Ritchie compass air bubble

[jimd333]

I just replaced the o-ring and compass fluid on my Ritchie "Navigator" compass. Does anyone have any tips on removing that last bit of air that creates an air bubble at the top of the compass?

[Bill O]

Was you compass oil and compass cold/refrigerated when you assembled? This will help.
It was a long time ago when I replaced a compass diaphragm, but do remember it took a few tries to get all the air out (eventually I was successful).

[jimd333]

I didn't cold soak. Thank you for the tip!

[Mickeyrouse]

If the air bubble is small enough it will evetually go into the fluid solution. But try to keep it as small as possible.

[Striker]

The easy way to ensure no bubble is to place the fluid in a vacuum for 24 hrs, fill the compass. The bubble that is present will disappear within 24 hrs.
Easy.

[jordanbigel]

Originally Posted by Striker

The easy way to ensure no bubble is to place the fluid in a vacuum for 24 hrs, fill the compass. The bubble that is present will disappear within 24 hrs.
Easy.

You do make it sound easy - so simple. Now, where do I get a vacuum? Will my hoover work? (of course not, just kidding).

So how do you "place the fluid in a vacuum for 24 hrs"? What equipment do you need to do this? Thanks.

[Yellowtulip]

Originally Posted by jordanbigel

You do make it sound easy - so simple. Now, where do I get a vacuum? Will my hoover work? (of course not, just kidding).



So how do you "place the fluid in a vacuum for 24 hrs"? What equipment do you need to do this? Thanks.

Perhaps he means to cool it then keep it in a vacuum FLASK to keep it cool?

[Striker]

No, I mean place in a vacuum. Years back on my first compass rebuild i made a container with plumbing fittings and attached a friends oil vacuum tank to it when the fluid was inside.
Now i would just put it in the vacuum chamber i use to stabilize wood for knife handles. That uses a vacuum pump, like used by air conditioner guys.
So, anyone you know might have a vacuum pump? Knock up a container and connect to vacuum pump. All the fittings available from home depot.
Or, know a bladesmith?. Just googled “vacuum pump” , harbor freight has a junky unit for $16. Amazon has a big unit for $54

[Chris Cringle]

Leave it alone. The bubble will go away by itself in a couple of weeks.

[NorthCoastJoe]

We filled ours and let it sit overflowing it a bit, the filling port facing up.
When we sealed it there was no bubble, even 3 years later.

[B25Matt]

Tilt the fill hole so that it's pointing upward and fill the last few drops from a syringe. Overfill by a few drops, make sure no air bubbles are trapped, its a small fill hole, and easy to trap minute air bubbles. Finally, seal it with the pre wetted stopper screw.

Pull the diaphragm out a little to increase volume for the final few drops.

[jimd333]

Incidentally, after replacing the o-ring seal at the dome flange, it was discouraging to watch the air bubble grow over the next few days. Then the slow leak stopped. Apparently, the new o-ring needed time to swell before sealing completely.