oven using mineral oil

[niner_007]

has anyone tried making an oven, by placing a PCB in a mineral oil bath and keeping it at a constant temperature? it feels intuitively that it could maintain a constant temperature better and more evenly than anything else, virtually eliminating temperature gradients, but I'm not sure about the effect of mineral oil on electrical signals, could it inject any noise? could very small currents flow thru it? and such, even if it is non conductive; P.S. to answer a part of my question, I guess it depends on its purity and contents, if it has impurities in it, that could be conductive, even if barely. It demands an experiment the next best thing could be to submerge a sealed PCB in mineral oil, then conductivity and purity wouldn't be a problem

[rhb]

The PC overclocking crowd do this all the time.  I have no idea what the long term effects are on the parts.  Resistance standards are measured in an oil bath at the national labs.

A conformal  coating on the PCB would probably mitigate any chemical interaction problems.

The way to do it would be to have a circulating pump with a heater and temperature sensors to measure incoming and outgoing temperatures with enough flow to have a short circulation time.  And, of course, lots of insulation.

[cellularmitosis]

This should work well, especially for components which don't generate significant self-heating.

Mineral oil will work, but over the course of years will turn acidic (which can start to alter the value of wire-wound resistors).  Vishay uses silicone oil to fill their hermetically sealed resistors.

Unfortunately, silicone oil is much more expensive than mineral oil.

You can find mineral oil by the quart at your local pharmacy (sold as a laxative).  If you have a "feed and general store" near you, they will carry mineral oil by the gallon (sold as a horse laxative), which is much cheaper per volume than at the drug store.  If you absolutely have to, you can use baby oil, which is mineral oil with added perfume.

If I recall, I think I picked up a gallon for about $20 at Callahan's: https://callahansgeneralstore.com/

Silicone oil comes in a variety of viscosities.  Here's a video comparing them:

Super Lube 56101 is a 1 gallon container of 100cst silicone oil, which is $86 shipped on ebay: https://www.ebay.com/itm/332207161532

edit: looks like mineral oil can be had for $15 per gallon: https://www.valleyvet.com/ct_detail.html?pgguid=30e078e9-7b6a-11d5-a192-00b0d0204ae5&sfb=1&itemguid=3269d80c-7b6a-11d5-a192-00b0d0204ae5&utm_content=11738&ccd=IFF003&CAWELAID=120295250000087149&CATARGETID=120295250000178974&cadevice=c&gclid=Cj0KCQjw0a7YBRDnARIsAJgsF3OStLdWFdBDtKRkJ8hBVSNjGn6TWz5t2_2n2FWW8AdL3Ey8bGXh3rMaApIvEALw_wcB

edit 2: silicone oil is also called "dimethicone", which is apparently $32/gallon here: https://tkbtrading.com/products/dimethicone-350?variant=739374657