Blower for laser: inside or outside?

[Pete Bejmuk]

Just want to do a quick poll of business laser operators that have their blowers located outside (roof or pad mounted) versus having the blower indoors (but still venting outside).

We have our 2 blowers inside in a semi-enclosed cabinet a few feet from the lasers, venting outside. Tends to be noisy, I'm trying to convince our owner to relocate them outside (possibly when we upgrade the blower).

[Mark Sipes]

inside... 4" inline... no noise.

[Joe Pelonio]

Same, I paid almost $400 for the fan because it was so quiet

[Michael Hunter]

Inside... 8" Inline... Noise perfectly acceptable without any form of soundproofing.

[Braden Todd]

2hp blower on roof for negative pressure, 5 2hp blowers inside. Gets a little loud, but we can still talk to one another without issue.

[Richard Rumancik]

Pete, with all due respect, I am not sure what the poll itself will do for you . . . the selection and installation of a blower can be a complex issue and I think it is one of the most debated topics. In just the few written responses, you will see people who use 100 watt in-line fans (maybe 1/6 hp) to those using 2 hp blowers. And most everyone says their blower/fan works fine for them. People often tend to do what is easiest and not necessarily what is optimum, as there are often restrictions on what is practical or permitted for their site.

You really have to look at your own site and needs. I assume your objective is driven by the noise issue. So it's not that important what everyone else is doing; you need to engineer something suitable for your situation. Obviously it will cost a bit of money to do this as there are construction and wiring issues to deal with. Your blower outside needs to be able to withstand the environment (summer and winter) and not cause issues with the neighbouring businesses and foot traffic.

[Jerome Stanek]

2 hp blower outside under eave. used to have it inside but was to loud with everything else running like dust collector and vac hold down for CNC

[John Frazee]

I have the "green" blower from HF outside under a shelter. I have a switch mounted on the side of my laser that powers it as well as a switch next to it that powers the air assist. I ran four inch white PVC sewer pipe from behind the laser through the wall to the outside. I can barely hear the blower outside. Next door is a high priced steakhouse and the employees hang around out back smoking. I've wondered what they've thought when I've been cutting nasty stuff like acrylic. I started out with the blower inside but even after using tape and caulk on the seams, it still leaked the smell inside not to mention the loud noise. I will never bring it back inside.

[Steve Morris]

You will get as many variations as there are users I suspect.
Having the blower outside means there is almost no risk of leaking from the output side into the workspace.

[Gary Hair]

Couldn't have said it better myself. Kinda like asking what car is best... or what laser to buy...

Pete, with all due respect, I am not sure what the poll itself will do for you . . . the selection and installation of a blower can be a complex issue and I think it is one of the most debated topics. In just the few written responses, you will see people who use 100 watt in-line fans (maybe 1/6 hp) to those using 2 hp blowers. And most everyone says their blower/fan works fine for them. People often tend to do what is easiest and not necessarily what is optimum, as there are often restrictions on what is practical or permitted for their site.

You really have to look at your own site and needs. I assume your objective is driven by the noise issue. So it's not that important what everyone else is doing; you need to engineer something suitable for your situation. Obviously it will cost a bit of money to do this as there are construction and wiring issues to deal with. Your blower outside needs to be able to withstand the environment (summer and winter) and not cause issues with the neighbouring businesses and foot traffic.

[Brian Leavitt]

My exhaust fan is on the roof, but we are in an industrial park so there are no neighbors to complain about any noise or smell. Now, if I were in a shopping center or strip mall, that would possibly be a different story. Another thing is it's a royal pain to get up there to change a fan belt, but that's just my situation. Everyone is different.

[Keith Colson]

Here are a few reasons why I stuck my extraction outside

1) My inside space is valuable. This let my put my laser cutter pretty much right up against the wall as the pipes do not need to turn, they go straight out through the wall.

2) Any smoke leakage will leak outside, I don't have any leaks though.

3) The noise is outside. I have a 2KW 3 phase blower, when cranked up to full speed is pretty loud. With my VFD I can set the speed/noise level. This is the same reason I purchased a super quiet dentist compressor for the air assist. I can hear the telephone when the laser is running which is a bonus.

Cheers
Keith

[David Somers]

I was fortunate to have a crawl space under the house, accessible through the wall of my garage/shop. I have run my hose from the laser through the wall and into the crawl space. The blower is up against an outside wall in that space so the output side of the hose is merely a few feet and I was able to use solid pipe so no leaks on the output side. Being under the house means the sound is almost gone from my shop and from outside. I control it with a switch on the side of the laser. Seems to be working fine at this point. If fumes become an issue outside I will build one of Dan Hinz homemade filters and try that first. I left room for that in the setup if needed.

The bad points are that the blower is not that accessible if I need to work on it. Doable, but it takes a few minutes of crawling to get there. I do have a smoke and heat detector mounted above it as a precaution.

Really interesting to see everyones setups!!! Thanks all!

Dave

[Joe Hillmann]

Mine is on the roof, In the winter when it gets below 0 I often have to climb up on the roof first thing in the morning to brake the fan free from the casing due to frost.

[Kev Williams]

I have 3 HF blowers, two are outside and one inside. My inside blower is in my garage shop with the Triumph, and it's as leak-free as possible using a HF blower. My basement laser's blowers are outside. I laser leather motorcycle seats in all 3 lasers. My basement smells like our living room, while my garage reeks like a burning slaughterhouse.

Noise notwithstanding, outside is always preferable (my opinion) simply because the positive air pressure that's PUSHING smoke out the vent hose from an inside mounted fan means that, unless you're vent system is actually perfectly sealed (good luck), you're also pushing fumes into the room. With an outside mounted fan, there's always a negative air pressure vacuum in the vent hose, meaning no possibility whatsoever of fumes entering the room, regardless of how 'perfectly sealed' the vent system is.