Boxing in Blower

[Jared Greenberg]

I am having problems with the blower (as it is not not very well boxed in) blowing dust around in the room where the laser is.

Any suggestions on what works best to minimize this. I have though of building a cardboard box to go around it or some sort of plywood box to contain the air that is turning up the dust.

[Craig Matheny]

Where is the air coming from if it is vented out side the only air should be from the cooling vane inside the motor

[Jared Greenberg]

Its almost like it comes out by the on/off switch. Maybe I should look at the flange again.

[Craig Matheny]

There should be some air coming out around the motor somewhere but I would not think it is so much to kick up dust. If you box it in it still has to have air to cool so air in air out dust will follow maybe a pad or something around the unit that is easy to keep clean.

[David Fairfield]

Your best option, if at all possible, is to place the blower unit outdoors, at the exhaust end of the duct. That way you only have negative pressure inside the ducting, which means no smoke leaks into your shop area. Also reduces noise and eliminates your problem with dust blowing around. You need to put it on a firm footing and protect it from the elements of course. You can DIY a shelter, or get a plastic dog house, or child's play house. Not too expensive.

Dave

[Jared Greenberg]

Your best option, if at all possible, is to place the blower unit outdoors, at the exhaust end of the duct. That way you only have negative pressure inside the ducting, which means no smoke leaks into your shop area. Also reduces noise and eliminates your problem with dust blowing around. You need to put it on a firm footing and protect it from the elements of course. You can DIY a shelter, or get a plastic dog house, or child's play house. Not too expensive.

Dave

Dave or anyone else have a picture of this by chance?

Right now in my set up, the blower is below the table that the laser sits on and we installed a dryer vent to the outside when we built the shop. One duct is hooked up to the laser the other to the vent out side.

I felt the air last night and it is coming from the motor area.

There is a wood shop located on the other side of the finishing area, it is seperated by a door, but dust is still a little bit of an issue.

[Mike Chance in Iowa]

Jared,

I made a quick shelter by using a cheap plastic storage container that was large enough to hold the blower & the remote control unit. It was fairly easy to cut 2 holes in the sides for the in/out ducts. When I need to do any maintentance, it's quick & easy to unsnap the lid and lift the blower out. I glued some cheap, plastic blast gates over the holes to make it easy to secure the duct hoses and keep bugs out if necessary. I would go out and take a picture for you, but an active swallows nest is above it right now and as you can all guess, the container looks really gross right now with all the droppings on it!

[Tony Lenkic]

Jared - Here is ULS suggestion on blower installation.

[Jared Greenberg]

Thanks...

So for those of you that have it outside:
Are you just using a plug in on an outside wall?
And what about frigid temps in the winter for the blower being outside? Is the box you use insulated?

[Richard Rumancik]

I doubt that you will have problems starting an electric motor at -40 degrees C. You could look at the motor specs and see if you can get any info. Often they will have maximum operating temperatures and not spec a lower starting temp. The only issue is the initial start-up. If the bearing grease was heavy I suppose it could lock up but I have my doubts that would happen with most motors. Once it starts, the bearing temp will rise very quickly. If it is a capacitor-start motor, I suppose you could change the capacitor value a bit if you needed some extra kick on start-up for winter operation.

Insulating the box would only help if it was also heated. In -40 weather an unheated box will be -40, insulation or no insulation.

I have my blower in a garage attic and have not had any problem starting in winter. In winter the attic will be at the same temperature as the outside air (at least in the morning.)

[Jared Greenberg]

I have my blower in a garage attic and have not had any problem starting in winter. In winter the attic will be at the same temperature as the outside air (at least in the morning.)

This is interesting...I assume you just have it blowing in the attic and not venting outside?

[Tony Lenkic]

Mine is also in garage attic close to external wall. From blower I installed short pipe to the vent. Something you would do for range hood.

[Jared Greenberg]

Mine is also in garage attic close to external wall. From blower I installed short pipe to the vent. Something you would do for range hood.

What vent or did you install a vent to the garage roof?

I'm just having trouble picturing it.

[Richard Rumancik]

This is interesting...I assume you just have it blowing in the attic and not venting outside?

No, I vent to the outside and I would not recommend venting to any part of the attic of a building as there is too much risk of fumes escaping back into the building.

The advantages of placing in an attic are:

Noise is removed from the shop area
Most of the duct is under vacuum (low pressure) not high pressure
No physical space is lost
No need for separate box outside
The disadvantages I see are:

You need to ensure attic temperature is controlled. Most motors are rated 40C ambient but my garage attic gets to 50C in summer. I have a 50 cfm blower bringing in fresh air into the motor enclosure in summer, and a powered vent on the roof in summer.
Servicing is more difficult
You should have a high-temp cutout switch on the motor to prevent operation if overheated.
Overall I am happy with the implementation I chose and have had no problems with it.

[Mike Chance in Iowa]

So for those of you that have it outside:
Are you just using a plug in on an outside wall?
And what about frigid temps in the winter for the blower being outside? Is the box you use insulated?

I originally ran an extension cord since the external outlet was on the other side of the building. It worked, but it was not the most efficient set-up. Now I have an external outlet on the building right next to the blower.

I have not modified my plastic storage container other then cutting holes for the vents. I have not had weather-related issues, but I can see that over time, the plastic will become brittle and crack from exposure to the sun. So far, it's held up 2-3 years, but I do put potted plants in front of it to not only shade it a little, but to not draw attention to it since it's not the most attractive setup. When the new dream shop with living quarters is finally built, I plan to enclose the blower with siding that matches the building and put a hinged lid on top so I can easily access it.

[Tony Lenkic]

See these pictures for an ideas.........

http://www.imperialgroup.ca/generalventing.cfm?c=231

[Dee Gallo]

Jared,

You might find this thread interesting: http://www.sawmillcreek.org/showthread.php?81763-Dust-Collector-Noise&highlight=laser+exhaust

[Jared Greenberg]

Jared,

You might find this thread interesting: http://www.sawmillcreek.org/showthread.php?81763-Dust-Collector-Noise&highlight=laser+exhaust

I do like the idea of going into the attic, then venting outside. I don't like the idea of putting holes in the roof.

I think I will give Dee's suggestion/picture a try, looks simple enough and there's already an opening in the wall where we're venting out of now.

[Dee Gallo]

I do like the idea of going into the attic, then venting outside. I don't like the idea of putting holes in the roof.

I think I will give Dee's suggestion/picture a try, looks simple enough and there's already an opening in the wall where we're venting out of now.

Jared, as a follow up, you should know that after 4 years of very serious weather (we don't see the grass from Thanksgiving to Easter) , the whole thing is doing well BUT - the silicone I used to seal the blueboard box didn't hold up well enough, so I put a tin roof A frame over the whole thing to provide more snow protection. I think the snow weight might have flexed the board enough to stretch the silicone. You might want to use some construction tape, like Parsec or GE or Zip System.

cheers, dee

edit: but whatever small amount of moisture that might have gotten through did not get inside the plastic box so maybe that was not really needed... I'm just OCD. When I opened it, everything was dry as a bone and as clean as when I first closed it up.

[David Fairfield]

If you have an outdoor electrical outlet, you might be able to use it for the blower unit, if you attach a wireless or remote on/off switch to it. That way you can place your on/off switch next to the laser, even if the wall switch for that outlet is far away.

While I am on the subject of on/off switches for the blower, I got a foot pedal on/off switch for mine. Its great, saved me a lot of awkward reaching over to the wall switch.

[Jared Greenberg]

There are a couple of plug ins on the outside of the shop, but of course nothing close to where I would need it. My plan is to run it back into the shop and plug it in, inside the building.

For those of you that live in frigid climates in the winter months that have the blower outside, do you do anything to prevent the cold air from coming into the laser? With the set up right now (blower under the laser and vented outside) I have a blast gat to "stop" the cold air. Not sure if it does anything but makes me feel better at least, and cold air doesn't seem to be in the laser. It could be as simple as the the warm air inside heats up the cold air coming in.

[Richard Rumancik]

I would say the blast gate is probably fine. You could add a gravity-operated damper at the exhaust end I suppose, but you have to ensure it is a type that can't stick open or closed.

In residential applications, kitchen exhaust fans and bathroom fans often have a gravity/flow operated damper close to the blower. If the damper was in the exhaust pipe on the roof or gable end it is harder to service and there is more likelyhood of it sticking expecially with snow/ice accumulation.

If you use only the gate, you need to remember to close it at the end of the day. You are concerned about cold air coming in, but it can work both ways - on a windy day it can pull air from the room, sucking out all your heated air overnight while the furnace/heater is running overtime to keep up.

[Dee Gallo]

Rich is right, I used blast gates and they work well. If I forget to close one, you can really feel the cold coming in. Closed, you feel nothing. Mine are about 3 feet from each laser outlet.

[Jared Greenberg]

So I bought a plastic container and a dryer vent, cut some holes in the container so the blower would sit in it and so I could pipe stuff in and out. Well what a world of difference that made. It took me about 45 minutes to do. I ran the laser for about 30-40 minutes and zero dust in the finishing area.

I will have to fill some of the gaps for weather, but not a huge deal. I will end up boxing it in with something else (for added protection), and then probably paint it (for asthetics).

Thanks to all for their advice and input!

[Richard Rumancik]

If your blower motor is in the airstream you should be okay thermally. But if the motor is not cooled by the exhaust air stream, then you have to be careful not to let the ambient temperature in the box exceed the motor spec (probably 40C or less). On a hot day, closed box, with motor running, it could get pretty warm in the box.

[John Frazee]

I installed my exhaust blower outside under a little shelter. I bought the green dust collector from Harbor Freight a few years ago. I bought 4 inch white PVC pipe and elbows to plumb it. The dryer type flexable hose has too much restriction in it. To turn on/off the exhaust is by a type of extention used for Christmas trees. On one end it just has a rocker switch and the other end has a male & female plug on it. I plugged the dust collector into the the female part and then plugged the male into the surge protector. I can turn on the exhaust without leaving my seat. I did the same set up with the air assist. I will try to add photos.206392206393

[Richard Rumancik]

The idea for a remote switch is good, John, but doesn't the blower have a ground pin? Seems the Christmas tree extension plug is missing the gound lead. Also be sure that the switch can handle the current of the Harbor Freight blower. One way or another the blower assembly must be grounded for safety. I have some concerns that this switch is really suitable for starting a 2 HP motor. An incandescent load (e.g. tree lights) does not have such an inductive kick on startup as an electric motor, and probably can get away with a light-duty switch. Might be safer to use the existing circuit to trip a relay to start the blower.

[David Fairfield]

Agree with Richard's concerns. Again, my recommendation is for the HFT foot pedal on/off switch for the blower. Its grounded, and stays out of the way.

[John Frazee]

The idea for a remote switch is good, John, but doesn't the blower have a ground pin? Seems the Christmas tree extension plug is missing the gound lead. Also be sure that the switch can handle the current of the Harbor Freight blower. One way or another the blower assembly must be grounded for safety. I have some concerns that this switch is really suitable for starting a 2 HP motor. An incandescent load (e.g. tree lights) does not have such an inductive kick on startup as an electric motor, and probably can get away with a light-duty switch. Might be safer to use the existing circuit to trip a relay to start the blower.

I have used this for about two years without a problem. I may be wrong but I think the switch only activates the plug. All the current for the blower may not run through it. I have never had anything heat up in this setup. I have even thought about seeing if I can get a remote control I could clip on my belt to activate the switch. There are times that I may be really busy 50 feet away from the laser area but have to return just to turn off the blower. The others that work here do not seem to think the blower is pulling the HVAC out of the building. Our bills are extremely high and think I would benefit with the remote, if it's possible.