Fixing a Suunto with air bubble - what's that liquid inside?

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Fixing a Suunto with air bubble - what's that liquid inside?

Postby dhcrusoe » Apr 22, 2010 3:12 pm

Hey all,

I've got a Suunto Tandem here, nice instrument, except for that it has an air bubble in the ascension / declination module - works great until I'm measuring anything -45 degrees and greater -- the best stuff to survey! Ok, I figure, that stinks. :doh:

I figure that it's probably possible to pop a small hole in an unnecessary part of the dial face and, with a syringe, fill it back up. It turns out that someone has tried it with a dive gage - http://www.alohashoredivers.com/project ... index.html .

But the question is, what is IT that I need to fill it with? Has anyone else tried this? Or, maybe accidentally broken one open and, in doing so, found out what's inside? Thanks for the tips - really want to measure at -45 and below!

--Dave

:bat sticker:
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Re: Fixing a Suunto with air bubble - what's that liquid inside?

Postby Scott McCrea » Apr 22, 2010 3:19 pm

The liquid is a very light weight oil, as one finds out when the capsule cracks. Suunto's web site says bubbles are ok as long as they do not affect the performance/accuracy. I tried to take the capsule out of one and gave up. I recommend just sending it to be fixed professionally.
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Re: Fixing a Suunto with air bubble - what's that liquid inside?

Postby Chads93GT » Apr 22, 2010 3:20 pm

Its an oil. throw it in the freezer so it expands and the bubble will disappear.

Lol I think I have it backwards.........heat will make it disappear. did you have the compass out in the cold? that generally causes air bubbles.
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Re: Fixing a Suunto with air bubble - what's that liquid inside?

Postby dhcrusoe » Apr 22, 2010 6:30 pm

Oh! Great point! I'll pop it into the microwave :big grin:

(er... or in the sun)
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Re: Fixing a Suunto with air bubble - what's that liquid inside?

Postby Chads93GT » Apr 22, 2010 7:47 pm

I had one of those hiking compasses you get for ......... hiking.......... and after years it got an air bubble. I think i left it in my truck over winter. put it in the freezer and the bubble got bigger. Never tried putting it under hot water...........maybe try that. do you really do that many 45* shots??? perhaps you guys should start doing vertical shots so youd ont have to do such huge angles, hahaha ;)
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Re: Fixing a Suunto with air bubble - what's that liquid inside?

Postby driggs » Apr 22, 2010 9:22 pm

This is a 75% working Suunto Tandem. Before you go taking some dude's advice to slap it in the freezer or high temperature, consider that you my ruin that semi-working clino module (expanding liquids can crack the plastic housing), and consider that creating even a tiny bubble in your compass module will render it frustratingly unreadable.

If you're willing to shell out $70 to have it repaired professionally, you may be interested in this thread: CaveChat - Suunto Repair

If you're a savvy bidder, you can find them new on eBay in the $100 range; perhaps selling yours (honestly!) could help fund the purchase of another. Search for Suunto Tandem on eBay
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Re: Fixing a Suunto with air bubble - what's that liquid inside?

Postby jharman2 » Apr 23, 2010 8:22 am

Chads93GT wrote:Its an oil. throw it in the freezer so it expands and the bubble will disappear.

Lol I think I have it backwards.........heat will make it disappear. did you have the compass out in the cold? that generally causes air bubbles.


Once you take it out of the high temperature environment won't the bubble simply return?
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Re: Fixing a Suunto with air bubble - what's that liquid inside?

Postby ian mckenzie » Apr 24, 2010 2:59 pm

Best (only) source of replacement fluid is another damaged instrument.

If your compass module is unusable because of the bubble, you have nothing to lose in trying to repair it. A clino bubble is no real problem.

AFAIK a professional repair job merely replaces the compass module with a new one. You can try a repair, bugger it up, and then still get the module replaced.

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Re: Fixing a Suunto with air bubble - what's that liquid inside?

Postby Spike » Apr 26, 2010 9:02 am

I have a compass with a bad air bubble and I got to thinking about this thread. I already knew what the fluid inside was from past breakage, but I didn't know what the gas inside was. Did a gas come out of solution when the compass got cold? Not likely. Well maybe the fluid would go into solution with some temp/pressure stress. So for fun I put the compass in a water bath and heated it up. All that happend was the plastic module went from being flatish to domed in about 10 minutes and the bubble got bigger. Not too surprised with that. Then afte removing from heat I saw that the module was loose and rotated within the housing. At this point we have a unusable compass as the sight line is no longer in the right place and now moves freely. Oh well, now we know. Then the interesting part. As the compass cools there is a string of air bubbles streaming into the compass. I was able to rotate the compass module to see where the air was entering the side of the compass. There was 2 small breaches in seal between the flat top of the compass(domed now on this one) and the flat side of the module. I suspect that these formed when the compass got too cold and the oil contracted, sucking air in through these micro breaches, forming an air bubble. As the compass later warmed I suspect some oil was expelled out through these same breaches.

The verdict, send them in for repair.
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Re: Fixing a Suunto with air bubble - what's that liquid inside?

Postby fr73ed » Apr 30, 2010 9:09 pm

snip (Thanks for the tips - really want to measure at -45 and below!)

Wow! Where do you survey at those temps ?

But I digress... Years ago I attempted to repair a leaky suunto, had a crack in the top.
Found a light weight oil as someone mentioned.
I refilled with some light oil, jet A or somethin, don't remember , and attempted to seal it back up with several types of epoxy.
Never could git it to stay closed.
The oil prevented a good adhesion.
Prolly need to contact a suunto repair shop, and buy a replacement insert. Usta be cheap, but now...?

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Re: Fixing a Suunto with air bubble - what's that liquid inside?

Postby ian mckenzie » May 1, 2010 12:02 pm

fr73ed wrote:I refilled with some light oil, jet A or somethin, don't remember , and attempted to seal it back up with several types of epoxy.
Never could git it to stay closed.
The oil prevented a good adhesion.

You need to push a heated pin into the bubble of the upturned module, then use a syringe to refill, leaving a small bubble so the hole doesn't get oily. Then reseal with a hot knife. I have done this successfully, though the reheated plastic is brittle and the module is not as strong as before, and you need to smooth it out so it fits back into the body. But nothing lost, as the module was previously unuseable anyway.

I tried using various light oils, but just could not duplicate the light viscosity of the fluid from another crippled module.
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Re: Fixing a Suunto with air bubble - what's that liquid inside?

Postby Evan G » May 1, 2010 1:20 pm

Most marine compass are filled with an alcohol/glycerin/mineral oil combo.

Here is an interesting read: Liquid Inside Compass

I can describe the basic ideas.

You (and the original makers), want something clear and non-yellowing,
moderately viscous, and harmless to metal and paint.
Mineral oil is pretty good in that regard.
100% Isopropanol would not be terrible, but it is not very viscous and
leaks and evaporates.
Glycerin is viscous and will not corrode metal (might even dissolve small
amounts of water leaking into the case, protecting metal from corrosion).
However it is a strong solvent and kills most paint in the not-too-long run.
It does the same thing brake fluid does to auto paint, but slower.
Fluorocarbon oils are entirely safe for paints, but it is overkill, and I
am sure that is not what was used in 1943.
Silicone oils can be harmless too.

At this time, you want something mutually soluble with the old oil.
so you need to get some of the old oil out of the compass to try it.
Put a drop into each clear glass of:
- water,
- drug-store mineral oil, (or maybe vegetable oil is quicker for you)
- 91%-grade rubbing alcohol (91% isopropanol, 9% water)
- drug-store glycerin
and let them sit still a while,
and watch to see which one bends to near-invisibility first, instead of
staying in a sharply-defined glob.
Only wiggle or shake if it takes longer than an hour to dissolve.
If shaking makes the solution cluttered or milky, that is bad, very insoluble.

My guess the mineral oil will dissolve first and smoothest.
I might keep all the old oil that can be poured out in some tiny bottle,
and fill the compass with the new mineral oil.

The most conservative way to clean out old oil is to refill with you
chosen new oil and shake or soak, then pour out and refill again.
If you wish to do a quicker or more thorough clean-out of old oil or new,
then 100% Isopropanol is your safe universal solvent that can evaporate to
dryness.
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Re: Fixing a Suunto with air bubble - what's that liquid ins

Postby Extremeophile » Oct 3, 2012 10:01 am

An old thread, but I thought I'd share a recent experience. I have a pair of Suunto Tandems that are in good shape. I recently went surveying in a cave here in Colorado at an elevation of ~10,000'. When I got the instruments out I had small air bubbles in 3 of the 4 capsules (2 compass and 1 clino). This seemed like quite a coincidence. When I got back to Denver (5,315') I only had one very small bubble remaining in one compass capsule, and the others had disappeared. I put that instrument in the sun and within 15 minutes that air bubble was also gone.

The preceding messages are confusing as to whether there's any benefit to putting the instruments in cold or warm conditions to help eliminate bubbles. I might have concluded that doing either will probably just make things worse. I'm confused as to whether the bubbles appearing had anything to do with altitude, or whether it's strictly a temperature phenomenon. It was colder where we were, but maybe just down to freezing. I can't imagine altitude causing the problem since the capsules are sealed and should maintain their own pressure, but maybe the capsule window is flexible enough that a reduction in outside pressure causes the capsule to balloon a little resulting in the air bubbles. In any case I thought I'd share my observations in case anyone else experiences similar issues. The bubbles were never big enough to create a problem in instrument reading.
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Re: Fixing a Suunto with air bubble - what's that liquid ins

Postby Hal » Nov 2, 2012 11:37 am

The Suunto capsules are made of acrylic, so you need to use an acrylic cement to solvent weld the leaks. Epoxies and other adhesives will not stick well. I have found that multipurpose cement for ABS, PVC, CPVC works great, but dries slightly opaque. Acrylic cement is just acrylic dissolved in a solvent, so it will probably dry very clear.

The dampening fluid in compasses used to commonly be kerosene (which is a light mineral oil). Older instruments with petroleum smelling oil, were probably filled with kerosene. The viscosity of kerosene is ~ 10 cSt. A silicone oil with a similar viscosity is probably what is in the Suunto instruments now. My best guess is this, or something very similar, is used to fill the capsules, http://www.clearcoproducts.com/pdf/damp ... -10cSt.pdf. You have to buy a gallon to get this stuff, and it probably is not cheap. Silicone oils are also known as Dimethicone and are used as cosmetic and food additives. I found a DM6 Dimethicone oil online in small quantities and have some on the way to test. This is a 6 cSt viscosity silicone oil, so it is very low viscosity. It freezes < -70 C and boils > 200 C. It also has very little change in viscosity or volume over large temperature ranges, and is very inert, so it seems like the best choice by far.

The silicone oils also evaporate easily and are miscible with the solvents in the cement, so a little leakage around the hole is no big deal. Just wipe off the excess and let it dry for a few minutes and the cement will make a permanent bond to the acrylic that should not leak. The filling hole should be melted closed and flat using a hot knife or heated needle, etc. and then sealed with the cement. I just fixed my Suunto tandem using the oil from an old sticky inclinometer, so I'll see how this holds up. I'll test the new oil when it arrives in the old inclinometer and report back on how well it dampens.

To really do this right, you could also de-gas the oil under vacuum before re-filling so any small bubbles remaining will dissolve back into the oil. However, a small bubble is not going to be a problem.

Hope this helps.

Hal
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Re: Fixing a Suunto with air bubble - what's that liquid ins

Postby Hal » Nov 5, 2012 10:36 pm

I received the 6 cSt dimethicone today. It is still heavier than the fluid in my old inclinometer. I refilled with the new oil and it is slightly sluggish, but still acceptible. If you are just topping off to displace a bubble, then this should make little difference.
http://www.lotioncrafter.com/dm6-dimethicone.html

The oil in my old instrument evaporated at room temp, but the new oil does not. Only oils <3 cSt will evaporate at room temp, so the oil has to be either 1, 1,5 or 2 cSt. My guess is the lightest dampening fluid available is the one used, which is 1 cSt (same viscosity as water).
http://www.clearcoproducts.com/pdf/vola ... F-1cSt.pdf.
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