Laser Pointer Point To Coine?

All said high power laser pointer can burn something such as paper and balloon, so if the pointer point to such like coin material quality, what result will it happen? Anyone try?

 

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Laser pointer?

 

I highly doubt a laser pointer has enough energy to affect the surface of a coin.

Coin doctors have been known to use lasers to doctor coins. I have heard of lasers being used to get rid of hairlines and small scratches on Proof gold. I also seem to remember lasers being used to enhance certain details, e.g. Liberty's hair on Large Cents.

 

A high power laser could affect a coin and by high power we are talking in the kilowatts and up range, but a "high power" laser pointer is typically somewhere in the 5 watt range.

 

it could hurt your eyes, coins do reflect light, if you use the wrong angle you could have some serious eye problems.

 

I'll pile in on this one, as a sometime laser (and general light-source) enthusiast.

Coins tend to be reflective, which means that most of the light that hits them bounces off. They also conduct heat really well, so even if you focus the light down to a pinpoint (which is what lets lasers pop balloons and light matches), the heat will just disperse throughout the coin.

So, unless you've got a serious metalworking laser, nothing will happen to your coin. Even an illegal 50mW laser "pointer", which can instantly produce blind spots in your eye, won't do a thing. The ludicrous 1W handheld lasers that are now becoming available would make the coin warm, but that's about it. Meanwhile, though, most of that power would be reflecting off the coin, and reflections at those power levels can burn a permanent blind spot into your retina before you can blink.

I have a big (16x20-inch) Fresnel lens that I can use to focus sunlight onto a spot about the size of a cent. By my calculation, it dumps about 100 watts of power into that spot.

If I put a clad dime or quarter at the focus, it gets really hot, and turns grey from oxidation.

If I put a copper cent at the focus, it gets even hotter, and turns black from oxidation.

If I put a zinc cent at the focus, the zinc melts, and escapes from the copper shell. If it's a very sunny day near the peak of summer, the zinc BOILS out of the shell, making wisps of zinc-oxide ash as it combines with oxygen in the air.

I haven't tried it with a silver coin. If the coin was toned black, it's possible that it would melt, but unlikely.

If you had a 10-watt laser that you could focus down to a tiny (<1mm) spot, you might be able to burn or melt a hole through a coin. But I doubt you'll ever have a 10-watt handheld laser. And if you do get your hands on one, unless you're extremely careful and extremely lucky, it's probably the last thing you'll ever see.

 

PCGS would disagree with you.

In 2010 Collectors Universe / PCGS filed suit against a number of coin doctors. Federal Lawsuit Filed Against “Coin Doctors” by Collectors Universe / PCGS


Collectors Universe and PCGS claimed that the coin doctors used various methods to doctor coins submitted to PCGS.

 

I think those guys know what they are doing, It can be done but you need to have the right equipment which costs money, and the know how, you will not be able to do that by looking it up online.

 

Hobo, the PCGS suit is NOT referring to "Laser Pointers" but is referring to "metal working lasers" which are way more powerful than anything that could be purchased at a Staples or stationary store.

I'd go so far as to say that IF a hand held laser pointer were powerful enough to affect metal that it would wreak havoc on skin and as such would be totally illegal to purchase without the appropriate licensing, training, and State Certification.

I think its important to understand that certain laser's can affect metal but certainly not the kind which is purchased down at the local mall.

 

L.a.s.e.r.

When I was fresh out of college we literally used rocket engine technology to create metastable state plasma for high energy laser. A coin was never intentionally targeted but I'm sure that the output would adversely affect a coin's luster. :devil: It was one heck of a laser pointer.

Even our highly efficient, actively cooled mirrors had trouble because if they didn't reflect a tiny portion of the energy, they would quickly over-heat & die. If targeted by the laser, I believe a proof coin with high reflectivity (without cameo) may have lasted about 1 nano second longer than a mint state coin. In any case, the coin & whatever it was resting on would turn to gas quickly.

The FDA and OSHA police laser pointers in the USA. I suspect that the OP's laser pointer has an output that is something below 2.5 milliwatts per square cm. That is just my SWAG. You could collect & focus that power onto a very small area of a coin. Any energy not reflected would cause the temperature of the very small area to rise. You can see how a system could be engineered to locally heat-up (melt) hairlines on a proof coin’s reflective fields. Only the less reflective hairlines would have localized rise in temperature and the reflective fields would remain cooler. The result is that the hairlines would melt away.

 

You misunderstood what I was saying. If you go back to Post #3 in this thread you will see that I agree 100% with your premise.

In Post #7 (the one to which you were disagreeing) I was responding to a previous post where the poster stated the heat from a laser beam would be "dispersed" and not affect a coin and "unless you've got a serious metalworking laser, nothing will happen to your coin". My point was that lasers HAVE been used to doctor coins. I did not mean to imply that laser pointers have been used to doctor coins. Sorry for the confusion.

 

In theory you are probably right but your laser is creating enough heat to melt the coin and my expertise with coins has shown that when coin metal is heated.........it discolors and the heat necessary to discolor the coin is no where near the melting point.

 

Conder, are you sure you don't mean 5 milliwatts? I happen to have a laser obsession, and particularly use green laser pointers for astronomy uses. I believe the typical laser pointer is 5 milliwatts...not 5 watts.

 

But it discolors because it is reacting with gases in the atmosphere. Operate in an inert gas atmosphere, such as argon or helium, and the discoloration does not occur.

Yes, but it takes that serious metal working laser that he was talking about to do it.

 

I wonder if a DVD burner laser would do it?

 

You would probably want to deliver more power than would be possible with a solid state DVD burner laser diode. The reason you would want more power is that you would want to modulate the power or duty cycle of the beam in order to deliver just the right amount of power to melt away your defects. You would also need some nice objective optics to focus the beam on the coin's surface & maybe even read the coin's surface through the same objective lens with a different light. This is the kind read-write stuff that is done in laser beam recorders (LBRs) that are used to make prerecorded DVDs (not burn DVD recordable discs). The laser beam recorders for DVD mastering typically use gas lasers or solid state lasers in the range of 50 to 100 watts.

 

BTW, it wouldn't surprise me if an expert laser welding enthusiast could wipe away hairlines by hand using a standard laser welding set-up.

An expert laser welder has great eye-hand coordination. Never play darts with a laser welder.

 

You say right, only if the over 500mw even 1W laser pointer just like laser cutting may be can make the surface of coin produce changed.

 

I'm going to dig in my heels as long as I can here -- a 500mW or higher laser is no longer a "laser pointer". Yes, it's a laser; yes, you can hold it in your hand; yes, you can use it to point at things. But calling it a "laser pointer" is like calling an AK-47 a "hole punch". (Yes, it can punch holes. But if you bring it into your office or classroom and use it for that, you can and should be subdued and prosecuted.)

It's considered a war crime to use blinding weapons on personnel. A one-watt-range laser is a blinding weapon. As these things get cheaper and more readily available, there's going to be a rash of blindings, and there's going to be a huge backlash.

But I digress. Yes, if you focus one watt of energy onto a tiny enough spot on a coin, it will affect the surface. It's going to be a challenge, though, because the coin reflects most of the light that hits it, and it rapidly conducts and disperses the heat away from the spot. With a darkly toned coin, reflectance would be reduced, and you'd get more heat (and more results) with less power.

If I had a one-watt laser, and hadn't yet managed to blind myself, I'd surely try the experiment.

I will say that a 50mW laser can sting your fingertip if you focus it down to a pinpoint, but I don't think it could cause actual burns (except to your retina). No way, no how, would it cause physical changes to a metal coin. And that's ten times the legal limit of power for a "laser pointer".

 

hah..anyone herd of or hold the laser pointer chould obey the rules, in the classroom or office just allow under 5mw laser pointer. And i think anyone use the powerful laser pointer or laser cutting should wear goggles.