Arzagh
Harmless
Posts: 1
Registered: 11-4-2018
Member Is Offline
Mood: No Mood
|
|
Heating mantle
Hello everyone, I've just registered on this forum. I didn't find a presentation section, if there is one.
I'm making this thread because I've got my hands on an old heating mantle like this from an old lab that was being dismanteled (heh). The heating is fine, but the stirring isn't. I've opened it and I didn't find anything out
of place. Since there are 2 options for stirring (mono- and bidirectional), I've tried both and with the latter I can see the magnetic stir bar
rotating 90° every half minute or so. This is in accordance with the product manual, since it states that the rotation direction changes every 20-30
seconds. The stir bar doesn't move at all aside from those moments, though.
Did any of you encounter something similar? Did you fix the issue? Got any tips?
Have a nice day.
|
|
|
XeonTheMGPony
International Hazard
Posts: 1636
Registered: 5-1-2016
Member Is Offline
Mood: No Mood
|
|
Picture of the inside of it would help
|
|
|
Ubya
International Hazard
Posts: 1231
Registered: 23-11-2017
Location: Rome-Italy
Member Is Offline
Mood: I'm a maddo scientisto!!!
|
|
| Quote: |
I've opened it and I didn't find anything out of place
|
well something must be wrong. can you post a photo of the inside?
the problem could be in the circuit or in the motor itself.
check if the motor spins freely or is seized
---------------------------------------------------------------------
feel free to correct my grammar, or any mistakes i make
---------------------------------------------------------------------
|
|
|
carbon85
Harmless
Posts: 11
Registered: 28-3-2018
Member Is Offline
Mood: No Mood
|
|
Hotplate stirrer eaten
Just got what was a brand new hotplate stirrer we are taking 2 to 3 hours use here which had been stored for around 3 years upon digging it out of the
shed i noticed that a white substance had formed all over it included the power lead , The original paint around the hotplate was harshly bubbled up
and also peeling to the point where it looked like it had been direct contact with something extremely corrosive almost like someone had a accident
evacuated and left it there since ... It was stored around very basic chemicals nothing appeared to have leaked although a smell of almond/aldehyde
was present in the shed yet no leak was to be found ?
Anyway upon wiping it down and cleaning it up i decided to get another lead since this white substance had made the outer casing , I placed the
correct and new 13A fuse into it and noticed to power light come on first instantly . The next thing i tried was the addition of a small magnetic
stirrer slowly increased yet nothing happened ? ... I slowly tried to heat it up yet nothing , So after 2 hours and a pack of cigarettes to undo
around 10 screws due to the heavy corrosion on the threads of the screws whilst being careful enough not to round of the head of the screws i was
finally inside
This white substance had made its way into the inner workings of the hotplate where loads more bubbled paint was observed and corroded a fair amount
of it yet i was still determined not to let this $250 nightmare be over just yet , I sanded down any signs of corrosion on bare metal and conductive
parts in order to eradicate my hotplate of this money wasting substance yet it seams to make no difference and its a shame i cannot remove the circuit
board that connects the heat and stir controls i even thought the nobs would screw of if screwed the other way to give me acsess to the board but it
seams not
Is this a lost cause ? I hope not but i don't want to throw it if it can be fixed what the hell is this white substance benzoic acid ? With such
corrosive ability's ? Its the only thing i could possibly think of since the smell of almond was present .
Word of advice if your thinking of taking a break make sure you equipment is well protected what planned to be a cheap return might just be quite the
opposite
[Edited on 15-4-2018 by carbon85]
|
|
|
Sulaiman
International Hazard
Posts: 3554
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
The knobs may have a tiny screw to hold them on, if so, loosen the screw
most knobs are just s tight spring-loaded fit,
pull the knobs off.
Behind the knobs will probably be nuts securing the shafts, and often the entire electronics.
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
Blue Matter
Hazard to Others
Posts: 107
Registered: 20-6-2013
Location: US
Member Is Offline
Mood: Optimus
|
|
I bought almost that exact same model mantle a while ago but a bit newer, unfortunately it did not last very long. One day I was messing around with a
reaction and wasn't paying attention and it ran away spilling out into the mantle, I noticed it immediately and turned off the heat but the damage was
done, the element was completely fried and never worked again after various attempts to fix it. I emailed electromantle to see if I could get a
replacement heating element and was quoted 300$+ which was far more than I paid for the whole unit, after this incident I bought a glascol heating
mantle and have spilled a million different things in it and it still works like a champ. If I were in your shoes I would thoroughly clean all of the
electrical connections inside the unit and see if it makes any difference, it kind of sounds like something may be shorting out. Also be careful
taking it apart, I remember when I tried diagnosing mine the internals were quite delicate and it was pretty annoying trying to put back together.
|
|
|
carbon85
Harmless
Posts: 11
Registered: 28-3-2018
Member Is Offline
Mood: No Mood
|
|
I see no screws or simply something to clamp onto from the inside while screwing the nobs of from the outside ... Dam sorry to hear your mantle was so
easily beaten .. I don't think it is much to ask for a sealed chemically resistant unit to be made of these heaters since the whole purpose of them is
tho have chemicals sitting directly ontop of them even the safest of chemists make spills from time to time
I should have made more of an effort to store it probably cry cry it had practically no use but since the only real threat would come from what thin
air ?
I cleaned everything i possibly could using sandpaper and dremel drill with a very a small bit so slowly sand down the conductive bits more
effectively than with sandpaper yet my efforts seamed to be laughed at
This somehow evaporating aldehyde seamed to be very effective at destroying my hotplate and somehow evaporating through a hole you would need a
microscope just to detect apparently as the same bottle was washed out and filled up with water and squeezed yet nothing was released a mystery i tell
ya
[Edited on 17-4-2018 by carbon85]
|
|
|
XeonTheMGPony
International Hazard
Posts: 1636
Registered: 5-1-2016
Member Is Offline
Mood: No Mood
|
|
Deschem has 500 and 1 L elements for mantles and so far seem to be of considerable quality as so far I have distilled over 2L of H2SO4 in it! and my
mantle is made out of a tomato can! and light dimmer!
Again some pictures will be of great help.
So far it seems to be these pieces of equipment are at blatant rip off prices for pretty looking garbage, from Nerdrage to fellow forum members.
If all ells fails get a pid controller from ebay and a pwm motor driver with a feed back option and you'll be able to make a far superior unit using
the old unit as a base
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
