To Caulk or Not to Caulk a Coil Cover

[aurumdigga]

I decided to caulk my NEL Hunter cover on my coil. I was going to use it in sandy creeks etc.. for relic hunting. After doing so, I noticed things were a bit different than before. I looked at the ingredients and it has Titanium Oxide as an ingredient to the black silicone caulk I used.

I caulked a cover on my Sovereign with a Sun 12 inch coil with clear caulk and I couldn't tell the difference. Now I am wondering if I screwed up with this black caulk.

Has anyone noticed a difference when you caulk a cover to keep out water and sand from the cover plate?

Anybody had any problems with caulk?

 

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[Tucson Dan]

Never used caulk. I buy coil covers for my coils. Good luck with that.

 

[cudamark]

I found that no matter how good a job you do caulking, the sand, dirt, moisture, etc will still get inside. I just remove and clean the cover when needed....not a big deal. I don't even use a cover in most places and have never worn a coil out.

 

[bzbadger]

I got tired of falsing because of salt water getting inside of the cover so I checked the caulking posts and videos and wasn't impressed with the idea. I have since removed the cover and bought the truck bed liner spray in the large aerosol cans and give 3 good coats to the bottom and sides and it has worked like a charm. no more worries about anything getting inside, anything eating the epoxy resin, any scratches or gouges that may occur. the stuff is as hard as nails and does not affect the coil's performance in anyway I have seen. I have coated 3 of my coils with no issues and because of it I have had others from my club ask for the same, I just finished earlier tonight my fifth coil for one guy. His minelab 705 coil's epoxy resin started to decay after something got into the cover and by me using that liner spray it sealed it back up and made it look like new again.

 

[aurumdigga]

That is a great idea. I think I will take the cover off and try this myself. The cover for the sun seemed to have a lot of space between the edge of the cover and the coil. It was easy to do a good job on a round coil. This DD coil is a maze of curves to cover. I just loaded the cover with caulk and pressed the coil in. Silicone oozed from every place I saw..... but ..... I bet, as you said, that some water will get in it no matter what.

I will take the dang cover off and try that spray stuff for bed liners. Great idea. Thanks.

 

[Fletch88]

Not to caulk! Or spray on bed liner. Just remove cover occasionally and clean it. I'm not willing to void my coil(s) warranties with bed liner.

 

[christo000]

Not to caulk! Or spray on bed liner. Just remove cover occasionally and clean it. I'm not willing to void my coil(s) warranties with bed liner.

+1 for not to caulk the coil just clean it

 

[IBdiggin]

I use corrugated plastic sign backing like in yard advertisement signs. Super tough, little wear even after six months. Sand rinses right out of the holes with ease. Just lay your coil on the signboard and trace the coil outline with a marker or pencil. Cut it with a scissors a little oversized to protect the edges of the coil when bumping against objects. Poke holes wherever you need fasteners and use zip ties to secure onto the coil. works great and is cheap.

 

[Sandman]

Cudamark is right about no matter how well you seal the cracks in the coil cover, black sand still finds a way inside to make it unstable. It is far better to coat the coil with marine epoxy after the warranty, not before. When a coil wears out it does so on the edges and once water gets in, its shot. It takes a long time to get the water vapor out and seal it up.

 

[Tom_in_CA]

marc and sandman are right: If you try to caulk the coil skid cover on there (thinking that you can keep sand and water out), that water and soil (even if only eventually accumulating dust) will make its way in. It only needs to be the tiniest of pin-holes through the caulk. And then it's a bear to pull the plate back off to clean it out, since you've essentially glued it on.

I like the idea of some sort of spray on bed-liner. I've used the seal-coat material that is put down on parking lots. It goes on sort of like thick paint, and does a good job at being a scruff-resister.

 

[BC1969]

I had a white's dealer tell me to caulk my coils the other day, now after reading these replies, I guess I will just clean them constantly, to see if that resolves the issue I am having...so frustrating.

Mike

 

[aurumdigga]

Update!
I easily got the cover off with the caulked cover that I described. I was surprise at how easy it came off. The cover itself had no silicone adhered to the coil cover for this NEL coil. All of the caulk adhered to the coil. Now I am in the process of scraping off the silicone with a plastic scraper. It is a tedious task.

I did notice that: Even though I filled the cover with silicone with half of the tube of silicone seal, I could tell where the coil did not seal. The coil seemed heavier too with the silicone. I could tell the weight was more that it was before very easily.

I am surprise at how difficult that it is to get this sealant off the coil. The cover was devoid of any silicone residue.

It will take me several more hours to remove this sealant.

I uses a steel table knife to pry the coil cover off .... and .... at first I tried to crap the sealant off the coil with this steel knife. I think I scratched the black paint in one tiny place to expose some of the coil. So, on a NEL coil, the coil is only covered with a little paint. The cover is very necessary. I have no choice but to put a coat of that bed liner spray on the tiny place that I scraped and the rest of the coil. I want to check out the makeup of this spray before I do it though. I don't want any coating of Titanium or other metal on my coil at all.

Titanium Dioxide may not do anything to screw with the detector but I did have to cut down on the sensitivity where I was wide open before I put the caulk on. I am just guessing the the titanium dioxide made the detector unstable in high sensitivity. There is no way to prove it unless you are just really intimate with your detector. This is a newer detector for me and I would have needed more hours on it to make a better determination on this issue of the titanium dioxide making the detector act funny or unstable.

Hey BzBadger, are there any metal compounds in the truck bed spray?

 

[bzbadger]

No metal compounds in the bedliner spray, I've sprayed 10 coils and no issues at all. I just got my replacement coil sent to me from the factory and what do I find..a hole in the epoxy resin..now what do you think will happen if I put my supposed waterproof machine in water with a hole? Nothing now because I sprayed it with bedliner spray and sealed that puppy up tight and I can beat the crap out of it with no worry. That stuff is as hard as stone, it won't scratch, scuff, dent or leak. I got tired of trying to delicately pull covers off and clean them over and over, don't have to now. 4 garret coils, 4 minelab coils, 1 tesoro coil, 1 fisher...no problems & I have more to do for other people who are tired of the same crap. Reason I know it's ok is one of our club guys is in the military and said the Garrett EOD detectors are covered with that type of spray so with that said why can't ours not be covered the same way..why because coil covers will break, we are so scared to mess up a coil we buy another and that's money out of your pocketbook, a $7 can of bed liner spray from WalMart covers 4 coils..1 coil cover $15+ plus shipping.

Get your facts first, then distort them as you please-Mark Twain

 

[aurumdigga]

Thanks BZ, I was wondering where you got the spray and since you said WalMart, I know what kind you mean. I could only find Rustoleum truck bed spray online online at Walmart. I went to Home Depot's site and they want $47 for on can. It has to be a misprint.

I scraped and scraped that silicone as much as I could. It is a bugger to get off all the way. The cover will not fit on the coil anymore. It just falls off. It just added weight anyway. I hope the bed spray will adhere to the leftover silicone that I can't seem to get off.

That is odd that they would replace a coil with a damaged coil.

Is Rustoleum the brand of spray you use?

 

[bzbadger]

Yep rustoleum is it. You have to get that silicone off at all costs if you are going to spray. It won't stock if u don't. There is some stuff u can get from NAPA to kill wax/silicone. I know like googone helps loosen some stuff like that but not 100% I do know since I've painted cars since age 12 that silicone is painters nightmare. As far as the replacement coil, yeh it kind of threw me that they send me one with a hole at the front edge in the epoxy and it was easy to see. Oh well its fixed

Get your facts first, then distort them as you please-Mark Twain

 

[aurumdigga]

I hope this thread has been a lesson for those that might be considering a silicon seal for a coil. I didn't read the ingredients before I did this and it is hell trying to get this silicon off.

I am going to try Bon-Ami after everyone goes to bed. I expect to be cussing during most of this last step in removing this silicon that seems to have permeated the plastic a bit. I figure if I scratch the plastic slightly, it will help the bed liner spray to adhere to the coil a bit better. Also, there is a sticker that was on the bottom of this NEL coil. It gave some diagram of how to swing a coil. (Like someone buying an aftermarket coil doesn't know that by now!) The glue for this sticker is like the glue from hell. Thanks NEL ....... Not!

My advice; NEVER USE SILICON ON A COIL!!!!!!!

 

[aurumdigga]

Oh yes, one last thing; I am hesitant to use some kind of solvent to get this silicone completely off. This coil has a two piece design. I do not want to corrupt the stock seal in any way.

 

[Frankn]

I have a really simple solution! Just use the coil as supplied by the manufacturer. Been hunting since the 70's, never used a coil cover, never had a coil go bad. My XLT is 12 years old with the same coil. If it's not broke, don't fix it. Ever heard that one? Frank...

 

[bzbadger]

Frank I actually have heard that but I've also heard about murphy's law, what can go wrong will go wrong. I'm glad you haven't had any coil issues, count yourself blessed and be thankful bit others here have had problems and feel the need to cover their investment. If the manufacturers make coil covers there must be a need, the covers are better than nothing but have drawbacks and don't last too long of you're hitting sand or rough rocky soil. My coils with the bed liner spray don't even look touched and I've had them in rough crap.

Get your facts first, then distort them as you please-Mark Twain

 

[jeff of pa]

I found that no matter how good a job you do caulking, the sand, dirt, moisture, etc will still get inside. I just remove and clean the cover when needed....not a big deal.

Exactly !

Never paste your cover on with anything.

there is a reason Covers are made to be removed.
just clean them out, when you clean your detector.