Recommendation for clear, non conducting oil to bathe electrical circuit/compoments?

[Skylark]

Not boaty but water sports based.

I’d like to change the battery on an old dive computer. I believe that the inside is sealed and bathed with oil.

Any suggestions for a readily available, plentiful and low cost clear, non conducting oil to refill.

I last changed one many years ago. I recall that it’s almost impossible to refill without trapping a small air bubble unless it’s fully submerged in an oil bath. I’ll hence need around 500ml.

Many thanks for any suggestions.

 

[ingenious]

In a previous life I used Shell Diala B or Mobilect 39. I'd imagine most of the oil companies have an equivalent
Had a quick look and the above are only available in 25l
A UK made alternative
Transformer Oil Uninhibited same as Shell Diala B

Meets same spec, available on EBay

 

[jamie N]

On ROV systems we frequently used 'Mazola' corn oil when offshore. This was for >480VAC equipment working at great depth, as well as in electronics boxes.
WHY Mazola FFS?? A normal question, it's cheap; it's non-conductive; it has a very high flash point; if there's a leak, well so what if it does, it's a non hazardous food oil so won't have any real COSHH implications, and most importantly offshore, it was available everywhere in any galley anywhere in the World, where they fried food.
I've used it as a pressure compensating liquid in electrical junction boxes on scores of ROV without any problems ever.
All designated oils such as Magna 2 & Diala cost more, and have COSHH warnings, and you'd have to carry them with you.

 

[Alex_Blackwood]

Not boaty but water sports based.

I’d like to change the battery on an old dive computer. I believe that the inside is sealed and bathed with oil.

Any suggestions for a readily available, plentiful and low cost clear, non conducting oil to refill.

I last changed one many years ago. I recall that it’s almost impossible to refill without trapping a small air bubble unless it’s fully submerged in an oil bath. I’ll hence need around 500ml.

Many thanks for any suggestions.

Transformer oil.
Google Search

 

[Boater Sam]

I have used 3 in 1 for inside oil filled mains electric motors.

 

[ingenious]

On ROV systems we frequently used 'Mazola' corn oil when offshore. This was for >480VAC equipment working at great depth, as well as in electronics boxes.
WHY Mazola FFS?? A normal question, it's cheap; it's non-conductive; it has a very high flash point; if there's a leak, well so what if it does, it's a non hazardous food oil so won't have any real COSHH implications, and most importantly offshore, it was available everywhere in any galley anywhere in the World, where they fried food.
I've used it as a pressure compensating liquid in electrical junction boxes on scores of ROV without any problems ever.
All designated oils such as Magna 2 & Diala cost more, and have COSHH warnings, and you'd have to carry them with you.

The only thing you have to be wary of using cooking oil or any other vegetable oil is that it can get contaminated with microbes which feed on it and you get a build up of a jelly like substance which does conduct. I saw this with the ROV guys down in Congo when I was working there ( I worked with subsea control systems so often dealt with ROV people). They switched to a product sold by Envirorite from the US but later discovered it was a repackaged product made by a Shell subsidiary called Midel. It was very expensive

 

[pete]

I'm pretty sure we have used liquid paraffin in the last dive computer battery change we did.

 

[alahol2]

Baby oil, non-perfumed. It's essentially highly refined mineral oil and relatively cheap in small quantities.