Can Acetone crack a Lens?

[Paul Phillips]

So the assistant that I trained to help use the laser cracked the lens badly, he says that he was cleaning a difficult spot with some Acetone and it "just cracked", he says that it was not hot to the touch (my first thought) and he only used light pressure with a Q-tip, not enough force to crack it as badly as it appears, he thinks it is the fault of the Acetone, I'm not sure what to believe because I've used it before with no problems, in fact it was Mike McKenzie that suggested the use of Acetone to me. Does anyone have/had any ideas/experience/problems with using Acetone to clean a lens? :confused:
Thanks.
Paul

[Gary Hair]

I use it all the time on my lens and mirrors and have had no problems. It is widely recommended so I can't imagine that it would cause a lens to crack, it must have been something else.

[Michael Kowalczyk]

Not sure if this helps but I noticed your guy was "Cleaning a difficult spot" and maybe that spot had permeated the coating and maybe that was the cause. I don't use Q tips or Acetone. I use the lens cleaner and lens cleaning tissue/paper. I have had one lens crack when I first got my laser and it was replaced under warranty and the other one I cracked when I thought I was sent a 2" lens but it was a 1 1/2" lens and tried to get it out. Found out I have one of the few lasers that has a RED carrier for a 2" lens instead of a black carrier. It worked out OK and I am still able to use it. I just clean it every time I use it.

[Joe Pelonio]

I agree with Michael, q-tips can scratch a lens. They are more sensitive than a camera lens. If needed to reach you can wrap a lens tissue around the cotton on the q-tip, but I only use lens cleaner.

[Kim Vellore]

Acetone itself will not break the lens. It is glass so I do not know of any solvent that can damage glass. You could damage the coating but that's all. From the broken pieces you can determine the cause of breakage. If dropped the drop point will have the impact mark and smashed glass. if it was a dirt that heated the lens non-uniformly and caused cracks you can most likely see the dirt point and cracks starting at the dirt point. If the cracks start from the concave part it is most likely from dirt.

Kim

[Rich Harman]

Acetone itself will not break the lens. It is glass so I do not know of any solvent that can damage glass.

Glass would not work for a lens material for CO2 lasers. Glass absorbs IR.

[Dan Hintz]

In short, 'no'... acetone itself will not crack ZnSe. At worst, the moisture within the acetone (such as when using old stock) may temporarily absorb into the ZnSe, but still no cracking. My guess is he was being a bit too aggressive while it was in the holder, or it broke during use (too much heat buildup from gunk buildup... exactly what he was trying to get off).

[Scott Shepherd]

How would you break a lens cleaning it, other than dropping it? I'd like to see someone break a lens with a cotton swab or a lens cleaning tissue.

What I suspect is that the lens had built up plastic on it, which caused it to get super heated which caused it to fracture. Then when cleaning it, it just opened those fractures up and caused the "crack".

But I'm not sure how you could ever break a lens with a cotton swab.

[Paul Phillips]

Thanks for the replies, he was cutting Rowmark ADA material with a 1.5" lens which tends to get dirty more often and he says there was a spot on the lens that would not clean-up with the normal lens cleaner and tissue method that we use, so then he tried the Acetone and Q-tip and that is when it cracked. Kim, I believe he is telling me the truth but will take a closer look to see if it was dropped.
Joe, nice tip, thanks, I will do that from now on just to be safe. Steve, I think all things considered, yours is the most likely explanation, thanks. I just want to know how to avoid this in the future.
Paul
Edit: upon closer inspection it appears that the lens is cracked from the inside? (no evidence of impact) which I think would lean towards Steve/Scott's explanation.
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[Ronald Erickson]

Trotec's website says the following about cotton swabs:

"Only use the provided cleaning tissues or high quality paper-bodied 100% cotton swabs together with the provided cleaning liquid."
(source = http://www.troteclaser.com/en-US/About-Trotec/News/Pages/2012-How-to-clean-lenses.aspx )

It sounds like swabs are fine as long as they are 100% cotton and paper bodied.

[Mike Null]

That's what I use and my lens is 7 years old. I also use acetone.

[Scott Shepherd]

Thanks for the replies, he was cutting Rowmark ADA material with a 1.5" lens which tends to get dirty more often and he says there was a spot on the lens that would not clean-up with the normal lens cleaner and tissue method that we use, so then he tried the Acetone and Q-tip and that is when it cracked. Kim, I believe he is telling me the truth but will take a closer look to see if it was dropped.
Joe, nice tip, thanks, I will do that from now on just to be safe. Steve, I think all things considered, yours is the most likely explanation, thanks. I just want to know how to avoid this in the future.
Paul
Edit: upon closer inspection it appears that the lens is cracked from the inside? (no evidence of impact) which I think would lean towards Steve/Scott's explanation.
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In my opinion, that's definitely caused by build up on the lens. The roundish shape of part of it, I'd bet money was a glob of rowmark. I believe the lens was cracked before he cleaned it and it just opened up as he put pressure on it. No way a natural crack would be shaped like a roundish glob like that, in my opinion.

[Paul Phillips]

Yeah Scott, I think that makes the most sense, more like a stress fracture, not sure if you can tell from the pics but what's weird is that the crack seems to be "inside" the lens, IE, you cant' see or feel anything on the surface.
Thanks.
Paul

[Michael Hunter]

On a side note - don't use any solvent in an aerosol spray can directly onto a lens (or pretty much anything else).
(The intense cold produced by the propellent evaporating can crack just about anything).

Learned this when working for a tape recorder company.
The plague of cracked (solid brass) tape heads turned out to be because someone had bought spray cans of isopropyl alcohol for the service department.