Compass air bubbles

[Wayland]

I'm starting to get annoyed now.

I just looked at my latest compass and it's got a big air bubble in it.

It's not a cheap one and it's not the first for this to happen to. I have a pile of old suunto and silva compass' that aren't worth a damn any more because they have big bubbles that affect the swing of the needle.

Does anyone know a way to repair these darn things.

 

[scanker]

Does (gently) warming it remove the bubble? I'm talking body heat or maybe airing cupboard at most. If the bubble's big, I doubt it would work, but might be worth a try if it's knackered anyway.

 

[stu1979uk]

Hi,
Only advice I had on this was to gentle heat the compass near a radiator or something.
I think the idea behind it was the water would expand therefore the bubble would disappear.
I tried this and the bubble got a little smaller but was still there- worth a shot though.
Stuart

 

[littlebiglane]

I found both warming it and taking it downstairs helped for some reason the bubble was bigger up stairs.

 

[Chopper]

I spoke with Silva regarding this very problem, unfortunatly the news was not good.

I was told that no matter what I tried it would not work.

They advised that I bought a new one.

 

[Wayland]

I found both warming it and taking it downstairs helped for some reason the bubble was bigger up stairs.

Do you live in a very tall house???

I spoke with Silva regarding this very problem, unfortunatly the news was not good.

I was told that no matter what I tried it would not work.

They advised that I bought a new one.

That's what I've been told before I think If I buy another one it may well be a dry type if I can find a good one.

It certainly won't be an expensive Silva/Suunto jobbie. :bluThinki

 

[Tadpole]

I'm starting to get annoyed now.

I just looked at my latest compass and it's got a big air bubble in it.

It's not a cheap one and it's not the first for this to happen to. I have a pile of old suunto and silva compass' that aren't worth a damn any more because they have big bubbles that affect the swing of the needle.

Does anyone know a way to repair these darn things.

If, as you say that, you have a pile that ‘aren’t worth a damn anymore’ because of the air-bubble, I think it would be worth sacrificing one as a test subject. Drill a small (and I mean small) hole in the base of the compass, and using a syringe draw out some of the liquid, find out what it is, (water, oil etc) then fill up the compass letting the fluid expel the air bubble. Carefully seal with silicon. Use as a second compass until you find if the experiment works or not

 

[PJMCBear]

How about warming it in a pan of water to see if you can force the bubble out? Once it's out, allow the compass to cool in the water so it can't suck air back in, only fluid.

Don't know if it would work, but it's something you could try.

 

[Dougster]

I spoke with Silva regarding this very problem, unfortunatly the news was not good.

I was told that no matter what I tried it would not work.

They advised that I bought a new one.

They said something simliar to me:

Last one you bought crap? Buy another one from us.....

 

[fishy1]

If, as you say that, you have a pile that ‘aren’t worth a damn anymore’ because of the air-bubble, I think it would be worth sacrificing one as a test subject. Drill a small (and I mean small) hole in the base of the compass, and using a syringe draw out some of the liquid, find out what it is, (water, oil etc) then fill up the compass letting the fluid expel the air bubble. Carefully seal with silicon. Use as a second compass until you find if the experiment works or not

I would think you'd need to drill two holes or you run a risk of imploding the compass, and I doubt you could manage to get any out with a syringe without two holes.

 

[andy_e]

If it's a decent Silva or Suunto then chances are it'll be oil-filled - mineral oil probably you could try PJMcBear's suggestion in a shallow oil-bath instead. Or Tadpoles suggestion, but sacrifice two compasses - using the liquid from one to fill the other - if you have two of the same type that are duff.

 

[Doc]

I have one of these:

http://www.trunord.com/

They are undamped - no liquid filling- so cannot get bubbles, and are beautifully made in brass. They also come from Minnessota which has a huge bushcraft/canoeing heritage.

The TruNords are much better than the current Marbles compasses which are liquid damped and made in China.

Old Marbles compasses from ebay are as well made as the Trunord and are not liquid filled. However the jewelled bearings can get slightly sticky with age (though I have 40 year old one that's still pretty good).

If buying a Trunord I would suggest you get it uncompensated - ie, without correction for magnetic variation. I had to send mine back as the correction was incorrect for the UK - I requested it reset to zero correction and all is well. The magnetic variation is pretty minor in the UK just now anyway, and I prefer to allow for it myself.

 

[Tadpole]

I would think you'd need to drill two holes or you run a risk of imploding the compass, and I doubt you could manage to get any out with a syringe without two holes.

If you have access to an 18 gauge needle (a common needle size) the OD of that needle is 0.838mm, so drilling a 1mm hole will give you 0.162mm clearance. More than enough when using mineral oil or water. If you can get hold of a needle used to inject Insulin, which is most likely to be a 30 gauge, (0.140mm) this would give you at least 0.86mm clearance.

 

[IanM]

I spoke with Silva about this and was told that the liquid was a proprietary mix and they would not say what.

It is a low freezing point oily liquid. I tried topping up with silicon oil which seemed the most likely but it would not mix and ran around inside worse than the air bubble so I dumped the lot and replaced with high alcohol vodka (as used for many years in the Arctic's) that just took all the paint off. Also the oily stuff prevented a glue blob to seal the hole from sticking.

So, I now have a spare case and a damaged capsule (no, Silva will not just sell capsules) I replaced with the same so I have a few spare parts now.

My recommendation, drill a couple of small holes, drain out the liquid and use it dry, but it will never be completely empty, the oily stuff seems not to evaporate.

 

[Doc]

An alternative would be to use the needle to drill the hole. You can easily drill a hole in a fingernail by just rotating a hypodermic needle on the same spot - we routinely do this to drain subungal haematomas (blood under the nail). It would probably work on a plastic compass capsule. Not sure about sealing it up again as the hole will be all oily.

Wayland, if you need any needles just PM me (sorry, this is not a general offer to everybody - you'll understand it's not the sort of thing I want to be sending out to people I don't know well.)

 

[Jared]

Have read that cleaning them out with 100% isopropyl alcohol does the trick as it will evaporate out, then completely refilling with new oil.

If you try and top up the existing oil, you have to identify it to put in something mutually soluble otherwise the oil will become milky/cloudy, which isnt good.

 

[spamel]

<snip>
It certainly won't be an expensive Silva/Suunto jobbie. :bluThinki

Ha! Ha! You said JOBBIE!

 

[rik_uk3]

You think you've got problems, try getting the bubble out of this

 

[Jared]

You think you've got problems, try getting the bubble out of this

http://www.bpsc-marine.co.uk/

 

[Glen]

If your going to try any of the heating methods I think you need to find were the leak/weakspot is in the seal and position the bubble there during the heating process. Else the air, which will also expand more than the liquid, will have no way of escaping, forcing more liquid out.

One way that _might_ work would be to break the seal in one place, position it with air bubble at the breach you made,so you know it will come out there, heat till air is forced out the break then quickly go over the whole seal with a sealant, hoping it seals both your fresh made breach and any original weak spot in one go.