WHAT YOU NEED TO UNDERSTAND ABOUT LASER ENGRAVERS – BEFORE YOU BUY PART SIX: VENTILATION
When I bought my first laser, I was told to buy a little inline fan intended to go in a dryer vent to increase the efficiency of a clothes dryer and I did. Using hose intended for a clothes dryer along with that little fan, I vented my laser to the outside – just as I had been instructed.
That’s what many overseas laser manufacturers recommend as well.
In my case, lasers were new, and no one knew how to properly vent one of these things. We all just made it up as we went. That is no excuse however for what some manufacturers are teaching today. We know better after 30+ years of laser engraving.
Laser engravers create a lot of smoke. In that smoke can be a ton of extremely toxic chemicals. Unless you do something to get those outside or filter them, so they become safe, you are playing Russian roulette.
Studies done by people who know what they are doing, have found a long list of highly dangerous substances in laser exhaust. These are all in that puff of smoke and if you don’t have an adequate ventilation system, you and your employees are breathing that day after day….
TWO WAYS TO VENT YOUR LASER: Blowers
ONE: The cheapest way, and probably the most common way to vent a laser is to use a special exhaust blower and 4” metal tubing to vent your laser directly to the outside where drafts and wind can’t blow the fumes back into your shop. Do not vent to an attic or crawl space!
These ventilation systems may seem like over kill for a little desktop laser but when you see what that laser is capable of producing, you will agree, this is nothing to play around with.
Blowers for this application are sealed units that take the 4” exhaust from a laser (some glass lasers only have a 2”) and move it out through its own exhaust pipe. These generate a lot of air movement. American lasers usually call for 600 CFM. for each laser being used. The blower pictured is rated at 720 CFM and costs less than $400. To determine what is needed for your laser, contact the manufacturer.
TWO WAYS TO VENT YOUR LASER: Filtering Systems
These are absolutely necessary if you plan on having a kiosk in a public place like a mall. In Europe, almost all laser engravers are required to be filtered this way.
As for cost, you can think in terms of $2,200+ for one of these systems plus the charcoal has to be recharged from time to time and paper filters have to be replaced so it introduces an on-going expense.
PIPE:
What is acceptable is ordinary stove pipe that you can buy at most any hardware store and a special PVC flexible tubing that is made for dust collection in wood shops. This tubing has a metal wire embedded in the PVC that keeps dust from building up and igniting. The wire should be grounded to earth at both ends for extra safety.
What you shouldn’t use is ordinary PVC pipe, those silver or white dryer hoses or PVC hoses that don’t have the grounding wire embedded throughout. The silver dryer hoses are ok for temporary installations but are easily punctured and should be checked on a regular basis.
Of course, it is very important that hoses or pipes be securely fastened to all fittings so no fumes can escape into the environment. This can usually be done with clamps and duct tape.
BLOWERS
In recent years, bad publicity has forced many Chinese manufacturers to stop sending plastic blowers for use in exhaust systems. Instead, they are using a metal unit like the one shown here. It has a powerful motor and is heavy but it’s efficiency of just over 600 CFM and its love for energy, it pulls over 5-amps of power, and its outrageous cost ($250-400) makes it a very bad investment.
Perhaps the only thing worse than the Chinese blower is this inline fan designed for use with dryer hose or stove pipe. Although it might be great for some things, it is a terrible choice for exhausting a laser – even a tiny one! To top things off, this fan only puts out 100 CFM – far short of the 600 CFM most good lasers demand.
As for this solution, it is just laughable. The manufacturer is obviously promoting this fume extractor for use with Class Four lasers and although it might be better than nothing, Class Four lasers are dangerous enough without adding inadequate ventilation. This thing moves only 52 CFM and was actually designed to be used with a soldering station.
Conclusion
There is a lot more to learn before shopping for a laser engraver. You should understand cabinetry, power, speed, cooling, ventilation, FCC classification, safety concerns, software and more. Part Seven will cover how lasers are kept cool enough they don’t burn themselves out. This one is all about safety so don’t miss it.
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