Acetone?

So, I wanted to clean my 405-G-1 lens with some spectrographic grade acetone. Although, I am a little concerned about how volatile it is. Is it possible that it could dissolve the AR coating?

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.

Not metals, usually oxides. Could be evaporated, could be some form of sputtered, could be some kind of chemical vapor deposited, any of those can do it.

Solvents could theoretically hurt some coatings, but oxides are generally pretty stable and hardy stuff, pretty impervious to solvents. Acetone doesn't really hurt any of the stuff we do with laser diodes in the labs, and I would guess that you would be fine, but I wouldn't guarantee that for you.

But then again, why risk it? I'd just go with a specifically-designed lens cleaning solution, and you should never have a worry.

I left some glass coated lenses in acetone for 3 weeks (i forgot them there ), and nothing happened to the AR coating.

Only, it melt almost all the types of glues, including superglue and cyanidric acid ones.

"cyanidric acid", thats not HCN, is it? the stuff smelling like almonds, and the stuff you only smell once? ;-)

i think i read the coating was made of MgF, if that helps anyone..

as far as i know pure acetone is used in optical labs too to clean surfaces, at least we did.. so it should be safe! ..if its pure, that is, with no residue.. try on a glassplate, what will be left from a whole drop.

manuel

Sorry, Manuel, you're right, it's "cyanoacrylic acid", not "cyanidric" ..... :bowdown:

glad to hear ;-)

manuel

I use Acetone in my stainless ultrasonic cleaner ...
for the Hi-Power lens assemblies with forced ventilation.

Works well, but remember it is Extremely Flammable.

LarryDFW

pseudolobster said:

A q-tip will be more effective than any solvent other than hydroflouric acid or aqua regia or whatnot.

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If this was NOT a typo, the vast majority of members of this forum should NOT get, or try to use hydrofluoric acid for ANYTHING.

Hydrofluoric Acid Burns: eMedicine Emergency Medicine

VERY small mistakes can lead to some VERY big harms.

There are some household products that contain a VERY dilute form, but we know that WE are not usually satisfied with such "sissy" products

Peace,
dave

very true! hydrofluoric acid is one of the really scary stuff. like the tiniest (barely visible) drop on your finger will almost definitely be cause for amputation. contact the size of a coin is easily lethal already. the stuff quickly goes down into your skin, right to the bone. fun thing #2: there is nothing (really) to do against it. its on your skin - its over.
fun #3: the stuff forms when you burn your teflon/ptfe-coated pan, and forms in burning cars. which is the real danger when approaching a burning car, instead of the car exploding.
fun #4: some very smart guys built markers with hydrofluoric acid to tag windows of trains. people leaned on the window minutes later. some of those markers leaked. in their pants.

enough fun for today. in fact for me its one of the scariest chemicals, almost as scary as radioactive material..

if you consider to buy anything containing HF (there are products to buy freely, seriously!), read about it.

manuel

edit:
unfortunately, its the only stuff (i know) which can dissolve quartz, SiO2.
one such use was done in canada, when they made rxplorations to find diamond-fields. they made bore-samples (?) (milling with kind of a tube, to get samples out of the earth), then put the whole sample into HF. anything would dissolve but diamonds. the only way to find sub-millimeter small diamonds, needed to learn how the rock is built.

Yeah, I know hydroflouric acid is pretty nasty stuff, it's just the only thing I could think of that'd probably remove an AR coating... Mind you it'd probably etch the glass making it unsuitable for a lens, but still. Those coatings are pretty durable.. They're fused directly into the surface of the glass, so the only things that can dissolve it pretty much have to be able to dissolve the glass itself.

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.

Wow, totally missed the references to HF and aqua regia in this thread. Yeah, neither of these are much fun, please be careful. aqua regia is a pretty color though, and cool coming from 2 clear liquids.

And one other safety concern that people forget with chemicals, especially solvents: take out your contacts, and wear glasses! First, contacts can trap fumes, which is bad enough. Second, if a solvent dissolves your contact lens while it's on your eye, it can do some really nasty stuff to your eye.

Krutz said:

very true! hydrofluoric acid is one of the really scary stuff. like the tiniest (barely visible) drop on your finger will almost definitely be cause for amputation. contact the size of a coin is easily lethal already. the stuff quickly goes down into your skin, right to the bone. fun thing #2: there is nothing (really) to do against it. its on your skin - its over.
fun #3: the stuff forms when you burn your teflon/ptfe-coated pan, and forms in burning cars. which is the real danger when approaching a burning car, instead of the car exploding.
fun #4: some very smart guys built markers with hydrofluoric acid to tag windows of trains. people leaned on the window minutes later. some of those markers leaked. in their pants.

enough fun for today. in fact for me its one of the scariest chemicals, almost as scary as radioactive material..

if you consider to buy anything containing HF (there are products to buy freely, seriously!), read about it.

manuel

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My only correction is that there ARE things you can do as first aid for HF exposure, you won't necessarily lose any body parts if treated promptly. Part of the problem though is that you won't necessarily feel it if you get any on you. It won't hurt, at least not at first, so you have to be aware and careful so that you can be treated promptly, because it won't hurt at first.

We actually use the stuff quite often in semiconductor processing, there are 2 wet benches/fumehoods dedicated to HF in the cleanroom I work in most. In case of HF exposure, you strip and hop in the shower (of course), and then apply calcium gluconate directly to the HF exposure area. There should always a tube of calcium gluconate available right next to the HF benches in any place that uses HF routinely, and there always has been everywhere that I have ever used HF. Calcium gluconate has saved many lives, and limbs, in the past. Then when you get to the hospital later, they'll know what to do as well (basically pump you full of calcium, if your exposure was bad enough). In our lab, the HF bench actually has an instruction booklet to take to the hospital with you in case of exposure, so there's no delay for the doctors to decide anything, it's all laid out for them.

My previous professor had a couple of safety horror stories to keep us aware, one of which involved HF. So everyone knows that you pour acids into water, and you DON'T pour water into acids, right? This is at least partially because of the heat generated in the reaction. Well my professor had a previous employee accidentally combine pure HF and water, about half and half relative amounts, in a plastic bottle. The guy poured them in, closed the lid, and SHOOK the bottle to mix them. Of course, the bottle then exploded in his hand. He had on an apron and a frontal face shield, but the explosion of the bottle covered the entire side of his head with what was then 50% HF. Luckily others were nearby, and they had calcium gluconate on hand, and they saved his life. (This professor's other favorite was a corrosive chemical, maybe lye?, spilling down INSIDE a guy's rubber boot that wasn't taped/sealed at the top).

Yeah, HF is nasty. When I used to work in the semiconductor industry, it was present in the gas residue of Tungsten Hexafluoride. Which was used to dope silicon into Tungsten silicide. This created some electrical connections on the chips. However getting back to the HF, the chamber when opened had HF gas residue that would react with moisture in the air to produce Hydrofluoric acid. This had to be manually cleaned out. ;-/

Calcium gluconate

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hmm, i read about that too, and somewhere they said its more to comfort and relax the unlucky person, but wont really help much..
and damn, that are horrorstories!

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 ;-)

manuel

HF is funny (with the obvious cares ) for engraving glass, so, a glass lens cleaned in it is not the best choice (it melt the lens, LOL)

But also

daguin said:

VERY small mistakes can lead to some VERY big harms.

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What about the second mistake in that sentence, too ?

I mean about "Aqua Regia" (or better said acqua ) ..... heheh, Acqua Regia, here, is the acid mixture that can melt almost any metals, including gold (i supposed he meant "acqua ragia", a thinner )