How safe are aluminium electrodes?

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estim_si
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How safe are aluminium electrodes?

Post by estim_si » Fri Apr 04, 2008 12:05 pm

Following on from an IC thread and a coincidental conversation with a customer I have compiled the following. I hope it clears up some misconceptions in relation to aluminium electrodes and safety.

All of the major E-Stim manufacturers use aluminium or aluminium alloys to create their electrodes, a material that makes up around 8% of the earths crust ,is also present in around 50% of cook wear and also in aluminium food containers (Cans & takeaway boxes etc). It is considered to be an excellent material, easy to work, lightweight, and in the correct grades safe. It has also been used in electrodes for at least the past 35/40 years, with no reported issues.

Nearly all metals used in electrodes contain some other materials. Stainless steel can contain high levels of chromium and nickel, both of which can cause issues with allergic reactions. Copper and lead are two materials that are classed as toxic for food use, hence they tend not to be used in professional electrodes. Titanium is far too expensive to make commercial sense and is very difficult to machine.

Plating
Incidentally beware of any plated electrodes. Chrome plate, gold plate or aluminium foil all will chip and degrade over time, thus transforming a smooth and shiny surface to a chipped and flaking surface ejecting small sharp shards of material.

Our insertable electrodes are generally made from solid high quality aluminium alloy and/or stainless steel. There have been concerns in the past regarding a link between aluminium and Alzheimer’s, leading to a lot of misconceptions and concerns regarding aluminium and the human body.

These days the medical consensus appears to be that there is no link between ingested aluminium and Alzheimer’s, as it is so prevalent within the daily environment.

In relation to electrode use the theoretical entry point for aluminium into the body is via a complex electro-biological process called ion migration, a process that generally occurs over a long period of time at elevated temperatures, high levels of acidity, and high DC voltages (similar to electrolysis), most of which are not present during normal E-Stim play, provided you are using professional designed and manufactured, made for play equipment. The 1915 trench telephone is probably not a good idea!

The CE mark
Whilst on the subject of control unit safety, have a look for the CE mark.
This states that the design of the device conforms to certain UK & EU
safety requirements (such as the Low voltage Directive). A lot of imported equipment does not have this mark (technically it is illegal to sell/import electrical equipment that does not carry the CE mark. All of the UK manufacturers conform to this standard.



References

Aluminium and Alzheimer’s disease

International food safety handbook

Aluminium and food safety

http://www.foodsafetysite.com/consumers ... rticle=373



zmatt
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Re: How safe are aluminium electrodes?

Post by zmatt » Wed Jul 09, 2014 5:02 am

estim_si wrote:Stainless steel can contain high levels of chromium and nickel, both of which can cause issues with allergic reactions.
Actually stainless steel by definition contains high levels of chromium, which is why I'd personally be far more concerned about using stainless steel for electrodes than about using aluminium, unless someone with sufficiently deep knowledge of electrochemistry can confidently assert that the possibility of generating non-negligible amounts of chromium(VI) really isn't a worry under the circumstances created by e-stim play.

(Also, I suspect many people will get exposed to much greater amounts of soluble aluminium by regular use of antiperspirants than they ever could manage through e-stim.)
estim_si wrote:DC voltages
You'll really really want to avoid DC-unbalanced sources for a much more urgent reason, as I found out the hard way during some early experiments with the PCB from an electric flyswatter (with charge capacitor removed and reduced supply power), which has a rectified output. While I was actually aware of the issues with DC currents, I hadn't expected it to become a real problem that easily... until I had two little chemical burns due to the severe change in pH -- acidic at one electrode, alkaline at the other -- caused by the DC current.

Especially the alkaline side is evil since initially it looks like the skin is mostly ok there, but it's basically gellified into aspic at that point, which moreover retains the alkalinity even after rinsing well and continues to damage surrounding tissue. I fortunately discovered the inadequacy of rinsing with plain water, by touching a pH indicator paper against the skin there and seeing it go off the blue end of the color chart (pH > 10) :shock:, so I quickly acted to neutralize it as much as possible with a citric acid solution to limit the damage (apply, rinse, repeat until the pH indicator stopped giving me the creepy blue).

Lesson learned: do not use a source that isn't DC-balanced, ever.

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