How to make a round-flask heater

[Arthis]

A few days ago I went to a shop to see the prices of a electric balloon heater, and prices are really too high.
You need to buy the heater, and the power regulator, considering heater with both-in-one present a few disadvantages. Total for a 1-L: >160$ so maybe this would be useful for everyone here to make one.
The ones we used at school had some cord, i guess it would act like a sand bath.

So, a few question: how to make one ? (apart from the power regulator)
How could it share out the heat it gives ? A long heating resistor ?
As for sand bath: how are they made ? Do you need to put something in the sand ? The fact is I don't understand the interest of the sand ? Better dispatch the heat ?

Last, would a heating plate be alright to heat a sand bath ?

[Mr Cool]

You can buy electric heating tape from lab suppliers, for heating reaction tubes etc. I think it's basically just nichrome wire zig-zagged through asbestos-substitute insulation. It typically goes all the way up to 400*C, depending on how much power you put through it. With a few feet of this it'd be easy to make a good heater. A light dimmer switch should work for the power regulator.
It would be basic, but should work.

[megalomania]

A sand bath is just a metal bowl of sand on a hot-plate. You should use a fine grade dry sand; I don't know what that would be at the hardware store, some kind of washed builders sand or playground sand I believe.

[jfk]

sand is silicon dioxide, right? (not silica i believe).

Im sure ive seen lab suppliers sell this - if you cant be fucked going down to the beach/sand selling place to get free stuff a supplier might be your best bet.

oter wise i would just get some from the beach, wash it with water with one of those metal coffee filter things (same mesh as the one on a coffee plunger) tog et the mud / shit out of it.

Also i read your post Mr. Cool, and i thought that if you taped up the inside of a metal bowl, immersed it in sand (about 1com below rim of bowl) then turned it on it would make a real good heating mantle.

[Arthis]

Yesterday, I found an old plate heater that my mum never used, that belonged to my gran' grandmother -> oh that could be used to heat a distillation setup.

So after having been here on the forum, I decide to first make a support to hold my Vigreux column, and the condenser. This is pretty simple to make: you put a vertical stick on a weight for it to be stable.

Next step: you need some pliers to hold your stuffs. I made some with a few clothespin, it's not really efficient, but don't forget that your flask will lay down on the heater (for me a sand bath).

Then the sand bath. One could use a plate heater, but i prefered to make my own, since I had what I needed to build one that would be exactly what I want. So I took down the plate heater: it's made with a heating resistor into small stones (granulometry ~3mm). Then you just need to rearrange it into a pyrex dish.
Now this can be easily rearranged to heat flasks from 250 mL to 2-3 L.

Thanx to motivation, I now own a complete distillation plant, hehe.

I'm wonder if all plate heater are made like that, but these should not be expensive, and it allows you to make a sand bath very easily.

Next time I try to upgrade to a better condensation system, I still got some problems with my Liebig condenser.
And I need to buy/find sand to replace these stones.

[Anthony]

Order sand from a chem supplier!? Madness!:eek:

"Kiln Dried Sand" is available from all builders merchants/DIY stores. It costs a few quid for a 10kg bag. It's fine, washed and as the name implies - thoroughly dried.

Another source is playpit sand, available from Mothercare et al.