Venting question

Hi all, we got our GF set up and printed the founder’s ruler with the hose hooked up to our dryer vent. Yay! However we noticed some smoke seeping from the lid during the cutting part, and I’m wondering if our dryer vent needs to be cleaned out, or if it’s just not set up correctly to properly vent the laser exhaust.

The dryer vent does not immediately go to the outside, as it’s located on an interior wall and vents to the water heater closet. I believe it then vents up through the roof.

My question is, assuming the vent pathway is clear/clean, if we are still having some smoke seepage when cutting, should I look for an alternative path to vent? I don’t have an available window in our workspace, which we converted from 3/4 of our 2-car garage by adding an insulated wall parallel to our garage door, leaving a small 4-foot wide garage space. My alternative idea is to have a second vent port fitted into the wall that is between our workspace and the garage, and then out through the garage door. Does that seem like it would work?

Any input is appreciated!

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Hey Congrats on getting your Forge!

On your questions:

Dryer vents always need to be cleaned. So definitely check that.

I assume you are shifting the vent from dryer to the Forge and back as needed? Not just “splicing” the forge into the shared vent? Because you do not want any laser exhaust heading upstream to your dryer (to say nothing of dryer exhaust heading into your forge!)

Check the vent material for your dryer vent; surprisingly, not all are fireproof, and that is a must. Minimize the use of the flexible stuff.

Not sure I’m picturing your setup right, but it sounds like you are saying that the dryer currently literally vents into the closet, with a totally different vent from there to the outside. If so, you DO NOT want to do that (even just for the dryer, really). You want to be sure that the vent is a straight, fireproof shot from the Forge to the outside.

I like your idea for a second, dedicated vent, even though the vent tube will have to run through the garage. Better: cut a hole in the garage wall to the outside for a real vent, rather than just out the door. Or drive a vent up through the ceiling out the roof dedicated to the workshop tools (like the Forge). I don’t know where you live, but in my neck of the woods, you don’t want the garage door open all year (chilly!). In any case, avoid the flexible vent material except coming right out of the Forge.

Almost forgot: sounds like you have some distance to cover between the Forge and the great outdoors; so consider a secondary blower on that vent line to help suck that smoke out.

Apologies if I misunderstood your layout. Post some pics, it’ll help us help you! Hope this was helpful!


If it is a gas water heater, do not vent through this space!
Never combine exhaust with combustion air exhaust.
Don’t combine two exhausts together either as one could blow back into the other.
Always have a unique exhaust vent for each type of exhaust.
If you are venting into a closet then you may not have enough force to push the all of the air out of the closet. Once a certain pressure inside of the closet is reached all of the smoke will just blow back.
You need to have a vent all the way to the exterior.
If it is more than 20 feet of effective length then you will need to add a booster fan. You can calculate effective length from this link. With a booster fan you might be able to double this but don’t push it too far. Some booster fans will come on automatically when they detect an increase in pressure but not all. Some people have made them work with a switch. Add the booster near one end or the other but it should be somewhere where you can access it for maintenance.
If you have a permanent or hidden vent-run, I would recommend using a smooth metal vent pipe with the largest radius sweep for bends that you can fit. Liquid mastic on all joints and seams seals best, but at least tape them.
Avoid excessive kinks or bends.


There are quite a few ingenious venting solutions listed in the Beyond the Manual category, something in there might work for you. (Search for “venting”.)

You do need to rig it up so that smoke isn’t coming out of the lid though when you print. Might need booster fans in the line, I believe the fans in the Glowforge are limited to about eight feet of run, with only two 90° bends.

Definitely not an expert, but there are a lot of clever people on the forum who have gotten very good results. I’m sure they’ll chime in.


Smoke coming out of the lid is an indication of a problem with your venting setup.


There is an intake fan as well as an exhaust, and the exhaust fan by design moves more air as insurance against leakage. All the little cracks in the machine case should be sucking air in.