Stereo microscope fogging up?

[smbaker]

Lately I've been having issues with long soldering sessions on the stereo microscope. Vision in one of the two eyepieces will slowly darken, and when I pull the eyepiece, I can see what looks like condensation down inside microscope. After not using it for a while, the problem will go away. This is an Amscope, which I've had for several years.

Anyone else have an issue like this and/or know of an easy solution? Seems like it is a recent phenomenon.

[DTJ]

Is it used in a cold environment?

Is it breath vapour condensation maybe?

I work in a warm environment 20 to 40 Celsius and have not had that issue with my amscope.

[SeanB]

Simplest fix is to heat the microscope body, using a power resistor or a heater mat bonded to the body, so it is at above room temperature.

[smbaker]

Is it used in a cold environment?

I use it in my second floor office, which I'd say is generally around 70 degrees Fahrenheit. So that should fit your 20 to 40 C range.

I will look into finding some way to heat it. I have some power resistors on hand, so that sounds doable.

[DTJ]

Perhaps email support at Amscope before you do too much. They might have some ideas on whats happening.
I found them quite helpful when I was purchasing my scope.

[RoGeorge]

If you keep the microscope at normal room temperature, fogging is not suppose to happen.
My no name microscope never gets foggy, but I don't think I ever used it continuously for more than a half an hour.

Fog and condensation forms only when the air get colder.
- when is warm, the water solubility in air is big, so a lot of water vapors (humidity) will be suspended in air
- when the temperature decreases, the water solubility also decreases, so less water vapors can float in the air
- the excess water vapors from when the air was hotter will need to go somewhere, so condensation will start to happen
- the temperature at which, for a given air humidity, the water start to condensate is called 'Dew Point'

Of course, breath will almost always be a source of hotter and humid air, so the 'Dew Point' from an exhalation will almost always produce condensation on the room temperature objects.

[jmelson]

Lately I've been having issues with long soldering sessions on the stereo microscope. Vision in one of the two eyepieces will slowly darken, and when I pull the eyepiece, I can see what looks like condensation down inside microscope. After not using it for a while, the problem will go away. This is an Amscope, which I've had for several years.

Anyone else have an issue like this and/or know of an easy solution? Seems like it is a recent phenomenon.

Well, you have to clean the objective lens from time to time, the solder smoke leaves a film there.  But, for INSIDE the scope, that is pretty strange.  You might leave the eyepiece out overnight or a weekend, maybe with something porous over the hole so the moisture can escape but dust won't fall in.

I wonder if the Chinese left a dessicant pack inside, and it is degrading and releasing moisture.

Jon