Exhaust Systems

[Ricky Gore]

Now I lknow I'm being cheap here but:

Doesn't this (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94029) look a lot like this (http://www.signwarehouse.com/shop/merchant.mvc?Screen=PROD&Store_Code=SC&Product_Code=ENA-PSI-DC3XX&Category_Code=&Search=Blower&Search_Type=OR&Offset=3)?

Suggestions on exhaust systems would be appreciated, we are on a tight budget and need to get this to work as cheaply as possible.

Thanks,
Ricky

[Barbara Buhse]

We bought our blower from Harbor freight for about 1/4 of the price the Epilog rep was going to charge us.

[Mike Mackenzie]

Ricky,

You can also get a good quality blower from sears.

http://www.sears.com/shc/s/p_10153_12605_00921335000P?cat=Wet-Dry+Vacs&pid=00921335000&vertical=TOOL&subcat=Dust+Collection+Systems+%2526+Attachments&BV_UseBVCookie=Yes

[Joe Pelonio]

Mine was sort of in between those prices, but it's an 10" reduced down to 4" and has plenty of power but is a lot quieter than a typical dust collection system. I got it from Grainger. I see it's gone way up in price since I got mine nearly 4 years ago.

http://www.grainger.com/Grainger/items/4YM41

[John Keeton]

Not even owning a laser yet, I probably shouldn't weigh in on this one. No doubt the more expensive one is probably overpriced. But, there are (claimed) differences in amperage, horsepower and weight, and those factors probably say something about the quality differences. Can't explain the CFM differences?? Again, not knowing the actual power need the cheaper one may do just fine.

[Ricky Gore]

Ok, say I buy a blower. Do I need some type of filter to keep the debris from going into the yard? Or is there a filter/screen in the machine before the debris exits?

[Frank Tralongo]

Eh Ricky,
Here is my 2 cents...
Got my laser about 6 weeks ago and was using my Penn unit without the sack. Kind of an overkill so I got the cheepee unit from Harbor Freight and am very happy with it. Has good suction power and is not too noisy when ruuning. I routed my hose thru the wall and have the exhaust unit outside thru 5 feet of hose. The other good thing is its small and only weighs about 20 pounds so I bring it out as needed. I run it straight without any filters etc and have not had any problems with waste materials even though I was cutting and burning some none treated wood scrapes

[Joe Pelonio]

Ok, say I buy a blower. Do I need some type of filter to keep the debris from going into the yard? Or is there a filter/screen in the machine before the debris exits?
There's really no debris. Sometimes cutting light card stock or paper pieces will fly out, but otherwise just a dark dusty film inside the exhaust plumbing that has to be cleaned every 2 years or so.

[Bill Cunningham]

Just don't 'suck' through that plastic flex vent hose stuff. It's OK to 'blow' through but when sucking, the inner lining will eventually collapse, and block the air flow, overheating your laser.. I 'almost' made that mistake, but spotted it in time..

[Dwayne Cook]

Bill
what kind of hose did you have problem with??? I use that Black Plastic hose from penn and have been for about two years

[Dwayne Cook]

Hi Rick
I went straight to Penn In Philly and they sold me same blower as i got from Epilog for about $250... Sorry i didnt catch the thread on what you were paying....

Dwayne Cook
Epilog 24TT & 24Mini Corel X3 and what ever works

[Richard Rumancik]

Mine was sort of in between those prices, but it's an 10" reduced down to 4" and has plenty of power but is a lot quieter than a typical dust collection system. I got it from Grainger. I see it's gone way up in price since I got mine nearly 4 years ago.

http://www.grainger.com/Grainger/items/4YM41

Joe, I'm sure you are satisfied with the Grainger unit but it is not quite what I was told was needed for a laser. The difference between a fan and a blower is how much pressure it can generate. Fans have very high cfm but very low pressure, where a blower generally has lower cfm and increased pressure. I was told I needed six or seven hundred cfm at 6" water pressure (I don't have my manual handy for the exact numbers). The Sign Warehouse unit exceeds mine. The fan you are using cannot generate anything near that pressure (it is spec'd at much less than an inch of water static pressure.)

There seems to be a pretty big range in what people are using - I don't know what is really needed - but I am just pointing out that the Grainger fan cannot pump the same amount of air that the Sign Warehouse unit can.

The Harbor Freight unit does not specify how much pressure it can generate, but it is probably around several inches.

Also, fans and blowers are spec'd as to what they can deliver at a specific pressure, but where they actually operate on the curve depends on the system they are installed into. A transition from 10" to 4" could affect the cfm greatly - it is hard to guess what the real cfm is in the installed system. The length of ducting, elbows, transitions, smoothness of tubing, etc all affect the delivered cfm/pressure.

I am not saying your unit is inadequate but it would probably not meet the specs of the major laser manufacturers. Are they asking for too much?

Lower cfm is good in that it reduces energy losses, as long as it is properly venting the fumes.

[Joe Pelonio]

This more than met the specs of my manufacturer, which was specified as CFM only. Any more pressure and it would blow all the parts out.

[Ed Maloney]

Rick - I have the same Harbor Freight blower that you posted. A little loud, but I've had no problems with it and nothing (with the exception of the one cat) fly out.

[Zvi Grinberg]

Just don't 'suck' through that plastic flex vent hose stuff. It's OK to 'blow' through but when sucking, the inner lining will eventually collapse, and block the air flow, overheating your laser.. I 'almost' made that mistake, but spotted it in time..

Bill,
The danger in 'blowing' (pushing) is that anything that blocks the line, would cause backward pressure. Blowers cannot overcome pressure, and it would all go back to the laser. This is also possible when the line is not straight and has several corners of 90 degrees.

'Sucking' (pulling) is peferable, especally for those who care to filter the line (eliminate fumes). We use airconditioner's duct pipes which seem to be flexible but persistent to air sucking.

[Joe Pelonio]

I used the flexible aluminum dryer vent hose. The only problem is that the ridges do catch the residue more than a smooth pipe but it's a lot easier than dealing with elbows.

[Ed Maloney]

I use the clear venting hose so I can see if anything starts to collect/build up in it.

[Rob Bosworth]

I am not here to defend the pricing differences between the Harbor Freight blower and the blower offered through SignWarehouse.

There is a difference between the two blowers. The Harbour Freight Mini is a smaller blower. It is a bit noisier, and does not move the volume of air. My brother bought one to use with his system, and it is a fairly low volume blower. They do have a 1 Hp. exhaust blower that specs out at 650 CFM at 4" of static pressure. It retails for ~ $ 150 - $ 200 and will do a nice job on most laser engraving systems. For those of you with the BIG machines, you might want to look at the 1.5 Hp. blowers, for a little bit more money, but it will save you a ton of money replacing damaged optics.

Me, I run a huge Grainger blower in my shop. I have four stations hooked up with slide gates. If I happen to be running just a Mini, with all but the one slide gate closed, I can barely open the top door of the machine to look inside. Matter of fact, I have lost a couple of small dogs and cats who happened to be standing a liitle too close when I kicked on the blower.

Of course, I did not buy the big Grainger blower, it came with a machine many moons ago. I think it is about $ 600, but it can be mounted on the roof without an enclosure around it. If I had to do it all over again, er, I mean have to pay for one, I would use a 1.5 Hp. dust collection unit and throw away the bag. If I only had one machine, I would use a 1 Hp. instead.

[Bill Cunningham]

Bill,
The danger in 'blowing' (pushing) is that anything that blocks the line, would cause backward pressure. Blowers cannot overcome pressure, and it would all go back to the laser. This is also possible when the line is not straight and has several corners of 90 degrees.

'Sucking' (pulling) is peferable, especally for those who care to filter the line (eliminate fumes). We use airconditioner's duct pipes which seem to be flexible but persistent to air sucking.

The hose I am referring to is the flexible plastic corregated metalized 'heating vent' type hose. It usually comes in 10' sections, that are 'accordioned' into a package. This type is cheap and handy for a quick route to the wall, but believe me, if you try to suck through this stuff, the by products of engraving, smoke, oil, etc. WILL affect the inside lining, and it WILL collapse. You can push air through it, because the positive pressure keeps the lining inflated, but the by-products will eventually destroy the lining and it will start to leak fumes into the shop.. Fixed metal vent pipe is always the best way to go. They may be a little more difficult to route, but as Joe said, they collect less crud. The less crud in your vent, the better the air will flow, sucking 'or' blowing..

[Mike Hood]

I bought the blower from Sign Warehouse with my laser. It's a "Harbor Freight" quality unit and is pretty overpriced (IMO).

It's the one part of my deal that I wish I'd have bought locally. :)

[Bill Cunningham]

I bought a 750 cfm portable dust collector from Busy Bee tools in Canada, on sale for just over 100.00 took off the bag, and piped it in.. 750 cfm @ 6" of suction is more than enough.. I would assume this is similar to the H.F ones..

Specifications
1 bag 15 U.S. Gallon
4 casters and carry handle
30 micron filter bag
4'' inlet
Bag Volume: 2.01 Cubic Feet
Static Pressure: 6"
Impeller: Balanced Steel, 9"
Motor: 3/4 HP, 110V, 7 Amp, 3450 RPM
Air Suction Capacity: 750 CFM
Weight: 20 kg.

[Mike Hood]

With all this talk of blowers... I keep meaning to share a trick I'm using. About this time last year I found home Christmas light remote controls at my local hardware store for $20 or so. They have a simple keychain remote and I use it to remote start my exhaust blower.

Much easier than going over when ready to turn it on and allows me to keep the blower fan (a bit noisey) further downstream than before. With a touch of a button I can now turn on/off the blower.

Also... at the end of the season I bought 3 additional sets (30% off) and am rigging another for a vacuum table (push button on/off). Pretty "Inspector Gadget"ish , but makes working small items easier. I keep the remotes on a velcro tab beside the laser.

I also use a MAC valve (controlled by the switched compressor outlet on my Explorer) to turn air pressure on and off as the air assist needs it.

Anyhow... keep meaning to share that... sorry to hijack

[Daryl Barberousse]

Ricky,

I have used a the harbor freight system for over 2 years. Had to replace one last year. Found out that the brushes wore out in the original one. Replaced them with brushes from the local hardware store and now I have a back up system.

[Brian Robison]

I've had my Harbor Fright :) blower for about 4 years with no problems, I'm only a part timer though. I also found a blower on close out at Lowes a couple years back and bought it as a back up. $49.00!

I'm sure some would disagree but I made a stand for my laser and I built in a switch panel that turns on the laser, another switch for the blower, another for the little airbrush compressor and another that goes between normal and timed with a timer that shuts everything off.
I don't use the timer because I'm afraid to leave it on after all this talk of fires. It's all on a 15 amp circuit and has been just fine for over a year.