Temperature and humidity

In reading through the Safety operating environment I see a recommended temp max at 81 and a humidity range between 10 and 75%. I am glad I am no longer in Tucson as without AC temperatures often go over a hundred degrees and with it, I have seen the humidity pegged at zero for months on end. However, as I am in Florida, we have the opposite humidity issue, that inside the house it is held at 80 degrees but will climb above that as the ac tries to keep up with usually 60-90% humidity and in a shed, both temp and humidity is exceeded most of the time.

We avoid the subfreezing issues many face and realize that the upper limit on temps means the equipment can overheat but can some compensation be made by increasing the volume of air through the machine, and if the work is actually damp does that change the humidity calculations. I have been thinking hard about the fire danger issues and thinking about sprayed on water with sodium bicarbonate or borax (that is often used in jewelry making) would make the material a bit harder to cut but also tend to snuff out any flame that got started.

I cannot see that any fumes from those two materials would be a problem.

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Apologies, but I don’t understand if there is a problem or question here?

The question is about the limits of “safe” particularly with respect to humidity, and if high humidity is a no go generally and especially while cutting. Also about temperature and if higher temperature can be offset by higher air volume through the system.

The using of water with fire retardant is also basically about humidity

I still read your post as already understanding the probable support answer. But perhaps this will be helpful for others that find this post.

The operating environment is specified in this note: https://glowforge.com/support/topic/safety/operating-environment

The temperature and humidity for storage currently reads:

And the printing temperature section reads:

From your description, I suspect that the ambient temperature will be be sufficiently high that the Glowforge will refuse to operate (Basic) or will pause frequently and for long periods (Pro).

I’m not sure if the Glowforge itself will stop you from operating in humidity greater than 75%, but it is outside the recommended operating environment.

Edit: to clarify storage vs. printing and add the printing temperature section


Perhaps your question is:

I’d like to treat my materials with water mixed with sodium bicarbonate or borax.

  • Is that safe for the printer and me (assuming proper ventilation)?
  • Will it still cut?
  • Will that remediate my temperature and humidity problems?

Is that correct?

I think those are likely best addressed in Beyond the Manual, but if you’d like to see if support has anything additional to say on the matter we should leave it here.

Again the point is just how “squishy” those numbers are and what could improve them. If all the air goes through the coolant system before entering the chamber that would be very different than if none of it did. just like your car’s cooling system runs cooler when a high volume of air is running through it and can overheat badly if you stop. I have seen the house go to 88 degrees on a hot summer day even with the AC at full blast, so setting it cooler would not help, and it was just replaced with a brand new unit. running at night would help in temperatures but have other difficulties like staying awake.

As for Humidity that will be a constant issue, not always above 75% but usually so particularly as things cool down at night. these issues are different in different parts of the country and the world so ideals are not always achievable.
Where better design (like more protection against humidity) is possible or identifying the specific issues would be better than an edict that there must be no challenges when the challenges naturally exist.

When I first got my 66 Volvo it had a tiny two-bladed fan, and a gadget to lower the amount of air that the radiator let through. In Sweden, this is very reasonable but in Arizona not so much, and so there was a huge 5 bladed fan that just missed hitting all around it and pull so much air that you could move the car just by gunning the engine in neutral. this was engineered and available to dealers where heat was a problem and not the sort of thing you could build in a shop anyway. that is the kind of thoughtful consideration needed where you have an international market. I realize that Glowforge is not Volvo in size or history, but is something to think about.

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Actually no the issue was always Humidity and those were examples of “soggier than usual” cases. You are correct on one point that a discussion about the use of them should be a separate thread in “Beyond the Manual” and worth the discussion for the safety side of reducing the burning of material near the cut.

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Unfortunately, not at all squishy. My Pro pauses to cool down at 81° ambient temperature, which means the tube is even hotter. And I live in an equivalent temperature/humidity zone.

The humidity hasn’t been an issue for the machines, not even for the Basic PRU during the worst flooding rain in a thousand years (no kidding, Harvey was a Thousand Year flooding incident), but it is murderous on warpage of the materials. (As you probably well know.)

But I had to do some things that folks in dryer climates don’t. I keep the machine and the materials inside the centrally AC’d house with me. I put humidity/critter flaps on the end of the vent hose where it connects through the window panel. And I put a quick connect on it so that it can be disconnected if needed. (Only disconnected it during Harvey so far.)

You’re going to have trouble getting complete cuts using the default values because of the warp. Just expect to slow the cut speed down ten points or so. Or print a bunch of those honeycomb pins, I wish I’d had those handy for the last year - they are fabulous.

For now, it’s not going to function as well outside of the recommended ranges.

(BTW, the Basic extended a little farther outside of the ranges than the Pro does. I never got nailed with a Cool Down condition on the PRU, but i’ve had it hit twice this winter, when i had to close the office doors late at night. Didn’t want to wake up DH, and it concentrated the heating in the room until it hit 81°, and down she went. Only down for about 3 minutes, but it did pause the print.)


I completely missed these the first time around, so if anybody’s looking for the “honeycomb pins,” here’s what they are:
What to do with precious proof grade scraps?
and here’s the post with the file:
Honeycomb bed holdown pins

Good to hear that (at least so far) humidity seems to only be trouble for material, not the machine.


Harvey = yikes
Irma was was scary and the shelters awful but little harm was done…

I have seen a change in humidity make a real mess especially a New Orleans antique brought to Arizona or a harpsichord brought to Miami , but both had lived well in their previous circumstance for quite a long time.

I suspect that as the moisture swells (or shrinks) the outside before getting to the inside that there would be a lot of warping that might take a long time to settle down. A similar thing happens with glass that is not cooled very slow and evenly.

A more major concern was any electrical connections etc that might be corroded or damaged by the moisture. If this is not the problem then I am much relieved.

As to the temp circumstance, I was asking about the extra air movement that the filter fans might generate. As you point out, the experience when just vented to the outside is very specific but am wondering if like the Volvo those sent to where there are heat challenges might have a larger or add on or other means of lowering the amount of temperature buildup.

I might have jumped the gun a bit by getting a commercial filter, and it is definitely more air handling than I bargained for but with an upper range of 500cfm it could definitely increase the airflow beyond what is normal. Fitting a 4inch hose to a 10 inch intake is the primary challenge in that case.

However when the official filters start going out, I hope they increase the airflow as well, and perhaps the issue of upper temp could be helped in the process, as we surely do not want to strain the machine, but better cooling would be a great help.

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Sounds like I could use that to vacuum the house! (All at once.) :smile:


I showed it here and linked to the source that was offered as an alternative but the picture on Amazon looked a lot smaller than it turned out to be. But it has a variable speed dial with 500cfm when maxed out.

Definitely big enough to do the job, I imagine.

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I guess I will end up the Guinea pig in this though I had hoped others would have gone before on this. I suppose there is a max coolant temp where you would have shutdown no matter how fast the too hot air went by as it would not cool (maybe even heat up) the coolant. There is so much “black box” here it is hard to get your head around it. We would not need trade secrets to know just a bit more of those details.

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I was actually surprised that the GF had a built in exhaust fan. I actually have been using a harbour freight 99 $ dust collector blower. its pretty noisy (0ver 100db @3feet) 120db is considered threshold of pain… it claims to be over 900 CFM and It sufficiently evacuates “Dr Evil” (old laser cutter). when i was cutting a job a few days ago, about a half hour in, I notices my workshop was smokey, despite onboard fan connected to outside window. I plan on installing this fan to help things along… I am awaiting the filtration system as well and am curious how that will . I passed on that purchase when i bought Dr Evil in 2006 because it was around 4K …hahaha as much as the whole GF . anyone else Using additional ventilation or experiencing a smokey shop?

No, the fans in the Glowforges have been perfectly good for the eleven months of operation so far. (Between the PRU and the Production unit.)

Only time I ever had a problem was when I didn’t have the vent hose completely sealed once after taking it off, and that was just a slightly sharper smell for a day or two until I tracked down the leak. Most of the smoke was still going outside.

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Lots of previous posts on how people vent their glowforge - a simple search using the search term ‘vent’ will get you started.

There have also been a couple of posts about debris building up on the fan itself that clogs the flow of exhaust leading to a smoky shop. The solution was to clean the fan, which is not straightforward.

Certain metals, most notably magnesium, and aluminium will just grab the oxygen away from the carbon so fast that you might as well be trying to put out the fire with pure oxygen! In such cases CO2 is more dangerous. So the big question is if those metals or something more exotic is burning that can take the oxygen from carbon? Aluminum will only burn in special conditions, and I am not silly enough to try and cut magnesium anytime soon (though there was a brief period when some genius thought magnesium was a good material for 18wheeler trailers and was proved wrong when it lit up mountains in broad daylight several miles away I was not looking in that direction to see the big show, but I saw where the road was damaged, and anything steel melted and ran down the storm drains like water.)

So again we have this black box with a question mark if it has anything that when burning would burn better in pure CO2?

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Thanks for asking about this.

I suggest printing within the operating environment outlined in the manual and cooling the room your Glowforge is in using A/C if necessary.

Anything beyond that is outside of our scope, so I’m moving this post to Beyond the Manual where the discussion can continue. Please keep in mind that advice in this section is unsupported and is not reviewed by Glowforge.


a 10" to 6" reducer coupled with a 6" to 4" reducer?