Ice based time-lock. New design!

IMG_9877IMPORTANT UPDATE!! (2009-01-13 @ 13:59:03) Do not double the rope/cord! The rope can be jammed because of  twisting and entangling. Use just one run of cord.  ~30-35 (the “working” free end) should be enough.

I will update the manual ASAP.

Just published the description of my new DIY ice padlock. Opinions?

11 thoughts on “Ice based time-lock. New design!”

  1. Nice design. Works, even 😉
    A word of caution: over-filling it with water will result in a broken end cap, not nice.
    Built myself one from 4 cm of 32mm pipe, a double socket, one screw cap (rope side) and one glue cap (SRD side). Left out the metal bridge to improve looks. Because of the smaller rings I used the SRD does not work too well with all types of rope, but it works great with straps.
    I insulated the inner side of the metal parts with polyurethane compound (not the foam type) and found that only the PVC outer surface is cool but not cold to the touch. Without any outside insulation it still took well over two hours to melt. Have to try on some 28mm foam insulation (that will fit) to increase the time, but the resulting time may be too long to be practical….

  2. Hi p-wee,

    The overfilling was not a problem in my case. The lock did not break.

    Do you have any photos? You can post them in the forum (there is an upload button).

    How long did it take the ice to melt down? I’ve just build a 32mm ice-lock, but haven’t tried it yet.

  3. The SRD end of the lock should definitely be welded/glued to the main tube. Screw type cap not necessary. A simple end cap with the rings attached as described should be sufficient.

    Foam pipe insulation could be used instead of rubber if desired. Tool (handle) dip might also be a possibility — covering just up to the base of the threads for the screw cap. You wouldn’t want it to remain on the SRD assembly. Perhaps it could be scraped away later.

    A small gauge steel cable with preformed loop (tiny bicycle lock cable) might work in lieu of the rope/clasp combination for the release end. The trick would be to get the cable to coil somewhat inside the tube without it kinking.

  4. Hi Ra! This is anothre project on my ‘to do’ list (and another one of those pleasure to preperation ratio’s that might look more 10/90!!!)

    Two questions:

    1) for those of use with less than 3hrs pleasure time (or live in cooler parts of the world) is there a simple formula to reduce the time? can I simply add less water or won’t the mechanism work?


    2) the very obvious question – how did you find out about no doubling the rope? Was there one of those dreadful ‘Oh no! I’m really stuck’ moments?


  5. is there a simple formula to reduce the time?

    – less size
    This is obvious and most effective

    – less water
    Also effective, however some part of the cord could be immediately pulled out, the rest will stuck in the ice.

    – shorter cord
    Mmmm… not sure, to be honest…

    how did you find out about no doubling the rope?

    Fortunately (thanks God!) I did not stuck. During the last busines strip I tried to freeze the lock outside on the balcony, but the temperature was not low enough.
    However, when I tried to pull the rope out, it did not go. I discovered that sometimes one rope can twist a bit and be jammed by the second rope, while the small hole acts as the “jammer”.

    Two possible solutions:

    – one run of the cord instead of two
    Just like in the announcement

    – wider hole
    This one is less preferred because the idea of this design is to spill as less water as possible.

  6. Wow, glad you didn’t get stuck. I made two pipes like this, but made my own minor modifications to it, the bid one being only one rope cord being pulled out of the end. After many tests of the it’s never jammed, and have used it in two successful sessions (Obviously if I’m typing this) I haven’t insulated mine, and keeps me locked up for 2 – 3 hours.
    I didn’t bother with the SRD device, instead I put an eyelet on the sealed end (only one end of my pipe unscrews, less chance of a leak IMO) and I snap on one of my rope ratchets to it to pull myself tight.

  7. Wow, glad you didn’t get stuck.

    You know what? I still have goose bumps and cold shiver …

    the bid one being only one rope cord being pulled out of the end.

    Is it what I suggested? Use only one run of rope? Or I’m confusing something?

    After many tests of the it’s never jammed


    I haven’t insulated mine

    There were two reasons for insulation:

    1- to be able to keep it against my body (the most important reason)

    2- to keep the amount of water as little as possible (to prevent excessive leakage)

    only one end of my pipe unscrews, less chance of a leak IMO


    BTW, could you please make a couple of photos of your construction and upload them somewhere? For example, in the Forum?


  8. I think the ice padlock is a great idea.
    However it is difficult for me to find the parts. Anyone how knows the name of the plastic parts (except the tube, of course) or even better a link to screw type caps (UK based).

  9. Arrghhh! Bad day in the office – why can’t I find the detailed description about how to make this device?

    Links seem to lead me to general pages not specifics



  10. This is a great device, just don’t make the pipe too long or you’ll be locked up for a long time 🙂

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