Sciencemadness Discussion Board

Copper wool "bath"?

Funkerman23 - 24-4-2013 at 20:50

Just thought I'd put this out there but has anyone else thought of using copper wool in place of BB's for a bath? http://www.briwax-online.com/GMTCopper.html don't want to start a fire or nothing but I thought this might make a good alternative to BB's( given the chance of stirrer assembly burnout) or copper shot( Can't seem to find it locally). Opinions comments or ideas are always appreciated* thanks for reading.

chemcam - 24-4-2013 at 21:34

IIRC the densities would come into play for a bath, even though they are both copper. The wool wouldn't hold heat in as long or as well as BB's, they are spread so far lots of air would be in the bath, lowering the efficiency. I don't know the correct term for this, sorry!

You're talking like sand bath, water bath, copper bath right? "Bath" being inside quotation marks makes me think you may be talking about something else?

Funkerman23 - 24-4-2013 at 21:55

Indeed,I am talking about a heating bath. At the moment all I have is a corning 320 hotplate to heat & stir my reactions. I don't know how well corning hotplates stand up to the magnetic interference Steel BBs would create so I thought about using copper wool. I have seen copper shot used elsewhere BUT given the uneven sizes I don't know how much mass of copper shot would be needed assuming the heating dish they are in has a capacity of about 1.5 liters.Hence I looked elsewhere until I remember the formulas I need( and no I would not use a dish that large for a 100mL flask) so I looked for another solution. Sand baths are a PITA. if I where using a Bunsen flame then yeah I'd consider sand, even with it's problems.
Quote: Originally posted by chemcam  
IIRC the densities would come into play for a bath, even though they are both copper. The wool wouldn't hold heat in as long or as well as BB's, they are spread so far lots of air would be in the bath, lowering the efficiency. I don't know the correct term for this, sorry!

You're talking like sand bath, water bath, copper bath right? "Bath" being inside quotation marks makes me think you may be talking about something else?

chemcam - 25-4-2013 at 00:31

Well what you could try is to compress the copper wool into little balls to get most the air out, but that would be a lot of work. I have never seen it done but could you make a coil with high gauge Cu wire as close together as possible but still leaving small gaps? I don't even know if that works but you could custom do it to fit whatever size was needed.

You may be shit out of luck and have to use sand if steel BB's will cause interference. <- My hotplate is old style with the coil that gets red hot. :(

Organikum - 25-4-2013 at 10:48

It would be a mix between an airbath and a coppershotbath, cover it with alu foil though. Not a bad idea IMHO, the fast response in lowering the heat an airbath has makes up for many of the drawbacks as slow heating up.
Generally I nowadays mostly use airbaths with the flask hoovering some millimeters over the hotplate and a jacket from alusheet covered by a cork.plate cut to fit the flask, one head or two-head whatever.
Ok it is actually a mixture of airbath and radiation heating with the flask so low over the plate. it works fine for me.

I changed to this setup after it got clear that I have rarely the problem to heat something up, but mainly the problem to stop heating rapidly when reaction reaches the point it sustains itself. And keep on stirring of course. Thats one point I love on microwaves, the ability to <snip!> cut the power from 100% to zero.

I suggest to analyse how your reactions are running and then choose the fitting heating.

/ORG

[Edited on 25-4-2013 by Organikum]

zed - 25-4-2013 at 11:36

Could strip used Romex, and snip it into 1/4 inch "Bits" with diagonal pliers. It would give you something to do with your hands, the next time you are watching DVDs.

hyfalcon - 25-4-2013 at 14:54

How about this?

http://www.ebay.com/itm/1-kilo-2-2oz-avdp-999-Pure-Copper-Bu...

thewanderer - 25-4-2013 at 18:53

These pure copper cleaning pads are quite inexpensive at grocery/supermarkets around here: http://choreboyscrubbers.com/Products/Ultimate%20Scrubbers%2...

Were you thinking of packing around a flask in a heating container on a hot plate? Or filling the gap between a mantle and flask when using a flask smaller than the heating mantle?

Funkerman23 - 25-4-2013 at 21:43

Bluntly I was thinking of packing the copper around the flask in a heating container. if I still had a mantle I would just place it on the hotplate's top and use the stirring function by itself. sadly 2 or 3 liter mantles are not easy to come by and I seem to have terrible luck with ebay.( Wish I had met Dr bob back when he had 2 liter soft mantles..)
Quote: Originally posted by thewanderer  
These pure copper cleaning pads are quite inexpensive at grocery/supermarkets around here: http://choreboyscrubbers.com/Products/Ultimate%20Scrubbers%2...

Were you thinking of packing around a flask in a heating container on a hot plate? Or filling the gap between a mantle and flask when using a flask smaller than the heating mantle?

GammaFunction - 27-4-2013 at 16:30

Quote: Originally posted by chemcam  
IIRC the densities would come into play for a bath, even though they are both copper. The wool wouldn't hold heat in as long or as well as BB's, they are spread so far lots of air would be in the bath, lowering the efficiency. I don't know the correct term for this, sorry!


I think you don't want to hold heat; instead, you want to conduct it. Holding heat isn't necessarily great, because it lowers the level of control. The nice thing about an air bath is that you can rip off the foil and instantly lose heating, but a sand bath will keep heating even when you don't want it to.

So copper wool seems like a great idea. The copper will have high conductivity, but low heat capacity. Maybe one could have it in a container that splits with a latch to make it removable quickly to stop heating.


chemcam - 27-4-2013 at 17:15

I thought what the OP was wanting is a replacement for copper BB's, copper wool would offer completely different performance specification.

Funkerman23 - 27-4-2013 at 17:31

well I was trying to avoid the copper coated steel BBs used as air rifle ammo, There is a thread here( P-toluenesulfonic acid synthesis?) that made great use of them but again I don't know how corning hotplates are designed. Unless there is a current limiter or some other safety, I'm concerned that during a ( longer) reaction I could lock up/damage the motor assembly that magnetically spins the stirbar. It isn't too hard to see how steel BBs might be a problem with magnetically driven stirring.Hence I curious about using copper wool as it is low cost, workable and copper is naturally a very good conductor.
Quote: Originally posted by chemcam  
I thought what the OP was wanting is a replacement for copper BB's, copper wool would offer completely different performance specification.