Opinions on Duct Hose Options

[John Breznicky]

Hey Guys, just wanted to get some of your opinions on duct hose options for venting our lasers. Most manufactures recommend using metal (galvanized steel or aluminum) vent piping. Which is fine, it does the job and is cheap, but in some cases adds unwanted vibration noise and the need to tape gaps to avoid losses/prevent fume escape. It's my understanding that static build up is the justification manufacturers use for not using alternate materials for vent hosing. However, there are manufacturers who make specific fume extraction flexible duct hose out of double wall fiberglass and a silicone coating that can withstand fume heat of 500F. These hoses are a bit expensive but are used in many other manufacturing applications and engineered with the specific purpose of extracting smoke and hot fumes. What are your guys opinion? Does everyone typically adhere to the manufactures recommendation in this area?

[Mike Null]

I use standard metal. Properly installed it will be trouble free. PVC is also an option as I think the static electricity thing has pretty much been debunked as far as being a major safety issue.

[Mike Lassiter]

Hey Guys, just wanted to get some of your opinions on duct hose options for venting our lasers. Most manufactures recommend using metal (galvanized steel or aluminum) vent piping. Which is fine, it does the job and is cheap, but in some cases adds unwanted vibration noise and the need to tape gaps to avoid losses/prevent fume escape. It's my understanding that static build up is the justification manufacturers use for not using alternate materials for vent hosing. However, there are manufacturers who make specific fume extraction flexible duct hose out of double wall fiberglass and a silicone coating that can withstand fume heat of 500F. These hoses are a bit expensive but are used in many other manufacturing applications and engineered with the specific purpose of extracting smoke and hot fumes. What are your guys opinion? Does everyone typically adhere to the manufactures recommendation in this area?

I have 6" metal piping that runs from corner my laser is in about 25 feet across wall thru a wall into the room I built for my blower (insulated for noise). Flex hoses (3 x 4") connect laser to metal ductwork and a short piece of 6" about 4 feet long connect the blower to that metal ductwork. Ductwork was 5 foot sections screwed together at joints and covered with high quality metal tape that is mounted on metal screw in hangars bought at Lowe's like to hang ladders or bikes on the wall. Then plastic wire ties securing ductwork to those hangars. All metal is fastened securely to the wall - NO vibration, and since using short flex hose(s) on ends there is none transmitted to or from blower or laser. Trouble free since installing in 2008. As noted smooth walls minimize air flow restriction - will not catch fire or burn. The longer you make your runs the more smooth inner walls are important to reducing air flow restriction. I don't understand taping gaps - didn't have any but did tape all seams in everything to make sure all air PULLED thru system came from laser and not sucked into any seams or joints. You want to have you exhaust "blower" at the other end from the laser and actually be sucking the air from the laser to the blower. This prevents the fumes you mentioned being blown out of leaky seams ( seal them all with good quality metal tape) back into the room you are working in. I purchased my ductwork special fittings and kits from Penn State and also my 3-1/2 HP blower, got the straight sections of ductwork from local Lowes.

I submit if there is vibration noise it is from poorly mounted ductwork. Things mounted solidly don't vibrate. I now have 2 laser cartridges and when the laser itself is turned on it is quite loud. I use to be able to hear the exhaust blower running in the other end of the building thru the insulated walls. Not that it was very loud, but I knew it was running. Now it is harder to tell with the cooling fans on both laser cartridges going. I turn my blower on and off by wireless remote that I also got from Penn State. Extremely pleased with my setup. Remote lays on top side of laser. I press "on" button to turn on the blower, hear it start up and give it a couple of seconds to get up to speed, then run the laser.

[David Somers]

John,

If you already have the metal ducting in place and have sealed it with tape to close gaps could you silence it cheaply with a wrap of insulation? Just a thought. Wasn't clear if you were trying to decide what to install or were thinking of replacing what you already had in place.

Dave

[Tim Bateson]

You can see my setup at the following post. I have much better extraction than I had with the metal tubing. Also quieter.
http://www.sawmillcreek.org/showthre...t=#post2213019

[John Breznicky]

John,

If you already have the metal ducting in place and have sealed it with tape to close gaps could you silence it cheaply with a wrap of insulation? Just a thought. Wasn't clear if you were trying to decide what to install or were thinking of replacing what you already had in place.

Dave

I have metal ducting for my epilog but just received our speedy 400 and I'm pondering exhaust solutions. The downdraft tube trotec provides is a flexible composite hose. I can think of many silencing/mounting options but I like to clean/inspect/maintain our exhaust system every few months.

[Keith Upton]

I tried one of those expensive silicone flex hoses before just moving to PVC for my extraction. I get better airflow (even with a smaller diameter pipe) and it is quieter.