How do I remove air bubble in oil-filled compass?

[divad]

-But how does one remove the bubble??

Quit buying Suunto compasses. My high-profile non-Suunto is going on 7 years without a bubble. Works fine without the bubble.

 

[tridacna]

Quit buying Suunto compasses. My high-profile non-Suunto is going on 7 years without a bubble. Works fine without the bubble.

Where did you read that the OP had a SUUNTO product? I have three SUUNTO compasses, one over twenty years old; none have any issues.

 

[divad]

I was answering the question "how does one remove the bubble?"

 

[mmerriman]

A sealed compass is like a scuba tank you leave in your car in the summer. What's inside expands and contracts with the temperature.

The bubble is there so the silica oil can expand in the heat without bursting the glass. That expanding silica oil has to have somewhere to go under pressure.

Air is "squeezable", Liquid is not. Remember?

So if you had a compass that was sealed and had no air in it, and say you left it lying on the dive boat seat in august in the noon sun, the liquid has room to expand without increasing the pressure very much inside the globe.

Military-style dive compasses are built to withstand pressure changes. Most dive compasses just have cheap plastic cases. Plastic doesn't handle pressure changes very well.

If the bubble grows to the point it's causing the needle to not function properly, then that's a leak. Otherwise an air bubble is normal.

My boat compass has a dime-sized bubble in it. The temperature in my garage in February is a lot different than the temperature is when I'm beached at Radio Island in August. That bubble allows the oil in the compass to expand and contract without increasing the internal pressure very much. On most boat compasses, there's a little brass screw you can remove on the bottom and turn it upside down to add more liquid silicon to it. Wrist mounted scuba compasses don't have that feature. They're made cheap and intended to be replaced when they start leaking.

while dive gear express has that opinion I find it ridiculous. As a mariner, there is no excuse for a bubble in a ship's compass and they are exposed to the elements all day. a good ship's compass has a port so you can fill and remove any bubbles. A cheaper one doesn't and should be replaced when a bubble appears.

 

[tridacna]

I was answering the question "how does one remove the bubble?"

No. You were answering why not to buy a SUUNTO compass. Extraneous, false and unnecessary.

 

[divad]

No. You were answering why not to buy a SUUNTO compass. Extraneous, false and unnecessary.

Certainly not false. In my case, I had three consecutive Suuntos develop hairline cracks in the clear plastic that endered them useless. This was well documented on Scubaboard. It happened to a lot of people.

 

[tridacna]

Certainly not false. In my case, I had three consecutive Suuntos develop hairline cracks in the clear plastic that endered them useless. This was well documented on Scubaboard. It happened to a lot of people.

n=3. Out of total sales over a zillion. Insignificant trifle. Based on my experience, I could argue a zero failure rate. And complaining on SB does not a scientific study make. Your poor handling is more likely a factor. You had 3/3 fail?

I think that we’ve already established that it’s impossible to remove a bubble.

 

[caruso]

I had three consecutive Suuntos develop hairline cracks in the clear plastic that endered them useless.

I suspect user error. Compasses are not intended for use as "anti roll devices for tanks"