Exhaust Question

[David Sabot]

Hi guys. I have a Pinnacle 25 Watt machine. I just got a job to engrave 100 boxes that are MDF. My engraver is in a large warehouse, but I need to purchase an exhaust fan. I am not looking to jurry rig some stuff together. Just a complete unit I can snap on and be ready to roll with. Any recommendations in the <$1000 range?

[Ed Lang]

I am happy with my delta AP300 for the blower. I connect the input to the lasers output and the output of the blower goes outside with a blast gate to make sure critters cannot get in at night as well as the cold air.

Hope this helps.

[Mitchell Andrus]

I'm with Ed on the 110V Delta AP 300. Plenty of suction, not too loud. I have a 25 foot run, 4" steel pipe with 7 elbows. Hard to imagine needing anything more powerful.

Mitch

[David Sabot]

Thanks guys. My machine has a 4 inch hole in the back. How does the tube connect to this. Is there a flange or something I need to get?

[David Sabot]

I found the flange, it was under the unit, hahaa, is 550CFM going to be enough, I was told by the manufacturer that around 700 was preferred.

[Joe Pelonio]

David,

It varies by manufacturer, ours called for 400 CFM but I went with 600 because of a long run. I used metal pipe to the fan and ABS after that.
4" is standard for dryers, look at the heating section of the mega hardware stores for fittings (don't use that thin flexible plastic pipe).
I bought my fan at Grainger for about $200.

Also when doing a lot of MDF clean mirrors and lenses freqently, it does produce a filmy smoke that coats them.

[Rob Bosworth]

I would buy what is spec'd out in your owner's manual. Another number that is as important as the CFM is thew static pressure of the unit. I would guess their requirement for your machine would be 700 cfm at 6" of static pressure. The 6" of static pressure allows the blower to pull 700 cfm through your machine, then push it out through the exhaust side of the exhaust system.

If you want to maximize your airflow, connect up to the exhaust manifold on your machine with 4" dia. tubing, then as soon as possible, expand to 6" dia smooth wall ducting. Even if you have to reduce the diameter of the ducting to get it into the exhaust blower, go with the larger diameter ducting. Smooth bore ducting is much better than ducting with convolutes in it. The fewer restriction you put between the machine and the outlet outside, the more effecient it will be. Try to also minimize the number of elbows you need to use, becuase they too are restrictions.

[Mike Null]

I use a blast gate at the machine connected to short piece of 4" flex metal duct then to 6" hard metal. My blower is an in-line blower from Grainger of about 300-350 cfm. It goes to the outer wall of my house through a dryer vent with a gravity type closer.

In use for more than 8 years and two brands of machines with 0 problems. Cost about $350.

Avoid L's when possible as they restrict flow and dramatically reduce efficiency.

[Scott Winstead]

Is the blower inside your office/shop space or external? I also use a Grainger blower (it's pretty loud) - right now it's external to my office but it's pretty loud. I'm looking for some ways to make it a more silent so that the neighbors don't get upset.

Options:
1 - bring the blower inside (office) and help silence it with a wood box and carpet. Cons: sound is now in the office
2 - move the blower inside the garage and use solid ducting to route exhaust. Cons: longer duct run
3 - move and get away from our neighbors ;) . Cons: none

[David Sabot]

Signwarehouse, where I got the engraver from is trying to sell me:

• Small Bio-Odor Reduction Unit & Blower- State of the Art, Bio-Odor Reduction Unit helps create a sphere of pure air for your shop. It neutralizes odors and dramatically reduces contaminates. The blower pulls vaporized particles, smoke and fumes out of the machine to help keep lenses and mirrors clean. thus promoting longer laser life. And by drawing air out the machine and pushing it through carbon pellets, it reduces the odor of your acrylic, wood, plastic and rubber stamp fumes since these must be vented outside. Activated carbon 5.5 lb/2.5kg (standard) AC110V

The price is around $400. Their argument being that it is a blower and odor remover. Should I go with this, or get the Delta vac for 1/2 the price?

[Scott Winstead]

I think Rob has posted the "best" advice - pay close attention to the technical specs of your machine. CFM and static air pressure were the two primary variables ...

Attached is the spec sheet on the Grainger/Dayton blower (4C108) that I have with my ULS laser.

[Gary Shoemake]

I also have a Pinnicle Mercury and have their odor reduction unit. Mine is not the small unit but the one I have does a great job. I do have it located outside of my laser room in a small shed like building to help with the noise. I guess the unit weighs in at about 175 lbs. but it is a combined unit with blower and activated charcoal filter.

HTH

[Mike Null]

Scott:

My blower is about 8 feet from my desk. My shop in is my basement. The noise is not so bad that I can't talk on the phone while it is running.

[Scott Winstead]

Mike - do you have the blower in a housing that you built inside your basement? I'm thinking a plywood box with carpet padding tacked inside to help muffle the majority of the noise. The Grainger spec calls it out at 84 Dba which is pretty loud. I'm going to have to do something before the "evil HOA" folks get involved.

[Mike Null]

Scott:

I had originally intended to build an enclosure but only got as far as 3 walls so it's next to the laser and more or less open. Here's a pic.

My shop is below the kitchen and we don't hear the blower in the kitchen.

[Joe Pelonio]

My blower is an 8" Tantec FX10XL from Grainger. I have placed rubber between the mounting bracket and wall stud that it's screwed into, and I get very little noise. I can talk on the phone with it on and the laser top up with no problem.

[Rob Bosworth]

Mike, do you get enough air movement through your system with that inline exhaust blower? Most of the systems I have seen, that use an inline blower like the one in your picture, do not move enough air through the system to properly evacuate the smoke from the laser cabinet. Most inline blowers have a failry high cfm rating, but not enough static pressure to pull/ push air through the system and out through the ducting.

If you run your system and the smoke rizes up off the material, then shoots right back to the exhaust plenum, then the inline exhaust blower is adequate. If you see smoke swirling around in the cabinet while engraving, I would suggest buying a bigger blower. A couple of hundred dollars for a good exhaust blower is much cheaper than replacing optics becuase of damage to the coatings caused by lingering effluents.

[Ed Lang]

If you run your system and the smoke rizes up off the material, then shoots right back to the exhaust plenum, then the inline exhaust blower is adequate. If you see smoke swirling around in the cabinet while engraving, I would suggest buying a bigger blower. A couple of hundred dollars for a good exhaust blower is much cheaper than replacing optics becuase of damage to the coatings caused by lingering effluents.

My Delta AP300 must have plenty of air movement as I never see smoke from any material unless I close down the gate valve to restrict air flow. I have 5' of 4" flex hose to the wall and then the AP300 is outside with nothing attached to the output side of it. There is a 4" plastic S&D pipe in the wall with the blast gate glued to the inside of the office end.

[Joe Pelonio]

Another way to look at it is, if the fan's on and the laser door closed, a sheet of paper should stick to the laser intake area without falling off.

[Mike Null]

This system has been in use now for more than 8 years without a single problem. It is quiet, efficient and does not suck material off the table.

This is not a case where more is better. The whole point is to be efficient enough to evacuate the smoke and odor from the engraver. The only instances I can think of which would call for 600 or more cfm are those with long duct runs or a lot of "L's".

I have no experience with vacuum tables and if they require more cfm so be it.

[Bob Yeager]

DAVID -- what is the brand name for the "Bio-odor reduction" unit? I'm doing some research on looking for something similar. Thanks.

Bob

[Scott Winstead]

Wow ... I went with what was recommended by ULS for the blower unit. It looks like Mike and Joe have something much smaller and quieter than the Grainger/Dayton unit that I'm using for exhaust.

I'm going to have to take a closer look at this.
Scott

[David Sabot]

DAVID -- what is the brand name for the "Bio-odor reduction" unit? I'm doing some research on looking for something similar. Thanks.

Bob

I honestly do not know the brand name. I ordered it as it was what the manufacturer specs so I wanted to be safe. I can let you know once it arrives.