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Transformer oil as dielectric

bob

Titanium
Joined
Aug 12, 2002
Location
Regina, Canada
The guy that does my electrical repair suggests that transformer oil would work as dielectric. Sure don't want to get into a bacon grease as cutting oil discussion
but there is a local supplier and sure would save money and bother if it would work.
Bob
 
Of course transformer oil is a dielectric and a very good one at that, so is diesel fuel. Somewhere between 5 and 50 Pico Siemen conductance if my memory is correct. That doesn't mean it is applicable to the EDM process though.
 
The guy that does my electrical repair suggests that transformer oil would work as dielectric. Sure don't want to get into a bacon grease as cutting oil discussion
but there is a local supplier and sure would save money and bother if it would work.
Bob
based on quick glance I would say that its not entirely problem-free.
Better EDM dielectric oils have sulfur content of max 5ppm whereas bog standard tranformer oil can have over 1500ppm. Other than that they have lots of similar properties.
 
Hi bob:
Remember when transformer oil was still full of super toxic PCB's?
Remember that no executives in the transformer business gave a shit until it couldn't be denied anymore?

For those who don't, here's a snip:
"PCB history is not pretty. As the timeline shows, the manufacturers and major users of PCBs knew by the 1930s and 1940s that PCBs caused serious health problems in their workers, and doctors advised them that other effects could be occurring as well. But this did not stop industries from producing and using PCBs, or from releasing PCBs into our environment, contaminating our public waterways, air, croplands, and wildlife. It appears from this PCB history that several companies also deliberately misled workers, customers, regulators and the public for many decades, allowing the PCB problem to spread and become much worse."

Do you know for sure that it's safe now?
Is it still safe once it's been chemically altered by EDM cutting with it?
Is it worth taking the risk to save a few bucks?

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
www.vancouverwireedm.com
 
Hi bob:
Remember when transformer oil was still full of super toxic PCB's?
Remember that no executives in the transformer business gave a shit until it couldn't be denied anymore?

For those who don't, here's a snip:
"PCB history is not pretty. As the timeline shows, the manufacturers and major users of PCBs knew by the 1930s and 1940s that PCBs caused serious health problems in their workers, and doctors advised them that other effects could be occurring as well. But this did not stop industries from producing and using PCBs, or from releasing PCBs into our environment, contaminating our public waterways, air, croplands, and wildlife. It appears from this PCB history that several companies also deliberately misled workers, customers, regulators and the public for many decades, allowing the PCB problem to spread and become much worse."

Do you know for sure that it's safe now?
Is it still safe once it's been chemically altered by EDM cutting with it?
Is it worth taking the risk to save a few bucks?

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
www.vancouverwireedm.com

Yes, but that stuff was the rust dissolver I ever used!
 
Don't know but I would trust what they say. company builds transformers pretty sure they have the pcb concerns under control.
 
some transformer oil is organic based.

Epoxidized soybean oil - Wikipedia

newer transformers with this stuff will have a sticker on it saying so. might be worth an experiment?

Back when I was in the usmc there was an issue with the new hydraulic fluid being used by a multitude of aircraft. It had such good dielectric properties that it was building up a static charge through the sight glass flow meter (500 division, hydraulic maintenance), a 2 foot long piece of glass, internally tapered with ribs and about a 1 inch diameter ball bearing, was good for 1 to 50 gpm iirc, at a few hundred pounds. i think they had it on the inlet of the pump, not the outlet, the side walls of the glass might have been half an inch or less.

Anyhow they blew up the flow meter in Iraq or Afghanistan (i don't remember which) in 2011 and they blew up two of the flow meters at cherry point if i recall correctly. said there was a lightning flash and the glass exploded. of course, no one would believe this to say the least about the situation.

I took a sample of the oil it and tried to get it to break down with the 18-1900 volts available from a microwave transformer. a paper thin gap was enough to stop that voltage. which, in hindsight isn't actually all that impressive. (i couldn't actually get the oil to break down. literally nothing would happen until i could literally feel the wires touching each other.. and yes i was playing around with 1800vac as carelessly as any other wire not energized..)


anyhow, transformer dielectric is basically formulated with chemicals for one purpose only: to absorb the byproducts of cellulose breaking down while not producing or containing any compounds that break down the cellulose faster. and it can't contain any components that will break down a long list of various kinds of plastics.

if you're going to try an experiment with transformer oil, you might as well add to the list of things worth trying.. anything else that costs the same amount.. including peanut oil, soybean oil, full synthetic non detergent motor oil, but why not try regular oil while you're at it..
 
Hi adh2000:
You wrote:
"Why do you think EDM oil is safer than transformer oil?"
You make a good point, and of course the answer is "I cannot make the claim with any certainty whatsoever".

However, there is a liability issue here too, (as well as an economic one).
Transformer oil is not supposed to be subjected to constant arcing as part of its function.
So it's been formulated with other objectives in mind as johansen points out, and decomposing it by subjecting it to continuous arcing and the risk of the decomposition products being toxic are forseeable, even if we don't know they actually occur.
So if you hire someone to run your machine and you've filled it with a non-approved dielectric and your employee is harmed and he sues, you are royally fucked.
Likely he will not even have to prove the oil caused harm...the onus will likely be on you to prove it did not.

Suppose you have a fire and the fire is determined to have originated at the sinker.
How likely is it, do you suppose, that your insurance will pay out your claim and that of the neighbour who's place you also burned down as soon as the insurance company finds out the dielectric in your worktank was not approved for the purpose you used it for?

For better or worse, this is the world we live in, so the risk is high and the reward is small.

Never mind the fact that the economic risk is high too.

Suppose the transformer oil doesn't work out, and you have to clean out the machine and replace it with proper dielectric.
Just the time it takes to thoroughly clean the system is going to cost more than the price of the oil, never mind you bought unusable oil, and then you had to buy solvent to wash it out, buy the proper oil and dispose of the scrap oil and the contaminated solvent.
If you struggle along with inferior oil and your machine burns 25% slower because of it, that has a cost too.
Don't forget, the EDM dielectric is formulated specifically for the things you are asking it to do, and those things are completely different than what you ask a transformer oil to do, so the chances are very high your machine's performance will suffer...how much is anyone's guess but it's expensive to find out.

Last, synthetic dielectric oils for sinker EDM have been around for a while now; at least 20 years.
In that time they've been used for die sinking in a gazillion shops and have a pretty long history of use.
It's a reasonable bet, in this much more litigious climate, that they would be less willing and able to just sweep the whole problem under the rug like Monsanto did from the 1930's to the 1970's with PCB's in transformers and fluorescent light ballasts.

So no, I can't claim EDM oil is safe and transformer oil is not, but I think the balance of probabilities works in favour of avoiding the experiment.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
www.vancouverwireedm.com
 
Probably better than kerosene what some cheap charlies are still using ;)
OK, possibly also too viscous.
 








 
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