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Ed Maloney
01-20-2010, 7:34 PM
My blower is on the way out. I have to hit the side of it a few times to make it turn on.

I ordered another from HF and it got lost in transit to FedEx. Now I'm being told it's on back order. No ETA from them. Anyone else having problems with HF these days?

Here's the questions:

Question #1 - I see that the manual says something about replacing the brushs. I took out the side retaining screws and I can't figure out how to get them out.

Question #2 - Once I get them out where do I find replacement ones?

Dave Russell Smith
01-20-2010, 7:57 PM
I saw replacement brushes in lowes or H/D the other day in those specialty draws they have. Not sure if they would be right might be worth checking out

Richard Rumancik
01-20-2010, 9:10 PM
If the hardware store doesn't have them, you may have to go to an electric motor shop but they will likely be able to match you up with something close if you bring in the old ones. Sometimes you will have to tweak the size a bit (i.e file them down) to match the size.

Bob Merhar
01-20-2010, 9:23 PM
I ordered replacement brushes directly from Harbor Freight.

sal shepherd
01-20-2010, 10:04 PM
I was in Harbor Freight on tuesday they had 3 on shelf. In Metarie, LA.

I got a great deal on a air eraser (pen type sandblaster ) 10.00 reg 20.00 It was missing the container of blast media 1 to 2 oz. I got a bottle about 10 x the size,an still under 20.00

Dave Johnson29
01-21-2010, 11:44 AM
Question #1 - I see that the manual says something about replacing the brushs. I took out the side retaining screws and I can't figure out how to get them out.

Question #2 - Once I get them out where do I find replacement ones?

Th brushes should have springs on them that pop out when you remove that plastic screw cover. Pull on the spring. If the spring pulls off and leaves the brush behind try tipping it on it's side and bumping the motor.

If the brush has worn so much that it is jammed between the commutator and the housing then you will need to pull the motor apart. In that case, the commutator would probably need skimming anyway.

Order from HF, in the back of the manual there is an exploded view, get the item number from that then look it up in the part table for the actual order part number.

Scott Balboa
01-21-2010, 3:10 PM
A word of advice for anyone here who shops at Home Depot or Lowes...

I worked for BIG ORANGE for years and know the company inside and out. Many people are unaware that the Pro Desk (also called the Contractors Desk, Contractor Services, etc.), a seperate section at the corner of the store (probably near the front) is NOT just for contractors, and has many HUGE catalogs with a million components for anything in your home or parts for your tools. What you see on the shelves is only a small slice of what Home Depot can get for you. Why the average customer is left in the dark about this has to do with the poor company training, bad management, and bad employees! Anyway, the pro desk can special order it at no extra cost to you and have it delivered directly to the store, at which point they call you and you just come in and pick it up. May be worth a try!

Ed Maloney
01-21-2010, 6:45 PM
Folks - Thanks for your replies and help. Here's the latest status.

I asked HF to ship me a replacement blower that they had in stock. Now they are telling me they canceled the original order and will be issuing me a refund check. They went on to tell me that I would need to place another order for the blower that they do have in stock.

So the new question is:

Who are their competitors where I can order a blower from? Need a 650CFM one.

Thanks again.

donald bugansky
01-21-2010, 7:18 PM
Go look at Penn State Industries.

http://www.pennstateind.com/store/DC3XX.html?mybuyscid=6133179899

They have a unit that works real well and is considerably quieter than the harbor freight versions.

Search the forum for "exhaust" and you'll find links like:

http://www.sawmillcreek.org/showthread.php?t=126167&highlight=Penn

Mike Null
01-21-2010, 9:47 PM
I am baffled by people who spend $20 or $30 thousand on a laser and want to go cheap on a blower.

Look at in-line blowers, a lower cfm, and much lower db. They don't cost that much more and will give you the benefit of quietness.

Unless you're pushing air a great distance or through many el's (90's) you generally don't need that high cfm.

I've used a 260 cfm blower for 12 years with two different brands of lasers and never had smoke or odor problems. I can stand next to my machine with the blower on and carry on a telephone conversation.

John Noell
01-21-2010, 11:44 PM
I can stand next to my machine with the blower on and carry on a telephone conversation. I can stand next to mine and talk - I just can't hear what the other side is saying. :) :)

Ed Maloney
01-22-2010, 10:11 AM
I am baffled by people who spend $20 or $30 thousand on a laser and want to go cheap on a blower.

Look at in-line blowers, a lower cfm, and much lower db. They don't cost that much more and will give you the benefit of quietness.

Unless you're pushing air a great distance or through many el's (90's) you generally don't need that high cfm.

I've used a 260 cfm blower for 12 years with two different brands of lasers and never had smoke or odor problems. I can stand next to my machine with the blower on and carry on a telephone conversation.

Mike - So where did you get your blower? The Penn State and HF blowers look like the same make, with Penn State being higher.

I would love to get a blower that is nice and quite. So where is a good source?

donald bugansky
01-22-2010, 12:49 PM
Here's a link on some in-line fans. I received the mfg info from Mike.

http://www.kanalflakt-us.com/K.pdf

Mike Null
01-22-2010, 1:05 PM
Check Grainger--that's where I bought mine. Also check inline blowers on the web. Mine is a 6" and is reduced to 4" at the machine and at the exterior duct.

Mine is a model K6 Kanalflakt which I think has been discontinued. It's 12 years old.

Rob Bosworth
01-22-2010, 2:30 PM
You can also check Grizzly Industrial Supply. They carry similar inexpensive dust collectors. http://www.grizzly.com http://www.grizzly.com (http://www.grizzly.com/)

The Penn Industry dust collection blowers seem to be a little bit better built and a bit quieter than the H.F. or Grizzly. Delta also makes a 1 and 1.5 Hp. dust collector, but it is a little more money.

W.W. Grainger sells a great exhaust blower, that can be put inside or outside, but they are really expensive.

Good luck.

Ed Maloney
01-23-2010, 12:12 PM
I forgot about Grizzly.

Thanks folks!

donald bugansky
01-23-2010, 1:32 PM
The new Laserbits reference guide has a blower...page 22, Rated at 660 cfm.

Ed Maloney
01-23-2010, 2:59 PM
I didn't know, but there is a HF store less than an hour away from me. They didn' have the blower I wanted, but did have model 31810.

The damn thing is so loud it sounds like the motor is rubbing on something metallic. Does anyone else have this model?

Dennis Solomon
01-23-2010, 3:29 PM
We ordered ours from harbor freight... now we keep a spare set- actually, a spare blower.

Ed Maloney
01-23-2010, 4:06 PM
The damn thing is so loud it sounds like the motor is rubbing on something metallic. Does anyone else have this model?

Upon closer inspection the grill over the impeller blades was bent in. Fixed the grill and I'm all set. It's much quieter than the other model. Quieter than a vacuum cleaner.

Thanks again for everyone's help. I will be ordering some new brushes for the other blower so I have a back-up one.

Richard Rumancik
01-23-2010, 4:34 PM
. . . Look at in-line blowers, a lower cfm, and much lower db. They don't cost that much more and will give you the benefit of quietness.

Unless you're pushing air a great distance or through many el's (90's) you generally don't need that high cfm.

I've used a 260 cfm blower for 12 years with two different brands of lasers and never had smoke or odor problems. . . .

I doubt that a 260 cfm blower would meet the requirements that most of the manufacturers have specified in their manual. If the blower is rated 260 cfm, you may actually be only getting 150 cfm through the system which will be inadequate for a lot of applications of members in this group. I realize that you are satisfied with what you have, but I doubt that there is an inline blower that will comply with manufacturer's installation requirements.

What is the HP or watt rating of the unit you are using?

Mike Null
01-23-2010, 9:04 PM
Richard

I feel that I'm getting nearly the full rated cfm due to my installation. That's why it works so well. My shop is in my basement so if it didn't work there'd be hell to pay with the boss.

Inline blowers are available in a wide variety of specs to meet just about any application.

When I did my research on blowers I found surprisingly little expertise available from manufacturers, including laser mfrs. I was finally able to find an engineer at Kanalflakt who understood my questions and my application.

Almost everybody opts for too much power/cfm. That is a recipe for noise and high heating/cooling bills as the blower sucks the conditioned air out of your room.

Ed Maloney
01-24-2010, 4:07 PM
I hate to repeat myself. I hate to repeat myself, but the new blower is working out nicely and is a pleasure that I don't have to put up with the loud noise from my other blower. As Mike pointed out I should have spent a little more money to begin with.

Now I'm hearing sounds from my laser that I never heard before!

Mike Chance in Iowa
01-24-2010, 6:31 PM
I have been using that model 31810 for over a year now and so far, it's been running great. It seems very quiet. I have it hooked up outside and use a remote to turn it on and off. I think HF discontinued the remote. It is model 97097 and I can't find it on their site. Even though I previously had everything hooked up to a light switch, I really spoiled by my remote key chain.

Richard Rumancik
01-25-2010, 11:36 AM
. . . I feel that I'm getting nearly the full rated cfm due to my installation. . . . .

With all due respect, blowers just don't work that way. If you think of a blower using an electrical analogy, flow = current, pressure = voltage. It would be nice if the blower could maintain constant flow over a range of pressures but it doesn't. At the highest flowrate, there is no pressure left.

It would also be nice if the laser system and ducting, tubes, exhaust grilles etc provided a constant load on the system, like a resistor in a circuit. Again, it doesn't. The "resistance" of the system is zero pressure drop at zero flow, and curves upward with a "slope" depending on overall system resistance. High resistance = steep incline.

The manufacturer can't accurately spec a blower performance with one value - such as saying it is a 1200 cfm blower. But they do. That is a technical shortcut for saying that the blower provides 1200 cfm at (approximately) zero static pressure - ie nothing attached to it that would resist the air flow. Often, they will also give the other extreme - saying it will provide a pressure of 10" water. (They will not necessarily say that the flow is zero at this point.) At both these points, the blower is essentially useless. Often, people will assume that this is a 1200 cfm/10" blower. It just isn't so.

So in reality and for lack of information (the system resistance curve) you might guess that you can actually get half of the rated flow @ 0" H20 of any paricular blower. Could be better, could be worse. But you will never get the rated flow at zero pressure.


Inline blowers are available in a wide variety of specs to meet just about any application. . . . .

I think you will find that people use centrifugal blowers when you need say 400 cfm at 6" water for a laser. I don't think in-line is common at these flowrates.

The blower you are using is about 0.11hp. Many people are using .50-2hp blowers. A quick survey suggests 250-400 cfm at 6" is typical for most small lasers. The Epilog EXT requires a significantly higher volume.



. . Almost everybody opts for too much power/cfm. That is a recipe for noise and high heating/cooling bills as the blower sucks the conditioned air out of your room.

I don't know what you are basing this on. The objective is to ensure that exhaust is safely removed from the system and environment. I realize that you are satisfied with what you have for what you do. But lots of people are doing things that may be a bit more toxic. The manufacturers have set these specs based to ensure safety. I agree that exhausting high cfm will cost some money. It will also add some noise. But it will also ensure that there are no fumes in the room. I am a bit concerned that people will opt for inadequate ventilation systems to reduce noise and heating costs.

With higher capacity system, users can throttle down the vent with a gate depending on what you are doing. You could also provide cool make-up air to reduce heat/ac costs. To reduce noise it may mean relocating the blower to another room or outside.

The Penn State type dust collectors 1.5-2hp are probably a good option for people who want a lower cost option while maintaining recommended airflow. Grainger and Peerless are a couple of the more "industrial" blower suppliers.

Quiet, cheap, airflow: pick any two.

Mike Null
01-25-2010, 12:19 PM
Throttling a blower with a gate would not be my choice. I'd rather buy the right size to begin with.

More simple considerations such as the length of the line and the number of constrictions might be an easier way to calculate loss.

Another consideration is whether the blower must provide cooling for the laser which apparently some lasers require.

Not being an engineer with training in air movement dynamics I can't provide or document such an argument to your position but will say that inline blowers are available and are generally quieter than the centrifugal blowers you are recommending.

I consider noise a major problem with any equipment and sufficient reason to pay more to have a quieter product.

Remote installations are certainly a good option assuming the remote location doesn't infringe on anybody else's peace.

Dan Hintz
01-25-2010, 12:30 PM
Do any of the recent models require forced cooling, or is that something Epilog moved away from years ago?

Richard Rumancik
01-25-2010, 12:50 PM
Dan, I looked at the Zing and it still asks for 400 cfm at 6". I don't know what cools the laser on the Zing or other Epilogs.

edit: the pdf for the Zing says it has "heat controlled cooling fans".


Throttling a blower with a gate would not be my choice. I'd rather buy the right size to begin with. . . .

I agree that it is best to buy the right size - if you have 250 or 400 or 600 cfm (@6") you can throttle it down for light marking, and open it up for rubber stamps. I did not mean throttle it all the time. If you are undersized to begin with, there's little that can be done if you want to laser a material that needs more exhaust air.

Bill Cunningham
01-26-2010, 9:22 PM
Upon closer inspection the grill over the impeller blades was bent in. Fixed the grill and I'm all set. It's much quieter than the other model. Quieter than a vacuum cleaner.

Thanks again for everyone's help. I will be ordering some new brushes for the other blower so I have a back-up one.

Go back to that grid, and cut it out of your machine. It's going to give you grief in the future..
Check out this thread
http://www.sawmillcreek.org/showthread.php?t=124106

(http://www.sawmillcreek.org/showpost.php?p=1259758&postcount=17)

Ralph Tesson
01-29-2010, 11:06 AM
I think that Mike raises a valid point. With some quick math I calculate that on a 6" duct 650cfm would be reasonable; it would equate to an air velocity of about 3200 fpm which is the conveyance velocity for average industrial dust. Change that to a 4" duct at 650cfm and you accelerate up to 7500fpm, enough to fire lead shot. I would call that overkill. Also consider the cost of heating and cooling. Say your 1000sq. ft. workshop has a 10' ceiling and is thus 10,000 cubic feet. If you were actually exhausting this at 650 cfm you would be exchanging the entire volume of air every 15 minutes or so. I don't know about you but where I live that cost is astronomical. The reality is that there is always some static pressure and that static affects the actual fan speed. My company manufactures fume exhaust systems. For all of the applications that we deal with and offer a filtration system for recirculation we have found that at 250 cfm+ (with systems that have a static pressure of 90" WC) we can effectively filter everything up to and including the large heavy duty lasers. If we went with more powerful blowers we would reduce the life of the filters since we would literally be pelting them with the particulate matter. That and a slightly more powerful blower nearly doubles the cost and as well requires an electrician to wire up since we will exceed the amperage of most circuits. This cost factor isn't true for an inline fan and thus why most laser manufacturers tend to perhaps be 'generous' when specifying a minimum system. We provide many of the laser manufacturers with OEM systems and 250 cfm with sufficient static pressure is ample for most applications out there. For those of you in either hot or cold climates (although who knows with the weather that we are having this year) you might consider a recirculation unit instead of an exhaust fan, typically they pay for themselves within a year in heating and cooling savings.


Richard

I feel that I'm getting nearly the full rated cfm due to my installation. That's why it works so well. My shop is in my basement so if it didn't work there'd be hell to pay with the boss.

Inline blowers are available in a wide variety of specs to meet just about any application.

When I did my research on blowers I found surprisingly little expertise available from manufacturers, including laser mfrs. I was finally able to find an engineer at Kanalflakt who understood my questions and my application.

Almost everybody opts for too much power/cfm. That is a recipe for noise and high heating/cooling bills as the blower sucks the conditioned air out of your room.

Ralph Tesson
01-29-2010, 11:40 AM
The ducting and fan specification is all based on conveyance velocity (the speed at which the air is moving so that a given particle size will be conveyed by the air instead of resting in the duct). In a 6" duct 400 cfm is equal to a conveyance velocity of approximately 2100 feet per minute. Change the duct to 4" and to maintain a conveyance velocity of 2100 fpm you only need to move 180 cfm of air. A 5" duct would be 280 cfm. This is perhaps important to note for any of you that happen to be reducing or enlarging your ducts with a collar and some duct tape thinking that it has little to no effect!
For the rest of you who wanted an alternative for a Zing you can rest assured that you have an appropriate solution. Feel free to PM me if you have any questions about ducting and exhausting your engraver or laser system.
[QUOTE=Richard Rumancik;1323680]Dan, I looked at the Zing and it still asks for 400 cfm at 6". I don't know what cools the laser on the Zing or other Epilogs.

Richard Rumancik
01-29-2010, 4:36 PM
Yes, I agree that Mike raised a valid point pertaining to the heat loss resulting from a high cfm blower.

Mike suggested just lowering the CFM exhausted to the outside by using a smaller blower.

My suggestion to members, if heat loss is an issue, was to try to use makeup air from the outside. If the laser could be set up so that it is drawing a significant amount of its makeup air from outside (rather than 100% from the heated room) the cost could be reduced considerably.

Your suggestion to reduce heat loss is to recirculate the air through an air purification system. Although your solution will reduce heating costs, it is not inexpensive either, in terms of capital cost and maintenance of filters.


. . . . With some quick math I calculate that on a 6" duct 650cfm would be reasonable; it would equate to an air velocity of about 3200 fpm which is the conveyance velocity for average industrial dust. Change that to a 4" duct at 650cfm and you accelerate up to 7500fpm, enough to fire lead shot. I would call that overkill. . .

I don't quite follow the approach you are taking on this. Generally we start with what the manufacturer specifies for a particular laser system. Now some people may disagree with this (as Mike does) but let's follow this for a moment. If the manufacturer asks for a blower capable of 400 cfm at 6" water column, my inclination would be to try to follow the recommendation. Also, most of the small lasers are using 4" ducts although there are a few that use 6". Also, most of the lasers call for 250-400 cfm at 6" water. (There are some exceptions.)

You seem to be starting with a 3200 fpm number which is apparently a typical "conveyance velocity" for an "average industrial duct". If I was sizing the system, I would first look at what the manufacturer is asking for, and size my blower appropriately. The fpm would not be a starting point, it would be a consequence of other decisions.

I would estimate that for a blower of 400 cfm a user might be paying $0.50 to $1.50 per hour operation for energy lost up the pipe during the heating season. (Depends on climate and local energy costs.) I think that by using outdoor makeup air this cost could be halved or better. For the rest of the year, energy savings would be negligible. I am running a 250 cfm exhaust and it probably costs about $0.50 per hour of operation with no makeup air, at -30C outside temp. (This is in Canada, it's cold but electricity is inexpensive.) Sometime I will take my own advice and install a makeup air duct and get the cost down to $0.25.

I have not considered air conditioning. I have a suspicion that few shops are air conditioned but I could be wrong.

Assuming around $2K for the fume extraction unit and a few hundred dollars of filters/year some users might be able to pay for it in a few years. I my case it would take quite a number of years to save $2000 in energy costs.

Richard Rumancik
01-30-2010, 12:51 PM
The ducting and fan specification is all based on conveyance velocity (the speed at which the air is moving so that a given particle size will be conveyed by the air instead of resting in the duct). In a 6" duct 400 cfm is equal to a conveyance velocity of approximately 2100 feet per minute. Change the duct to 4" and to maintain a conveyance velocity of 2100 fpm you only need to move 180 cfm of air. A 5" duct would be 280 cfm. . . . .

Ralph, I read this a couple of times trying to figure out how to apply this info and understand what you are getting at.

Seems like you are saying that if a manufacturer asked for 400 cfm through a 6" duct, they are really asking for a velocity of 2100 ft/min. And if what they really want is 2100 ft/min, then by using a SMALLER duct, you can get the same velocity with lower cfm (smaller blower). Is this what you are saying?

If so, how small of a duct can I use? It seems contrary to what we have been told before - which is keep system impedance low by using large diameter ducting (even if larger than the laser exhaust port itself.) None of the manufacturers specify air velocity requirements; they specify cfm @ inches water column.

It would seem to me that lower flow would mean that less contaminated air is captured and exhausted.

The other point is that for laser engravers, I don't think there is a substantial amount of particulates. The main reason for the exhaust vent is for smoke and vapor. Now I realize that smoke is potentially particulates, but it is not on the same scale as conveying sawdust. A smoke particle is a few magnitudes smaller than sawdust. I really don't expect smoke particles or acrylic vapors to settle in the duct to any significant amount.

Some laser processes can be dusty, but in those cases a lot of the heavy particulates remain in the laser itself and need to be vacuumed up.