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dkCambridgeshire

Sensor cleaning with isopropanol

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Isopropanol is currently mentioned in threads and even suggested / recommended by Leica as a sensor 'wet clean' fluid.

 

However, it could be unwise to purchase the first bottle of isopropanol / isopropyl alcohol / rubbing alcohol you see because they differ in strengths and in additives. TTBOMK manufacturers/suppliers add perfumes, oils, and water to their products in various dilutions- water being the main additive. Hence the product is available in e.g. 40% or 50% and 80% and w.h.y.% solutions .. and with small amounts of added oils. Cleaning with isopropyl alcohol which has an oil additive might do more harm than good to a sensor.

 

Are there any chemists on the forum who can give professional advice as to which types/concentrations of isopropyl alcohol are safe to use for sensor 'wet cleaning'?

 

Are there any other solvents more suitable?

 

Is it safe to use a 60% water based alcohol solution from which water may not evaporate quickly?

 

Leica Camera AG needs to be more specific in its wet clean recommendations.

 

dunk

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I'm not a chemist but I suspect that the 'grade' required may well be what is be termed 'anhydrous', which appears to be 99.9% pure and which is used for scientific purposes. This should be available from scientific chemical suppliers I would think. (A biologist friend uses 'pure' ethanol for preserving but there is some question over tax (duty) I seem to remember). As you have pointed out before it will also need to be stored in a way that avoids contaminants from both the container and atmosphere.

 

If you look at Leica's recommendations, I'd suspect that the products that they mention are of the standards required. But it would be worth while actually asking Leica if they would recommend a specification ('anhydrous', bp (british pharmacopoeia), or whatever) for isopropanol which they believe to be acceptable for sensor cleaning

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I'm not a chemist but I suspect that the 'grade' required may well be what is be termed 'anhydrous', which appears to be 99.9% pure and which is used for scientific purposes. This should be available from scientific chemical suppliers I would think. (A biologist friend uses 'pure' ethanol for preserving but there is some question over tax (duty) I seem to remember). As you have pointed out before it will also need to be stored in a way that avoids contaminants from both the container and atmosphere.

 

If you look at Leica's recommendations, I'd suspect that the products that they mention are of the standards required. But it would be worth while actually asking Leica if they would recommend a specification ('anhydrous', bp (british pharmacopoeia), or whatever) for isopropanol which they believe to be acceptable for sensor cleaning

 

I have in front of me a 40% Isopropyl Alcohol solution and it 'stinks' of additives - bought from my local oriental food store where bottles are dumped into a cage and sold as a general household/industrial cleaner. I wouldn't use it for optical or electronic contact cleaning - it's not sufficiently pure.

 

Yes, if Leica is recommending isopropanol for sensor cleaning they should specifically state which types/brands/concentrations are safe.

 

And any organisation recommending use of potentially toxic chemicals (and isopropanol can be toxic) needs to mention H&S issues and precautions. Not mentioning same could be deemed negligent. We live in an 'over-compo-orientated' society where there are those who will try and make a claim for the slightest alleged ill suffered.

 

dunk

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I was in the electronic and semiconductor industry before I retired. The high purity or semiconductor grade IPA is 99.99% purity. You can purchase this from supplier such as Sigma Aldrich. But do note the health and safety issue.

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I have in front of me a 40% Isopropyl Alcohol solution and it 'stinks' of additives - bought from my local oriental food store where bottles are dumped into a cage and sold as a general household/industrial cleaner. I wouldn't use it for optical or electronic contact cleaning - it's not sufficiently pure.

 

Yes, if Leica is recommending isopropanol for sensor cleaning they should specifically state which types/brands/concentrations are safe.

 

And any organisation recommending use of potentially toxic chemicals (and isopropanol can be toxic) needs to mention H&S issues and precautions. Not mentioning same could be deemed negligent. We live in an 'over-compo-orientated' society where there are those who will try and make a claim for the slightest alleged ill suffered.

 

dunk

40% purity would be bad idea, you may just use supermarket vodka or after shave. I have (still unopened) 500ml 99% pure bought from Amazon for few quid.

 

Liquid is stored in original plastic PBS bottle. Can somebody advise on suitability of PBS for clean long term storage of isopropyl alcohol.

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You can purchase this from supplier such as Sigma Aldrich.

Found it, 99.999% apparently and at over £50/litre which whilst costly, should last a long, long time. Very useful thanks.

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40% purity would be bad idea, you may just use supermarket vodka or after shave. I have (still unopened) 500ml 99% pure bought from Amazon for few quid.

 

Liquid is stored in original plastic PBS bottle. Can somebody advise on suitability of PBS for clean long term storage of isopropyl alcohol.

 

Even 99% pure isopropanol has 1% additives which may leave streak residues on glass. Would be prudent to test it on a piece of glass and examine with a loupe afterwards - with the glass illuminated from various angles so that any residue shows. Given that some isopropanol solutions do contain oils, consider how just a tiny/miniscule drop of oil can create a film (oil slick) on water surfaces.

 

dunk

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Even 99% pure isopropanol has 1% additives which may leave streak residues on glass. Would be prudent to test it on a piece of glass and examine with a loupe afterwards - with the glass illuminated from various angles so that any residue shows. Given that some isopropanol solutions do contain oils, consider how just a tiny/miniscule drop of oil can create a film (oil slick) on water surfaces.

 

dunk

 

Dunk,

 

If you check on Amazon there is also 99.9 purity for sale, but agree with you testing would be prudent first move.

 

Personally I had my sensors wet cleaned by Leica (Mayfair and Stevens), I use rocket blower for routine cleaning, bought isopropyl for just in case and general household needs.

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Found it, 99.999% apparently and at over £50/litre which whilst costly, should last a long, long time. Very useful thanks.

 

If you were to compare this to Eclipse, which is methanol, £50/l is reasonable. The sensor swabs are expensive as well. I have used Eclipse for cleaning DMR, M8, Sony A850, M240 and A7R sensors. So far so good.

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I am unable to verify the effect this may have on the surface but as a pharmacist I would advocate Isopropyl Alcohol BP 70% as a thoroughly good cleaning solvent which is free of additives and carries away the water content as it evaporates. this is not of use to our friends outside the Uk but there will be both a european and american equivalent. Hope this is of use.

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I am unable to verify the effect this may have on the surface but as a pharmacist I would advocate Isopropyl Alcohol BP 70% as a thoroughly good cleaning solvent which is free of additives and carries away the water content as it evaporates. this is not of use to our friends outside the Uk but there will be both a european and american equivalent. Hope this is of use.

 

70% is that correct? So what is remaining 30%, water?

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Found it, 99.999% apparently and at over £50/litre which whilst costly, should last a long, long time. Very useful thanks.

 

May be pure when you buy, keeping it pure as the bottle is used is different.

 

I would decant into smaller containers like I do with film developer.

 

Eclipse is a nice bottle that dispenses one drop at a time, which helps but is still not perfect. What does work is the rubber stopper bottle like injectable medicine is delivered in or like Rodinal used to come in, talking 1960s before someone says I am crazy. Remove with a syringe & needle.

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I have used the RS Components IPA for cleaning Arctic Butterfly brushes and lenses but as the purity is not fully stated, I would be reluctant to use it on sensors. For the mixture I am brewing (95% Absolute Ethanol and 5% IPA), I am sourcing some 99.99% from an industrial chemical supplier, who I used to insure and from whom I bought the Aniline, Benzene, Toluene and Furan (Oxacyclopentadiene) for historic racing car fuel additives. They are sending me a 250ml can free of charge. I suspect it is one of those substances you are not supposed to send through the post nowadays, like model nitro engine fuel.

 

Wilson

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I suspect it is one of those substances you are not supposed to send through the post nowadays .....

Yes, be aware that Royal Mail, having been privatised, are now doing their very best to make themselves uncompetitive by restricting what they will carry:confused:. I've had to switch to couriers as I can no longer send most batteries (not just Lithium) by post. And be aware that restricted materials can be removed and destroyed:eek:!

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I'm a Ph..D. chemist and use ethanol, methanol and isopropanol for cleaning lenses and sensors. Any of these seem to work well, but depends on the material coating the sensor. For oils, isopropanol will be the better solvent. For salts, methanol. The handling characteristics are quite different, isopropanol has higher viscosity, but it's not really an issue. It will dry off the sensor more slowly but it's a matter of seconds.

 

My best advice for procuring pure grades of solvent is try Sigma Aldrich and buy a small bottle of "Analytical Grade". Anything that's 99+% should be fine, but test for residue on a clean sheet of glass. Don't worry about keeping these solvents dry, the small amount of water that they take up evaporates and is of no consequence. Pure solvents are usually sold in glass bottles as some plastics can leach cross-linkers and additives into the solvent.

Denton

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