Finding the melting point of Solder

[JoeMK]

hey, just need some help here

this for some school assignment. We made our own Solder by melting tin and lead in the correct ratio. Now we need to remelt the Solder to find its melting point. Look i now this might sound stupid, but what is the most accurate method of findng the melting point.

 

this is very impotant, there are 2 questions about it that pop-up in this in this assignment:

 

1> Suggest a suitable technique and sound experimental practise that should be used so the reasonably low melting point can be accurately measured and confirmed

2> What changes did you make to the procedure in this experiment in an attempt to gain more accurate results. (It is very unlikely but possible that you used the correct procedure for finding the melting point of Solder)

 

Ok i know these might sound like very simple questions, but that teacher wants us to synthesise on a very high level of thinking, so the answerers ain't quite as obvious as they may seem ...any help srongly apreciated

[Dave]

Moved to Homework Help.

[H2SO4]

try getting an infared thermometer and when it begins to liquify measure the temp.

 

Then just make it seem complicated by throwing an another thing, like you heated it very slowly and steadily under a small flame or something.

[JoeMK]

i wish we had infrared thermometers. but we're stuck with the standard themometers (300*c). Is there somekind of special technique we can use?The solder is in an evaporating basin, we're using a bunsen burner in a smoke cupboard. I know the melting point should be around 180, but we can't get that exact point when it melts, and there's gotta be some kind of technique to use.

[H2SO4]

try just heating it realy slowly. Are you missing the mp as in, is it heating to fast find the mp? It should stay at its MP until it is all melted away.

[Yggdrasil]

Well, the melting point of an object should be the same as the freezing point. If your equipment doesn't allow you to heat the object slowly enough to obtain an accurate melting point, you could alternatively cool liquified solder slowly to find its freezing point.

[DQW]

The standard method for determining a melting point involves putting the material (a powder of it, perhaps) in a capillary that is heated controllably to the melting temperature. The melting of the powder is clearly noticeable (better to use a magnifying glass for accuracy) by the appearance of a well-defined meniscus.

 

One way to do this is by using standard equipment like the Mel-Temp or the Thomas Hoover apparatus. Alternatively you can use a clear oil bath that you heat on a hot-plate (with a thermometer in it) and immerse the sealed capillary in the bath.

[DQW]

The simple method (and obvious one), on the other hand, is to get a soldering iron with temperatuer control and wait for the solder to wick onto the tip (while slowly raising the tip temperature).

[JoeMK]

Thanks guys, i think the slow heating and the powder will help me get a better MP

thanks

there's still one question i need help in...i'll make a new thread

[YT2095]

use a variable temperature hotplate, you could even make one with a regular hotplate and a dimmer switch/speed controller, then all you`ll need is a cooking thermometer or similar. raise the temp slowly and when it melts, read the temperature

[gnpatterson]

cooling curve is key to finding the melting point of a eutectic mixture see

http://www.ce.berkeley.edu/~paulmont/CE60/alloys/sld008.htm

[gnpatterson]

better link http://www.chemguide.co.uk/physical/phaseeqia/snpb.html