PDA

View Full Version : Dust collector



gld
01-17-2007, 03:28 PM
I want to build a dust collecting table to do sanding on using this type of collector.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94029 (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94029)


This unit is rated at 914 cfm. lets say my table is 24" X 36" ,,,,,,,,holes spaced 3" ...

How do I calculate hole size???????

Or maybe I will need slots instead of round holes??????

Help

bcreely
01-17-2007, 04:13 PM
Do a Google search on home shop dust collectors. There is much danger in using ones that don't vent to the outside. 35 micron particles wreak havoc on your lungs.
Bob Creely

Your Old Dog
01-17-2007, 04:21 PM
Do a Google search on home shop dust collectors. There is much danger in using ones that don't vent to the outside. 35 micron particles wreak havoc on your lungs.
Bob Creely

I think that problem is even compounded by the fact that not only does the vacuum suck, but it also blows. That meant I had to work with my garage door down in order to make the dust collector work more efficieantly. When I opened the garage door it did almost nothing, when closed it worked very well. Don't know how much of an overrated system one would need to vent outdoors. Not trying to cry wolf here but he's right, the real danger is in the crap the collector passes and not nearly so much as what it traps. The cyclonic collectors are supposed to be superior but of course more money/effort.

Maybe we need to keep some perspective! You gonna be sanding 8 hours a day or just occasionally, in which case your suggested setup might not be lethal !! :D (after all, people been sanding since the beginning of time!)

Mcgyver
01-17-2007, 04:57 PM
doesn't help your question much, but i agree with Bob. unless its to contain mess and you are wearing a proper mask, don't bother as it will just creat more airborne particles. same with those expensive ceiling mounted unit, they'll take the dust of the air, 5 hours later. vent outside or spend big bucks for the Felder

have you read Bill Pentz's site? gives a lot of info

http://billpentz.com/woodworking/cyclone/Index.cfm

I'm not a doctor, but Bill's info and logic seem solid. If he's right, and I think he is, because there is not an easy or cheap solution to this problem, most hobby wordworkers have either choose denial or aren't aware of how bad these units are. YOD i agree in a sense, but i figure someone looking at a dust collector is doing enough volume for it to be an issue, or at least is concerned about the health risks - yet most diy products fail at this. Average Joe, not knowing anybetter, is concerned about health risks and buys the dust collector thinking he's done the smart thing, that he's addressed the problem. meanwhile damage his lungs goes unabated. The product shouldn't be sold without making it clear that it keeps the shop marginally cleaner but does nothing to protect the user. kind of reminds me of the evil tobbaco companies promoting the idea that the filter made all ok , well ok maybe not that bad but close. :D evil harbour frieght & busy bee.

jdunmyer
01-17-2007, 09:17 PM
The dust collection system in my wife's woodshop consists of a bunch of 4" PVC going to a 6" blower that exhausts outside. No problem with inadaquet filtration. :-)

See: http://www.oldengine.org/members/jdunmyer/woodshop/index.htm there's several pics of the setup.

Those sanding tables aren't quite as simple, nor do they work as well as they appear: you can't simply set your work on the table and sand away, expecting all the dust to be sucked up. There's not nearly enough air flow with most to even come close. It helps a lot to cover the "extra" holes so as to increase the air velocity in the remaining ones, but the best solution is some sort of shroud around the sander that has a suction hose attached to capture the dust as it's being created.

TECHSHOP
01-18-2007, 03:53 AM
gld:

Most of the "shop" made sanding tables I have seen use 1/4" pegboard with a chamfer added to the holes. "Inside" the box you will need to create a "suction geometry" for the airflow (it's not just an empty box, but it ain't rocket science, just trial and error to get "working" collection).

The other end, output side, is really important. I am not sure if they have a filter specific to your machine, but you should be able to adapt something. I go here as a customer:

http://www.wynnenv.com/index.htm

You may also need to "raise" the perimeter to help contain the dust and, of course, the sander should also have some dust collection off the "top".

gld
01-18-2007, 10:55 AM
IF i build it, the bet solution would be too vent outside. That means cold outside air is going be drawn into the building and it's blowing my heat out(Don't like that)


Think i will just keep on using my shop vac to clean up. When the weather warms up I'll just go outside to do sanding.

Thanks all for your input.

Your Old Dog
01-18-2007, 12:14 PM
Gary, If you're good with sheet metal you should consider making a cyclonic unit for the dust collector you are looking at. There's plenty of articles on some of the wood working forums. Many guys have made their own cyclonic units and they work much better than just the filter alone. This all assumes of course that you have enough of this work to justify the time spent to fabricate one.

andy_b
01-18-2007, 12:32 PM
I want to build a dust collecting table to do sanding on using this type of collector.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94029 (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94029)


This unit is rated at 914 cfm. lets say my table is 24" X 36" ,,,,,,,,holes spaced 3" ...

How do I calculate hole size???????

Or maybe I will need slots instead of round holes??????

Help

i have a similar "dust collector". as has been pointed out, they are more of a "woodchip collector". they certainly don't filter out small particles of dust, as would be generated with sanding. to do that you need an air filtration system. the easiest way to do it is to vent the air outside. :) of course, in the winter this also vents your heat outside. you can build an air filter using a small blower motor and a filter box that contains a bunch of air filter elements. if you use elements that can be cleaned (either with water or just banging them on a wall outside) than it isn't a bad way to go. i have a blower and you can get filters online, i just haven't got off my butt to build one (as with most of my projects).

andy b.