On a C4 Cam's nylon attached to the thumb loop, is it safe to write your name on it with a sharpie? I heard Nylon is more prone to chemicals weakening it down. A friend of mine who I climb with writes his name on it heavily and was just wondering. I doubt it'll be enough to compromise it but it seams to really seep into it. I thought it would be best to be asked here at the "Lab" forum because you guys probably know this stuff.
Well, most will tell you no. However, I have marked dozens of ropes with Sharpies and I know countless climbers who use a Sharpie to mark their slings or draws. I have also pull tested slings heavily marked in a verity of different permanent markers and I did not really notice a drop in strength.
The problem is that Sharpie can change the chemicals they use in their markers at any time, which would nullify what testing does exist on Sharpie ink. None the less, I dont suspect we will be reading about any injuries or deaths anytime soon that came as a result of a Sharpie marked sling failing. Climbers have been marking their gear with Sharpies since the beginning of time and to my knowledge, there has never been a recorded instance in which a sling failed as a direct result of having been marked with a Sharpie.