[volt-nuts] Resistance Standard Oil - Plain Mineral Oil?

[Robert Atkinson]

Hi,
"industrial" transformer oil tends to be golden brown in coulour and may be part synthetic. Older oils may contain PCBs that are toxic and expensive to dispose of. You should avoid these at all costs. The more highly refined USP (United States Pharmacopeial) or BP (British Pharmacopeia) food / medical grades are preferred for laboratory applictions. The additional cost over transformer oil is off-set by the ready availabilty in small quantities. The only disadvantage I know of is that when used for a long time in high temperature baths (not our application), it can suffer sudden polymerisation. It expands and turns to a gell and is hard to clean up. Transformer oil has additives against this and oxidisation  but they can have other problems such as smell and toxicity. I've used medical grade  oil in many work applictions from insulation through temperature calibration baths to keeping air away from anerobic bacterial cultures and never had any issues.

Robert G8RPI.



________________________________
 From: J. L. Trantham <jltran at att.net>
To: 'Discussion of precise voltage measurement' <volt-nuts at febo.com> 
Sent: Saturday, 26 November 2011, 3:48
Subject: Re: [volt-nuts] Resistance Standard Oil - Plain Mineral Oil?
 
I wondered about the oil in the other two.  They come from very different
sources and one was NOS, including the calibration certificate, original box
and packing, etc., and both seem to have the same oil although one is GRAY
Industries and the other is Leeds & Northrup.

Joe

-----Original Message-----
From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
Behalf Of Mitch Van Ochten
Sent: Friday, November 25, 2011 9:37 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Resistance Standard Oil - Plain Mineral Oil?


Hi Joe,

I just ordered it today. Might have been foolish to spend so much on mineral

oil.
ESI recommended "Drakeol 9 LT mineral oil" in their literature but I 
couldn't find it in small quantities.
I investigated a synthetic oil replacement called SpectraSyn PAO and Exxon 
offered to send a sample.
After checking with a chemist at work I decided not to.
He said over many years of immersion the "long chain parrafin" would be the 
best, and
less likely to deteriorate the insulation than a synthetic replacement.

I suspect someone may have substituted motor oil in your other resistor.


Regards,

mitch


----- Original Message ----- 
From: "J. L. Trantham" <jltran at att.net>
To: "'Discussion of precise voltage measurement'" <volt-nuts at febo.com>
Sent: Friday, November 25, 2011 9:32 PM
Subject: Re: [volt-nuts] Resistance Standard Oil - Plain Mineral Oil?


> Thanks for everyone's reply.  If all it takes is just plain old 
> Mineral
> Oil,
> I can get that easily at the local grocery or drug store.
>
> Mitch, have you received the Drakeol yet?
>
> I also have a Leeds & Northrup 0.1 ohm and a GRAY Inst. Co. 10000 ohm 
> Standard Resistor, both of which came with oil.  Their oil, though, is 
> very dark with quite the odor.  Somehow, I don't think plain old 
> Mineral Oil is quite the same.  If it is an acceptable substitute, I 
> can certainly get it very easily.
>
> I had always thought the oil was as much for elimination of moisture 
> as it was for insulation.  Also, of course, it seems to be for the 
> purpose of adding some 'thermal mass'.
>
> Joe
>
> -----Original Message-----
> From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] 
> On Behalf Of Mitch Van Ochten
> Sent: Friday, November 25, 2011 7:43 PM
> To: Discussion of precise voltage measurement
> Subject: Re: [volt-nuts] Resistance Standard Oil - Plain Mineral Oil?
>
> Joe,
>
> I just ordered some Drakeol 7 from this company:
>
> http://www.cqconcepts.com/chem_mineraloillight.php
>
> It's $12.23 per quart and they take PayPal.
>
>
> Regards,
>
> mitch
>
> ----- Original Message -----
> From: "J. L. Trantham" <jltran at att.net>
> To: "'Discussion of precise voltage measurement'" <volt-nuts at febo.com>
> Sent: Friday, November 25, 2011 1:17 PM
> Subject: [volt-nuts] Resistance Standard Oil - Plain Mineral Oil?
>
>
>>I have looked back over the archives about this and have found some  
>>information but I am not really clear on whether or not local grocery 
>>or  drug store mineral oil is acceptable for my Leeds & Northrup 10 
>>ohm  standard  resistor.
>>
>>
>>
>> I emailed Ohm-Labs (that I think maybe acquired Leeds & Northrup?) 
>> and they suggested Drakeol 7 or Blandol.  However, I can't find a 
>> source for it. They suggested Fisher Scientific or VWR but I can't 
>> find either brand listed
>> on their websites.  They do list 'light mineral oil'.
>>
>>
>>
>> Any information or suggestions appreciated.
>>
>>
>>
>> Joe
>>
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