TheNerdyFarmer
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HotPlate Repair
I have been having troubles with my hotplate. I don't think that it is reaching max temp. I was making some ferrous chloride and I wanted to
crystalize it. So I set my hot plate to around 130 Celsius and nothing happened. Not even steam. So I cranked it up to 200. I got some steam but
that's it. So I cranked it up to 300. Same Thing! I eventually had to crank It up to 500c to get it to boil. At that point it should just about
vaporize. What could be the problem? The Brand and Model number is "Corning, PC 420D". I am running it on 110v so if its 220v please let me know.
Please share if you have had this problem before. Also if you happen to know how to repair it and/or know any links for repair parts that would be
much appreciated. Thanks.
[Edited on 5-10-2016 by TheNerdyFarmer]
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gdflp
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Since you seem fairly new to this, my best guess is that you're simply not used to the equipment. How large a solution volume were you trying to heat
up, and in what container? The temp quoted by the hot plate is the theoretical surface temp, I have a similarly designed hot plate and even the
surface never reaches what the setting claims it will. To boil large amounts(1L or more) of water on my hotplate, I'll typically set it to ~330°C.
It takes a while to heat up water to boil, and hot plates aren't necessarily designed to add massive amounts of energy in a short time if you put them
at a low temperature setting. Heat transfer between the plate and the flask/beaker and heat loss to the air by conduction are massive losses.
If you want to heat something up quickly, I would insulate the container well and crank the temperature to near the maximum, otherwise the hotplate is
putting out substantially less power than it's specced to, and is losing a lot to the surroundings at the same time. Oil and sand baths can sometimes
help as well, but these add a significant thermal mass to the system.
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TheNerdyFarmer
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Yes I am quite new to this stuff so I kind of expect to ask some stupid questions lol. I was heating 400ml of ferric chloride solution in a 1 liter
beaker. I cranked the heat up to 500C then lowered it to around 250C to see if it had gotten hot enough to sustain a boil but it did not. I was
planning to one day boil sulfuric acid with this to purify it. Should I just get a heating mantle or will this work. (I would rather not buy a heating
mantle but if its necessary I will invest a couple extra bucks) Thanks for the info.
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diddi
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hot plates are a very inefficient heating unit. they heat a large square surface onto which we usually place a small round vessel. heat loss is
substantial. we often use tricks to conserve heat, which you may have seen in videos. sometimes an oil bath is a good idea, other times we heap sand
around the flask, or use aluminium foil. the temp on the dial is near meaningless in a practical sense. I have an IR thermometer which is useful for
checking oil baths etc so that I don't need to mess with glass thermometers.
Beginning construction of periodic table display
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TheNerdyFarmer
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So does that mean if I crank the heat up, insulate it, then turn the heat down a little, it would sustain a boil???
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diddi
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I would expect so
Beginning construction of periodic table display
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