How to Use the Garrett ACE 300i Metal Detector

The detector you're hiring is a Garrett ACE 300i. It's a popular beginner-friendly machine and you don't need any experience to use it. This page covers everything you need to know to go from switching it on to digging up your lost ring.

Switching On

The detector takes four AA batteries, which will be fresh when you collect it. Press the power button in the middle of the control panel and it will start up ready to go. If you need to put it down for a while, switch it off to save the batteries.

Choosing a Mode

Press the MODE button to cycle through the search modes. For finding lost jewellery, the two that matter are:

  • JEWELLERY is the mode to use in most cases. It ignores most iron rubbish like nails and bottle caps while still picking up rings, necklaces and coins.
  • ZERO detects absolutely everything, including iron. If you know roughly where the item fell and don't mind digging a bit of junk, this mode makes sure you miss nothing.

My suggestion is to start in JEWELLERY mode, and if you haven't found the item after covering the area, go over it again in ZERO mode.

Understanding the Signals

When the coil passes over metal, the detector beeps and shows a number from 0 to 99 on the screen. This is the Target ID and it tells you roughly what's below:

  • Low numbers (under about 35) with a low grunt sound are usually iron or foil.
  • Mid numbers (roughly 40 to 70) with a medium tone are where most gold rings, ring pulls and smaller jewellery show up.
  • High numbers (above 70) with a high bell tone are usually coins and larger silver items.

Gold jewellery often reads lower than you'd expect, so if you're after a gold ring, please don't skip the mid-range signals. A repeatable signal, one that beeps consistently every time you sweep over the same spot, is worth digging. A crackly one-off blip usually isn't.

Sweeping Technique

Hold the coil about 2 to 3 cm above the ground and keep it level and low through the whole sweep, rather than letting it lift at the ends like a pendulum. Move it slowly from side to side, about one sweep per second, and step forward a little at a time so each pass overlaps the last. Work in straight lines, like mowing a lawn, so you cover the area properly. Most people who fail to find their item are sweeping too fast or leaving gaps.

Pinpointing a Find

Once you have a good signal, hold down the PINPOINT button and move the coil slowly over the spot. The tone gets louder and the screen fills up as the centre of the coil passes directly over the target. Mark the spot, then dig a small, neat plug of soil to one side. On dry sand you can simply scoop and sieve the sand through your fingers. Check the hole again with the detector, as the item is often in the pile you dug out rather than still in the ground.

Searching on the Beach

Dry sand is easy and the detector will behave itself. Wet sand near the waterline is more challenging because salt water can cause false signals. If the detector chatters constantly on wet sand, lower the sensitivity a couple of notches using the left and right arrows under SENSITIVITY, and slow your sweep down. The signals will be quieter but far more trustworthy.

Looking After the Detector

The round coil at the bottom is waterproof and can go in shallow water and wet sand. The control box with the screen is not waterproof, so please keep it out of the rain and well away from waves. Sand and mud rinse off the coil and lower stem with fresh water once the detector is switched off. If anything seems wrong with the machine during your hire, please stop and give me a call rather than trying to fix it.

A Few Quick Rules

Please only detect where you're allowed to. The beach between Brighton's piers and most public foreshore is generally fine, but parks and private land need the landowner's permission. If you dig a hole, fill it back in. If you happen to find something old and potentially valuable that isn't yours, finds of gold or silver over 300 years old must be reported under the Treasure Act 1996.

Good luck, and I hope you find what you're looking for. If you get stuck on the day, you're welcome to give me a shout.