White's PI Pro Floating Coil Solution?

[Sven]

Giving this a try, using supplies and materials I have on hand to make a removable search coil weight.

Put the coil into a large bucket of water. Geewhiz, it floats. Put a plastic container onto the coils center and slowly started to fill it with sand.
When the coil started to sink, that was the amount of sand (weight) it needed to keep it submerged.

I build a fast mold around the PI search coil in which I poured a mixture of epoxy and the sand.

In a couple days, will pull the cured epoxy weight out of the mold.

Will post more results with pictures in a few days.

 

[GoGoGopher]

Not sure if using the sand is a good idea...doesn't sand give false signals if it gets between a coil cover and the coil????
I have never used a PI machine, so I may be totally wrong on this...

HH,

 

[Sven]

Already checked the sand, not mineralized. The weight will sit on top the coil.
Bad for sand to get in between a VLF detectors coil and cover.
Some one else mentioned just add a bag of sand on top of the coil rather not drag a bag of sand around.

Right now this is a simple fix which is cheaper than buying a weighted coil.
I believe I got a bargain buy on this detector as it didn't have the weighted coil.......

 

[Sven]

My conclusions, good concept if the lower rod was attached to the search coils center and not the edge.
Land hunting the coil will want to tip forward. But in actual water hunting, the natural buoyancy of the coil would
counteract that tendency?

Since I still have plenty of sand and epoxy, I will make a slightly different version.

 

[Sven]

Just cut the weight down, now weighs 1lb. 2oz..
If distributed along the coils as pictured it has perfect balance and easily sinks.

By cutting off another 3 oz., wight should be perfect. The coil will have just a wee bit of a tendency to float at the surface and still can be easily pushed down so it will hold it's depth--neutral buoyancy.

I still think I will make another ring weight using less epoxy and sand and build it up a little heavier towards the back of the coil.

The Radio-active look below

 

[hershey1]

You would think White's would fix that. A water machine does not need a floating coil. It's ashame people spend that kind of money for a suppose to be top of the line detector and have to figure out how to keep the coil down to where the targets are. Good idea you have there Sven but you should'nt have to deal with a problem like that. HH

 

[Sven]

Hi,
Not sure that really is a problem with White's.
They do offer two search coils that the customer has the option to chose when purchasing.
Just not sure how aware customers are to the extent the non diving coils floats, more so in salt water!
I just happened to get a super fantastic, once in a lifetime buy on this particular used PI Pro, so I can't complain, just have to
work around the floating coil issue.

The standard coil for the PI or PI Pro is made like most "lightweight" search coils, the void inside the coil housing is
filled with foam. This is great for skimming across the waters surface if hunting 1-2" of water and hunting dry sand or inland hunt sites.
You can still use this coil for shallow water hunting, just takes extra muscle force to keep the coil down. Makes your shoulder sore after
a couple hours of hunting. Haven't eaten Wheaties or Popeye Spinach in a long time......

The diver coil is filled solid with an epoxy type resin to add weight to make it neutrally buoyant at 15', which is the coil of choice for
shallow Water hunting and diving.

 

[Sven]

Made a new coil weight based on the results of my first attempt to weight my coil.

I mixed up exactly 10 oz. of sand with 5 fluid oz. of mixed 2 part epoxy. Stirred
the sand in until it was a nice thick paste like texture. spread the mix into the mold
with the majority of it pushed back to the rear of the search coil. Tilted the front
of the coil upwards to make sure the mix would not flow towards the coils front.

I popped it out of the mold, it weighs in at 13 oz.

Placed it back on the coil, filled up a tote with water
and placed it into the water. 13 oz. is the perfect weight that will make the coil slowly sink
in freshwater.


After another 48 hrs letting the weight fully cure before I can
finish it off and paint it.

Still deciding how to attach the weight so it is removable for dry sand hunting. 2 sided tape, velcro, cable ties...

 

[Tom Slick]

I put about 4 inches of sand inside the lower rod then dropped lead egg sinkers for fishing that were just smaller in diameter than the rod untill the rod was full leaving enough room to reinstall the spring clip. Next I melted some parafin wax like used for canning (available at any grocery store) and poured the wax over the top of the egg sinkers. The wax keeps the sinkers from moving inside the rod. It can be removed if you want and doesn't cause any additional drag when swinging in the water. Then you can change lower rods if you're detecting the beach out of the water and want to lighten it up some.

 

[Frank in NH]

Tom that sounds like the way to go, then just change rods for beach hunting.

 

[Sven]

Tom that sounds like the way to go, then just change rods for beach hunting.

Sounds good but, the coils tip wants to rotate upwards on the clevis if the rubber washers or the coils mounting tabs are worn.
I have a unit that was used extensively over the years so it shows more wear on the coils tip and where the clevis rubber washers
slowly carved out washer sized divets on each of the mounting tabs, which I filled in with JB WELD.
To understand the floating problem you have to experience it.

The sand and weights in the rod only keep the rear of the coil down it does nothing for the coils tip...

 

[Mel Parker]

It's not needed on the coil shown but I have used it with other coils like Garrett.

 

[Sven]

Thanks for sharing, always good to see what others are doing.

 

[desertdon]

simply put some sand in a sock and tie it around stem ABOVE COIL!

 

[Sven]

simply put some sand in a sock and tie it around stem ABOVE COIL!

Read my above post and you'll see why I won't do that.
http://www.findmall.com/read.php?22,1263933,1267997#msg-1267997

I am 100% happy with my coil weight as it turned out.

 

[Mephysto]

I think it's a very good idea. It could fix a lot of floating problems.

 

[Sven]

I did use the PI with the weight this week. Still will float at the surface, so it has just the right amount
of weight. Sinks slowly after 1', perfectly neutral at 2-3', in freshwater. Easy to swing in the water, no arm fatigue
after 5 hours of hunting . I'm happy with the way it works.

 

[andreak77]

Actually, this is very good method for weigh down the coil - all you would need then is a search coil steady bracket which prevents the coil from moving up and down.

 

[Sven]

Actually, this is very good method for weigh down the coil - all you would need then is a search coil steady bracket which prevents the coil from moving up and down.

Those break sorry to say. And they still do not answer the question of keeping a floating coil submerged. To understand fully, take a plastic inflatable ball, try and push it under the surface and hold it there, feel the strong resistance, feel it taking extra muscle power to keep it down. Try and do this for hours. You will get the idea. Take the floating coil, what makes the matter worse the clevis is not mounted in the center of the coil, it is on the edge of the coil. The floating pressure is not spread over the coil equally, being mounted on the edge, the upward force is compounded and if the stem screw and nut is not tight, this type of coil is constantly trying to float upwards from the front of the coil. If the coil bushings are worn, it is almost impossible to keep the coil from folding upwards while hunting, that's where that angle bracket helps out. I made a bracket that does not have a large sideways surface area, which needs a bit force to move the coil. My bracket made was found in one of Clive Clynicks water hunting book. Notice that it is sideways mounted, no water resistance against it.


As I mentioned unless you have a detector with a highly buoyant coil, you may not understand. Do the floating ball test, attach one to your coils front end, plastic bag, cable tied, then go to a pond pool, you'll get a very good idea what I am talking about. Freshwater is not as dense as saltwater, objects need more lead to get them to sink, so my weight probably is not heavy enough for saltwater use. Please remember the White's non-diving coil is filled with a foam core, foam floats, it doesn't take much foam to float the coil. Take a look at how much is needed to float a person wearing a foam filed life jacket. The White's coil also has a large surface area that provides extra resistance to sinking. You'll notice the new Dual Field and other water detectors use an open spoked coil. Less surface area, the faster it will sink. Imagine the large Fisher coil pictured being foam filled and not center mounted........better eat your spinach. Water hunters know where I am coming from. Please remember the floating coil is not an issue, if you purchased your White's PI with the optional sinking "diving" search coil. The standard coil was meant to be used for dry and wet sand hunting or land hunting, it's incredibly lightweight. I actually like the floating coil, super easy to swing land hunting. Secondly, with the weight I made, gives me the option to use it for effortless water hunting.

[video]http://www.youtube.com/watch?v=BY7WFyCVO_A&feature=related[/video]