Pre Release: Exhaust Noise Experiment


#1

An A-B comparison of vent hose type on noise levels outside

For those of you who followed my visit from @clone the other day, there was a discussion about the noise outside, along with many prior posts by me and others.

So on the debate went, and @dan suggested it was the type of hosing I had chosen. Now I have to say I am a big fan of solid metal tubing for fire resistance and sealing (with a dryer I care only about fire since a little humidity isn’t going to kill anyone). and the tube I bought was the expandable solid metal tubing with integrated elbows at both ends. This would provide a great seal and absolute fire protection (not that it should be an issue with a GF, but safety first).

But given that @dan has many, many glowforges on his skull shaped island, and I’m a scientist, the only solution was to do a controlled experiment.

Set up 2 basically identical engraves (well they are mirror images of each other on the shelf brackets). On the first I used my existing tubing, and for the second I used flexible dryer hose (the aluminized polyester).

I again remain a not-fan of the thin flexible stuff since there were pin holes in it, but using real aluminum duct tape found all of them I hope; but @dan is right, wow what a difference:

Here is the A-B comparison video (and to get your volume right, in the first one I am talking very loudly, and it’s about the volume of my shop vac at the beginning)


(in case you are wondering that was the leftover piece from the famous (infamous?) GF delivery shot. And yes the sun set between the 2 parts of the video…)


No Vent? No Problem!
Glowforge is loud
Weekly Highlights for the Week Ending May 13th, 2017
#2

And yes, before someone mentions it, I have not power washed the deck yet this season, but given it was 38 this morning, seemed a tad chilly…


#3

something weird is happening with the video I don’t hear anything for the50 sec and my head phones are on max then at the 50 sec mark the video freezes and then I can hear you talking


#4

what is that? OK hold on, will edit the OP with a fixed video. It’s doing it to me too…


#5

“this type of video file isn’t supported”


#7

Video is now fixed


#8

Video works! Thanks for the experiment! I am in an apartment, and this is really good news!


#9

Huh. I guess the fact I have a long run is damping the noise. I am still using the flex hose but with insulation. Nowhere near that loud.


#10

The hose I was using is the standard Home Depot hose like this:


#11

Right. And I am using PVC.


#12

This makes me wonder how loud the Pro W/Filter is.


#13

Great comparison! Thanks for doing this. I’m using a solid metal duct. Wonder what that will sound like. But I ordered the filter, the duct is a backup.


#14

Whew. Had me worried there about how that story was going to turn out for a bit.


#15

The other thing you can do is wrap it in fiberglass insulation if you don’t mind bulking it up a bit. Standard wall stuff or the thinner water heater kind will both cut the resonance and absorb noise even more.


#16

A few things:

  • The more noise coming out of the tube, the less in your house
  • if you are able to run another angle at the end of the pipe, you can bounce the noise coming out the tube down to a soft, noise absorbent material on the ground
  • wrapping the portion of the tube thats inside the house with bubble wrap or insulation will massively reduce the noise you hear inside (I am one with the Forge, the Forge is one with me)

I personally prefer the more rigid/smooth interior walled tubing because it keeps the sound in better, and keeps cfm higher.


#17

WOW that is a WORLD of difference thanks so much for doing this. I’m sure that is going to put allot of condo dwellers at ease


#18

On @takitus suggestion back in Jan, I did this.

Before.

After.

Exterior.

Piping.


#19

Very cool! For anyone who doesn’t have one yet: The noise isn’t that loud to begin with…far less than an old school dish washer


#20

Inside? At least mine is plenty loud when cutting.


#21

Yeah; it’s a semi-loud whirring sound, but definitely quieter than a 2003 dish washer that I have.

I can stand 4 or 5 feet away, in a small room, and have a phone conversation…not really wonderfully, but definitely doable…