Is 300cfm too high for filtering the GF?

I’m asking because I have had conversations with people in my office about bringing my GF in when it returns from being repaired and doing a demo in the office. We currently have a BOFA AD1000 IQ hooked up to our Universal laser. It will run at 500cfm or 300cfm. I know I’ve read that the fans in the GF run at ~200cfm. Would the 300cfm filter be safe?

I don’t know, but with that much suction, it seems it would be easy enough to insert a 4" fitting between the exhaust exit and the vent hose, with an adjustable port (hole with a moveable cover to regulate)… :thinking:

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maybe, but i don’t want to make this complicated. this is a quick set up for a couple of hours. hopefully 300cfm is fine. :crossed_fingers:

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My understanding is the circuits are protected from fan over-spin generating any current, but frequently my understanding has some holes in it. Hopefully support will chime in with an answer for you.


Confirmation would be great

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i suspect it’s ok, too. but i’m not gonna chance it w/o confirmation.

That was confirmed by @Dan back in the old days when exhaust options were being discussed as to booster fans for long hose runs.


I have an auxiliary fan at the end of my exhaust hose, where it goes through to the outside, because I’ve got about 8’ of hose. When I power things up to do a job, I start that auxiliary fan and its suction spins up the GF fan (you can clearly hear it). There have been times I’ve left the fan running for as much as an hour while I tweaked a job prior to printing. My GF still works great, this hasn’t done it any harm. And if it was going to, it would have by now…


I’m not an expert on other company’s products so I don’t have details for you about the BOFA. I’m going to move this topic to Beyond the Manual so other folks here can help.

With that much suction, you might collapse the vent hose.

One option would be to have a Y adapter with an adjustable opening. You would attach the outflow of the GF to one side of the Y and have the adjustable opening on the other end, with the “stem” of the Y going to the BOFA. Then you could balance the amount of relief venting so that the entire system is still under (less) negative pressure.

Maybe overthinking it.

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I’m not using the GF vent hose. Haven’t in a long time.

In this case, I would be connecting the vent hose currently leading from the universal to the BOGA to the back of the GF. Should be stable.

@stephen4, I’m not looking for info on the BOFA, I have those specs. I’m looking for info on the Glowforge. Will the GF handle 300cfm? Is that too much load for the glowforge?

I run a 435 cfm exhaust fan at the end of my 18’ of ducting (with two 90° bends and two 45° bends), just before it exits through the ceiling. Has been working thus far.

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muchos gracias.

When my exhaust fan died I tried to keep going with a 200 CFM fan that I can easily say was quite inadequet. If it had been 300 CFM it might have done the job. I had a room cleaner 500 CFM filter that made the difference but smoke came from everywhere when the cutting produced a lot of smoke.

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