I am getting my new laser in a couple of weeks and I'm looking at the specs. for the exhaust blower. The selection chart given to me by my sales rep has both indoor and outdoor units. But the separate exhaust requirements sheet says (in bold letters) "the exhaust blower MUST be mounted on the OUTSIDE of the building on the roof or on a cement pad. Neither of these is practical for my building.

My question is: why MUST the blower be mounted outside. It seems to me that if the exhaust pipe vents to the outside, that should be all that is necessary. Also, I spoke with a technician at Penn Industries and he said that they sell the indoor units to both Epilogue and Universal.

Hi ,
I originally had an expensive Fumex filter that did not do the job. I took it out and used Penn's blower. Recommended to me by my Hermes rep. It does a great job and very inexpensive. Just make sure your exhust pipe is large enought to carry the air out.
Larry

My blower is on the floor under the table the laser is on. The duct then goes three feet across the floor and up and out the window. I used the rigid, but flexibile, 4" metal dryer vent hose. Sealed all connections and around the window.

edited to add: do a search. There have been several threads discussing exhaust blowers.

Garry &/or Kris,

Uncle Steve is correct in that it is easier to pull the exhaust air than to push it, so mount the blower (in this case it will be a sucker.... (devil) )as close to the outside wall as possible with as few elbows as possible. In doing so, you will also find there is less chance to exhaust fumes into the room where you and the machine are. Some fumes can be very pungent as well as toxic, plastic is especially bad in both respects.

Also, use as little of the "flexible" tubing as possible, all of the ridges in it cause a restriction which will cut down on your airflow and build up with crud. I am using 10' lengths of the 4" PVC which need fewer couplings and has a smooth inside wall for less air restriction.

I thought I could probably mount the blower above the drop ceiling directly above the laser (about 8 - 9 feet straight up) and about 2 feet from the outside wall using rigid pipe to exhaust it out with just flexible PVC between the rigid pipe and the engraver. My concern was why does the blower unit NEED to be outside. It just didn't make sense as long as everything is tightly sealed.

I just want to make sure that I can do what I WANT to do and not have to spend $1,000 when I can meet all of the specifications for about $300.

I'm not happy about it but mine is in the same room as my laser (for now anyway). I'm careful to check for leaks but thankfully, my room is old and not airtight anyway.
Looking into getting it outside but I didn't even know they made outdoor units.

Depending on what laser engraving system you are purchasing, there are a number of manufactures selling inexpensive dust collection units which can be used for exhausting laser systems. You can buy almost any of the dust collection systems for less than $ 200 and they are relatively quiet. Just throw away the bag and pipe it outside. Harbor Feight, Grizzly Industrial, Delta Industrial, all sell these blowers. If you need about 400 CFM at 6" of static pressure, the 1 hp. models will do fine. I think some of the units can be run with a remote control. Kinda nice when that phone rings and you want to hear what is going on.

If you want to spend a bunch, you can always buy one from Grainger.

Great idea but is the air going thru the blower enough to keep it cool for those long jobs? I worry about the heat build up or, am I worrying about nothing?
Thanks for the great idea!

Thanks, I've already started the 'mental' process of doing this. Gotta put out a few fires first.
I appreciate the info.