Sciencemadness Discussion Board

Glass Frosting?

JnPS - 3-9-2016 at 19:27

The glass cover that goes over my scale when not in use recently had a small bit of what looked like white frosting on it so I decided to try and remove it with a squirt of water and a towel but it didn't come off...Then I tried using some acetone but that actually seemed to cause more to appear :(

I thought nothing much of it and decided I'd recycle another odd bit of plastic to cover the scale but then some of this mysterious frosting appeared on my brand new sep. funnel.

Any idea what this stuff is???

Attachment: Weird Frosting.docx (334kB)
This file has been downloaded 246 times

Deathunter88 - 4-9-2016 at 01:43

1. Are you sure the cover on your scale is glass? Acetone can cause frosting on a lot of plastics.

2. Is the frosting on the sep funnel the same as the cover? Does the frosting on the sep funnel wash off with water?

JnPS - 4-9-2016 at 08:21


1. I thought it was glass but it might be a hard plastic, if its plastic is there a way to remove the frosting?

2. The frosting on the sep funnel looks the same and doesn't wash off with water, but it didn't spread when I tried acetone.

j_sum1 - 4-9-2016 at 08:55

There are three ways that a transparent material may appear frosted.

1. inclusions or opacity within the material -- that is material being changed
2. etching of the surface of the material -- that is, material being removed
3. deposition of a substance on the surface -- that is, material being added

#1 is unlikely. It implies a chemical reaction of your material. This can happen to plastics (slowly) for example if exposed to light. It won't happen to glass.
#2 will not happen to glass unless it comes into contact with one of a very small set of chemicals -- which includes HF and molten NaOH. You should be able to rule out this possibility. However, etching (or crazing) is quite likely to occur with acetone and many plastics
#3 may occur if there is something dissolved in your acetone. You should be able to wash it off. Bear in mind that really clean glassware might highlight scratches that are already there.