DP - 21-8-2005 at 06:01
Having to use oil baths is really starting to annoy me so I'm about to get some soft heating mantles, but lets say you have to magnetically stir
and heat a solution at the same time. If I put one of these mantles on my Hotplate/Stirrer and just use the plate for stirring won't the mantle
burn the surface?
[Edited on 21-8-2005 by DP]
Taaie-Neuskoek - 21-8-2005 at 06:59
Can't you use sand?
neutrino - 21-8-2005 at 08:00
Burn the surface of what? The plate?
Fleaker - 21-8-2005 at 10:42
I find that a plastic flower pot (into which you place the round bottom flask) holds it nicely. It's plastic but it seems to be good to about
180C where it starts to char. The plastic doesn't interfere with the magnetic stirring, and it conducts heat fairly well.
Hopefully I attached a picture of a bromine distillation where the flower pot is in use. :-)
neutrino - 21-8-2005 at 10:52
Hit the edit button and choose the 'Delete This Message' option. Or ask a friendly mod.
What kind of plastic is that?
[Edited on 23-8-2005 by Ramiel]
Fleaker - 21-8-2005 at 11:03
Thanks very much, I had never needed to edit before, guess I should have experimented before asking. As far as what kind of plastic it is? No idea,
most plastics start to decompose around what? 140C? All this material did was char and smoke rather than melt. Next time I use it, I'll see at
what temp it melts/decomposes. Seems to be rather rigid.
neutrino - 21-8-2005 at 11:08
Some sort of thermoset, then. Is there a recycling number on the bottom?
Fleaker - 21-8-2005 at 11:18
I'll check next time I get a chance, Neutrino as it's at a friend's house currently.
BTW, to elaborate on the bromine synth. That was done with reagent grade NaBr and a concentrated peroxysulfuric acid solution. What you see in the
separatory funnel (now serving for addition purpose 
) is 30% H202. All of those
white specks and spatter over the area are sodium bromide.
DP - 22-8-2005 at 12:05
Oh yeah... like a pile of sand on the bottom? That sounds good. I don't know if I would want to use plastic on this hotplate/stirrer. Maybe I
could keep the mantle like an inch above the plate with an aluminum ring.
copper tubing..
greenyppols - 24-10-2005 at 13:39
I used 1/4" copper tubing from a hardware store....bent it in a nice circle shape to fit the mantle's circumference and left about 3 inches
sticking from it, and then into a clamp.
A separate magnetic stirrer to sit under it is on my want list now.
But it works great for me so far...Im putting up with boiling stones for now.
I imagine any metal tubing would work, even the solid 1/4" copper grounding wire I noticed.
How's about those steel brake line hoses from an auto store that come in lengths of 3 feet or so? Its not as easy to bend though.
A coat hanger, even? It'd have to be strong enough to support a fully loaded flask though..and consider it may get soft and bend (dumping the
flask) if its really heated up...