Your opinions matters

[Finderskeepers]

Found mylar foil to work very well. Recently used nickel spray paint to reshield a Coiltek mono coil and works well on my GPX4500 - no problems ground balancing and no loss in sensitivity. But a very thin layer is to be applied.

[Goaty]

manganese dioxide (MnO)

Sorry - my poor typing skills!

Manganese Dioxide should have the formula MnO2.

Magnesium Oxide is a monoxide with the formula MgO.

[Tibuck19]

Sorry, not wishing to be pedantic, but the black powdery layer around the central carbon rod in a zinc/carbon 'dry cell' is a mixture of powdered carbon and manganese dioxide (MnO).
Magnesium (Mg) is an entirely different element to manganese.
I'm not sure about which form of carbon is used in these cells. It could be amorphous or graphite. Both are the same element (as is diamond) just with different crystal structures.
The whole contents of a C/Zn cell are saturated with an electrolyte which used to consist of jelled ammonium chloride.
How this helps.

That is a good point, and well said.

[Goaty]

Great thank you , but I meant with old batteries that contained Magnesium dioxide.

Sorry, not wishing to be pedantic, but the black powdery layer around the central carbon rod in a zinc/carbon 'dry cell' is a mixture of powdered carbon and manganese dioxide (MnO).
Magnesium (Mg) is an entirely different element to manganese.
I'm not sure about which form of carbon is used in these cells. It could be amorphous or graphite. Both are the same element (as is diamond) just with different crystal structures.
The whole contents of a C/Zn cell are saturated with an electrolyte which used to consist of jelled ammonium chloride.
How this helps.

[Tibuck19]

[ATTACH]39947[/ATTACH]

Great thank you , but I meant with old batteries that contained Magnesium dioxide.

[kt315]

Interesting, Isn't there also magnesium dioxide mixed in there?

[Tibuck19]

I bought the graphite powder of eBay years ago.

PVA glue is just wood glue I had lying around.


I attach two small squares of copper slug tape and attach a thin insulated wire to each.


into a bowl I add about a tablespoon of PVA and then keep adding the graphite till its goes like toothpaste.


The stiffer the paste the lower the resistance will be. Normally spread it with a knife. Save loosing half of it soaking up in a paintbrush.


You have to be quick it dries fast.


However the resistance will lower some more when its fully dry. The resistance between the two wires normally comes out at between 500 ohms and 1K after drying over night

I use epoxy resin and it seals it fine. Never tried this method with polyester resin.


Tried a few thing. Yacht varnish worked can't remember why I moved to PVA. Tried some other glues and they failed badly.

I have no shortage of PVA glues as I am a woodwork, I can try with a pva glue call mod podge it is still water base mind you ,

[Tibuck19]

i use aerosole '33' (look pic) and put so far a wet a graphite powder on the lacquer. the powder i do by abrasion of a graphite rod from any oldest batts
(i find them up everywhere at fields). that gives good result and economy of the 33.

http://www.sapphire.ru/linkpicsW/00000006201.jpeg

Interesting, Isn't there also magnesium dioxide mixed in there?

[kt315]

i use aerosole '33' (look pic) and put so far a wet a graphite powder on the lacquer. the powder i do by abrasion of a graphite rod from any oldest batts
(i find them up everywhere at fields). that gives good result and economy of the 33.

http://www.sapphire.ru/linkpicsW/00000006201.jpeg

[Koala]

I bought the graphite powder of eBay years ago.

PVA glue is just wood glue I had lying around.


I attach two small squares of copper slug tape and attach a thin insulated wire to each.


into a bowl I add about a tablespoon of PVA and then keep adding the graphite till its goes like toothpaste.


The stiffer the paste the lower the resistance will be. Normally spread it with a knife. Save loosing half of it soaking up in a paintbrush.


You have to be quick it dries fast.


However the resistance will lower some more when its fully dry. The resistance between the two wires normally comes out at between 500 ohms and 1K after drying over night

I use epoxy resin and it seals it fine. Never tried this method with polyester resin.


Tried a few thing. Yacht varnish worked can't remember why I moved to PVA. Tried some other glues and they failed badly.

[homefire]

Metallic Nickel is going to cause issues.

[Tibuck19]

I use graphite mixed with PVA glue works fine.

What brand do you use ? if you have a link to it.

[Tibuck19]

I use EZ-SLIDE graphite brush on coating for shielding. Works for me. Just finished an IB coil for a PI. Looked at amplifier out while bringing my hand to the coil with a scope before shielding. The change in signal was a lot greater as the TX coil was discharging. A small change if any on the scope after maybe 6usec. Change at integrator out so the coil needed shielding. Since the change in signal is higher when the TX is changing, is it harder to shield a VLF detector? Haven't tried the Nickel, Carbon or Silver spray.

It I for this reason I am looking in to shielding I am also making a complainer coil and want to use small size wire to take advantage of the minipulse plus.

[Tibuck19]

I use graphite mixed with PVA glue works fine.

Funny you mention this , I was thinking of doing the exact something , and I was not sure if it was a good idea, I was also worried about the PVA glue being water base if it would have problems with the polyester resins which I use to fill the cavity, any advice ? 50/50 mix ......

[Koala]

I use graphite mixed with PVA glue works fine.