storing a compass in a metal container?!

[forrestdweller]

sorry if this is a daft question...: last year i bought a ""sliva mini ranger"" (they had two laying around in the shop-strangely one of them (=mine now) said ""made in sweden"" while the other had no markings...) as a backup-compas for my EDC bag. i made a wooden container for it and(recently) a leather cover for the container and just stored it in a ziplock bag. i'm planning to put all the small items into a box to keep a better order in my shoulder bag; the question i'm pondering about is "" plastic box or stainless steel(providing i can find one the right size)?!" BUT would that effect the performance of the compass?! (as everyone on this site will know: reading a compass next to a source of magnetism will result in misreadings... but scrolling through the net shows me TONS of survival tins with button compasses in them...)

 

[mrcharly]

*storing* it in a metal box won't have any effect on accuracy.

You just need to take it out to use it.

 

[forrestdweller]

after 83 views finally a reply...
i was aware of the fact that i have to take it out... . i lost the instruction sheet which came with the compass, but it said something about NOT storing it near metal objects- so i was worried that storing it inside a metal object could affect it's accuracy. (my maincompass- a recta dp65- has been often stored NEAR metal objects over the years without ill effect, but this might vary from maker to maker...(=better safe then sorry, hence my question))
so now i can ""hunt"" for a suitable stainless-steel container

 

[sandbender]

"...i made a wooden container for it and(recently) a leather cover for the container..."

That sounds nice, any pictures?

"...i lost the instruction sheet which came with the compass..."

Here you go...

http://store.tech4o.com/media/document/Ranger_CL_Eng_IM_09.pdf

 

[forrestdweller]

for the link to the instruction sheet- bookmarked to my PC (it's NICE to have my own internet access after all these years...)

have'nt taken any pics of the container, yet as it's nothing special- just some pieces of wood glued together, ""attacked"" with my magnifying glass (=humble attempt at decoration) and oiled... . i'm technically challenged and have to figure out yet how to post pics...

 

[forrestdweller]

for the link to the instruction sheet- bookmarked to my PC (it's NICE to have my own internet access after all these years...). it says ""placing next to metal objects,microwaves, high tension wires, loudspeakers (although i will NOT carry them in my pockets) etc. can reverse polarity""...

have'nt taken any pics of the container, yet as it's nothing special- just some pieces of wood glued together, ""attacked"" with my magnifying glass (=humble attempt at decoration) and oiled... . the leather cover is just made from some scraps, too...
i'm technically challenged and have to figure out yet how to post pics...

 

[Joonsy]

It’s often stated compasses are affected by being close to metal, however it’s not often stated ''which'' metals. As I understand it I believe they are only affected by ''ferrous'' metals (metals containing iron) because iron can be magnetised. i don’t think they are affected by ''non-ferrous'' metals. Put a magnet on a bit of metal, it will stick to the ferrous but not the non-ferrous., non-ferrous metals are not magnetic. Incidentally the triangular metal bit on the top of trig points for holding the theodolite is brass so you can sit your compass directly on the top and take an accurate bearing to check the accuracy of your compass.

Examples of non-ferrous metals (non magnetic):- lead, copper, brass, aluminium, stainless steel.

However electrical items can affect compasses.

 

[sandbender]

"...Examples of non-ferrous metals (non magnetic):- lead, copper, brass, aluminium, stainless steel..."

So keeping my compass in my zebra billy can won't be a problem then?

 

[pysen78]

a note on stainless: some can be magnetic, some not. Depends on the alloy I suppose. Try it out with an ordinary fridge magnet.

 

[Joonsy]

So keeping my compass in my zebra billy can won't be a problem then?

as i understand it if your (stainless) zebra has no iron content apparenty not Just to add to my reply above, in this link explaining how to use a trig point to check if your compass is accurate it states why certain metals (brass in this case on a trig point) do not affect your compass:-

read about the 26th line down in explanation http://micronavigation.com/forum/index.php?topic=35.0

edited just to add;- it would have to be 100% stainless steeel, some cheap 'reputed' stainless is not actually 100% stainless, try a magnet to see if it sticks.

 

[mrcharly]

edited just to add;- it would have to be 100% stainless steeel, some cheap 'reputed' stainless is not actually 100% stainless, try a magnet to see if it sticks.

I'm sorry but there is no such thing as '100% stainless steel'. Stainless steel is an alloy mostly containing Iron, with some Chromium and usually other metals.

Different proportions of the metals produce stainless steel with differing characteristics; strong resistance to acid, for instance, or harder.

Some stainless steel alloys are magnetic - my SAK is magnetic.

There are other alloys, not containing iron, that are magnetic. Certain alloys of Platinum are magnetic.

 

[Joonsy]

I'm sorry but there is no such thing as '100% stainless steel'

happy to be corrected if wrong there is a big variation in quality of stainless steel.

 

[sandbender]

All steels have an iron content, some steels are 'non magnetic'. I can imagine that billy can steel will vary from batch to batch and brand to brand. However if we are talking about a plastic bodied compass, like a Silva, is there any likelihood that its accuracy might be compromised by being stored/carried in a billy can?

I would be curious to have a definitive yes/no answer for this.

 

[rik_uk3]

I store my compass in a wooden box...its a bit big for hiking though

 

[Joonsy]

All steels have an iron content, some steels are 'non magnetic'. I can imagine that billy can steel will vary from batch to batch and brand to brand. However if we are talking about a plastic bodied compass, like a Silva, is there any likelihood that its accuracy might be compromised by being stored/carried in a billy can?

I would be curious to have a definitive yes/no answer for this.

Looking in to stainless steel a bit more (there are many variants), the amount of nickel added affects the structure of the iron and it’s degree of magnetism. Zebra pots are made from Austenitic stainless steel which has an amount of nickel added that makes the stainless steel virtually non-magnetic. The type of Austenitic used for Zebra pots is called Type 304, (you can see this on their labels), sometimes it’s also called 18/8 which is the same thing. Therefore accordingly one would think it would be safe to store a compass in a zebra pot as Austenitic Stainless Steel Type 304 is non-magnetic. This is the most widely used type of stainless steel for cooking utensils. Swiss army knives are made from Martensitic stainless steel which is magnetic as it has a completely different structure to Austenitic. See this link sandbender, scroll down to bottom of page where it explains the different Types of Stainless Steel.

http://en.wikipedia.org/wiki/Stainless_steel

this link explains the ''non-magnetic'' stainless steel as used in Zebra Pots

http://mtm-inc.com/reduce_project_risk/how_nonmagnetic_are_304_and_316_stainless_steels/

Austenitic Type 304 Stainless Steel is regarded as non-magnetic, zebra pots are made from this.
The least magnetic of all stainless steel is Type 316 which is often called Marine Grade.
Swiss Army Knives are made from Martensitic stainless steeel which is magnetic.

 

[mrcharly]

You can *store* your compass in any metal tin.

the main risk to damaging your compass is other magnets - so there is an argument for storing it in a steel, magnetic, tin, to protect it from other magnets.

Compasses on Ships and boats have large lumps of iron near them (carefully placed by an expert) to remove the effects of other bits of iron on the ship. The close proximity of these lumps of iron definitely don't damage the compass!

 

[santaman2000]

It’s often stated compasses are affected by being close to metal, however it’s not often stated ''which'' metals. As I understand it I believe they are only affected by ''ferrous'' metals (metals containing iron) because iron can be magnetised. i don’t think they are affected by ''non-ferrous'' metals.....

Copper is non ferrous. Would you want to tke a compass reading near a copper object?

a note on stainless: some can be magnetic, some not. Depends on the alloy I suppose. Try it out with an ordinary fridge magnet.

as i understand it if your (stainless) zebra has no iron content apparenty not.........

I'm sorry but there is no such thing as '100% stainless steel'. Stainless steel is an alloy mostly containing Iron, with some Chromium and usually other metals.

Different proportions of the metals produce stainless steel with differing characteristics; strong resistance to acid, for instance, or harder.

Some stainless steel alloys are magnetic - my SAK is magnetic.....

Actually not just stainless, but MOST if not ALL steel is an iron alloy of some type. Indeed it's the other alloying elements that make it stainless. The most common non-magnetic stainless alloy is 301 series (the most common alloy in aircraft stainless)

I have no knowledge or experience with Zebra (or any other billy cans) but most stainless kitchen cookware is magnetic.

All that said, the OP's question about was about storing his compass. If you're going to take a reading why on earth would you still have your cookware out? Not being flippant but it just seems moot that it would be nearby when you could just put your pack down and step away while you shoot an azimuth; surely other are other metal objects in your pack to avoid anyway? Not just the billy can?

 

[santaman2000]

You can *store* your compass in any metal tin.

the main risk to damaging your compass is other magnets....

Yeah. Such as tossing it in the car's dash pocket (near the speaker magnets)

 

[sandbender]

"...The type of Austenitic used for Zebra pots is called Type 304, (you can see this on their labels), sometimes it’s also called 18/8 which is the same thing. Therefore accordingly one would think it would be safe to store a compass in a zebra pot as Austenitic Stainless Steel Type 304 is non-magnetic....Martensitic stainless steeel which is magnetic..."

Brilliant, there is I think nothing that one cannot find out by asking on BCUK.

"...If you're going to take a reading why on earth would you still have your cookware out?..."

Not so much the out, I was thinking about it being stored in there, the billy is tough and I often use it to store fragile items during transit, such as food when out walking or chargers and camera bits when in transit to a destination. I was simply curious to know if keeping my plastic bodied Silva 54 in there would harm it.

I don't think it will but was curious to what folks had to say.

 

[demographic]

as i understand it if your (stainless) zebra has no iron content apparenty not Just to add to my reply above, in this link explaining how to use a trig point to check if your compass is accurate it states why certain metals (brass in this case on a trig point) do not affect your compass:-

read about the 26th line down in explanation http://micronavigation.com/forum/index.php?topic=35.0

edited just to add;- it would have to be 100% stainless steeel, some cheap 'reputed' stainless is not actually 100% stainless, try a magnet to see if it sticks.

If I remember it right Austenetic stainless steels (think, kitchen sink or 18/8 type) aren't ferromagnetic but Martensitic (stainless knife blades if I remember right) can be.
Fairly sure Cobalt can be magnetised also.
Thinking back a few years but I used to test welds using a technique called Magnetic Particle Inspection so I remember a bit about it.

There's ferromagnetic (attracted to a magnet) and can be magnetised.
Nonmagnetic.
Diamagnetic which is generally a fairly weak effect (except in superconductors) and actually repels a magnet.
And Paramagnetic which is attracted to a magnet (usually a weak effect) but it can't be magnetised. Aluminium and Copper being in this bracket.