DC3300 suction power?

[eagspoo]

I just got a used DC3300 and was surprised how weak the suction is compared to my cheap shopvac. It still does basically work so maybe it isn't meant to be so aggressive? Or does this thing have some issues? If so, any suggestions on how to debug and fix?

Thanks

[RonKlein]

A dust collector is not a vacuum, and does not work by suction power. It works by moving large volumes of air (cfm). Your DC3300 is probably OK. You should look for anything that might reduce the air flow, if you are having problems.

[RFGuy]

The DC3300 is anemic as a dust collector. I actually got better airflow using my ShopVac than by using my DC3300. I know because I measured it with an anemometer. How dirty is the dust hood on it? You can clean it which will help with airflow, but unfortunately this will let smaller dust particles get through that are dangerous for your lungs. This kind of filter has to have a sufficient "cake" built up inside to act as a filter, so a clean filter is actually bad for it in terms of collection efficiency. I stopped using my DC3300 because I got better results with a ShopVac + ClearVue CV06 mini cyclone. Using a HEPA cartridge and HEPA bags in my ShopVac releases far less of the harmful small micron dust particulate than the filter hoods on the DC3300. By the way, the Shopsmith 12" tall filter hood only captures down to 7μm, the 24" tall filter hood captures down to 5μm, whereas the 42" tall filter hood captures down to 1μm. In comparison my HEPA filters on my ShopVac captures down to 0.3μm.

[chapmanruss]

The one thing that can be wrong with it would be the fan itself. If damaged it will reduce airflow. Broken vanes equals less ability to move air. You will have to open it up to see if that is a possible problem. Check link below for item A to see what the fan should look like. Otherwise the the previous posts explain what you are experiencing.

https://www.shopsmith.com/service/mostf ... dparts.htm

[dusty]

The one thing that can be wrong with it would be the fan itself. If damaged it will reduce airflow. Broken vanes equals less ability to move air. You will have to open it up to see if that is a possible problem. Check link below for item A to see what the fan should look like. Otherwise the the previous posts explain what you are experiencing.

https://www.shopsmith.com/service/mostf ... dparts.htm

Would a broken vane cause some objectionable vibration along with reduced air flow???.

[davebodner]

I don't think an anemometer is a good measure of airflow. Speed of airflow, sure. But, the anemometer ignores how much air is being moved. Kind of the difference between voltage and current.

I can blow through a straw at, say, 10 mph. But, I can't come close to the airflow of your screened-in porch in a gentle breeze.

[RFGuy]

I don't think an anemometer is a good measure of airflow. Speed of airflow, sure. But, the anemometer ignores how much air is being moved. Kind of the difference between voltage and current.

I can blow through a straw at, say, 10 mph. But, I can't come close to the airflow of your screened-in porch in a gentle breeze.

Dave,

Thanks. I am not an airflow engineer so I may be wrong, but how are you suggesting I measure it differently? HVAC techs have used anemometers for years to measure airstream speed and compute airflow (CFM) using the equation CFM = FPM * cross section area of duct. I agree that I am not measuring airflow, but air speed and computing airflow based on the size of the inlet to the DC-3300 or ShopVac.

P.S. I haven't seen anyone do it any differently after watching many, many videos evaluating dust collectors, but then again YouTube isn't exactly full of experts so I am open to suggestions for how we can better quantify dust collector performance.

[reible]

Actual the only difference is that you need to get to cubic feet per minute. The device measured units of course can make this a bit of a math problem but for now lets say the meter is reading in Linear Feet per Minute. This gets us in to all measurements in feet. So if the air were measuring 10 lfm and you happened to have a circle of 1.12 feet (plus a little) you have a square foot area. So it is the 10 times the 1 foot square gives you 10 cfm.

But for reference measurements if you hook the same 2" hose to each thing your testing the difference in air flow would clearly show the difference even if it is not in actual units of cfm. The units don't even matter so if the meter reads in mph you will still see the difference between air flow and as long as you are using the same hose that number is significant.

Ed

[RFGuy]

Thanks Ed. Yeah, I agree. The units don't matter for my case because both used a 2-1/2" hose so the aperture was identical between the DC-3300 and the ShopVac, so it was a relative measurement comparison between the two. Bottomline is the ShopVac was noticeably better than my DC-3300 both in measurement on the anemometer and in my uncalibrated hand measuring suction at the end of the hose. Dave however has raised a concern with regard to an anemometer being a good instrument to use for measuring airflow...presumably because an anemometer measures airspeed, not airflow. Airflow is actually a calculated value based on measured airspeed.

[davebodner]

Since you used the same size hose, I have to admit my objection is no longer valid.

I don't know if there's anything else we're missing, any other variables. Compressability of air? Seems like I'm grasping at straws now. I want the answer to be different, but that's not good enough.