I suspect that most vegetable or nut oils would have a tendancy to go rancid and putrify if used long term as a thermal transfer medium. I think it would be much better to use a mineral or synthetic oil. Of course, best would be to use a fluid specifically designed for the purpose (Fluorinert).
thanks guys.
I'm leaning towards mineral oil. That is what most people have suggested. They use it to cool transformers, so it should work. The only thing is someone told me it has a tendency to break down over time when its at an elevated temperature. So I'm going to have to do some tests to see what temperature it would rise to and how long it would take to break down.
I'm leaning towards mineral oil. That is what most people have suggested. They use it to cool transformers, so it should work. The only thing is someone told me it has a tendency to break down over time when its at an elevated temperature. So I'm going to have to do some tests to see what temperature it would rise to and how long it would take to break down.
If you've got the kit and skills to be gluing bottles back together could you put a "liner" into a bottle? The now purely decorative fluid held between the bottle and the liner with an inner open bottomed chamber to take the amp.
Picture a large bottle with a smaller bottle inverted, glued in through the base and cut flush to the bottom of the larger bottle.
If your seam was watertight the outer bottle could be filled with a fluid of your choice while the amp stays lovely and dry but appears to be immersed.
I hope you can follow this, my drawing skills leave a lot to be desired and really wouldn't help any.
Picture a large bottle with a smaller bottle inverted, glued in through the base and cut flush to the bottom of the larger bottle.
If your seam was watertight the outer bottle could be filled with a fluid of your choice while the amp stays lovely and dry but appears to be immersed.
I hope you can follow this, my drawing skills leave a lot to be desired and really wouldn't help any.
I used to work for an electric utility so I know a little about the issues with mineral oil.
First of all understand that this stuff is normally used to cool and insulate transformer windings with potentially 1000s of volts between turns. It is a much better insulator than air. Moist air, gasses from arcing, particles, and overheating can all break down its dielectric strength. Oil is frequently tested for quality. If it is bad it usually means there is a problem with the transformer. If the stuff becomes as conductive as air... BOOM!
I also know that if oil comes out of a transformer looking like a batch of French Fries had been cooked in it, that is VERY bad.
I think the idea of submersing a chipamp in mineral oil is great. I agree that an LED in there (maybe even one of those color changing ones) would be even cooler. I don't expect you'll have any problems with the oil breaking down or overheating. Transformer cores can run in the 120C range. I would suggest you use a heatsink on the chip to help conduct the heat into the oil better. At the power levels your talking about I doubt this will need to be very big.
If your sealing the bottle leave an air pocket (preferably with dry air) in there. The oil will contract and expand due to thermal effects. If it was sealed tight with no air pocket you might even crack the bottle.
How do you plan on making the connections outside the bottle?
First of all understand that this stuff is normally used to cool and insulate transformer windings with potentially 1000s of volts between turns. It is a much better insulator than air. Moist air, gasses from arcing, particles, and overheating can all break down its dielectric strength. Oil is frequently tested for quality. If it is bad it usually means there is a problem with the transformer. If the stuff becomes as conductive as air... BOOM!
I also know that if oil comes out of a transformer looking like a batch of French Fries had been cooked in it, that is VERY bad.
I think the idea of submersing a chipamp in mineral oil is great. I agree that an LED in there (maybe even one of those color changing ones) would be even cooler. I don't expect you'll have any problems with the oil breaking down or overheating. Transformer cores can run in the 120C range. I would suggest you use a heatsink on the chip to help conduct the heat into the oil better. At the power levels your talking about I doubt this will need to be very big.
If your sealing the bottle leave an air pocket (preferably with dry air) in there. The oil will contract and expand due to thermal effects. If it was sealed tight with no air pocket you might even crack the bottle.
How do you plan on making the connections outside the bottle?
Another approach would be to use a heat pipe from a CPU cooler that would exit the bottle and form the basis for a "flower" or other decoration made from aluminum or copper.
You have to be careful when using mineral oil. It has an annoying habit of dissolving some plastics over time. The HV supplies for some of our equipment have suffered this fate.
You have to be careful when using mineral oil. It has an annoying habit of dissolving some plastics over time. The HV supplies for some of our equipment have suffered this fate.
Thanks for the insights drew and drproton.
Drew: how can i test if the oil will dissolve any plastics on the amp? can I simply soak it for a while, or do these things happen on the order of years?
Drproton: I haven't quite decided yet. I'm either going to run them out the top, drill a hole in the bottom and lie it horizontal, or file a notch in the cut I make. All holes would be epoxied tight.
Drew: how can i test if the oil will dissolve any plastics on the amp? can I simply soak it for a while, or do these things happen on the order of years?
Drproton: I haven't quite decided yet. I'm either going to run them out the top, drill a hole in the bottom and lie it horizontal, or file a notch in the cut I make. All holes would be epoxied tight.
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