poor man's melting point apparatus

[Sigmund Roid]

This is how some people do melting point tests outside a real laboratory.

They have a soldering iron with a precision digital temperature control going from 20 C to 350 C +/- 1 C. Before heating the soldering iron you place a few grains (say 1 mg) of material X on the tip and slowly heat until the powder turns into a liquid or sublimes, or sometimes even decomposes. It really helps if you have a microscope or at least a magnifying glass to look at your material. The accuracy they find is within 1 to 2 degrees. Besides, the amount of material needed is very small. Absolutely great!

[candle25]

Outstanding! I was going to buy a MP Apperatus untill I saw the prices. That is a great idea. I have a sterioscope that I can easily watch the crystall melt on the iron with. I'll look on the net for a digital iron. Thanks bro!

[GATOR]

Digital irons seem expensive? Does anyone know how much they cost?Where can I grab one?

[GIJoe]

Here's an even cheaper method I learned from a Jewich buddy:

Lab thermometer
Capillary tube
Beaker
Oil of choice
Rubber band
Pan to place beaker in
Heatsource

Take the powder to be tested and grab a capillary tube, push open end of capillary tube into powder a few times; turn tube around with open end up, tap on hard surface until powder falls to bottom (closed end) of tube. Place bottom (closed end) of tube with powder next to the thermometer bulb at the bottom of thermometer (silvered end w/o loop), with open end facing up, and place rubber band or similar holding device toward top of capillary open end to fasten tube to thermometer; make sure capillary closed end is .25 inch from the bottom of the thermometer. Your powder is now ready to be tested.

Place beaker in a suitable pan capable of the heat range your powder shall require, and turn heat on medium; you need to fill the pyrez beaker with your choice of oil or PEG, and cover the bottom of the pan with a 1/2 inch of oil to aid in conductivity if you'd like; careful with the oil and high melting points, as oil likes to smoke, and can potentially catch on fire. Place thermometer in beaker while holding thermometer, and keep an eye on the whitish powder -- it will turn clear when reaching its melting point. You can turn the heat up fairly high until close (30-40 degrees) to your target melting point, then turn heat down so your melting point test is more accurate -- stir the oil within the beaker occasionally to aid in accuracy. If you do it slow enough that the thermometer can keep up, accuracy should be within the tolerance of the thermometer.