Acetone?

funny, what you guys (in usa/uk) name those chemicals.. "spirit of .." "aqua .." noone has any clue what that would be.. come on, "white spirit".. its ethanol, or at least alcohol..
but then you guys surely are used to those names, so whatever.. hehe

manuel

edit: its called "kings water" here, by the way.. *smiles*

Krutz said:

funny, what you guys (in usa/uk) name those chemicals.. "spirit of .." "aqua .." noone has any clue what that would be.. come on, "white spirit".. its ethanol, or at least alcohol..
but then you guys surely are used to those names, so whatever.. hehe

manuel

edit: its called "kings water" here, by the way.. *smiles*

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White spirit is a paraffin-derived chemicla not a alcohol its a hydrocardon mix , but yer there are some funny names lol

Heheh, the more funny part is when different countries calls the same thing with different names, that also have different menaings in the other countries ..... sometimes, the mess and confusion that come with these things, is almost unbelievable, LOL

Same as in your example, where there white spirit is paraffine derivate, here is just the name of pure edible ethylic alcohol ..... and means also a "white ghost" (white as "good soul" )

..see what i mean? lol!

manuel

Around here "white spirit" is pure ethanol, "white gas" is naphtha or hexane fraction sold as camping fuel, and a "white russian" is kahlua, vodka, and milk.

heh, true! ..and i make sure to always have a "screwdriver" handy ;-)

manuel

Krutz said:

funny, what you guys (in usa/uk) name those chemicals.. "spirit of .." "aqua .." noone has any clue what that would be.. come on, "white spirit".. its ethanol, or at least alcohol..
but then you guys surely are used to those names, so whatever.. hehe

manuel

edit: its called "kings water" here, by the way.. *smiles*

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Hey hey, you can't blame "aqua regia" on Americans or the English, that one comes straight from the Romans before North American had even been discovered by Europeans. Aqua regia is latin all the way, can't blame that one on us.

"King's water" makes sense though, since aqua regia would be latin for something like "royal water".

okay, i stand corrected.. should maybe have chosen latin instead of french.. uh.. naaah.. ;-)

some of these should be interesting for dissolving gold-plated electronics, not? (all but the gold, obviously!) or, alternatively, collect all the metal parts, melt them to one bar, and dissolve all lesser metals by electrolysis.. i was thinking about buying a bag of chris' (heerursciences) junk laserdiodes for that.. but i wouldnt be able to melt hundreds of innocent diodes.. ;-)

manuel

Yeah, aqua regia will dissolve/etch gold, although nowadays there are better etchants that are designed for specific metals in semiconductor processing. You can use aqua regia, but we use a specific gold etchant instead. One of the major things is that aqua regia doesn't last that long, but the etchants we use instead are designed to be stable for a long time, so you can buy a bottle and use a little bit whenever you need it. Also, aqua regia may harm your substrate or other films, where something like gold etchant might not be so bad on your substrate.

A cool aqua regia story copypasta from wikipedia: When Germany invaded Denmark in World War II, the Hungarian chemist George de Hevesy dissolved the gold Nobel Prizes of Max von Laue and James Franck into aqua regia to prevent the Nazis from stealing them. He placed the resulting solution on a shelf in his laboratory at the Niels Bohr Institute. It was subsequently ignored by the Nazis who thought the jar—one of perhaps hundreds on the shelving—contained common chemicals. After the war, de Hevesy returned to find the solution undisturbed and precipitated the gold out of the acid. The gold was returned to the Royal Swedish Academy of Sciences and the Nobel Foundation who recast the medals and again presented them to Laue and Franck.

That WAS a cool story PBD!

I remove iron stains from many mineral specimens with "wood bleach."

Peace,
dave

Benm said:

Please do not use HF for any kind of optic cleaning or etching. While from a chemical perspective you could see it as hydorchloric acid (HCl) on steroids, the biological danger comes mostly from the fluorine anion. Fluroide ions bind strongly to calcium in the body, which is essential for many functions. This makes even dilute HF a dangerous contact poison.

There is no 'proper' method of removing a AR coating if its something like magnesium fluoride. As far as i know there are no agents that will effective dissolve such coatings that do not etch the underlying glass.

As for using acetone: It will not dissolve or harm any metal oxide/salt AR layers, but it will dissolve or plasticize most polymers over time.

For cleaning, i'd recommend about 50% isopropanol in (distilled) water. There are very few things that do not dissolve in that, but will dissolve in other solvents. If you have greasy residue on glass, acetone is fine, but only on pure glass elements - any plastic components will be damaged.

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Well, there are no plastic components, so it should be fine.

And cool story!

Krutz said:

since were OT already, about chemicals: whats the "best" organic solvent? like a solvent where i could dump a LED in, to totally dissolve the dome, and be left with the bare, connected die (to remove the phosphor and other silly things). tetrachorinemethan? chloroform/dichlorinemethan? acetone didnt do anything to the dome (acrylic?) .not that any of the nicer ones would be easy to get ;-)

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What the best solvent is, obviously entirely depends on what you are trying to dissolve. For table salt, it would be water, for nail polish acetone and so on.

Also, its important to notice the difference between a solvent, and a reagent. Solvents do not chemically alter whatever you dissolve in them, and if you where to evaporate the solvent away, you'd get back exactly what you dissolved in the beginning (chemically that is, a cube of sugar will obviously dry down to disc of sugar when you do this with water).

Things like HF and aqua regia are reagents - the later forms gold chloride from metallic gold. If you removed the solvent, you'd get goldchloride (a salt), not gold metal.

For dissolving plastics, nonpolar or semipolar solvents usually work best, but not all plastics can be dissolved. Crosslinked polymers for example, basically are one big molecule the size of the entire object, and will not dissolve in anything. Other plastics like polystyrene will readily dissolve in acetone.

I'm not sure what LED casings are made of though. You could try do dunk a led in acetone overnight and check the result. If its still entirely there and not softened or changed, there is little chance that any other solvent will be able to completely dissolve the material. You can try something like white spirit (turpentine, very light mineral oil, paint stripper) or toluene/xylene too.

Solvents like chloroform, CS2 or CCl4 are even more non-polar, but realistically will not be much better at attacking plastics. There are plenty of applications where other properties of the solvent are important too, and using these is justified, but they are pretty hazardous materials and even (suspect) carcinogenic.

thanks for explaining! i didnt think about it in that detail yet. but yes, now its obvious that i'll run into limitations in my search for the all-solving (plastic) solvent..
(no, acetone didnt touch the led at all)

manuel

I'm affraid the reality is that many plastics actually have no solvent.

Also, most plastics are chemically inert, and it would not be possible to find an agent that reacts with the plastic to remove it, that does not also destroy whatever you are trying to get out of it.

pseudolobster said:

I purposely tried to get the AR coating off a glass aixiz lens coated for red using acetone.. Didn't work in the slightest. Also tried isopropanol, trichloroethane, xylene, and naptha. None had any effect. I suspect these coatings are metals that are fumed onto the glass. A q-tip will be more effective than any solvent other than hydroflouric acid or aqua regia or whatnot.

That said, I've never tried anything on my 405-G1 lenses.

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Most of those solvents (such as xylene and vm&p naptha) are either surfactants (which allow for the surfaces to be more permeable by water) or they dissolve plastic/silicone polymers. That's why they won't work.

pullbangdead said:

A cool aqua regia story copypasta from wikipedia: When Germany invaded Denmark in World War II, the Hungarian chemist George de Hevesy dissolved the gold Nobel Prizes of Max von Laue and James Franck into aqua regia to prevent the Nazis from stealing them. He placed the resulting solution on a shelf in his laboratory at the Niels Bohr Institute. It was subsequently ignored by the Nazis who thought the jar—one of perhaps hundreds on the shelving—contained common chemicals. After the war, de Hevesy returned to find the solution undisturbed and precipitated the gold out of the acid. The gold was returned to the Royal Swedish Academy of Sciences and the Nobel Foundation who recast the medals and again presented them to Laue and Franck.

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That's beyond cool. That's simply genius!