Down draft sanding box????? - Page 2 - RC Groups
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Mar 01, 2013, 06:43 PM
KOMET 44's Avatar
Guys,thanxs for all the help.I will keep you all updated on what I build.I apprciate all the imput
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Mar 01, 2013, 11:35 PM
B for Bruce
BMatthews's Avatar
Well, you guys got me started and today I ran across some high efficiency smaller particle furnace fans in the hardware store. It looks like I'm going to give up a 4 foot section of counter top and drawer cabinets below to incorporate a sanding station in my new model shop area.

More details to follow when I get to that stage. I'm just putting in a dust collection system so I can begin fabricating the kitchen cabinets that will be used in the model, wood and metal working areas.
Mar 01, 2013, 11:57 PM
Registered User
The speed controller is a good idea if using a furnace blower. Sometimes mine moves so much air (full speed) that it can be kind of a nuisance for small jobs (and the wind chill makes my fingers hurt).

FWIW: got my blower/motor from my commercial HVAC technician. Seems that there are only a few recycling places that take furnaces and all the contactors take their stuff to them. Basically, they back their trucks in the yard and kick the old furnaces off the back. Most of the time, the problem requiring their replacement is not the blower, but in the exchanger. However, many of them are 220v. My contractor replaced a smaller, 110v unit and saved the blower for me. Needless to say, his service contract was renewed at the end of its term.
Mar 01, 2013, 11:58 PM
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Joker 53150's Avatar
Originally Posted by eflightray
Does this thread give any ideas -

Cheap DIY water pre-filter for workshop dust
I just noticed this thread and you beat me to it - the water bucket method works well for my drywall sanding dust. When I get to the point where I'm creating enough balsa dust (when I give up my foam addiction) I'll probably build a collection system from 5-gallon buckets and a shop vac.
Mar 02, 2013, 01:07 AM
Registered User

sanding box

I have built the sanding box from a set of directions posted by MinnFlyer over on RCU forums. Great size at about 4 by 2.5 feet as I recall. My small 2.5 horsepower does not however provide enough suction to really get a good down draft flow. I can tell however that the dust in the air directly above the box is controlled and does not leave the immediate area nearly as much to float about the shop space. At some point I hope to get a larger vacuum to attach. The idea of a blower mechanism is intriguing as well.

What about the dust cyclone systems such as:


This seems like a reasonable way to reduce filter clogging with the fine dust we are generating.

Keep the ideas coming gentleman. We are on to something good here...
Mar 02, 2013, 10:37 AM
Bellanca Kruesair
epoxyearl's Avatar
Luckily, I'm a hoarder,and I have a furnace 'squirrel cage' blower sitting around. I use it for cooling the dog in the summer,when she's outside in the sun.

Any way, I plugged it in,and dropped a hand full of saw dust in it's intake.Holy Cow !

It pulls so much,and blows it so far.

Are we thinking of putting a furnace air filter in the box, or just blowing the sanding dust outside through the fan?
I bolted it tight against the wall,and it sets up a 'harmonics', like a poorly adjusted's obvious why they're iso-mounted in a furnace.
Latest blog entry: Rut-roh !
Mar 02, 2013, 11:15 AM
Registered User
You set them up to draw the dust through a furnace filter or 2
Mar 02, 2013, 01:07 PM
Registered User
If the filters are placed so that the motor is on the "clean side" of the air flow, then the motor should last longer, don't you think? If there are no filters and the motor is in the flow of dirty air, then it's only a matter of time before the dust takes its toll and the motor or bearings/bushings go bad.

I maximized the surface area of the filters because they get really clogged up very fast. Smaller filter surface area means lower air flow and more cleaning. My table is 30" x 72". Originally, I used four, 14" x 20" x 1" pleated furnace filters. Later, I added two layers of open foam filter media (Graingers item # 6U592) that are 1/4" x 30" x 72", and I removed two of the furnace filters. The foam stuff is convenient because it traps the big chunks of wood and a lot of the smaller stuff and prolongs the clean up interval. And when it is time for clean up, I lay the foam on the driveway and hose it down.
Mar 02, 2013, 02:57 PM
B for Bruce
BMatthews's Avatar
tdholm, the cyclone style cone filters are used to separate the chunks from the dust. The fine dust stays in the air and exits the cyclone outlet. The fine stuff either has to be filtered out with a dry or possibly wet filter or sent outside. To properly filter out fine balsa or possibly dust from sanding primer coats you want to be using a filter which is able to filter out down to 1 micro dust.

A cyclone separator is a good thing for classic wood working tools but we modelers simply don't make the sort of chips or shavings that a wood working shop produces. So a cyclone separator isn't of any worth to us.

The issue with venting the dust to the outside is that in the winter you're dumping a LOT of heating dollars into the Great Outdoors. So a filter system which keeps the warm air we paid for inside seems like a better option even if it means we need to buy new ones regularly.

Really though I expect that with knocking out the excess a few times that our $10 filter set should be fine for a good solid year unless you hook up a power sander to the system.

And obviously we want to set the fan up so it's moving the filtered air to avoid clogging it up with dust. Although with a direct to the outdoors fan this isn't a big deal.
Mar 02, 2013, 03:38 PM
AndyKunz's Avatar
What Bruce said!

Originally Posted by AndyKunz
I have a Craftsman dust collector. Simply sanding in front of the end bell is sufficient for reducing the free dust to almost nothing.
This is the unit I have (the discontinued one in the picture).
Mar 03, 2013, 02:38 PM
Registered User
mhodgson's Avatar
Here is an article from rc-universe. A little smaller than you're thinking perhaps but should give you a start.
Mar 03, 2013, 09:06 PM
A few years back I took a 3M hand sanding block(the kind with they two halves and hollow inside) I modified a small flexible attachment to the top that i hooked a vacuum hose too.Then drilled small holes down each side near the bottom to suck the dust up. It worked good. Sometimes is a bit awkward. Due to the hose being attached to it. But it worked good for early rough sanding. I sent it off to my mom, who knew a guy who was looking at a patent for me. But never got it back. But it did work well.
Mar 04, 2013, 01:32 PM
Bill Pentz is the internet dust control expert. His cyclone design removes an incredible percentage of super-fine dust. has licensed his design and sells a mini cyclone that goes in front of your shop vac. They also sell large systems.

I have both, and my shop does not have a film of dust on everything, even though I do a lot of woodworking.
Mar 04, 2013, 06:33 PM
B for Bruce
BMatthews's Avatar
Myron, the woodworking side of me started drooling at the sight of your setup. It got worse when I looked up the web site....

That's one slick system. And the control of dust down to .5micron is nothing short of amazing. They truly have done their homework to optimize the cyclone separator design to let it work as well as you found.

But you have to admit that the price, not to mention the size, will put off all but the most ardent model builders. That and the obvious requirement for a 220v dryer rated power plug to handle the 5hp motor.

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