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In the Corner with Dan Hughes

Mar 17, 2011

Does the fact that you have to pay extra for a coil cover for your metal detector indicate that the manufacturers think you don't really need one?

Or are they hoping you'll wear a hole in your coil and have to buy a new coil from them?

In this show, I discuss some reasons you should use a coil cover, and some reasons you may not want to use one after all.

For more articles about metal detecting and treasure hunting, visit

Dan Hughes
over eight years ago

Ricardo, the coil covers for the Fisher CZ series detectors fit the coil exactly, with cutouts where the coil cutouts are.

I actually prefer this, because I have noticed no more drag with holes in the coil, and I can see the exact blade of grass I'm pinpointing on - My target area is not obscured by my coil (or coil cover).

over eight years ago

Good topic to touch up thing that was overlooked is that a coil cover can help minimize the sweeping effort by reducing drag caused by blades of grass snapping into the hollow areas of a coil. Some companies offer "Plugs" for this purpose, but a coil cover also has the same function. I huge benefit in my opinion is the resale value of a coil that has been used with or without a cover. There will be a time when we buy a coil that we simply do not like or want anymore, and when it comes time to sell it, you're going to get more for a coil that looks new as opposed to one that has lots of wear. I think the benefits outweigh any disadvantage. I would of course keep in the practice of washing the cover out after every hunt or every other one at least.

Dan Hughes
over eight years ago

Zeke, I wouldn't wrap it with electrical tape, and I wouldn't clean it after every hunt.

The more often you take the cover off the coil, the faster it will become loose and let junk in more easily.

I'd take it off and clean it only after hunts where it got wet and muddy water was likely to get inside the coil cover.

over eight years ago

Like your podcasts. Just got an ace 250 and got the coil cover. Can I wrap it with electric tape to keep it clean or is it better to take it off and clean it after a hunt?

Dan Hughes
over eight years ago

Bob, I have mixed feelings about spraying my coil with truck bed liner.

I seldom hunt rough ground, where a coil cover might be a good idea. When necessary, though, I can snap on a coil cover. Then I can take it off when I'm back to grass.

But once you spray your coil with truck bed liner, it's there forever. No going back. Here's a photo of a sprayed coil:

I don't know if I want to do that to my coil.

Bob Robinson
over eight years ago

Thank you for the article on coil covers. What do you think of the practice of coating the coil with a product like truck bed liner?

Dan Hughes
over eight years ago

Kev, my "loss of depth" comment was poorly stated - let's try again.

First, you are absolutely correct, the strength of the signal is not affected by a coil cover.

But your depth is affected, because the actual wires of your coil are raised farther above the target when you use a cover - the thickness of the cover raises your coil exactly that much away from the target.

Say you were using a "super-coil-cover" that was five inches thick. You have just lost five inches of depth! Not because the signal can't penetrate the extra plastic, but because the extra plastic raises your actual coil five inches into the air, out of the range of most small targets.

Sorry I wasn't more clear - hope it makes sense now!

over eight years ago

First of all let's be realistic. Most coils don't come with a coil cover hence the manufacture makes additional monies. Also the manufacture will have an opportunity to sell another coil once you wear a hole in the coil by not spending for a coil cover. I too have been a treasure hunter for many yrs. 31 to be exact and I have to disagree with your theory of losing depth with a cover installed. I have done this test numerous times with cover installed and removed. I used a vernier digital height gauge that measures in thousands of an inch with the machine and coil in a wooden fixture and can tell you that there is NO loss in depth. To sum this up think about your analogy of this test, the cover is made of the same material as the outer coil it's self plus containing no ferrous or non ferrous material in the coil cover. With a bead of RTV silicone applied to the meeting seam and sealing the coil to cover eliminates any material getting between the coil and cover. As far as removing the coil cover for replacement that is an easy task since RTV silicone remains pliable, a metal pick or razor blade can easily break the bead making it able to replace said damage coil cover. I feel I am capable of performing this test since I am a master machinist and have an MBA in mechanical engineering so my test was done correctly.

Joe Downs
over eight years ago

Hi Dan,I just heard your podcast about coil covers,this may sound funny but, I got a Minelab Safari a few months back and just realised they had covers on them. I don't know if they ship that way or if it was an extra add-on.(Kellyco),I do know to clean them after a hunt to prevent possible falsing.I always keep them on and don't think the extra weight is an issue. Also losing 1/8"-1/16" of possible depth is too little to uncover the coil ,IMHO ,I know coils are pretty rugged, I think I'll just keep them on for now. Thanks for the podcasts, good info.

Steve in so az
over eight years ago

If one does not use a cover then they wont be apt to scrub on the ground. If they do not scrub they will be gaining distance from the target and missing some things.