Discussion in 'Darkroom Equipment' started by CatLABS, Feb 24, 2014.
Is there a way to "unsplit" an alcohol thermometer?
You mean when there's a "gap" between various bits of the liquid in the tube?
Methods I've heard generally result in heat/cooling cycles (if you can cool it down to the point where all the liquid is back in the bulb then it should work but I've never tried), and just inertially-shaking the hell out of it to force the liquid back towards the bulb (without letting it fly out of your hands and smash, ask me how I know).
I saved one once a long time ago by holding it vertical and heating the bulb slowly in a small cooking pot filled with water. The very top of this particular thermometer had a small bulge inside, so as the alcohol reached the top it spread out and the split bubbled itself away. This will only work if the thermometer's maximum temperature is below the boiling point of water. Be careful not to overheat it, or you.
Disclaimer: This worked for me. Once. I tried it another time on a different thermometer and it didn't work. Your mileage may vary, but you've got nothing to lose at this point other than a little time and energy to heat the water.
I had one with a split that just spontaneously fixed itself over time. I used it a bunch of times up to 38/40c and it probably got down around to the 4 or 5c mark some nights where it was stored. Split just gradually narrowed and then disappeared.
I fixed one by holding it in the steam from a boiling kettle. I was very careful as it reached the top of the column but as it did so the gap disappeared and i've continued to use it without problem. Like Steve, the thermometer I use had a small bulb at the top as well as the bottom which allowed the space for the gap to escape into.
How does this split develop? Or perhaps I should ask the best method of storing the thermometer, to avoid having the split develop.
I've had mercury thermometers develop this split, but I've never been successful in restoring them.
My cause was rough handling during a move.
This was on APUG last year. Here is the Kodak paper on how to do it. It's for mercury filled thermometers, but should work. Hope you can read it.
How once thermometers were made:
That is really cool. That man is a real craftsman! My wife makes glass sculpture & jewelry over a torch. Wonder if I can have her make me a thermometer?
There are two aspects to fluid thermometer making: the glassblowing and the calibrating
Specifically drawing out the stick with a hole of uniform bore.
Thank you for posting this old Kodak fix article. I have the same mentioned Kodak Type 3 mercury thermometer that has had a split in it for the last year or so.
I fixed mine in like 10 seconds, doing this:
1 graduate with tap water - 50F.
1 graduate with 170F water.
What I found if I quickly ran it near the top in the 170F and then immediately over to the cool 50F water, the rapid rise/fall made the mercury split disappear magically.
Heating method is the only way to solve it. The only problem is the media used to heat it up.
If the thermometer is somewhere lower than 100degree Celcius, you can use boiling water to achieve it.
In case you have some high temp thermometer, you have to use different media to heat it up.
Glycerin (pure, 290'C) or cooking oil (i.e. olive oil, approx 250'C or higher, but it may has reached burning point) can do the work.
IF you have a thermometer higher than 300-350'C, you'll need special media to get that hot. Sorry I forgot the name of the oil (wax), if you need the name, let me know. I'll have to check it out.
Be aware of the cooling steps. The higher temp, the shorter reacting time to remove it from boiling oil.
You may try din-in (long time) & out (short time) to raise the temp gradually until "splited part" "unsplited".
ALSO, the higher temp, the longer, smoother cooling needed. You can also use dip-in (shorter time) - out(longer time) until it's lower than 100 degree'C. Fast cooling will cause craking.
Be slow to get to the top. They do not like overpressure.
That is why cooling should be an alternative method.
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