<p>Glass. Or more specifically, insulating two or three layer window panes between which is a vacuum or low heat conductive gas.</p>
<p>These panels are quite effective, compared to single panes: on a  two layer sandwich, 9.5 mW/(m K) can be achieved with a Krypton filling, 5.5 mW/(m K) with Xenon. The sweet spot for avoiding too many loss from convection is usually below 10-15 mm per gas layer, depending on the gas. Three or even four glas panels can get away with much thicker total panes and avoid convection by having the gas insulator broken up into multiple layers as thin as 5 mm.</p>
<p>Such Mehrscheiben Isolierscheiben (insulating glazing) is often obtainable in any size from window makers and can come with a frame that contains the needed mechanisms to open or lock the box.</p>

CC BY-SA 4.0
2021-07-10T19:37:26.643Z
Acrylic is actually less thermally conductive than glass, and OP already has it on hand
craftxbox
CC BY-SA 4.0
2021-07-12T07:39:47.153Z
I wonder whether it would be possible to have custom made double layer glass. Which would be heavy of course, but effective.
FarO
CC BY-SA 4.0
2021-07-12T12:23:36.307Z
A window maker could deliver any shape and form as needed.
Trish
CC BY-SA 4.0
2021-07-13T07:51:56.627Z
@craftxbox not by a magnitude if it's double pane glass with halogen.
Trish
CC BY-SA 4.0
2021-07-13T08:27:18.010Z
This seems the easiest solution, I was not aware of cheap two pane glass. However 1) it will be much heavier than DIY double-pane acrylic (see my comment to the other answer); 2) thermal break, meaning that with 60 °C temperature difference (20-80 °C) it may crack, or at least the metallic coating may detach from the glass (I was also told not to put curtains too close to my new house windows, to avoid overtemperature and damage to the coating); 3) HR++ I found has about 1.3 W/(m^2 K), which is about 25 mW/(m K). I'm not sure how to reduce it by another factor of 2.5-5x, but it doesn't matter.
FarO
CC BY-SA 4.0
2021-07-13T08:38:45.340Z
Higher temperature differential might warrent 3 pane, but you should discuss the setup with a window maker, who might have an idea and the knowledge to make it. Laboratory inspection windows are usually rather thick, round and in steel frames, because of the pressure in high temperature machinery.
Trish
CC BY-SA 4.0
2021-07-13T08:50:28.597Z
For info: 500x700 mm triple glass weighs 10 kg, not an option. Double glass with hardened glass (to withstand more than 40 °C deltaT) costs at least about 150 €/m^2, also likely too much. I'll contact some seller to check better.
FarO
CC BY-SA 4.0
2021-07-13T08:51:43.680Z
Sadly price and the best solution are enemies.
Trish
CC BY-SA 4.0
2021-07-18T02:54:31.713Z
+1 - FWIW, *Mehrscheiben Isolierscheiben* in (British) English is called "Double glazing" (or "Triple glazing"), and "double/triple glazed windows", or just "Insulated windows". Not sure if it is the same in American English.
Greenonline
CC BY-SA 4.0
2021-07-10T06:38:11.113Z
2021-07-13T07:12:21.683Z
2021-07-13T07:12:21.683Z
Trish
<p>Unfortunately there are very little solutions for fully transparent and thermally insulating materials. You may be able to use panels commonly used for greenhouses and hydroponics if you can accept losing full transparency and only being translucent. Another option may be to have <strong>two layers of your transparent material</strong>, with an air-gap in between, as dry and still air is a very good thermal insulator.</p>

CC BY-SA 4.0
2021-07-10T05:53:53.157Z
Two panels is of course acceptable. Are you able somehow to estimate the insulating properties based on the air gap? By the way, air is a good insulator but only when it's not moving, that's why foams have small pores. If air can move, you get vortices and a much better heat transport.
FarO
CC BY-SA 4.0
2021-07-10T19:43:13.573Z
Typical glass has a thermal conductivity of 1-0.8 W/mK, Acrylic has around 0.2 W/mK, and  dry, still air comes in at about 0.025 W/mK
craftxbox
CC BY-SA 4.0
2021-07-11T21:07:13.363Z
Obviously air inside won't be still, but it should be surely lower than acrylic alone. I could also build a double layer of acrylic, seal it and pump out air when maximum insulation is needed
FarO
CC BY-SA 4.0
2021-07-12T17:17:17.980Z
Pumping air out is probably not an option due to the pressure on the outside of the glass sandwich..
cmm
CC BY-SA 4.0
2021-07-13T07:16:57.100Z
It's W/m K, as in watts per meter-Kelvin. Not watts per Millikelvin. The space is crucial here: the meters is for the thickness of the panes. And note that modern windows are in the 5-10 milliwatt/meter-Kelvin area, so a magnitude or two better than acrylic.
Trish
CC BY-SA 4.0
2021-07-13T08:16:24.220Z
@cmm why not? you 3D print a T support to be used as spacer at the edge, then you glue various small "+" supports in various spots between the panes, then you use silicone sealant to glue/seal the T around. You leave a hole (with O ring and cover for automatic sealing) for the vacuum pump and you are done.
FarO
CC BY-SA 4.0
2021-07-14T07:26:42.333Z
@cmm you are right, half bar under pressure would already result in 10 tonnes force per square meter. Vacuuming home made double pane is not an option.
FarO
CC BY-SA 4.0
2021-07-09T22:25:12.647Z
2021-07-10T19:45:03.257Z
2021-07-10T19:45:03.257Z
craftxbox
<p>How about using thermally insulating transparent silicone rubber sheets?</p>

CC BY-SA 4.0
2021-07-12T16:14:25.593Z
I can't find any datasheet
FarO
CC BY-SA 4.0
2021-07-12T14:11:06.530Z
2021-07-12T14:11:06.530Z
Perry Webb
<p>Never saw double pane windows of houses? Triple panes are not impossible.</p>

CC BY-SA 4.0
2021-07-18T02:41:56.860Z
Welcome to 3D Printing SE and thank you for your contribution. Could you elaborate a bit more on your answer. As it is, it could be deleted for being a bit thin on facts and/or sources.
agarza
CC BY-SA 4.0
2021-07-18T02:50:39.157Z
AKA Double glazing - double glazed windows (or triple glazed). This is the same as [Trish's answer](https://3dprinting.stackexchange.com/a/16700/4762)
Greenonline
CC BY-SA 4.0
2021-07-17T19:17:13.713Z
2021-07-17T19:17:13.713Z
Uwe
<p>When considering enclosures able to reach higher chamber temperatures, insulation is essential to keep the heater power low.</p>
<p>Typical insulation materials are not transparent: cork (fire retardant, good for the inner hot side), rock wool, styrofoam panels, aluminium insulating panels (aluminium walls with foam in between).</p>
<p>Still, most of the time it's preferable to have one side of the enclosure transparent, to see what is happening inside without having to use a webcam (which may not work well or which may have a reduced lifespan when operated at 60-80 °C, due to capacitors and thermal noise in the sensor).</p>
<p>Rock wool, styrofoam panels and cork all offer about 0.032-0.038 W/(m K) thermal conductivity. In other words, a panel which is 50 * 50 * 1 cm will require about 0.85 W per each °C of temperature increase, or 8.5 W per 10 °C. A cubic 50 * 50 * 50 cm enclosure 2 cm thick  would require 26 W to increase the inner temperature by 10 °C.</p>
<p>Replacing just one side with a transparent acrylic panel 3 mm thick would push the power requirement to about 190 W for every 10 °C of temperature increase, therefore finding a transparent insulation would be quite interesting.</p>
<p><strong>What are the options to have a transparent, but still reasonably insulating, panel?</strong></p>

CC BY-SA 4.0
2021-07-09T16:41:54.337Z
How about a dual pane thing? It helps in houses to get a better R value from the windows. And keep the window small as it can while allowing you to see the print progress.
ChinchillaWafers
<enclosure>
What are the options for an insulated but still transparent door for a 3D printer enclosure?
FarO
# What are the options for an insulated but still transparent door for a 3D printer enclosure?

(Asked by: username_0 on 2021-07-09)

When considering enclosures able to reach higher chamber temperatures, insulation is essential to keep the heater power low.

Typical insulation materials are not transparent: cork (fire retardant, good for the inner hot side), rock wool, styrofoam panels, aluminium insulating panels (aluminium walls with foam in between).

Still, most of the time it's preferable to have one side of the enclosure transparent, to see what is happening inside without having to use a webcam (which may not work well or which may have a reduced lifespan when operated at 60-80 °C, due to capacitors and thermal noise in the sensor).

Rock wool, styrofoam panels and cork all offer about 0.032-0.038 W/(m K) thermal conductivity. In other words, a panel which is 50 \* 50 \* 1 cm will require about 0.85 W per each °C of temperature increase, or 8.5 W per 10 °C. A cubic 50 \* 50 \* 50 cm enclosure 2 cm thick would require 26 W to increase the inner temperature by 10 °C.

Replacing just one side with a transparent acrylic panel 3 mm thick would push the power requirement to about 190 W for every 10 °C of temperature increase, therefore finding a transparent insulation would be quite interesting.

**What are the options to have a transparent, but still reasonably insulating, panel?**

**Tags:** enclosure
> **Comments:**
> **username_1**: How about a dual pane thing? It helps in houses to get a better R value from the windows. And keep the window small as it can while allowing you to see the print progress.  

---

## 4 answers

### Answer by username_3 on 2021-07-09. Score: 6

Unfortunately there are very little solutions for fully transparent and thermally insulating materials. You may be able to use panels commonly used for greenhouses and hydroponics if you can accept losing full transparency and only being translucent. Another option may be to have **two layers of your transparent material**, with an air-gap in between, as dry and still air is a very good thermal insulator.

> **Comments:**
> **username_0**: Two panels is of course acceptable. Are you able somehow to estimate the insulating properties based on the air gap? By the way, air is a good insulator but only when it's not moving, that's why foams have small pores. If air can move, you get vortices and a much better heat transport.  
> **username_3**: Typical glass has a thermal conductivity of 1-0.8 W/mK, Acrylic has around 0.2 W/mK, and  dry, still air comes in at about 0.025 W/mK  
> **username_0**: Obviously air inside won't be still, but it should be surely lower than acrylic alone. I could also build a double layer of acrylic, seal it and pump out air when maximum insulation is needed  
> **username_5**: Pumping air out is probably not an option due to the pressure on the outside of the glass sandwich..  
> **username_2**: It's W/m K, as in watts per meter-Kelvin. Not watts per Millikelvin. The space is crucial here: the meters is for the thickness of the panes. And note that modern windows are in the 5-10 milliwatt/meter-Kelvin area, so a magnitude or two better than acrylic.  
> **username_0**: @cmm why not? you 3D print a T support to be used as spacer at the edge, then you glue various small "+" supports in various spots between the panes, then you use silicone sealant to glue/seal the T around. You leave a hole (with O ring and cover for automatic sealing) for the vacuum pump and you are done.  
> **username_0**: @cmm you are right, half bar under pressure would already result in 10 tonnes force per square meter. Vacuuming home made double pane is not an option.  

---

### Answer by username_2 on 2021-07-10. Score: 3

Glass. Or more specifically, insulating two or three layer window panes between which is a vacuum or low heat conductive gas.

These panels are quite effective, compared to single panes: on a two layer sandwich, 9.5 mW/(m K) can be achieved with a Krypton filling, 5.5 mW/(m K) with Xenon. The sweet spot for avoiding too many loss from convection is usually below 10-15 mm per gas layer, depending on the gas. Three or even four glas panels can get away with much thicker total panes and avoid convection by having the gas insulator broken up into multiple layers as thin as 5 mm.

Such Mehrscheiben Isolierscheiben (insulating glazing) is often obtainable in any size from window makers and can come with a frame that contains the needed mechanisms to open or lock the box.

> **Comments:**
> **username_3**: Acrylic is actually less thermally conductive than glass, and OP already has it on hand  
> **username_0**: I wonder whether it would be possible to have custom made double layer glass. Which would be heavy of course, but effective.  
> **username_2**: A window maker could deliver any shape and form as needed.  
> **username_2**: @craftxbox not by a magnitude if it's double pane glass with halogen.  
> **username_0**: This seems the easiest solution, I was not aware of cheap two pane glass. However 1) it will be much heavier than DIY double-pane acrylic (see my comment to the other answer); 2) thermal break, meaning that with 60 °C temperature difference (20-80 °C) it may crack, or at least the metallic coating may detach from the glass (I was also told not to put curtains too close to my new house windows, to avoid overtemperature and damage to the coating); 3) HR++ I found has about 1.3 W/(m^2 K), which is about 25 mW/(m K). I'm not sure how to reduce it by another factor of 2.5-5x, but it doesn't matter.  
> **username_2**: Higher temperature differential might warrent 3 pane, but you should discuss the setup with a window maker, who might have an idea and the knowledge to make it. Laboratory inspection windows are usually rather thick, round and in steel frames, because of the pressure in high temperature machinery.  
> **username_0**: For info: 500x700 mm triple glass weighs 10 kg, not an option. Double glass with hardened glass (to withstand more than 40 °C deltaT) costs at least about 150 €/m^2, also likely too much. I'll contact some seller to check better.  
> **username_2**: Sadly price and the best solution are enemies.  
> **username_4**: +1 - FWIW, *Mehrscheiben Isolierscheiben* in (British) English is called "Double glazing" (or "Triple glazing"), and "double/triple glazed windows", or just "Insulated windows". Not sure if it is the same in American English.  

---

### Answer by username_6 on 2021-07-12. Score: 0

How about using thermally insulating transparent silicone rubber sheets?

> **Comments:**
> **username_0**: I can't find any datasheet  

---

### Answer by username_7 on 2021-07-17. Score: 0

Never saw double pane windows of houses? Triple panes are not impossible.

> **Comments:**
> **username_8**: Welcome to 3D Printing SE and thank you for your contribution. Could you elaborate a bit more on your answer. As it is, it could be deleted for being a bit thin on facts and/or sources.  
> **username_4**: AKA Double glazing - double glazed windows (or triple glazed). This is the same as [Trish's answer](https://3dprinting.stackexchange.com/a/16700/4762)  

---

