<p>The aluminum plate is being heated by the heater element although I suspect the element does not encompass the entire area of the aluminum portion. There are going to be cooler spots on the aluminum but not enough to significantly affect the transfer to the glass.</p>

<p>Once you extend the glass, without a corresponding extension to the aluminum and/or heater element, you are ensuring cooler spots. The glass will be surrounded by air, and begin to conduct some of the heat, certainly, but will also radiate a substantial amount.</p>

<p>If you are printing with PLA, you may get away with doing this modification. Very little of the heat from the aluminum will reach the glass.</p>

<p>A quick check shows the thermal conductivity of aluminum to be 205 W/m K compared to borosilicate glass at 1.2 W/m K in the range of temperature used for 3D printing. I did not research the rate of energy dissipation for the same range of temperatures, but if it's not too high (unlikely), it would still take forever for the unheated areas of glass to reach temperature.</p>

<p>Consider your extension to be an unheated bed and print accordingly.</p>

CC BY-SA 3.0
2017-07-30T17:33:48.137Z
See the photos I got confirming your conjecture.
markshancock
CC BY-SA 3.0
2017-07-16T15:07:10.607Z
2017-07-16T15:07:10.607Z
fred_dot_u
<p>After Fred's answer, I realized there was a way to test out how much the temperature would drop by offsetting my current glass base to extend past the exge then using a <a href="http://www.flir.com" rel="nofollow noreferrer">FLIR</a> IR Camera to see what the effect would be.</p>

<p>Here are the results:</p>

<p>The the glass plate does seem act a bit as an insulator causing the print surface to be about 1°C cooler.  Here are two photos showing that.</p>

<p><a href="https://i.sstatic.net/KCCQZ.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/KCCQZ.jpg" alt="enter image description here"></a>
<a href="https://i.sstatic.net/pINUZ.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/pINUZ.jpg" alt="enter image description here"></a></p>

<p>As Fred proposed, where the glass extends past the base, the temperature drops pretty quickly.  It is still warmer than ambient; but is definitely not "Hot".</p>

<p><a href="https://i.sstatic.net/4j7Cs.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/4j7Cs.jpg" alt="enter image description here"></a></p>

CC BY-SA 3.0
2017-07-30T17:33:00.810Z
2017-07-30T17:33:00.810Z
markshancock
<p>I have a TronXY printer (i3 Clone).  It has a 220x220&nbsp;mm heated aluminum bed and I print with a Borosilicate glass plate.</p>

<p>I have a slightly longer print (245&nbsp;mm) I would like to do and I think I could adjust to settings and end stop to stretch the y-dimension travel and I have found a 229x257&nbsp;mm plate.  This would extend over the edge of the aluminum bed.</p>

<p>Will the thermal conduction and mass of the glass plate be sufficient to still keep the bed warm enough?</p>

<heated-bed><tronxy-x3>
Extending TronXY print bed
markshancock
# Extending TronXY print bed

(Asked by: username_0 on 2017-07-16)

I have a TronXY printer (i3 Clone). It has a 220x220 mm heated aluminum bed and I print with a Borosilicate glass plate.

I have a slightly longer print (245 mm) I would like to do and I think I could adjust to settings and end stop to stretch the y-dimension travel and I have found a 229x257 mm plate. This would extend over the edge of the aluminum bed.

Will the thermal conduction and mass of the glass plate be sufficient to still keep the bed warm enough?

**Tags:** heated-bed, tronxy-x3

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## 2 answers

### Answer by username_1 on 2017-07-16. Score: 3 | Accepted answer

The aluminum plate is being heated by the heater element although I suspect the element does not encompass the entire area of the aluminum portion. There are going to be cooler spots on the aluminum but not enough to significantly affect the transfer to the glass.

Once you extend the glass, without a corresponding extension to the aluminum and/or heater element, you are ensuring cooler spots. The glass will be surrounded by air, and begin to conduct some of the heat, certainly, but will also radiate a substantial amount.

If you are printing with PLA, you may get away with doing this modification. Very little of the heat from the aluminum will reach the glass.

A quick check shows the thermal conductivity of aluminum to be 205 W/m K compared to borosilicate glass at 1.2 W/m K in the range of temperature used for 3D printing. I did not research the rate of energy dissipation for the same range of temperatures, but if it's not too high (unlikely), it would still take forever for the unheated areas of glass to reach temperature.

Consider your extension to be an unheated bed and print accordingly.

> **Comments:**
> **username_0**: See the photos I got confirming your conjecture.  

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### Answer by username_0 on 2017-07-30. Score: 2

After Fred's answer, I realized there was a way to test out how much the temperature would drop by offsetting my current glass base to extend past the exge then using a [FLIR](http://www.flir.com) IR Camera to see what the effect would be.

Here are the results:

The the glass plate does seem act a bit as an insulator causing the print surface to be about 1°C cooler. Here are two photos showing that.

[![enter image description here](https://i.sstatic.net/KCCQZ.jpg)](https://i.sstatic.net/KCCQZ.jpg)
[![enter image description here](https://i.sstatic.net/pINUZ.jpg)](https://i.sstatic.net/pINUZ.jpg)

As Fred proposed, where the glass extends past the base, the temperature drops pretty quickly. It is still warmer than ambient; but is definitely not "Hot".

[![enter image description here](https://i.sstatic.net/4j7Cs.jpg)](https://i.sstatic.net/4j7Cs.jpg)


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