if you didn’t believe me about the jeans, scroll down to the video at the bottom.
First of all, let’s have a blitz-tour of waterproofing, as not everyone means the same thing when they say something is waterproof. For the purposes of this post, waterproof will mean something that simply will not let water through. At all.
Breathable, or not?
With rain coats (which you certainly want to be waterproof!) you basically have two choices. Breathable fabrics, work with varying degrees of success, but – excepting Gore-Tex – usually won’t keep you dry for long. Your other option is non-breathable fabrics, for that freshly boiled-in-the-bag feeling.
When buying a rain coat, you’ll need to decide for yourself which option you’d prefer. My choice is for coats made from non-breathable fabric, but with vents I can open of hot rainy days. If you’re going to do a long ride in the rain, just accept that you’ll get wet, and that the best you can do is delay that somewhat. But what about your panniers?
Panniers, or bikepacking bags, obviously are used to store all your kit, and if your panniers let water through, chances are you’ll end up with your kit getting wet inside the panniers. And if your sleeping bag gets wet, you’re in for a grim and unpleasant night! There are steps you can take to help prevent that, and that starts with the panniers themselves – you can spend a fortune on Ortlieb panniers, which are claimed to be so waterproof that you can use them as buckets, to carry water around. If you didn’t quite feel like selling a kidney to pay for Ortlieb panniers, you can use cheaper, but really good panniers, even ones that don’t even pretend to be waterproof, and use dry-bags inside them, or (as I do) use rubble bags.
Get it treated!
Finally, we get to the only option left if your existing kit isn’t completely waterproof: you can apply a treatment. There are various aftermarket treatments available. Some you add to the washing machine, and it treats the kit while washing (no idea what that ends up doing to the washing machine itself, though) and some treatments require kit be tumble-dried afterwards, while others don’t. Some treatments claim to “re-waterproof” breathable fabrics, but again with the exception of Goretex, I’m exceedingly sceptical of such claims.
As my choice in rain coats would hint at, my preference is for a treatment that is totally waterproof, or as near to that as you can get, and with that in mind, my go-to waterproofing treatment has been Fabsil for a long time. Fabsil is a treatment for tents that are no longer waterproof, and I’ve treated plenty of other things with it, including a rain coat, my old panniers, and indeed my tent. Until very recently, if you asked my advice about waterproofing anything, Fabsil would have been my answer. But not anymore!
The new treatment
Nope, there’s a new king in town. Oddly enough, you’re very familiar with it: clear silicon sealant. Yes, that you buy at any DIY store. Now silicon sealant is a jelly, and is extremely flexible, and hydrophobic. Simply put, you cannot wet silicon sealant. Even if you submerge it for a year, the moment you bring it out of the water, it’s dry again. In theory, you could smear silicon sealant over whatever you want to waterproof, but that would be a silly idea. You see, the silicon would (at first) cling to the surface, but would eventually be scraped off through normal wear, and you’d struggle to make whatever you’re coating with it look anything other than a mess. So what’s the secret then?
Simple: you need to dissolve the silicon, using a solvent. There are various solvents you can use, but I use common old white spirit, again available from any DIY shop. Do note, you want clear silicon, and not the stuff with added fungicide – we want it as pure as possible.
It’s all in the mix
From the outset, a very big warning: silicon gives off strong vapours, as does white spirit. White spirit is a petroleum product, and is flammable, too, so these are things you need to handle with care. If you’re going to handle these materials, do so entirely at your own risk, and do so in a very well-ventilated area (ideally outside!) With the Health & Safety warnings out of the way, let’s proceed.
You will want a clean bucket that can comfortably contain the volume of white spirit you’ll be working with. Also ensure that whatever you’re planning on treating is clean and dry. Any dirt will be sealed in!
Generally, use 1 part silicone to around 5 parts white spirit. I had a tube containing just over 200 ml silicone, and I squeezed all that out into my bucket, before adding a litre of white spirit. The first thing you’ll notice is that the silicone doesn’t seem to dissolve. You’ll have to speed that along by stirring the mixture, and keep stirring, until the silicone’s all dissolved. The mixture will noticeably start getting thicker, as the silicone dissolves into it.
Paintbrush at the ready
You will need a normal paintbrush – the type you use for painting and decorating around the home – as well as a coat hanger (if waterproofing a coat). Put the coat on the coat hanger, and hang it outside, where you can easily access both the front and the back of the coat.
Next, simply dip the paintbrush into the mixture, then start painting it all over your coat. Pay particular attention to any seams, and work systematically, ensuring you cover every square centimetre of the coat with the mixture. Don’t worry about over-applying – more is better, in this case.
When finally done, simply leave the coat to dry. Silicone requires at least 24 hours to fully cure, and I suspect the white spirit delays that further. If you wanted to give a coat multiple coatings, leave at least 24 hours between each coating.
The result
As you can see in the video below, I coated some old jeans I had. Once the treatment dried, the patch I coated is slightly darker. Also, compared to the untreated denim, it feels slightly stiffer. Beyond that, it looks, and feels, just like ordinary denim. However, that patch I treated is now fully waterproof, and you simply cannot wet it at all.
I also treated two cycling coats – an old rain coat that became less successful at keeping the rain out, and a coat that was never waterproof. I expect both to now be reliable rain coats.
So, what are you waiting for? Don’t you have stuff to go waterproof?