HJ Wrote:
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> Hi everyone,
>
> I just bought a 100k thermistor from my local
> store, but it's not the glass bead type, wondering
> if I can use it?
>
> This is the datasheet I found, it's "radial lead
> resin coated". The model is TTC--104.

The data sheet says that Thermistor has a maximum operating temperature of 125 degrees C, which is too low for a hot end.

Thanks for the advice. How about using it at the hot bed?

May I know roughly how high the temperature on the hot bed and hot end can be? Thanks.

HJ Wrote:
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> Thanks for the advice. How about using it at the
> hot bed?
>

I can't immediately see a reason why not. Heated beds usually go up to 110 degrees C. I suppose you could use it. You'd need to generate a thermistor table for it.
[reprap.org]

I'd recommend going for one of the recommended thermistors as you'll know for certain that you've got a good thermistor table when uploading your own firmware. Firmwares have in-built thermistor tables for popular thermistors.

> May I know roughly how high the temperature on the
> hot bed and hot end can be? Thanks.

Heated bed - up to 110 degrees C with ABS. Only 60 degrees C with PLA. Maybe a little higher or lower depending on accuracy of the thermistor and depending upon how you get on with bed adhesion.

Hot end - 185 degrees C for PLA, 220 degrees C for ABS. Again maybe a little higher or lower depending upon the bed adhesion technique you use and thermistor accuracy. Some people work with even higher temperatures for "experimental" type plastics. Most people currently use PLA or ABS.

The glass bead thermistors go up to 300 degrees C and cost about 5 dollars each. Given the thermistor is a critical component, most people would recommend using the glass bead types.

Also - thermistors are commonly attached by inserting them into a small drilled hole in the heated bed and hot end. The small size of the glass bead thermistors makes this easier. Of course there are other ways to attach thermistors without drilling holes (fire cement, kapton, glue) but by putting the thermistor inside the bed/hot end, the accuracy of the thermistors should be better.