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Old 27th Feb 2007, 4:10 pm   #3
Ray Cooper
Retired Dormant Member
 
Join Date: Jan 2007
Location: Porthmadog, Gwynedd, UK.
Posts: 199
Default Re: Screen magnifiers - 40s/50s TVs

Mike Phelan:
Quote:
I have heard mention of glycerine, as well.

A little taste should confirm, but don't swallow it, just in case.

Liquid paraffin is very greasy with little taste. Glycerine has a strange hot but sweet taste.
The few magnifiers I've met before were filled with liquid paraffin - I've not heard before of glycerine (glycerol) being used in this application - interesting.

Take care with glycerine. It's actually very hygroscopic in its pure form (hence, possibly, the strange, hot taste as your tongue dehydrates...) so if used in a magnifier would need to be properly sealed to prevent exposure to the air (and leakage, of course).

Try taking a small sample of the liquid, and mixing with water. Glycerine is highly soluble, but liquid paraffin isn't - it will float on top of the water.

Liquid paraffin is odourless, but is alleged to smell slightly oily if you warm it up. But take care - liquid paraffin is (potentially) flammable - I don't think glycerine is.

When you've decided on a replacement liquid, mix a small sample of it with a sample of the original liquid - I don't think Liquid Paraffin and Glycerine are miscible, so if they don't mix, you've made the wrong choice. Then try a small sample of the replacement on a non-exposed part of the plastic case where it won't be seen, and check for any adverse reaction. Liquid paraffin is fairly non-reactive with most things, probably why it was used in the first place. If you can get enough of the replacement liquid, I would recommend replacing the entire contents of the magnifier rather than just topping-up the existing fluid. Mixing old and new might result in slight cloudiness.
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