fingerprints last

[mrnoface]

i know this may seem like a lame post.. i am aware that fingerprints which are on paper can last for up to weeks.. but how about plastics and metals? was curious to know how long they would last... it cant be forever?

-mnf thanks for not banning me on this one

[nbk2000]

Dude...grammer!

:rolleyes:

Use punctuation marks at the end of a sentence, like . or ! or ?, understand?

Capitalize the beginning of a sentence.

Use "I" when referring to yourself, not "i", which shows you're too lazy to even hit the shift key. :mad:

Show that you care about the Forum by using proper grammer, so the rest of the world doesn't think we're a bunch of illiterate 'tards who can't even use our own language properly. ;)

It's hard to take someone seriously when their posts look like a 3rd grader typed it. :p

You're the second person in a minute that I've had to tell this.

Anyways, it is true that fingerprints can last for many decades on some surfaces. But, there are differences in fingerprints. Childrens fingerprints tend to disappear because the oils secreted from their fingers are composed of more volatile factions than those of adults, which form permanent residues.

[Koviack]

Originally posted by nbk2000

Anyways, it is true that fingerprints can last for many decades on some surfaces. But, there are differences in fingerprints. Childrens fingerprints tend to disappear because the oils secreted from their fingers are composed of more volatile factions than those of adults, which form permanent residues.


Does this mean you could say, wash your hands in something that would eat away the oil, just to be on the safe side if you left prints somewhere?

[Cyclonite]

Hmmm...Well if you left prints washing your hands in a solvent afterwards would be pointless...If you ment before I guess your planning on leaving prints or you would wear gloves...No wait, you don’t have to wear gloves if you soak your hands in 90% H2SO4 for 30 min before you plan on leaving prints......

[vulture]

Not only would it (product to remove finger grease) severely dehydrate your skin, resulting in poor handling, but it would also irritate thereby increasing the production of grease and other fluids.

[Anthony]

I have a question related to this topci that I've been meaning to ask for some time.

The scenario is steralising materials/supplies that you intend to cache.

Some items such as weapons are too much of a legal liability to have in/around your home, but you want easy access to them if need be, so you cache them. But there's always a risk of them being discovered, they could end up with the police who might decide they're serious enough to try and find out who put them there.

Say our example is a regular auto handgun, how can we ensure that fingerprints are removed from it?

Would scrubbing it (old toothbrush would be handy) with a detergent such as washing up liquid suffice to remove any prints?

I imagine that removing DNA samples such as fair and skin fragments would be more difficult, could it be done with damaging the item? E.g solvents and corrosives would damage the gun, immersion in water would cause corrosion in storage.

[zaibatsu]

If I was planning to remove all traces on a gun, I'd look at the degreasing processes used prior to anodising or bluing. If have to remove all the oils before you can blue or anodise something, then that'll obviously remove any fingerprints. Put it in an oven at a low temperature for a while to dry it out. After that you'll need to oil it up quickly, with thick grease, possibly something like the moly grease used in lubricating airgun cylinders, also available in bulk from car shops.

[mrnoface]

I believe coating the hardware with WD-40 would be sufficient.

- mnf

[Agent Blak]

oils from you skin can cause oxidation on the metal; basically etches your print into the steel. This wouldn't be true on Stainless(ie. 400 series steel) but, definitely would be true on higher carbon steel and alloys(which most knives and guns are).

[zaibatsu]

I don't think WD-40 is a good idea, it does displace water (hence the W D bit) but I believe it will evaporate over time and can "gum up" a mechanism. What I think is the best way is to use a really thick grease, like the cosmoline I believe lots of surplus rifles are stored in. They come out of all the grease with nice bores etc, so it must work to some extent.

[vulture]

After I've treated the barrel of my airgun with WD-40 I can spot hundreds of my fingerprints.
It seems to increase their visibility and if you touch the barrel, the prints tends to be much "deeper".

[zippoxiv]

Military surplus rifles are stored in extrmely heavyweight grease called cosmoline as zaibatsu said. Anyone who has purchased such a rifle knows how much of a bitch it is to remove from every crack and crevice of a rifle, but it does do the job of preserving the gun. Cosmoline can be substituted with any heavyweight grease such as axle grease for any long term storage of a firearm (long term would be over a year). It primarily helps to protect the metal surface from moisture and other corrosion elements, and must be completely removed before you go about firing the firearm again. A lightweight gun oil or WD-40 does the trick for between trips to the range, but something long term enough to be called a cache would call for a kind coating of cosmoline.