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Posted by Cefiar 
August 16, 2010 06:16AM
One of the few things I need now is a thermistor.

Any recommendations for places in Australia to get a thermistor suitable for use on an extruder?

I'm hoping for something that'll handle 250 Deg C or more, and is in a radial lead (ie: NOT an axial lead) package. Something like this: [australia.rs-online.com] perhaps?

FWIW: I'm thinking of getting a few (I plan on making a number of extruders).
Re: Thermistors
December 06, 2010 01:07AM
I'm in the same position of needing a few high temp thermistors at the moment.

Where did you end up getting your thermistors from? I did have some on order from mendel-parts, but gave up waiting after a month and cancelled my order.
Re: Thermistors
December 06, 2010 02:17AM
I got some originally from Element14 (back when they were Farnell), but they were way too small (0.8mm diameter) to do anything decent with.

I ended up getting two from Makergear, mainly cos the kit came with the PTFE sleeving and I was ordering other stuff from them.

The thermistors are 2.1mm in diameter, which makes it a LOT easier to physically mount them. The leads are thicker which makes wiring a lot easier. Ultimachine also carry the same thermistors, though they don't have any PTFE sleeving.

Element14 carries the same thermistors, but they charge about 3 times the price for just the thermistor. The advantage is however that they don't charge shipping.

Next time I'm on the Element14 site (read: tomorrow) I'll look up their part number for the same thermistor and post it here.

Note: Yes, now I appear to have a working hot end. I'm currently testing it to ensure it works fine before it gets anywhere near plastic filament.

Edited 1 time(s). Last edit at 12/06/2010 02:19AM by Cefiar.
Re: Thermistors
December 06, 2010 09:46AM
Thanks for the prompt reply, I will check back tomorrow.

Best of luck with the hot end testing!
Re: Thermistors
December 06, 2010 08:24PM
Ok, the thermistors from Element14 that should be ok (supposedly) are:


Main reason for choice (apart from larger body size compared to the old ones) is the climatic category: 55/300/56

This means it should be able to stand temperatures from -55 to +300 Deg C for up to 56 days. Should prove quite suitable for an extruder.
Re: Thermistors
December 07, 2010 02:13AM
Thanks for that.

I can see why you attached them to another order, they dont come cheap from element14.
Re: Thermistors
December 07, 2010 02:21AM
i might be buying a bunch from altronics.com.au, because i plan to sell nozzles along with my extruder kits.

Thank you for your request for quote.

PLEASE NOTE OUR MINIMUM ORDER IS A$300.00+ per line for these type of parts.

We are a bulk wholesaler of electronics if your after a small quantity of parts - you could try

WES Components.

If you would like a quote.

1, Please confirm the quantity you need.
1, Please confirm you can take a higher qty.
2, Please confirm the FULL part number, package and Manufacturer.
3, Please confirm your contact information. FAX # ?
4, Please tell us what your company is doing, MFG, Repairer, R&D ?

PLEASE NOTE OUR MINIMUM ORDER IS A$300.00+ per line for these type of parts.

Thank you
Re: Thermistors
December 07, 2010 02:42AM
i think this will be fine:

but i would still like to test one before dropping $300
Re: Thermistors
December 07, 2010 10:05PM
That's an EPCOS B57550 series thermistor, which should be ok size wise.

Do not buy the B57540 series, as they are just too small to work with.

The ones I have are B57560 series, which are slightly larger still, but works fine.

B57540 = 0.8mm (dia) x 1.4mm, 0.15mm wires, 250 Deg C rating
B57550 = 1.3mm (dia) x 2.2mm, 0.2mm wires, 300 Deg C rating
B57560 = 2.3mm (dia) x 4.1mm, 0.3mm wires, 300 Deg C rating

Note: I suggest you consider using PTFE sleeving over the wires. Unfortunately you'll have to buy a roll of it, so make sure you get stuff with the appropriate Inside Diameter.
Re: Thermistors
December 07, 2010 11:47PM
is it easier to put on than kapton tape?
Re: Thermistors
December 08, 2010 01:59AM
Just slides over the wire like heatshrink tubing. Doesn't shrink though. PTFE will withstand fairly high temperatures, probably better than Kapton.

Note: As Kapton tape heats up, the tape expands, lifting the tape off the object. Many of the glues used on Kapton tape also stop working while at high temp, losing their bond. Expansion happens with PFTE sleeving, but as it's a complete sleeve and not joined by glue, it doesn't fall off.
Re: Thermistors
December 08, 2010 02:24PM
kapton tape from makerbot has worked pretty well for me but PTFE sounds much more appropriate and would look neater, thanks for the tip.

when i built my first extruder and heated bed it was all about massive amounts of kapton tape.. now i'm using heaterblock with resistor, (i use old computer powersupply wires after sawing off the plastic molex i use the female little connector as a crimp to join to the resistor), printing on blue scotch tape ($10 from mitre10 works drastically better than printing on kapton), ptfe sleeves would totally free my machine of kapton tape smiling smiley
Re: Thermistors
December 08, 2010 02:30PM

Just wondering where we can buy some of this PTFE tubing???

Re: Thermistors
December 08, 2010 09:00PM
Unfortunately most places only carry it in 100m rolls, which makes it expensive. We really don't need a lot of it.

Something like [au.element14.com] or [au.element14.com] should be fine, but at about $67 ex for 100m, it's not worth it for such a small job.

Also make sure that you get tubing of the right inner diameter. No use if you find your wire is too thick. Not going to happen on the thermistors, but if you plan to use it for other pieces (eg: resistor block leads), then you need to factor it in.

FWIW: Sometimes it's cheaper to buy some PTFE coated wire (eg: certain types of wirewrap wire), strip the insulation off and use that. Also useful in other ways.

Edited 1 time(s). Last edit at 12/08/2010 09:09PM by Cefiar.
Re: Thermistors
December 09, 2010 10:00PM
I just checked that thermistor from RS that Mlagana linked.

its only $3.70 aust. so i might pick up 3-4 and see how they go.

Supposed to be in stock. so shouldnt take long to get even at this time of year.

Re: Thermistors
January 16, 2011 03:23AM
I have tested this puppy and it works fine:


Still having trouble finding .2mm ptfe sleeving, or any sleeving that small for that matter. found some .2mm wire meant for outdoors and sun so need to strip and test the sleeving at 240C i kinda doubt it will work.
Re: Thermistors
January 16, 2011 07:20AM

I brought some from [cgi.ebay.co.uk] they have it on sale for £1.17 per meter.
Hope that helps.

Re: Thermistors
January 18, 2011 03:20AM
yes that does help a lot! thanks.
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