How to Build an Airsoft Trip Mine.





Introduction: How to Build an Airsoft Trip Mine.

About: Avid Geocacher and fan of all things iBles.

The airsoft land mine that I bought was a pitiful waste of $50. The self proclaimed "loud boom followed by a large blast of powder" was a tiny pop and half inch high puff. Enemies didn't even notice that they triggered it. Frustrated, I built a better, more powerful mine. It's easy to replicate and simple to use. It shoots BBs twenty-eight (28) feet and powder six (6).

Step 1: Materials.

This project is fairly inexpensive, depending on the materials you already have. I only had to buy the springs.

You will need:
  • 1 inch diameter pipe.
  • 3/4 inch diameter wooden dowel.
  • 3/4 inch diameter washer.
  • 3/4 inch diameter spring (ID # C-756).
  • Screws, 1/4 inch diameter.
  • Fishing line.
  • Smaller dowel.
  • Small metal dowel.
  • Suitable safety pin wire.

Step 2: Cut to Length.

Cut your pipe to lengths of 61/4 inches, or about 21/2 inches longer than your spring. Cut your 3/4 inch diameter wooden dowel into 3/4 inch length plugs. You will use two of these plugs.

Step 3: Build the Mechanism.

This is the heart of the trip mine. The device acts like a piston, the spring is compressed and held in place by the pin. When released it springs back, inertia causing the contents to fly out.

First you need to drill a 1/8 inch guide hole through the center of both your plugs. Use a clamp to hold the plug in place. Now for the tricky part. Place your 3/4 inch washer over the base of your spring and line it up with the plug, try to make it as flush as possible. Tightly screw the washer and spring in place, you can do this through the side of the spring. Repeat this for both ends of your spring.

Step 4: Safety Pin Hole and Securing the Mechanism.

Stand the pipe upright and drop your mechanism inside. Push down the mechanism as far as possible with your smaller dowel (the plunger). Keep your thumb on the dowel where it meets the end of the pipe. Remove the plunger, keeping your thumb on the spot, and place alongside the pipe. Mark where the end of the plunger is, this is where the compressed mechanism will end. Remove the mechanism from the pipe so it does not get in the way of the drill bit. Drill a hole with a diameter equal to the safety pin through both sides of the pipe, slightly above your mark. This will account for any error.
. Reinsert the mechanism, making sure it slides smoothly. Make sure that the base plug is flush with the bottom of the pipe. Drill a guide hole through both sides of the pipe and plug, roughly 3/16 inch from the bottom. Secure the mechanism with a screw on both sides of the pipe.

Step 5: Finishing Touches.

Search the house for an appropriate safety pin. I was lucky enough to find these beauties. Cut the pin to length with wire cutters. It should pass through the pipe with about 1/4 inch to spare.

Epoxy a 71/2 inch metal dowel slightly below the pin hole. This serves as a stake, allowing the trip mine to be secured to the ground.

Use another small wooden dowel for the tripwire's stake. Whittle one end to a point and split the other end. The tripwire will be fastened to the split. Tie the other end of the tripwire to the safety pin.

You can spray paint the trip mine to blend in with it's surroundings. I did a base coat of black and misted light green over it. The prototype is a base paint of green with a mist of black. I used some ghillie left over from my ghillie suit to further camouflage it. You can also attach local flora with a black rubber band.

Step 6: Operation.

As I said, this is basically a piston. It uses inertia to fling it's contents out of the pipe. Plant the trip mine at roughly a forty-five degree angle. String out the tripwire and plant the stake on the opposite side of the path. Push the mechanism down with the plunger and insert the pin. Make sure as little of the pin as possible is holding the plug in place. Then pour the appropriate amount of BBs and powder into the trip mine.

View the video below to see the trip mine in action. YouTube's quality is horrible, I'm using Metacafe instead.

This is the detonation of the trip mine at 1200 frames per second:

Step 7: Measurements.

This land mine shoots baking soda an average of six feet with one spoonful, but the powder effect isn't as impressive. I find that two spoonfuls is a good balance between distance and powder effect. Three spoonfuls would be good at close quarters, it will cover you with powder. You're victim won't know what hit him.
You can pour a good amount of BBs into this, I'd say about twenty or thirty. These average twenty-eight feet. Combine BB's and powder for the best effect.



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    212 Discussions

    im a big airsofter and in making a new corse and I needed some traps and I think I just found one

    I'm thinking of putting one on each side of the path so they get hit on both sides. I love it and I'm gonna make them.

    I don't know how I landed here - but seeing as I did ... I suggest that you could file a generously-sized notch into the edge of each washer, big enough for the spring wire to clear. (Make the edges of the notch nice and smooth to avoid stress cracking the spring (sorry, my engineering discipline insists on being heard, LOL)).

    This should facilitate the task of locating the spring reliably.

    why don't people just have the airsoft tripmines so that they cannot step over it,or even have a fisherman with a fishing rod to angle it in and make it seem so that they cannot escape

    1 reply

    Funny guy. No sane person would want to stand still with a fishing rod while there are people shooting at them! haha

    You only really need eye protection. I wear my full faced ghillie mask, but I know people who go into the battlefield with goggles or aviators.

    I happen to know a guy who would disagree very strongly with that statement. One of his front teeth got broken off at the gumline by a 500 fps sniper from 30 yards away. Its better to have something. Even if its just a bandanna tied over your mouth.

    Mouthpiece really isnt needed, just eye protection, besides, i would keep my mouth shut if i was getting peppered by bbs

    Great idea.
    Will test build a version and if it works out I will mass produce them for our next Airsoft event

    im gonna make 2 of these but using a confetti cannon things which operate in the same way with springs :)

    it's stronger usage advised to first off use invisable fishing line, second to use camo on the trap like a ghillie suit then have a pulling handle for when playing with strong people that could snap the fishing line and to not use the drill unless you are bolting it on,this is what from what i could see happening

    if your drilling a hole then why not bolt on a spring instead of screwing cuz when your screwing in if theres a hole then it's not as strong but harder to screw in

    how about a more exact awnser how about measuring the compressed height of it being standing up of the mechnisim before it's secured then on the same measurement mark where the pin should be

    Absolutely had to try this, your design is amazing. Works like a charm.

    awesome design and easy to make