Sciencemadness Discussion Board

Where to get those flexible heating mantles?

Triflic Acid - 2-4-2021 at 06:33

The title says it all. something like this .ds but cheaper for a 100mL flask, and also on amazon/ebay. Also, do I need something like a variac to use these?

[Edit] If a mod knows how to fix the link, please do. I can't figure it out :(
[Edited on 2-4-2021 by Triflic Acid]

[Edited on 2-4-2021 by Triflic Acid]

Dr.Bob - 2-4-2021 at 07:09

What size mantle are you looking for?

You will need either a variac or a power controller to use these without damaging the mantle, they will overhest and burn/fuse/melt at full power if cooled via a flask of cold water or something that can absorb the heat. Most organics only need 30-50% power to create a strong reflux.

I have some used Glass-Col brand ones, mostly in 250 and 500 ml left. This is what Chemglass sells under their name. A simple light dimmer control will work fine for them, just never plug them direct into 110 if you want them to last.

TheMrbunGee - 2-4-2021 at 08:41

I use these, because light dimmers may get way more expensive if more power is needed.

zed - 2-4-2021 at 09:53

Yup. That's some of the good stuff. Smaller ones are readily available on ebay. Used ones are quite reasonable. Inexpensive even. I prefer them in a "can".

At full list price, new, they are very expensive.

You don't need to have every size. That could get spendy. I have a 500, a 1000, and a 2000. At the moment.

Use a Variac, if you have one. I bought one at a reasonable price last year. Might have to bide your time if you are on a budget. Sometimes, Variac prices are reasonable, often they are not.

Thanks for the tip, Mrbungee. I'll take a look at those power-voltage- converters.

[Edited on 2-4-2021 by zed]

draculic acid69 - 4-4-2021 at 18:57

Type the following into Google:
2000w 220v 25A scrap motor controller ebay

This will bring up 1000s of different ppl selling these.
I have one of those other ones mentioned above
but don't use it as I find these to be better.they are
basically a mini Variac for $ won't be disappointed below is the picture of what to look for

images (5).jpeg - 27kB

Fyndium - 5-4-2021 at 04:23

Those dimmers are good and stand their power. I've used electric ovens and other high power stuff and my fuse switches have always given up before the dimmers.

Triflic Acid - 5-4-2021 at 14:28

Looking at price, I kind of gave up on buying on of those and just put a sand bath on my old SH2 hotplate and called it a day.

Texium - 5-4-2021 at 15:06

Sand baths suck.

Triflic Acid - 5-4-2021 at 15:13

I couldn't agree with you more Texium

[Edit] That eutectic alloy idea looks interesting. Maybe I should look more into that. Now, to find a cheap eutectic mixture.

[Edited on 5-4-2021 by Triflic Acid]

Tatjam - 5-4-2021 at 15:52

I want to share my design of a cheap and simple 200W mantle. It has some advantages, such as being pretty flexible and adjustable to a variety of flasks, but it also has some problems.
Cost is very low, probably around 15€ if you have a sauce pan to sacrifice.

You will need some heating tape, I used this one. It's pretty low power for its length, though, so you may be interested in expending more or searching further to find a higher rated tape. I'm satisfied with these as of now.

Afterwards you will need a power regulator. I used a 5€ one from aliexpress too that looks like the one TheMrbunGee shared. It came with a considerable dent but works fine and is rated to 2000W (Although I wouldn't trust it)

I don't like having exposed wiring, so I built a wooden box with a switch. I also added a fuse and a relay just in case I need rough control over the temperature of some reaction. If you find a power regulator that comes with a plug you will probably not need all of this, but mine just had some screws to hold the wires.

Then you just solder as many heating tapes as you need IN PARALLEL (so their power adds up) and wrap them around the inside of a sauce pan or some kind of metal container to help insulate the heat. This is actually quite tricky, I ended up dumping the tape into the skillet and molding it using a RBF.

The first big problem is that the heating tape left some stains on the flasks during the first uses. It could be cleaned with bleach, patience and some scrubbing. It also emitted some acrylic smelling fumes during the first half hour of use, so you may want to "precook" the tape outside before putting your glassware in it!
It's also fairly low power, 200W will heat up very slowly, but it can achieve temperatures of around 250ºC, probably higher, with some patience.
The durability is probably not expectacular, but considering how cheap the heating tape is, it may not matter much. I have run this setup at full power for around 10 hours and so far it's still working fine.

(Note: Don't put the pan directly over wood! It gets really hot and made some nasty black marks on my stands)

[Edited on 6-4-2021 by Tatjam]

zed - 6-4-2021 at 08:21

Hmm. I'm in the USA. I recently bought a pristine 1000ml Glas-col in a can, for less than $40.00. They show up on Ebay, at very reasonable prices. The guys say those $5-$10 dollar solid state controllers, do work.

Just bide your time, and settle for pre-owned.

Small, for me. Only 250 ml, but it would handle all of your smaller flasks.

500ml. Decent condition, most of 'em. They just look like you would quickly make a new one look. Need ten?

[Edited on 6-4-2021 by zed]

[Edited on 6-4-2021 by zed]

[Edited on 6-4-2021 by zed]

SWIM - 6-4-2021 at 13:21

Yeah, Ebay and a little patience will get you a great deal.

For a 100 ml mantle a little rheostat like for a lamp should do the job, but if you buy something better you'll be able to use it on larger mantles as well if you buy more.

I'm a big fan of mantles with separate power control units as they're easy to deal with if something burns out or gets clogged with strawberry jam.
Also, the 'bird's nest' type can usually be used with a rotating magnet below for stirring.
At least the smaller ones. Haven't tried this on a multi-liter flask mantle.

If you do much work at high temperatures, keep an eye out on Ebay for STS and STR(?) glas-col mantles.
These are high temperature units with higher wattage and special refractory fiber bodies.
They're rated for something like 600 or 650 degrees C.
Most regular mantles start getting pretty crispy at those temperatures.

I'd like to pick up one of those myself to use with a quartz distilling flask.

One other thing: These mantles are mostly designed to sit in a metal ring and not actually sit on a lab bench.
They do work okay mostly sitting on a bench, but may overheat at the bottom at high power settings.

The rings glas cols sells have a crossed hammock of fiberglass to support the mantle, but any old metal lab ring the right size will do a decent job.

zed - 6-4-2021 at 22:21

The Sabin Oral Vaccine for Polio. Polio is still around.