02-23-03 00:09
No 410874
In any chain grocery store, where you would buy the cupcake tins and whisks, there exists a stainless steel coil (~4in) attached to a plug in cord. This coil is made to keep liquid foods hot when clasped onto the side of any pot/heat-resistant bowl/or cookware. G**d C**k. I love its compactness, its freedom from hot plates in general. However, it gets a 2-quart pyrex bowl oil bath way too hot for my purposes. 275f. A knowledgeable friend suggested I make a rheostat but it is beyond my capabilities i believe. Is there something i can put in the bowl to lower the temperature of the oil? I know that I could use a much larger vessel and try lowering the temp that way but I want to ask this first because I like using scaled down things. If I am missing something obvious, please point it out after a suitable dressing down. Thanks.
(Hive Addict)
02-23-03 00:15
No 410878
Get an adjustable light dimmer switch at any hardware store. Hook it up and now you have a variable temperature oil bath
Chemistry is hard to learn, but its worth it.
(Chief Bee)
02-23-03 00:16
No 410879
Use an ordinary lamp dimmer as a rheostat, but make sure that it is rated for the rather high wattage (power?) of your heating element.
(Synaptic Self-Mutilator)
02-23-03 01:20
No 410894
Cool, I was looking for something like that. The closest I found was an immersible water tank heater--rated 1500W. The highest power dimmer you can find is rated 600W, so make sure what ever you've got, that it's below that power consumption.
(Hive Addict)
02-23-03 08:40
No 410986
I've got some kind of big dimmer.It weighs about 8 kg's or so.Has a big coil inside and some graphite wheel running on that coil so one can regulate voltage 0-250 V.It's rated to 10 amps,that's 2,3 kwt's over here.
For those about to synth,we salute you
(Hive Bee)
02-23-03 22:45
No 411173
I've got some kind of big dimmer.It weighs about 8 kg's or so.Has a big coil inside and some graphite wheel running on that coil so one can regulate voltage 0-250 V.It's rated to 10 amps,that's 2,3 kwt's over here.
That sounds like a variac transformer, not a dimmer..
-SpicyBrown
(Stranger)
02-24-03 06:01
No 411342
I appreciate everyone's input and will try to attach a dimmer switch. Although I have never seen a dimmer switch. I would imagine that this dimmer switch plugs into any outlet and in turn the plug from the immersible heater is plugged into the switch? The heating element is 200Watts/120volts. Anyway, thanks for the push in the right direction.
(Newbee)
02-27-03 04:57
No 412142
The dimmer switch Swim bought at the flea market cost two dollars (US). It is rated at 600-watts. It is connected to a hot-plate. It comes with two wire nuts. Swim or Swiy would have to cut one side of the power cord, cut off the insulation of the two ends, and twist one wire from the dimmer to one of the cut wires, and the other d.s. wire to the other cut wire. Just twist them together. Then insert the twisted wires into a wire nut while turning the wire nut to screw it onto the twisted wires to make a safe and secure connection.
callen
(Newbee)
03-15-03 20:20
No 417348
Don't most of these immersible heating elements have thermal cutoffs? - especially the modern ones. They are designed to heat water to 100 C - so I wouldn't be surprised if they won't go above that temperature.
A deep-fryer (~ $5 from a garage sale) can be used as an oil bath - but not with a magnetic stirrer.
Likewise portable electric camp stoves make nice heating elements.
Look for 2nd hand heating mantles available on *-*** or **** The ones with magnetic stirrers are invaluble.
(Hive Addict)
03-15-03 20:23
No 417351
but not with a magnetic stirrer
Why not?And yes that was probably variac that i described before,we don't call it variac over here so that's why i might have been wrong...
For those about to synth,we salute you
(Stranger)
03-16-03 21:27
No 417676
the current traveling though simple loop heating elements induce strong B fields (magnetic fields). This will disrupt your magnetic stirrer every time there is a change of current, which is every time it turns on and off. Elements in hotplate/stirrers are designed in a way that the B fields that are induce cancel eachother out. I have been trying to figure out a way to use simple heating elements wired together and placed in such away that their B fields cancel so that a stirrer can be used.
(Hive Bee)
03-17-03 19:43
No 418115
think it'd be possible to design a mag. stirrer that in essence ran off the EMI field created by a coiled element? kind of in essence make it an electro magnet of some sort?
(Exotic Beauty)
03-26-03 02:52
No 421278
Don't most of these immersible heating elements have thermal cutoffs? - especially the modern ones. They are designed to heat water to 100 C - so I wouldn't be surprised if they won't go above that temperature.
Nope. Try putting one of those G**d C**k, $3.95, 200W elements in some vegetable oil. The oil easily gets to 150c. That was Autumn's problem. It made the oil way too hot for her purposes.
Free Speech Free Choice
(Hive Bee)
03-27-03 02:35
No 421575
The Variac or Rheostat will be fine..
In the ghetto, one might try current limiting the heater element.. Perhaps by placing a high wattage lamp in series with the element. Lab lighting and cooler heatsource.
easy and worth a try
Tirds CAN fly ! they can !
(Hive Bee)
03-27-03 19:32
No 421762
or be really ghetto and try not immersing it all the way somehow ;)
(Hive Addict)
03-27-03 19:45
No 421763
The best thing i have ever come across is something like that:
With this heater i have heated various roundbottoms ranging from 100 ml to 7 liters without problems,that 7 liter one was a little to big but solution got to 100 degrees C easily,have distilled safrole at atmospheric pressure in 1 liter roundbottom and safrole temp rose to 232 from 20 in 10 minutes.Have vacuum distilled MDP2P,have made methylamine,no problems keeping 2 liter roundbottom @ 103-104 degrees for several hours straight without keeping an eye on it,just checked occasionally.I just love that piece of equipment,i think everyone should have one.It's 600 watter so it's quite powerful also.Oil baths suck pretty much,if you get your hands on a heating mantle or on something i have,you'll never return to oil bath...
For those about to synth,we salute you
(Hive Addict)
03-28-03 05:53
No 421894
What is that type of heater called? Can it heat the RB flasks evenly?
Looks nice!
Chemistry is hard to learn, but its worth it.
(Hive Addict)
03-28-03 14:02
No 421984
I have seen something similar in Aldrich catalogue,but i don't know how it's called,it pretty cheap,that i know.
For those about to synth,we salute you
(Hive Addict)
03-28-03 18:28
No 422026
It's made by Gerhardt.I have a model from year 1995 or so,they don't make old ones but they still make flask heaters.
http://www.johnmorris.com.au/html/Gerhar
These new ones heat flasks from 250 to 1000 mls,i think they can take 2 liter ones aswell and maybe even 3 liter ones if not very high temperature is needed.This page says they heat upto 650 C which is more than enough but temp is controlled with stepless controller.
For those about to synth,we salute you