# 4" vs 6" dust collection



## jimmyjj (Nov 20, 2011)

I need to rerun much of the duct tubing in my shop. It is all 4" today, but was thinking of making some of the new main trunk at 6". However, the main trunk will not be able to run all the way back to the vacuum at 6". Ie, after the 4" connections from the shop machines, there will be about 20" of 6" trunk tubing before it will have to down convert to 4" to navigate the last 20" to the vacuum). Do you all think this makes sense to do, or just go with all 4"? the vaccume i am using is the HF unit.


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## DIYaholic (Jan 28, 2011)

Only switching out the "middle" of the runs to 6" won't improve performance. I wouldn't waste my time with that non-upgrade.


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## gtbuzz (Sep 19, 2011)

Won't do a thing. I'm also not sure the HF is capable of supporting 6" runs. I'd leave everything as-is.


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## shawnmasterson (Jan 24, 2013)

you've got to have serious power for 6" lines. anything under 3hp and a 14" impeller really needs 4" to perform its best.


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## wapakfred (Jul 29, 2011)

+1 for the waste of time/effort/money.


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## crank49 (Apr 7, 2010)

The 6" section will fill up with dust over time to equal the size of the 4" connected to it. Don't do it.
The HF will work fine with a 5" pipe, or a 4" and a 3" connected at the same time. 
A 4" reduces the volume somewhat, but not too bad with a short run.
A 6" reduces the velocity somewhat, but would help a long run.
Don't run 6" pipe vertical with the HF as you may have drop-out.

edit. For what it's worth, I add that a pair of 4" pipes would have about the same characteristics as a single 6".


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## jimmyjj (Nov 20, 2011)

thanks all


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