Venting Through Ceiling

Actually a friend of mine wanted me to make vinyl bug stickers so it would look like a game of Hive, but I don’t really want my kitchen to look like a board game.

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Personally I would go the roof vent path. Duct it completely to the outside and place your inline fan as close to the exit as possible as @jrnelson said. That way the entire run is under suction instead of pressurized. Zero leaks in the run.

Took me 2days to run mine out the roof so odor will never be a concern. I am so glad I did it well, instead of the eaiser way of dumping the exhaust out the shop window between our houses.

There is also a benefit to the booster, in that it will continue to pull air through the unit after the glowforge fans have stopped.
I second @smcgathyfay’s blast gate idea for winter temperatures when the machine is not running.

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How did you deal with power? All the inline exhaust fans I’m seeing have standard plugs. If it’s in the attic, I’ll need to add a box and patch into the wires currently in the ceiling. I could cut the plug off and splice it in, but perhaps you did something else?

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I have an extension cord running down along the inside wall to a plug and a switch…
Just flip it on and off when needed…

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My situation is kind of unique, and my solution was a bit easier than yours will be.
We upgraded the furnace to 98% efficient which vents through the wall with PVC, so the metal duct to the roof was abandoned, but still vents the water heater. I ran about 15 feet of duct from the laser in the next room to that duct that was shared between the old furnace and water heater. My booster sits above the junction of the water heater and the duct from the shop.
The new furnace has a dedicated circuit with a duplex outlet available, so I plugged the fan into that and soldered a speed controller into the fan. I run it full speed when operating the laser, and crank it down otherwise - so it runs all the time.
There is still the venting required by the old furnace for combustion air, so there is a good air turn over in there.

Your situation will be a bit more complicated. Running a conduit for a remote switch to be within reach will be required.
If it was me, I would run the conduit right along the ductwork. If the vent run has to pass through multiple walls, I might consider running the conduit through the duct.
I believe there are automatic sensing systems that would trigger the fan, but I am not familiar with them, and they would still require a circuit to be available to the fan.

Yep, a PITA but that pain will pass quickly. I am really glad objectionable odors are not a pain for me and my neighbors.

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There’s a thread for that… So feel free to repost your excelent tile work over there

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if you want to be even lazier, you could buy one of those current-sensing plugs like they use for power tools. tool turns on, so does vacuum. :smiley:

“turning on a switch? how very pedestrian.” – @smcgathyfay in a few weeks

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So I’m thinking I’ll cut a hole in the ceiling slightly larger than the ducting. I’ll attach the inline fan close to the end of the ducting and create a vent in the eaves for the outtake.

I’ll attach an extension cord to the fan and run it through the same hole in the ceiling as the ducting. Both my Forge and the fan will be plugged into a power strip, so when I flip the switch on the strip, both the Forge and the fan come on.

When the Forge is up and running, I’ll cut a cover for the hole in the ceiling to make it look less ugly that there’s a hose and extension cord coming out of it.

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you may not care, but it’s probably against code to run extension cords in the wall / ceiling like that. (not saying you shouldn’t do it, just something to think about, especially if you ever need a permit for something else).

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I have a few details in my shop that wouldn’t pass a home inspection, but present zero hazard (to me). The area is an unfinished bedroom, and all of the equipment including the laser I consider a temporary installation.
When the house eventually goes up for sale, none of it will remain.
I did finally connect the florescent lights to the Romex with a metal junction box instead of dangling wire nuts. :grimacing:

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When I did my shop, the electrician told me that code requires ground wires to be bonded (by screw or equivalent) to every junction/outlet box. Even if it’s plastic.

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This may be what you mean by:[quote=“brooklyntonia, post:21, topic:8570”]
create a vent in the eaves
[/quote]
It could be connected to a hole in the eave with something like this, not loose in the eave.
If you have a path to the exterior then you should not need an additional in-line fan.

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Not quite the case. The GF exhaust fan is only rated to reliably exhaust the machine with a maximum 10’ of flexible 4" diameter hose and 2 90 degree bends. Longer than that and the machine may not exhaust properly and in the OP’s case up into the ceiling and into the eaves is almost certainly likely to exceed the GF design limit.

@takitus (I think) or @karaelena have long run exhaust systems setup with booster fans (placed at the terminus so as not to leak through the run).

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Thanks for letting me know that.
It looks like they recommend a 20’ effective length (10’ plus two 90 degree bends which calculate to 5’ each)

I had a previous post where I compared this to a dryer duct.

I am concerned about fire safety with some of the exhaust runs.
I would be careful about using flex where it cannot be easily cleaned.
Debris laden exhaust can sometimes catch fire.
There might be special in-line booster fans for debris laden exhaust (I have looked and can’t find any).
A simple in-line exhaust fan will be the exact location where debris will collect (as well as in flex duct).
I am not sure of the flammability of the particles coming out of the Glowforge (as they are already burnt), or the temperature of the exhaust.
I know that it is different than a dryer and dryer lint, but not sure how different.

Nothing shameless about show and tell…we all do it here unabashedly. Great job on your backsplash!

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I can imagine that when cutting lightweight paper, some small unburnt bits may get caught up in the air assist and be drawn into the exhaust stream.

When I have cleaned my window screen and the exhaust port on the Glowforge, there are visible bits of stuff and not just ash or powder. Not much, but it’s there.

That was precisely what I was planning, though I was concerned about the Forge fan being strong enough to push the air the extra length. I thought an additional fan may be needed if it’s going to have to travel more than the 8’ that the included hose will reach.

I wonder what could build up after a few years of use.
If the hidden lengths of duct are smooth metal, one of those pipe-cleaner looking brushes could be run through it. Not so easy with hidden flex duct, an impossible if an in-line fan is in the way.

Maybe if the fan was at the end (in your case near the eave), and could be accessed there and removed for cleaning?
Another option could be to install some sort of access panel at the fan so that it could be removed for cleaning of the fan and ducts.

I may be sounding overly cautious, but fires in dryer ducts, for example, are very common.
This exhaust, although not the same as dryer exhaust, does have debris.
Particles being pushed this way can generate static sparks, and if there is a build-up of un-burnt “fuel”, can spell disaster.

The best long-term solution might be to get an air-filter and/or put it near a window until the filter arrives, rather than jerry-rigging some sort of long venting contraption.

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