Hi all, I need some help with growing alum into crystals.

[oakleyguy89]

Hi, im new to these forums and I figured I should come onto here and ask some of my questions on here. So recently (Not for school or anything just for a fun little experiment here at home with my girlfriend) I started to make alum crystals. I started lastnight and brought about a 1/2 C. of water to about boiling and added the alum to get the water supersaturated. Well I left it overnight and I got alot of little crystals. When I was looking on the internet I got the instructions on how to make a big alum crystal. Well I was going to use one of those little crystals as a seed and tie some thread around it but they are just too small to do so The solution has been sitting in that glass for about 15hrs and the crystal sizes hasnt seemed to increase. So what i did was resolve and reheat all the crystals and the solution except for the biggest crystal. I poured the super saturated solution into one glass and poured just a little bit of solution in another glass and put the alum crystal that I seperated before reheating in. Will this crystal get bigger even though it is not suspended by a string enough so I can actually tie the thread onto it? Do you guys have any other better ideas to make my seed bigger? Thanks

[Mr Skeptic]

A supersaturated solution will get you crystals quickly, but as you observed they will be small. The slower the crystals form, the larger they tend to be. I suggest putting some saturated solution and letting it evaporate (eg put it on a radiator). Throw a few seed crystals in there too, since you have some. It doesn't need to be suspended from a string, but their shape will be limited by the bottom of the dish.

[DrP]

If you just hang a thread into the solution you might get growth seeded by the thread anyway. Just leave it hanging in there for a few days if nescessary. When all the solution has evapourated, then transfer the thread (which should have crystals on it by now) into a fresh saturated solution and they will continue to grow. You can pick off the seeds from the thread and concentrate on growing the larger ones.

[oakleyguy89]

Thanks for the replies guys. Just a quick question Mr. Skeptic. What do you mean by radiator? Do you mean a hotplate?

[Mr Skeptic]

Well, for us folks up here in the north, it is winter and we need to heat our houses so stuff doesn't freeze. There are radiators around the house where warm water is pumped into them and they radiate the heat into the rooms. They are a bit warmer than the rest of the house (but not very hot).

 

The warmth isn't really necessary, it would just help the solution evaporate quicker.