Clever ways to stop a mineral oil computer leaking?

JonJ678

JonJ678

JonJ678

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Youre probably familiar with the concept, immerse a board in nonconductive oil instead of air.

One of the (several) problems is oil seeping out along cables. So, were you daft enough to place the motherboard in a box full of oil, how would you seal it while allowing cables to be connected?

On a related note, how would you deal with occasionally changing expansion cards?

Im thinking of ways to extend the lifespan of an embedded platform.

Cheers
 
Anewbe4u said:
Make it so the cables run upwards so oil can't seep out of them?
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Not very "clever" though is it? :p

A clever solution would be,

1. Invent, design and create your own custom wireless standard to transmit all of the data usually transmitted from the motherboard.

2. Use a wireless power system to supply the mobo. Then you can seal the mobo in an air tight box. No cables = no seepage.

3. Build a small robot capable of maufacturing all likely upgrades over the next 10 years and seal him in with the motherboard.

4. Post pics.
 
rubber steals. Or you can mount the motherboard 90degrees so the monitor/keyboard and mouse cables are coming up out the top of the case.


Get one large box to hold the oil, then make a removeable motherboard tray for it. If your planning on just motherboard under water, make everything external. and just have the motherboard pulling out of the top of the case.

If everything is going to be internal from the PSU to optical drives. simly make the box quite large, have the motherboard so all wires come out the top of the case. At the bottom of the motherboard have a small platform for the PSU and hard drives. Then simply unclip 2 things and pull the motherboard out and change hardware. You may have to un plug optical drives. Everything should come out the top of the case to avoid draining off to change hardware. Should be stronger aswell and easier to seal.
 
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Burty88 said:
Not very "clever" though is it? :p

A clever solution would be,

1. Invent, design and create your own custom wireless standard to transmit all of the data usually transmitted from the motherboard.

2. Use a wireless power system to supply the mobo. Then you can seal the mobo in an air tight box. No cables = no seepage.

3. Build a small robot capable of maufacturing all likely upgrades over the next 10 years and seal him in with the motherboard.

4. Post pics.
Click to expand...

Sometimes the simplest ideas are the cleverest!
 
Im fairly certain that oil moving through the cable insulation is driven by concentration gradient. Cables out the top would need an air gap at the top too. Otherwise it would work.

Currently thinking of sealing the ports with epoxy. As long as this is insoluble in mineral oil it'll be fine. Could similarly epoxy the cards in place. It would be particularly irreversible however.

Edit: cant quite see what you mean by rubber seals
 
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JonJ678 said:
Im fairly certain that oil moving through the cable insulation is driven by concentration gradient. Cables out the top would need an air gap at the top too. Otherwise it would work.

Currently thinking of sealing the ports with epoxy. As long as this is insoluble in mineral oil it'll be fine. Could similarly epoxy the cards in place. It would be particularly irreversible however.

Edit: cant quite see what you mean by rubber seals
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My old fish tank had wires comeing out from the bottom left hand side of the tank. All what was stopping the water from coming out was a rubber seal. it was made of 2 apartments (very very small) you can push things into the tank without water coming out. Even if you pushed things through from water side to outside the tank water would not come out. Please dont ask me the name about this or how to make it. I have no clue.
 
Cheers marc, much appreciated. Do you think draining the oil away then swapping cards around would suffice? Im worried that a thin film of oil over the copper contacts could cause problems.

The system i have in mind is far simpler than most, which it probably needs to be for oil to make sense. It's an alix board, cpu and ram soldered on. So only need to worry about a mini-pci card, and a compact flash one.
 
JonJ678 said:
Cheers marc, much appreciated. Do you think draining the oil away then swapping cards around would suffice? Im worried that a thin film of oil over the copper contacts could cause problems.

The system i have in mind is far simpler than most, which it probably needs to be for oil to make sense. It's an alix board, cpu and ram soldered on. So only need to worry about a mini-pci card, and a compact flash one.
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i dont know much about what effects it would do. Im an engineer not an electrician :P i dont think it would cause problems aslong as it didnt settle on the PCBs.. doesnt the water from watercooled pcs leave a thin film inside the waterblocks anyway?

but i can safely say even draining a tank every year or something then having to buy new mineral oil every time to replace it. Would be costly and very much time consuming. which is why you need to design something so you dont have to drain. but being a small system like yours. A fairly simple system i should say i dont think you will have to spend that much time draining and filling up again. I dont think you can get away with draining then filling up with the stuff that already came out.
 
The aim is improving reliability, bearing in mind it's intended as a poe networking device.

Relative to air-filled itll resist external temperature changes and will never have problems with condensation. If properly sealed so oil cant get out, it can also be used in damp places. Or dusty ones.

Oil should cool better than passive air, so lower temps. Higher heat capacity means smaller temp changes so better fatigue resistance. So longer operating lifespan.

Problems are whether the oil will attack it, and maintenance. Its a tempting enough trade off to be worth considering.

Typing on a phone, so apologies if i dont notice newer posts while writing. Cheers all

edit: other people seem to have verified that oil plus computer is good for a year or so, if their processor was fine it should follow that this will be. Unsure about plugging a card into an oily socket though.

Agreed, oil changes would suck. Id be hoping to never open the box, started this thread looking for a way for it to be possible to change hardware if needs must.

You've lost me on the water analogy though :(
 
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JonJ678 said:
The aim is improving reliability, bearing in mind it's intended as a poe networking device.

Relative to air-filled itll resist external temperature changes and will never have problems with condensation. If properly sealed so oil cant get out, it can also be used in damp places. Or dusty ones.

Oil should cool better than passive air, so lower temps. Higher heat capacity means smaller temp changes so better fatigue resistance. So longer operating lifespan.

Problems are whether the oil will attack it, and maintenance. Its a tempting enough trade off to be worth considering.


edit: other people seem to have verified that oil plus computer is good for a year or so, if their processor was fine it should follow that this will be. Unsure about plugging a card into an oily socket though.
Click to expand...

Quick question. What type of oil are you planning useing ? different factors can do different things. I heard somebody used fully synthetic castor oil as used in high revving 2 stroke engines. Suppose to work the best but the draw side the guy made special plates up for the graphics card, processor and ram. He also had to use slot covers for the PCI as it got very thick and clogged up. I read it in a magazine a couple months back.
 
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Look at using potting compounds. This would give you the sealing needed. Remember that the oil can also make its way up inside of cables.
 
Double Glaze the box if you get what I mean, Double rubber stoppers round where the wires come out, then if it leaks the first one it will drip down and take a while for it to fill up to leak out the other hole.
 
I would love to see photos

I can't quite picture the scene in my head, but could not just buy some teflon tape from B&Q and seal the rubber stoppers from the inside of the tank, as well as the ends of the wires. Or even better, go to toys r us and get some playdough, then mould it around the exit and then cover it with teflon tape :)
 
Not sure regarding oil. Horse laxative seems a favorite online, and some people sell liquid designed for this.

Potting compound may be better, or may be worse. Im not sure lower viscousity epoxy would make a difference to the end result but it could be easier to apply.

Im envisioning a continous layer of epoxy covering the back of the ethernet/serial port, overlapping with the i/o plate. Probably a patch covering the sockets soldering points too. Im fairly sure that'll seal it, if not then i cant imagine what would.

At least if i go with epoxy it shows confidence in the products mtbf
 
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