As a lightweight shell, the late lamented TNF DIAD, has a lot going for it. It’s just under 200g, with proper velcro wrist closures, pitzips and a decent hood. It’s biggest weakness is the reversed zips. The main zip has a flap behind it to guard against water ingress. However, water soaks into the material either side of the zip, making it less than ideal.
So, I had a brain wave. Why not impregnate it with some silicone seam sealant? This afternoon I used some SilNet and a thin paint brush to do just that. I painted the main zip, the pocket zip and the pitzips. While I don’t think it’s going to turn the DIAD into a full-on mountain jacket, it will convert it into a good summer waterproof jacket for occasional use. I’ll be taking it to Dartmoor, unless the forecast is bad.
blogpackinglight 
I too had thought about sealing a garment though I thought it could be effective on the inside of a windproof garment like my Fuera Smock. It seems that it’s the seams that allows the ingress of water rather than the face fabric thus prolonging the need to don a waterproof!
It’s easy to do. Next time I might use masking tape either side of the zip for a cleaner line.
Yes, something as a guide to keep it clean. I wonder if you could buy the special tape so you could apply it yourself to the inside of a windproof.
I’m waiting for the long term review on this procedure. Best of luck.
I suspect it’s not as effective as a proper water resistant zip, but even those leak.
http://www.phdesigns.co.uk/techfab.php? YKK Aquaseal zips?
Tricky to retrofit 😉 This is just a bodge to make a jacket more usable.
Amazing that so few (like next to none) manufacturers actually fit waterproof zips.