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Author: Subject: First hotplate
spoofy
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First hotplate

I just got my first hotplate which in theory should heat up to 380C. Just to test it I put a 500ML beaker with 400ML of water in it and put it on "5" (the temp knob goes up to 9). Its been roughly 45 minutes and the water has not come to a boil yet.

So my question, do hotplates normally take a very long time to warm up? I'm using the BioMega h4000-HS
User
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What is the rating if your plate?
I have a couple of plates and one of them also has a hard time reaching high temp.
Low wattage can be the cause.

What a fine day for chemistry this is.
DJF90
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You should never fill your flasks that full. 2/3rds maximum. For a 500ml flask, I would expect 150-200 watts to be (more than) adequate.
spoofy
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Speed Range: 60—1500 rpm

Temperature Range: Ambient +5 to 380 C

Platform: 7.5 x 7.5 in.

Control: Quick Adjustment Knobs

Dimensions:8(W) x 9(D) x 4.5(H) in.

Electrical Data: 120V, 60 HZ / 230V, 50/60 HZ

EmmisonJ
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i don't know if that's common for many people or not but mine is the same way with similar specs.

in my personal experience hotplates take a little bit of getting used to, to get a feel for them. ie: get a feel for how quickly it warms up or cools off and what temp you can expect from the dial settings as well as the time it takes to get there, mine does both very slowly. i feel you though, mine is painstakingly slow. maybe should've bought a $1000 hotplate instead of a$350 one. a while back i lost power while maintaining a nice reflux, it took an hour afterwards to dial it back to the right constant temp, overshooting and undershooting the temp until i eventually got it.
User
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I can confirm this, u indeed get a feel for the dials.
I now that distilling sulfuric acid is not gonna work with one of my plates as it just hasn't got enough surge for it.
This is also an advantage for situations where i don't want to exceed certain temperatures.
This plate is rated 525watts and it just isn't that much.
Another hotplate sitting around is rated 2800watts and i can tell , that's a difference. It turns almost redhot in a matter of seconds.

[Edited on 20-6-2009 by User]

What a fine day for chemistry this is.
EmmisonJ
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 Quote: Originally posted by User I can confirm this, u This plate is rated 525watts and it just isn't that much. Another hotplate sitting around is rated 2800watts and i can tell , that's a difference. It turns almost redhot in a matter of seconds.

that is excellent advice for shoppers of hotplates that don't want to spend an hour to reach desired temperatures. perhaps when mine kicks the bucket (it better not for a long time! haha) i'll upgrade to a higher wattage hotplate. will definitely stick with a hotplate, not a big fan of mantles even though they have their benefits, hotplates are more versatile. just my personal preference there

[Edited on 20-6-2009 by EmmisonJ]
spoofy
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update..

first place couldn't boil water .. so i sent it back

second plate took 10 hours to heat 400ml of oil to 200C

I would suggest others avoid this brand if possible.. they are cheap.. but from my experience not useful at all.

[Edited on 3-7-2009 by spoofy]
entropy51
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spoofy, it sounds like you accidentally bought the model with training wheels on it

Next time try a Corning. I've killed lots of hotplates, but I've had a Corning for 20 years and it refuses to die.

Better to remain silent and appear a fool than to open your mouth and remove all doubt.
Saerynide
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When mine arrived in the mail, the first thing I did was set it on the counter and cook lunch (pasta).

I was disappointed to find the stove was much better at accomplishing this task (30 min and the pasta is still only half cooked!). However, it works fine for chemistry, so thats a relief .

[Edited on 7/4/2009 by Saerynide]

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EmmisonJ
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i'm in the same boat spoofy, live and learn.

i've had mine for only a year, it is a different brand but the specs are the same as yours so it's either comparable or is the same thing but re-branded.

if one can save up the money for a real brand, they do pay for themselves eventually.
UnintentionalChaos
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I'm not sure what models everyone uses, but one that crops up a lot is a Corning PC-351. I have one and it works very nicely. I snagged it on ebay for about \$120 although I'm under the impression that this was very cheap.

[Edited on 7-7-09 by UnintentionalChaos]

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User
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If you just need brute force without stirring one could buy a second hand electric cooking plate.these things often don't cost shit and i have seen them going well over 2000watts.
I have one which i use often to just heat things quickly.
for example to boil down battery acid it is very useful.
Nothing special, just brute force and cost next to nothing.

What a fine day for chemistry this is.
Phosphor-ing
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You have to be aware that those cheap electric burner/cooking plate things are not sparkless. Using them to heat flammables could be hazardous to your health.

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 Sciencemadness Discussion Board » Fundamentals » Beginnings » First hotplate Select A Forum Fundamentals   » Chemistry in General   » Organic Chemistry   » Reagents and Apparatus Acquisition   » Beginnings   » Responsible Practices   » Miscellaneous   » The Wiki Special topics   » Technochemistry   » Energetic Materials   » Biochemistry   » Radiochemistry   » Computational Models and Techniques   » Prepublication Non-chemistry   » Forum Matters   » Legal and Societal Issues