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Frank Defert
08-25-2008, 10:29 PM
I have recently moved and need to reconfigure the laser exhaust system. I am running a 750 CFM 1HP dust collector that works really well. The dust collector was located at the end of a 20ft 4in hose and then there was a short 3ft run to the outside.

My question is how far can the dust collector "push" the exhaust after "pulling" it 20ft from the laser? It now needs to travel upwards 12 - 15ft to clear the building and the neighbours. Is there a formula to calculate this or would someone know off hand or a rule of thumb?

Thanks .... Frank

David Brasfield
08-25-2008, 11:18 PM
Hi, Frank.

The easiest way to take care of a potential increase in static pressure is to simply increase the size of the output pipe for the longer run. Changing from 4 to 5 inch should do it, going from 4 to 6 would be great. You will want to change sizes at the exhaust with an adapter, with the larger pipe as near the blower as possible. Avoid flexible hose as it introduces additional losses/restriction.

All the best,
David

Mike Compton
08-25-2008, 11:41 PM
Does anyone have a link to the best fan for a Helix.. I am sure I can get it cheaper than from my Epilog dealer. Noise is a huge factor, I don't want to listen to an exhaust fan all day and night, and early mornings after being up for 32 hours trying to complete a large run of pens...lol

The truth is that I have ZERO idea of what I will be engraving. I think these lasers emit some kind of intoxication fumes or pheromones that chemically attract or alter my thought process to them..:eek: It also totally messed up my ROI calculations, if I owned a laser I would probably etch/burn/cut/destroy this calculator because I will be dead before I recoup my 25k (if I buy)..

MC:D

Keith Outten
08-26-2008, 5:33 AM
Mike,

Buy a small dust collector for your engraver and throw away the bags. The really cheap one horse DC's from HF are weak but a good 1.5 HP unit should be more than you need. I have a very old Grizzly 1.5 HP DC that I use for my workshop. I tied my Laser Engraver into my shop piping and it works extremely well. There is about 30 feet of piping from my engraver to the exhaust and it pulls so hard there is a whistle at the engraver inlet holes.

At CNU we purchased a HF one horse DC, it is useable but nothing to brag about. I have it mounted in the ceiling just above the engraver, the exhaust blows directly outside through an exhaust vent. There is less than ten feet of hose from the engraver to the vent.

Neither system uses bags, at home I use a chip box located outside about four feet from the DC exhaust port.

.

David Brasfield
08-26-2008, 11:36 AM
Hi, Mike.

The manuals for the Helix are online and will state what the airflow requirements are.

I suggest that you take the manufacturers recommendations and multiply by 1.5, and buy that size unit.

Lastly, if you want quiet, check that the blower you are considering is brushless (no brushes). If it has brushes, it will be loud, usually, - VERY LOUD-.

As Keith said, picking up a Grizzly (or similar brand - Shop Fox, Penn State, etc) DC and toss the bags. It will usually cost less to do that than to buy the blower outright (a proper blower, anyway). Also make sure that you use metal ductwork, and flexible metal looking dryer hose is NOT metal ductwork.

David

Bob Cole
08-27-2008, 1:54 AM
How much more umph should you get by taking the bags off? I still have the bags on my Delta AP400 and have been wondering if I should get a different blower/dust collector because at times cutting a full sheet of wood the smoke doesn't clear as quickly as I would hope.

David Brasfield
08-27-2008, 2:09 AM
The bags ARE outside, right?

Removing them will improve flow regardless.

David

Bill Cunningham
08-28-2008, 7:23 PM
If you have had the bags attached while cutting/burning/engraving wood, with all the oil and smoke emitted, they probably have their inside surface just about sealed and airtight by now:eek: The bags are great for sawdust, but not so great for wood oil, fumes, and smoke particles. They may even restrict the flow enough to overheat the tube, and shut down your machine.. Could even cause some perm. damage.. Scrap the bags...

Keith Outten
08-28-2008, 10:45 PM
I scrapped my DC bags many years ago, way before I ever purchased my laser engraver. Since then I blow all of my chips and the laser effluent into a chip box outside.

Since the resistance of the bags is removed the efficiency goes up dramatically. This setup may not be the best for some people who have very close neighbors or who live in areas where extreme climate changes are the norm. Here in eastern Virginia it works well and the impact on heating or cooling is negligible.

Last week I performed my annual chore of dumping the chip box at CNU. We don't have a planer in our sign shop but the CNC router produces plenty of chips and dust. The two horse HF dust collector does a great job of keeping the chips moving outside and the air inside clear of fine particles.
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