Another dust seperator question

[Marshall Harrison]

For those runnig a trashcan lid seperator - what brand/type of can are you using? Will one of the heavier plasic cans work for a 2HP DC drawing 1600 cfm?

Need to purchase one tomorrow so looking for answers before I get the wrong thing.

[terry richards]

Hi Marshall,

I have the same setup, 2 hp with a 30 gal metal trash can lid separator. Once the system if fully revved up, it is difficult to lift the lid off the trash can. The bottom of the metal can warps up every time until it gets about half full. Then it's time to dump it. I would be concerned that the plastic trash can would not stand the suction. If the sides cave in, the top lip would probably not hold the seal.

Also, I have a 3/8" thick weatherstrip glued to the bottom of the plastic separator lid. Make certain you use good glue, not just the peel-off stickem that comes with the weatherstrip. You don't want the DC to suck the weatherstrip into the impeller inlet.

tr

[Charlie Plesums]

The metal can from Home Depot fit and works fine, and is significantly different size than the plastic cans. Further, since there is suction in the can, I would worry more about the plastic bending in. (My DC has the same specs as yours).

[Jim Becker]

The single limitation for the trash can separators is that you are restricted to a 4" connection...anything larger will prevent the material from dropping out of the stream. For this reason, many folks will dedicate the separator to the planer (and/or jointer) inserted in the drop so that the rest of their system doesn't have to be down-sized. If you do use the separator, be sure that you have a "perfect seal" between the lid and the can. Any leak, no matter how small, will cause blow-by and will be frustrating.

BTW, that "1600 CFM" figure for your 2hp DC is, umm...overly optomistic. The 2hp Commercial cyclone system I use has a max CFM of 1405 and that's at only 1" SP--more realistic performance is in the 600-800 CFM range max for 5" and 6" drops with a good hood and duct design and typical SP of 4-7" of water. Most manufacturers/vendors only give "free-air" figures (no filters/no duct work) and even those are suspect since they don't provide fan curves. Real-world performance is generally no more than half the rated figure and the duct work also affects it. For example the maxium CFM that you can get with 4" hose or duct is about 350 CFM...that's all the air that can physically fit in the space at the typical velocity of flow.

[Marshall Harrison]

Thanks guys. It looks like I'll be picking up a metal can.

Jim - thanks for the info. I figured that the CFM is kindof like the HP ratings on motors - optimistic. I do figure that the higher the HP/rating the better off I am but didn't expect it to be too accurate. I'm only running one machine at a time and since my biggest dust maker is the TS I'm not sure if I'll be hooking it up to the seperator. I mainly got the seperator because I wanted a floor sweep and I wanted to keep things from it out of the impellers.

Question - how would I go about measuring the CFM without resorting to some expensive tool or guage?