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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?

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    $\begingroup$ 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. $\endgroup$ Jul 9 at 16:41
  • $\begingroup$ Glass........... $\endgroup$
    – user77232
    Jul 17 at 20:28
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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.

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    $\begingroup$ 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. $\endgroup$
    – FarO
    Jul 10 at 5:53
  • $\begingroup$ 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 $\endgroup$
    – craftxbox
    Jul 10 at 19:43
  • $\begingroup$ 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 $\endgroup$
    – FarO
    Jul 11 at 21:07
  • $\begingroup$ Pumping air out is probably not an option due to the pressure on the outside of the glass sandwich.. $\endgroup$
    – cmm
    Jul 12 at 17:17
  • $\begingroup$ 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. $\endgroup$
    – Trish
    Jul 13 at 7:16
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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.

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  • $\begingroup$ Acrylic is actually less thermally conductive than glass, and OP already has it on hand $\endgroup$
    – craftxbox
    Jul 10 at 19:37
  • $\begingroup$ I wonder whether it would be possible to have custom made double layer glass. Which would be heavy of course, but effective. $\endgroup$
    – FarO
    Jul 12 at 7:39
  • $\begingroup$ A window maker could deliver any shape and form as needed. $\endgroup$
    – Trish
    Jul 12 at 12:23
  • $\begingroup$ @craftxbox not by a magnitude if it's double pane glass with halogen. $\endgroup$
    – Trish
    Jul 13 at 7:51
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    $\begingroup$ Sadly price and the best solution are enemies. $\endgroup$
    – Trish
    Jul 13 at 8:51
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How about using thermally insulating transparent silicone rubber sheets?

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  • $\begingroup$ I can't find any datasheet $\endgroup$
    – FarO
    Jul 12 at 16:14
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Never saw double pane windows of houses? Triple panes are not impossible.

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    $\begingroup$ 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. $\endgroup$
    – agarza
    Jul 18 at 2:41
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    $\begingroup$ AKA Double glazing - double glazed windows (or triple glazed). This is the same as Trish's answer $\endgroup$
    – Greenonline
    Jul 18 at 2:50

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