At the crag this weekend I noticed that my climbing partner's carabiner had a great feature: a red line painted such that you know the carabiner isn't locked until the red is hidden.

Awesome Locking Carabiner

I love this feature. Unfortunately, I already own dozens of carabiners without this wonderful red line.

How can I safely paint a red line onto my carabiners? Red nailpolish? Metal markers? What is permanent? Is there a community standard?

(I would also like to be able to write a date on all my carabiners, so I know how old they are. So this would be doubly useful information.)

  • 1
    So did you have any success with marking the gates of your carabiners? Did it last?
    – montane
    Commented Aug 28, 2014 at 15:56
  • I tested nail polish on a carabiner I use for my car keys and yeah, everything gets rubbed off pretty fast. Useless to bother. I have marked non-gate parts of my carabiners with nailpolish and electrical tape just to ID them as mine, and that worked fine (I prefer colored electrical tape). Commented Aug 28, 2014 at 16:03
  • Did you ever find a method that worked?
    – endolith
    Commented Jul 2, 2018 at 14:47
  • 1
    @endolith I never did find a method that worked. The various things I tried rubbed off after a couple trips to the crag. And the only other options I could think of seemed like they could gunk up my biners, so I didn't try them. I do not yet have a solution: I just wish all carabiner makers would anodize from the start. Commented Jul 2, 2018 at 16:39

4 Answers 4


The method by which carabiners in any color are coated (either gate or body) is anodizing, which is going to be nearly impossible to sufficiently replicate with anything practical and cost-effective at home. With anodizing, the coating essentially becomes part of the aluminum itself. So anything you put on the gate will wear off relatively quickly and potentially cause the screw-gate to jam up. Nothing you paint on a carabiner or its gate will be permanent. Even the anodizing eventually wears off, unless of course you never use them.

Don't use the "metal markers", aka paint pens. The coat of paint they apply would definitely be too thick for a carabiner gate, and while quite tough, it's also less durable than fingernail polish.

That said, fingernail polish, as others have mentioned, is worth a shot. Carefully put a very light, thin coat on only the gate itself and not any crevices or threads. Before you apply it, make sure you clean everything well so the polish adheres with a green Scotch-brite pad, or similar pad (not the non-scratch kind). Aluminum oxidizes over time and will prevent the fingernail polish from sticking, so if you don't clean it, the polish will flake/rub off rather quickly for sure.

Whatever you do, do a test on just one carabiner first to make sure that the marking has adhered and also that the gate still functions as intended.

For what it's worth, I've never known anyone that has painted/marked the gates of carabiners. Spines are usually where any markings or taping end up. So any community standard that exists would be for identification purposes, either to determine ownership or if a piece has been retired to non-critical purposes (doesn't need to keep you alive).

Here is an example of even hard anodizing wearing off. You can't see it so much in this photo, but the under/inner side is even more worn than the outside. worn carabiner

  • 9
    "Aluminum oxidizes over time". Actually, it oxidizes essentially instantly. Aluminium is an extremely reactive metal and oxidizes as soon as the surface is scratched. You have never touched aluminium: any time you touch an object made from aluminium, you're actually touching the oxide layer on the surface. You've seen the thermite reaction, right? That's how keen aluminium is to oxidize. Commented Aug 26, 2014 at 16:37

Unfortunately nail polish would probably gunk up the locking mechanism. I wouldn't put nail polish on any moving piece of a carabiner.

You can use nail polish to mark your gear so you know that it's yours (and not your partner's). You may be able to find a multi-color scheme that indicates the carabiner's date, but generally that's not an issue (if it looks worn out, replace it). Carabiners last a long time.

  • That is an interesting point. You didn't exactly answer my question though. Is there something that would work? Commented Feb 7, 2013 at 2:46
  • 2
    I would not worry about nail polish disturbing the mechanism if used as pictured, especially on a screw-gate. A nail polish layer will be very thin as long as you don't gob it on all over the place, and snapping the carabiner shut a few times will take care of any bumps in the polish. Commented Feb 7, 2013 at 4:51
  • 4
    Nail polish tends to chip off rather than gum up. That's why it's used so often for mechanical marking. Commented Feb 7, 2013 at 15:39
  • It might be nice to link this answer to the nail polish answer with a comment.
    – DudeOnRock
    Commented Feb 7, 2013 at 17:06

Nail polish is the way to go. Everyone I know, including myself, uses it to identify whose gear is whose.

  • 4
    Nail polish is super common to mark who's gear is who's, but in this case, the question was about replicating the red paint in the pictured carabiner. This is not all that common, I got confused originally too.
    – DavidR
    Commented Feb 7, 2013 at 1:14
  • Yes, and nail polish will work for that. Commented Feb 7, 2013 at 4:49

Red sharpie works without interfering with the gate but is very short lived and must be recoated frequently.It is is a pretty quick touch up. Alcohol will remove it if desired.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.