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November 29, 2020

My Extended Glowforge Exhaust Solution

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If you're looking to purchase one of these, then your first project will be to design a Glowforge exhaust solution.

Each of the Glowforge 3D Laser printer models comes with an 8-foot length of 4-inch flexible vent tubing. They recommend that you place your new unit within reach of a window using this venting. The exact wording from the Glowforge website is:

"Choose a location in a well-ventilated room with a 4-inch outdoor exhaust vent, which is the same type of vent used to connect a dryer. The exhaust vent should be at least 3 feet from property lines and openings into a building and at least 10 feet from mechanical air intakes. You can also put the hose out an open window, so long as the end of the hose is at least 3 feet from the window and meets the other criteria above."

The New Arrival

If you spend some time reading the Glowforge community forums, you'll find that many owners vent out a window using a dryer type vent which fits right in the window itself. Portable air conditioners use this same type of vent, so you can find many different options by searching for one of those.

When I ordered my Glowforge plus unit, I did a quick search on Amazon and saved the Jeacent Window Seal Plates Kit for Portable Air Conditioners to one of my lists. I also bookmarked the AC Infinity CLOUDLINE S6, Quiet 6" Inline Duct Fan with Speed Controller Exhaust Fan.

This inline fan was rated high in the Glowforge community. A friend of ours had an extra 4" to 6" vent adapter, along with some additional 6" flexible aluminum ducting. Once I received the shipping notification from Glowforge, I ordered the above items, and I felt prepared for the unit's arrival.

It wasn't long, and my new Glowforge plus unit arrived:

Boxed Glowforge Plus Laser

I had a spot in the corner of my office where I would set the new unit. It was close to the window and should work correctly.

Table Workspace for the Glowforge Plus

My friend, who was also a Glowforge owner, helped me to get everything connected. We had all the venting attached, and for now, I opened the window and stuck the vent duct against the screen. It was far from a perfect solution. The window seal plate did not have a way to attach the flexible duct, so I did not even open the package after it arrived.

As it turned out, I received a defective unit. The laser light did not work, so it could not do anything except make some noise. Glowforge customer support was easy to use. Within a couple of days, they had issued me a return authorization and had also ordered me a brand new replacement unit.

Even though I was happy with their resolution to this point, it would be another couple of weeks before I had a working Glowforge Plus laser. I decided to use that time to re-engineer my Glowforge exhaust solution completely.

My Permanent Glowforge Exhaust Solution – Design Phase

Now that we knew how the Glowforge laser cutter would fit in the room, I realized several difficulties. The 6-inch flexible ducting took up a lot of space. Along with the inline fan, it filled that corner of the room, blocking the window.

I also realized that the window seal plate was not weather-tight. We get some frigid Winter weather in west-Michigan. I had two choices, open the window while using and placing the seal plate during that time. It would not keep all the drafts out but would be better than an open window.

The other option would be to seal the vent adapter into the window permanently. We had just recently built this new home, and the window I was using sits right next to our front door. Having a DYI vent in the window would not be attractive. It would also be difficult for me to open the window in milder weather.

Outside View of Window for Glowforge Exhaust

I began looking for an alternative venting solution other than the front window. There was no room to drill a vent-hole through the front wall, as the window took up the whole width.

The only reasonable option was to go through the floor and out the side of the house. The basement underneath my office was an unfinished mechanical room with access to an outside wall. It was about the only place in the house where this solution would work.

My concern, though, was that I estimated it could be nearly 50-feet from the Glowforge laser to the vent on the outside wall. I spent several nights researching and could not find any good examples or recommendations for this kind of Glowforge vent.

I briefly considered calling a professional to help, but this was the summer of the COVID-19 pandemic, and good contractor availability was scarce in our area. I had already called around for help with a garage heater and learned it could be several months before service availability.

I put together my plan:

  • 8-feet of 4-inch flex ducting from the Glowforge unit into the basement, where it would connect with a 4-inch to 6-inch adapter. This section of the vent would also include a blast gate to keep outside air from the Glowforge when not in use.
  • From the 6-inch adapter would be 15-feet of 6-inch flex duct.
  • I would mount the AC Infinity CLOUDLINE S6 Inline Duct Fan near the top of the wall. I was not exactly sure how I was going to use the speed controller for the fan. I didn't think it would reach the Glowforge unit.
  • 25-feet of 6-inch flex duct would then go from the fan's output to the outside wall's exhaust vent.

It was about 50-feet in total length with about three 90-degree elbows. It seemed like a perfect plan; what could go wrong?

Installing the Exterior Wall Exhaust Vent

The task I was dreading most was drilling a 6-inch hole through a wall of our new house. There were several existing mechanicals already going through this section of the wall, so there was only one spot I could put it.

The spot between the outdoor faucet and some plastic electrical conduits I had installed the previous year was the only location.

Exterior Wall Vent Location for the Glowforge Exhaust Solution

I spent some time looking for a decent 6-inch vent. So many options are plastic and cheaply made. I settled on this Imperial VT0503 6-Inch Heavy-Duty Outdoor Exhaust Vent. Menards had it locally at a reasonable price, so I bought it there. It also had 10-inches of steel duct which would stick into the house, making it easier to connect inside.

I'll skip over some of the critical details for now, but drilling the hole was a success! I watched a couple of YouTube videos first. The "pro-tip" I came away with was to go through the siding with the drill in the reverse direction. Reverse-direction would keep the hole-saw teeth from chewing up the siding. It worked fantastically, a nice clean hole.

Exterior Wall Vent 6-inch hole for the Glowforge Exhaust Solution

I should have bought a 6, and 1/8-inch hole saw as the vent did not initially fit in the hole. Some time with a curved wood file solved this problem, and it ended up being an excellent snug fit.

Exterior Wall Vent Installed for the Glowforge Exhaust Solution

The next picture shows the finished wall exhaust vent install from the inside of the basement. It also offers a couple of significant issues that could have made this install go wrong.

  • The big, grey cable within an inch of the vent is the 200-amp aluminum electrical main cable. It goes from a disconnect on the outside of the house to the mechanical room's electrical panel. Nicking this cable would have been a costly repair, as the electrician would probably replace the whole length.
  • There is a plastic water pipe a few inches to the side of the new vent.
  • The orange cable is a 30-amp electrical wire for the generator connection on the outside of the house. It was not live at the time but would have been expensive to repair.
  • The yellow and black cables provided the internet and cable tv.
Interior View of Exterior Wall Exhaust Vent

I didn't want to drill the outside vent hole until I knew exactly where it should be. No measuring, as depending on your point of reference, this could be slightly off.

I separated the hole saw and the auger bit (see the two images below).

  1. 1
    Using just the hole saw from the basement side, I found the best spot and turned it by hand until I had removed all the spray-foam insulation. I now had a nice clean hole through the insulation to the exterior wall plywood.
  2. 2
    I added the auger bit back into the hole saw.
  3. 3
    Using the spray foam insulation to guide me, I started the auger hole into the exterior plywood. Once I had it started, I again separated the auger from the hole-saw.
  4. 4
    Using just this auger bit this time, I finished the pilot hole through the exterior plywood and the vinyl siding. I now knew exactly where to drill from the outside of the house.
Exhaust Vent 6-inch hole saw with auger
Exhaust Vent hole saw auger only

I had a siding guy doing some work for me on the outside of the garage heater vent we were also installing. He applied a nice bead of caulking across the top of the Glowforge exhaust vent, completing the installation.

Exterior Wall Exhaust Vent with Caulking

The Basement Flexible Air Duct Installation

I continued working backward with the installation from the exterior wall to the Glowforge laser. Since the exhaust vent itself was up in the basement rafters, I used some steel, adjustable elbows. I thought that the flex duct would collapse with the sharp turns and restrict the air flow. So I used steel here instead.

However, using these adjustable elbows ended up being a mistake, as I'll later describe.

Exhaust Vent Steel 6-inch duct elbows

I then installed 25-feet of the AC Infinity Flexible 6-Inch Aluminum Ducting. Mounting this duct was pretty easy. I cut various lengths of this hanger strap and, along with some short screws, accomplished this install in short order.

6-inch Flex Hanger Strap for the Glowforge Exhaust Solution
Glowforge Exhaust Solution 6-inch flex duct

The next step was to mount the AC Infinity CLOUDLINE S6 Inline Fan on the wall.

AC Infinity CLOUDLINE S6 Inline Fan for the Glowforge Exhaust Solution

I installed an electrical outlet nearby the fan. I also installed a separate switch for it, higher up the wall than standard light switches. I didn't want the younger grand-kids to be able to reach it.

Wall Switch for the AC Infinity CLOUDLINE S6 Inline Fan

Connecting the 25-foot flex duct to the fan outlet brought my project to about the half-way mark. I was now on the home-stretch.

Infinity Inline Fan connected to 6-inch Flex Duct

Finishing My Glowforge Exhaust Solution

After installing the inline fan, I started working from the Glowforge unit direction.

The picture below shows the finished installation. I used about 4-feet of the AC Infinity Flexible 4-Inch Aluminum Ducting.

As a side note, connecting any 4-inch flex duct to the Glowforge unit itself is nearly impossible without an exhaust port extension. There is barely a half-inch of connector sticking out from the laser unit itself.

You can see my blue port extension in the picture itself. A friend of mine printed that for me on his 3D printer. There are also many good options on Amazon, including the POWERTEC 70193 Screw End Quick Coupler for 4" Hose and the Exhaust Port Extension (for Glowforge).

Glowforge 4-inch flex exhaust duct

The Powertec blast gate assembly I put together based on their website product images. Along with the blast gate item itself, I used two of the POWERTEC 70149 Dust Control Flex Cuff with Hose Clamps, 4-Inch, and two of the POWERTEC 70123 O.D. Splice, 4". The pieces all fit together perfectly, and the whole assembly sat on the floor, making it easy to operate.

4-inch blast gate assembly for Glowforge exhaust solution

The remaining 4-feet of 4-inch flex duct, I connected to the splice in the basement. Note the speed controller wire from the inline fan. I had just enough length included with the fan to get the connector above the floor into my office.

4-inch flex duct

It turns out that the connector for the AC Infinity controller is a simple Molex connector used inside computers. I only needed about 4-feet more in length to lay the speed controller on my table. This 4 Pin Molex Sleeved Fan Cable extension - 48" worked perfectly!

AC Infinity Inline fan speed controller for the Glowforge Exhaust Solution

The final steps were to mount the remaining 15-feet of 6-inch flex duct coming from the AC Infinity inline fan. I connected this duct to a 6-inch to 4-inch duct adapter.

6-inch to 4-inch flex duct adapter

All that was remaining was to connect the 4-inch flex duct to this same adapter.

4-inch flex duct connected to adapter

In the picture below, you'll notice I ran the cable from the AC Infinity inline fan speed controller alongside the flex duct.

6-inch flex duct with inline fan speed controller cable

First Time Testing My New Glowforge Exhaust Solution

My Glowforge Plus replacement unit arrived at about the same time I finished my new exhaust setup. The setup of the new machine was much quicker this time as we just needed to push the exhaust port extension on to the back of the Glowforge Plus.

This unit was working correctly. So we did some cuts of simple projects. After turning off the internal fan and using the AC Infinity speed control to turn on the inline fan, I was delighted at the low noise level and how well it exhausted the smoke.

We finished some cutting projects and then went downstairs to show off my venting setup. Unfortunately, all of the smell was in the basement, near the external wall. I had left the fan on high, so I felt around all of the flex ducting.

It turns out that the steel elbows were leaking air through their joints. You could adjust these elbows from 0 to 90 degrees. This extra flexibility allowed more air to escape.

The solution at this point was more aluminum tape.

6-inch steel duct with Aluminum tape

The extra tape did eliminate most of the smell. However, there was still some residual odor after running the laser cutter for a more extended time.

 I wanted to eliminate all residual order, so I started replacing things. The first to go were the steel 6-inch elbows. I replaced these with Semi-Rigid Aluminum Duct.

This attracted my attention as I was looking for a way to smooth out the two 90-degree turns at the end. I probably should have just used insulated flex duct, but I was concerned it would collapse too much with the turns and restrict the air flow. This aluminum duct did not do that. However, it punctured relatively quickly while installing, so I had to be careful. I taped over the couple of holes I made.

6-inch Semi-Rigid Aluminum Duct

After replacing the elbows, I did notice a small improvement. While doing some online research, I read some complaints about the 6-inch flex duct I used having very small pin-holes. That was the next piece I replaced.

The hanging straps I used to support the flex duct made it surprisingly easy to swap out. I just unscrewed one side of the hanger, taking out the old flex duct. After removing all the old, I then came through with the new insulated duct and screwed the strap back up.

6-inch insulated flex duct installation for the Glowforge Exhaust Solution
6-inch insulated flex duct installation - 2
6-inch insulated flex duct installation - 3
6-inch insulated flex duct installation - 4

Finishing My Glowforge Exhaust Solution – Part 3

So far, I had already replaced the 25-feet of 6-inch flex duct with an insulated flex duct. I had also replaced the last 6-feet of steel elbows with a semi-rigid aluminum duct.

While the result of all this was a near-perfect solution, I did smell some lingering odor after running the Glowforge laser for a time. It was coming from the section of the duct near the external wall of the house. So I knew where my problem lie.

Due to my perfectionist tendencies, I was not ready to call the installation finished, although I could have.

I realized that I could have punctured the aluminum duct somewhere I did not see. I didn't want to cover the entire section with aluminum tape, so I went online for options.

I initially searched for insulation options or some plastic enclosure that was sealable. While reading through different forums, I stumbled on this Red Devil 0841DS RD-DS 181 Acrylic Latex Duct Sealant, 1/2 Gallon, Gray.

Red Devil Acrylic Latex Duct Sealant for the Glowforge Exhaust Solution

According to what I read online, it was a sealant used where two steel duct pieces join together. It could be applied using a brush or putty knife.

My plan with it, however, was to cover the whole section of the aluminum duct. Since the duct was ribbed, the sealant would still be filling the area between two steel pieces. That logic sometimes gets me into trouble.

I recognized the Red Devil brand, and at the time, it was only $8.79 a half-gallon, so I bought it. The two-day delivery time gave me time to buy a couple of cheap 2-inch brushes from our local True-Value hardware store.

While reading online, someone said the sealant was a peanut-butter type texture. I thought the brushes would be easier to apply to a round duct than a putty knife.

After it arrived, I opened it, and yes, a peanut butter texture was pretty accurate.

Red Devil Acrylic Latex Duct Sealant

The brush worked pretty well. I did try to scoop it out of the container, putting a thick coat on the duct.

Red Devil Acrylic Latex Duct Sealant on a brush

I then smoothed it out with the brush, filling in all the grooves in the flex duct.

6-inch semi-rigid aluminum duct with duct sealant applied

After coating the entire section, I still had about half the container remaining. It was messy but nowhere near as bad as spray foam insulation. I'm guessing this had to do with Latex in the name. It cleaned up very quickly.

Red Devil Acrylic Latex Duct Sealant with 2-inch brush

The directions indicated 48 to 72 hours of drying time before pressurizing. Since I was not following standard usage, I knew I would need at least that amount of time.

I also had enough left over for a second coat. I did not want to do it again after it was thoroughly dried. So that is what I did after 24 hours had passed.

6-inch semi-rigid aluminum duct with duct sealant applied
6-inch semi-rigid aluminum duct with duct sealant applied - 2

Final Conclusions

  • I was glad I kept the first 8-feet of vent duct out of the Glowforge at a 4-inch diameter. The smaller diameter allowed the hole through the floor to stay smaller. It also made it easier to assemble a blast-gate. The Glowforge arrived with the same size flex duct, so I figured this was an easy decision.
  • Transitioning to a 6-inch flex duct in the basement was necessary.
  • I LOVE the AC Infinity CLOUDLINE S6 Inline Duct Fan. It's well worth the price. It's quiet, and the speed controller allows whatever you need. It also moves a lot of air.
  • I was glad I could lengthen the speed controller cord another 4-feet using a simple Molex connector style cable. It's great having it sit right next to the Glowforge laser. My backup plan was to install the Lutron PD-5WS-DV-WH, Wireless In-Wall Switch in the basement. This one is similar to the Lutron switch I installed installed in our sunroom.  I could have then set the speed controller to a certain level in the basement and programmed a Lutron Pico remote to use in the office.
    I did also contact AC Infinity support to see if they had an optional extension cable for their speed controller. They were speedy to respond and friendly but did not offer a solution. I asked what other option I had? They replied that cutting the controller wire and extending it would void their warranty…
  • I completely under-estimated the pressure build-up on the output side of the inline fan. I'm sure it had everything to do with the two 90-degree elbows at the external wall of the house. If I had a do-over, I would have used a steel duct on the output side with the duct sealant in the connections. A better solution would probably have been to increase the last section's diameter, including elbows, to 8-inches. However, I don't think I had room to drill that size hole.
    I don't know if moving the AC Infinity inline fan closer to the external wall of the house would have helped? I think that the last section of 90-degree elbows would still have been a problem, and it might have reduced suction at the Glowforge end. I'm sure a professional would have calculations for this scenario.
  • I achieved my end goal of keeping the front window clear of a DIY vent. More importantly, we can still use the window. The Glowforge also runs very, very quiet. I've already left the inline fan running overnight since I forgot it was on.
    I've turned off the internal fan in the Glowforge, and it efficiently clears any exhaust fumes. I usually run the external inline fan at about 50-percent speed.

One last thing that needs to be said:

I worked as an electrician for a few years earlier in life. I'm comfortable doing this kind of work in my own home, especially the electrical portion. I would instead have hired out the venting, but it wasn't a convenient option.

If you're not comfortable drilling large holes in your house, then don't! Hire a reputable professional.

It's not worth the risk. Below is the same picture I had earlier with four issues circled, any of which could have been a significant problem.

Risks involved with installing the Glowforge Exhaust Solution

Glowforge Exhaust Solution Materials List

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  1. Did you turn off the internal fan on your glowforge after you completed this installation? On youtube some ppl say to turn off the internal fan. I have a similar setup to you and it feels like if i turned that fan off i lose some extra venting power. Thanks for your help

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