Self heating mode?

My Glowforge is in my shop, which I heat with a wood/coal stove. It’s been below zero here at night. So it takes a while for me to get the shop up to a temperature (>40F) that will allow the GF to operate. Wondering if there is some way that it can be programmed (Feature Request) to go into a warmup mode to self heat somehow before running parts. That way, if the shop isn’t quite up to 40, I can still run parts.

Any thoughts? Other than a self heating mode, any other ideas on how to keep things warm enough without burning through lots of wood to get the shop up to temp for a shortish printing run?


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There isn’t anything in the device for the specific purpose of heating. So, no, there really isn’t a warmup mode that could do much good for that massive a temperature differential.

I’d suggest potentially building some kind of case or containment for the GF. Not only could it have some heating capability, but you could also integrate an exhaust fan to dispel any lingering burning essence (that I find to be pretty common post job).


40 is too cold. GF specs >60F as the operating temp.


Just throwing out a couple of ideas…
What about an electric blanket or plant / propagation heating mat under the GF, and the heat could possibly rise and gently preheat.


You can treat it like a water pump.
Not too graceful, but a tarp box extended a foot or so around the glowforge with a heat lamp under it would keep the unit very warm, even in freezing temperatures.
The exhaust is a concern, and if it is exposed to the outside, the door of the GF may have to be open in some manner to allow the heat inside.

Heat lamps worked well out in the field but inside a shack with no wind, I imagine just an 60 watt incandescent bulb would keep it warm (and no worries about the heat lamp shifting and melting the GF frame).

You could rig the tarp in such a manner as to open a front flap to use the GF, and since it is already warm, no waiting.


Anything you do to warm it will be somewhat undone by the massive airflow of running the forge sucking in ambient air. If your shop is below operating temperature, warming the forge alone won’t be enough.

I have a small space and use a 1500 watt delonghi oil filled radiator style space heater. I leave the forge door open to let heat into the unit, and leave the space heater set to 60 degrees overnight.

Heater recommendation came from the wirecutter:


I had a project at one point to bend some plexiglass that was 6’ x14’ so I built a quicky oven out of insulation but the little electric heater was not enough BTU, So we used one of these and the oven worked very well. You are not needing to reach 300 degrees but as pointed out you will be putting 400 cfm out the door. On the other point if you ran the exhaust through the heater it would turn itto more energy.

Wow!! did they take that off an F-16?!? :stuck_out_tongue_winking_eye:

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In big factories up north or other large open areas they might have dozens of them turned up to the max as we did trying to get to 300 degrees as fast as possible (still twenty minutes or so) but they would use it at the lowest level with the GF not working and only crank it first thing and when the GF was actually cutting.

In terms of fuel they are quite efficient.

Anything that draws power within the unit will add heat to the inside of the unit. For example, running the coolant circulation pump without the exhaust fan will add heat at a rate equal to the power draw of the pump. Turning on the laser power supply will also add heat to the unit, even if the laser isn’t firing. So it wouldn’t need to be a dedicated heater, per se, to make the unit stay warm.

i get how you could make that work. but i would also be surprised if GF would create settings to run things that generate heat w/o commensurate cooling just to keep the system warm in temperatures below their normal operating range.

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There is a temperature sensor in the unit somewhere, so presumably, you could cycle the pump intermittently to keep the sensor satisfied. But I suppose it could be cold enough in a room that even the pump wouldn’t be enough to keep GF internal things from getting too cold?

again, is it possible? maybe.

but i see no reason why they’d do it. it just adds other issues that could create problems on their end and for a very small benefit from their perspective. they’ve given you a safe temperature range and you’ve chosen to put the machine in a space well outside that range.


Perhaps they won’t, but I’m just saying that it would be a relatively straightforward piece of software programming, which seems completely feasible given that all required hardware seems to be in place. Yes, it’s a potential headache, but it’s also a potential selling point that would allow more flexibility on the part of the user. It’s ultimately a decision for @dan and others to make. I imagine it would also be straightforward enough for the user to get an email or text message warning of any issues, i.e. pump failed, or temperature out of range, etc.

I guess it depends on what the definition of “well outside” is. I have a thermometer in the shop right by the door. The shop itself is well insulated but the door is a little drafty. The lowest reading I’ve seen on that thermometer in our recent cold snap is mid 30s the morning it was 5 below outside. The Glowforge sits well away from the doors to the shop and I’ve been running my stove every day. I suppose I will mount a temperature logger at the unit to see what is happening right by the forge.

The only time the electronics inside the Glowforge are going to be capable of generating much heat is when the fans are running full blast and the laser is firing. Just applying power to the power supply does not make it generate heat. Heat is a waste product of using power–and is representative of the inefficiencies in the process.

Take common light bulbs, for example. You can get the same amount of light out of incandescent, compact fluorescent, or LEDs. But you will use 100W, 25W, or 16W to create the same light depending on the technology. They all have some inefficiencies–even LED lightbulbs get warm–but the incandescent bulbs will be very hot to the touch because they are much less efficient.

The circulation pump and computer board probably draw no more than a few tens of watts. The big power draw happens when the laser is firing, and even then I would wager most of the waste heat is generated in the laser tube itself–thus the need for liquid cooling of the tube.

The only way you could get significant heating in the unit without the laser firing is if there were a resistive heating circuit that could be switched on…but there isn’t.

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Academically speaking…

Other than the laser, there are two potential sources of heat:

  1. The lid LEDs generate enough heat that they have four temperature sensors dedicated to them. Probably not enough to warm the unit up in a cold garage, though.

  2. In the case of Pro models, there is the Peltier cooler. Those suckers are only about 10 - 15 % efficient, so dumping power into that without running the intake/exhaust fans would give a good amount of heating. The power supply will also generate some additional heat under the load (the 12V supply is good for 32 amps - most of which is for the cooler)

You could run the air assist fan to provide circulation within the unit while it ‘warms’.

Or, just heat the space you plan to use it in.


As for the unit it’s self ever having a “keep warm” option. Even if feasible, I don’t see it happening.
To solve your problem, I’d suggest using a heating pad places directly into the unit sitting on the crumb tray. You could, if you so desire, connect it to a temp control such as This one used in home brewing systems
They’re easy to make and you could make the box on your Glowforge.

A reptile heating stone would probably do it, they are thermally controlled and easily attainable. It’s no substitute for heating your workspace but it might help in a pinch.

I know this was written a few years ago, but I have tried this and it works. We keep ours in the garage that stays about 45* F and the heating blanket makes it usable.

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Do you know if this stone is supposed to be warm all of the time? I purchased one but it is only warm to the touch some of the time. Other times it is cool.