[Jasim]

Meltemps are awesome, but also very expensive. A quick search gives the cheapest (used) at around 1,000 USD.

Certainly it can't be that difficult to build your own, but i can't find any specifics on this (save one thread at DMT Nexus*).

Has anyone on here ever made or thought about making a melting point apparatus? Any guidance or other assistance would be appreciated. I'm sure it can be done without too much trouble for a LOT less than a thousand bucks.



* I do not post or support anything at DMT Nexus, just saw the thread on a google search.

[Borek]

Check old books on organic chemistry, before melting apparatuses became commercially available common practice was to use just a thermometer and a capillary tube. I suppose google books should have something, they have a lot of old science books scanned.

[fledarmus]

Basically, all you need is a beaker of silicon oil (preferably with a stirrer for more even heating), a controllable heat source, a thermometer, and a magnifying glass. And a framework of your own design to hold all the pieces together. A combination magnetic stirrer/hotplate works for the heater and stirrer, and clamps with a ringstand will handle just about everything else. The magnifying glass is just so you can get away with melting tiny amounts of your material in a capillary tube rather than much larger amounts in a small test tube.

[Borek]

a controllable heat source

In Otto Dimroth lab a "controllable heat source" was just a burning cigar

(quoted after Was nicht in den Annalen steht, by J. Hausen)

[rjb]

Does anyone remember Kofler hot-stages? Not exactly accurate, but I would imagine it wouldn't be difficult to build one...

[fledarmus]

Does anyone remember Kofler hot-stages? Not exactly accurate, but I would imagine it wouldn't be difficult to build one...

I never found accuracy to be that much of an issue, and it was much less messy and had a smaller footprint than the Mel-Temp. I much prefered them.

[Jasim]

Since I posted this I learned about something called a Thiele Tube. It's a piece of glassware ($50-$100) that can be used to find the melting point of a substance.

You clamp this tube and put a heat source on the side opposite the hole (it's an oddly shaped piece), fill the thiele tube about three quarters full with oil, using a second clamp to clamp a thermometer holder and a small piece of rubber tubing cut into a ring to attach your sample capillary, submerge into oil, and slowly heat. The oil increases in temperature and heats the sample, it circulates around the tube to allow for slow and uniform heating.

There are more details you need to learn about if you are actually going to do this, but it seems very simple and easy. The major drawback I see is that the heat source in this case would have to be an open flame.

[fledarmus]

If you're worried about an open flame, a heat gun actually works just fine on a Thiele tube.