High Voltage Insulator

[Anthony P]

I am constructing a home-made high voltage capacitor for use on a dye laser flashlamp. Mylar and Al sheets were used to build the cap. It clocks in at 600nF and will run upwards of 20kV.
Is there any reason not to use food grade mineral oil as an insulator? The whole cap would be submerged.

 

[Encap]

Would think it depends upon operating temperature.
Primary concern with mineral oil is flammability.

https://en.wikipedia.org/wiki/Transformer_oil

 

[Seoul_lasers]

I am constructing a home-made high voltage capacitor for use on a dye laser flashlamp. Mylar and Al sheets were used to build the cap. It clocks in at 600nF and will run upwards of 20kV.
Is there any reason not to use food grade mineral oil as an insulator? The whole cap would be submerged.

I'd opt for something other than food grade mineral oil as your insulation as it will likely have moisture content.
Something like shell diala ZX would be better for longer life and has superior dielectric properties.

Mineral Oil can be heated up to 100C to drive off any moisture but do be careful heating it.


Many people have stopped making homerolled caps due to the hazards involved and instead have gone the MMC route.
For 600nF @ 20KV you could easily build a cap this size out of a few CDE940-942 type caps.

Great link for making MMCs here: http://hvtesla.com/mmc.html

 

[Anthony P]

I hope heat does not become an issue. It will only be fired in single shot pulses with plenty of down time in between.
As for commercial caps, I am going for ultra low inductance and my home made one is designed accordingly. Thanks for the tip on heating the oil to remove moisture. I will definitely look into diala ZX.