Dust collection question

[jleiwig]

Does anyone use a shop vac with a chip seperator as a dust collector? I'm planning on running mine this way with a 30 gallon fiber drum/thien baffle I picked up as the chip seperator.

Now here comes my big scientific question. I have a ridgid professional 5 hp 4 gallon vac that currently has a 1 7/8" hose on it. I can upgrade to the 2 1/2" hose as all the outlets on the vac are 2 1/2", but I'm wondering if I need to.

Would it be better to leave the 1 7/8" hose for more suction power since theoretically little to no chips will get past the seperator? I've read that a smaller diameter hose will provide more sucking power or lift if you want to be technical.

Please opine!

 

[bradh]

The smaller hose will provide more pressure at the nozzle, but the larger hose will move more volume of air.
I have not run one but, the chip separator should help keep the bags from filling too soon. I had that problem, but I solved it a different way. I bought the big bags for the shop vac. They are intended for drywall dust and run 100 times longer before clogging.
The bigger issue you will encounter is noise. Those shop-vac's are loud. I eventually gave up on mine and made myself a proper dust collector from some scrap wood and an old furnace squirrel cage fan. It is a big improvement to be able to hear the chisel cutting and not have to wear hearing protection for the shop-vac.
The shop vac will work. Many of us started out with one.

 

[jleiwig]

The smaller hose will provide more pressure at the nozzle, but the larger hose will move more volume of air.
I have not run one but, the chip separator should help keep the bags from filling too soon. I had that problem, but I solved it a different way. I bought the big bags for the shop vac. They are intended for drywall dust and run 100 times longer before clogging.
The bigger issue you will encounter is noise. Those shop-vac's are loud. I eventually gave up on mine and made myself a proper dust collector from some scrap wood and an old furnace squirrel cage fan. It is a big improvement to be able to hear the chisel cutting and not have to wear hearing protection for the shop-vac.
The shop vac will work. Many of us started out with one.

Yup..trying to make do with what I have till I can afford better.

 

[KenV]

Think energy, fluids (air behaves as a thin fluid) -- you lose energy with friction and velocity changes. Loss of energy means it works less for the watts you invest. Bigger pipes are less friction than smaller pipes. Cyclone separation units slow the fluid (air) that then needs to be speeded up again (energy).

Since in energy, there is no free lunch, you trade off the convience of having a big container for chips for reduced effectiveness in the flow of air and the watts used. If you use smaller piping and the extra loss of the cyclone separation, you will get less from the vacuum than other choices. Will it work good enough for your purposes - probably. Will it last as long and be more quiet -- probably not.

Most shop vacs use air flow to cool the motor, and the higher energy draw for less air movement will generally be a lowered service life and more complaints (noise).

P.S. Dust collectors are high volume low pressure and are make a lot of low frequency noise too -- but do not scream like the shop vac. they all diserve to be in a separate room or outside --

P.P. S. do not believe any HP claims associated with shop vacs -- read the amps because that is a real metric that cannot be fudged by the Ad folks -- volts times amps is energy in watts -- 1 effective HP is about 5 amps 230v or 10 amps 115 volts (not mathematically precise -- an approximation)