I'm specifying an exhaust blower for my 2'X4' laser. I've read the posts in the laser exhaust threads a couple of times before, but I just read them again as I'm now making the purchase. My business has grown to the point that I'm bumming eight hours of laser time on my friend's laser every week, and I'll never be able to repay him for that, not to mention that it's a hassle to pack everything up to lase my parts across town.
One option I looked into was an air mover from a home central heating and air conditioning unit. Apparently, some of them are 120 VAC... maybe the air movers used for gas furnaces as opposed to heat pumps. My brother works in the HVAC industry, and might be able to snag me a used HVAC blower for free, but I have doubts that they'll be able to push enough air against the expected static pressure. I have another friend who has a good knowledge of this sort of stuff and he assures me that the performance would be weak. Apparently, even though HVAC air movers are designed to move a lot of air, they do that through a large cross section of air ducts at a relatively low velocity. An HVAC fan would probably move more air through a laser than some of the smaller fans that are being discussed, and may provide adequate exhaust for a laser, but would certainly be bigger and less efficient than a more suitable blower.
I plan on using make up air from outside so I don't pull all of the heated or air conditioned air from my shop. To avoid condensation, I'll only run my laser when it's not raining or very humid outside.
Based on my laser use, I know that I definitely don't want a marginal exhaust system. I don't want the smoke and debris hanging around and depositing on linear rails, timing belts, bearings, stepper motors, optics, etc.
The laser I'm using now has a nice Dayton industrial blower but the exhaust is weak. I think that blower is running with the blades mostly stalled - spinning but not moving much air because the back pressure is too high.
I guess I'll go with the 1 HP Hazard Fraught dust collector.
http://www.harborfreight.com/13-gallon- ... 31810.htmlBTW - Search for "Harbor Freight coupons" and you can always find an online coupon to use. I just found a 20% off coupon. I'm taking it to my local store, although they may claim that the dust collector is already on sale for $10 off (less than 10%) so the 20% off coupon isn't valid. There's also a good chance that they won't have it in stock, and I'll need to try back later.
I have no doubt that the inline centrifugal blowers will work well, and they look like better quality at a comparable price to Harbor Freight, or maybe even slightly less expensive, but I've learned a few things using and maintaining my friend's laser for over six years. The materials that I cut produce black powdery debris that's a mess, or black oily gunk. Cutting acrylic and similar plastic sheets results in light gray-white powder that's very abrasive. I'm going to design my laser with the simplest exhaust path possible, and I'll make sure that the entire exhaust path is accessible for cleaning and maintenance. I'll be using my laser a lot and I cut some nasty stuff. I absolutely wouldn't want the exhaust motor in the exhaust path. I guess if the inline blower was inexpensive enough, I could replace it every year or so, but I'm trying to design my laser to require very little maintenance. If you're cutting cleaner materials and it's a hobby laser that you don't use very often, some form of inline exhaust may be your best option. If you will be creating a lot of greasy or gritty debris, I'd keep the exhaust motor out of the exhaust flow. I feel pretty good about the reliability of an exhaust that's designed to move air containing 50 gallons of sawdust and small chunks of wood per day. I might need to de-gunk the impeller blades and housing once or twice a year, but I could live with that.