Thermistor - spec/part number anyone?

Hello,
Before taking the plunge and purchasing a RepRap kit, I have (of course), spent ages looking at websites and forums and am most likely going to go for the current Huxley campaign which EMaker are running. I'm trying not to get put off by some of the "it's not working" and "problem here.." posts but would be keen to find out the part number / spec / source for replacement of what seems to be a very delicate component, the thermistor used in the hot end and heat bed as this component seems to be the one which is most likely to break during assembly.

Can anyone advise or have I missed the spec somewhere in the depths of the instructions? Is the part easily available from UK sources such as Maplins?

Thank you in advance,

Alan

I thing that having done some "research" I can answer my own question - would still like some comment though if anybody has any! (Apologies if what I am about to write appears obvious but don't forget, things are only obvious if you know the information already).

The list of parts needed to build the various controller boards, Sanguinololu boards included, are relatively easy to find and the parts could be sourced independently from the supplier of the printed circuit board if the builder wished to do so. (Should repairs be needed for example). However, details of the sensors - the thermistors - used for the RepRap machines are not listed alongside the board components, which is where my question came from.

Various websites I have found talk about a 100K thermistor for the Sanguinololu and the Maplin catalogue carries a thermistor with the following spec - Maplin part number CRO5F - which makes me feel more confident about starting a RepRap project knowing that I should be able to source replacements should I need them.

Bead thermistor with a resistance of 352.4K @ zero deg C, 100K @ 25 deg C and 4.77K @ 100 deg C

As the firmware will be expecting a specific thermistor resistance profile, getting a matching sensor is key to success - does the above sound about right - similar to the thermistor used in the "kits"?

Alan

That has a maximum temperature rating of 155C, so no it is not suitable. You need glass bead thermistors rated for 300C. They are available from RS and Farnell in the UK.

[uk.rs-online.com]

[uk.farnell.com] (slightly bigger version).

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[www.hydraraptor.blogspot.com]

And in general any 100 K negative temp coefficient thermistor will work if it is rated to 300 C. You may have to change the temperature conversion table in firmware to get really accurate readings though.