DC 4" to 6"

[Al Deutscher]

Hi Guys,

Absolutely new guy here. As most (I think) people do, I lurked for quite a while before committing to joining. Personally, I like the great attitudes and the wealth of information being shared when asked. Those are hard combinations to beat.

I built my wood-working / electronic shop (2 rooms, one door separating them) after retiring and the wife bought me a Delta AP400 Shopmaster, 1-HP @ 650 CFM, 120/240 VAC. - Had to install it and show her how well her surprise works. ;)

This unit has a 4" intake hose. I went the cheap way and used thin-wall PVC (white) throughout, building my own Blast gates out of wood. Everything works fairly well, except it is all 3".

After reading every thread I could all the way back as far as I could go, I could not find any reference to my question, which is:

Having a 4" intake hose on the DC, what can I expect if I use thin-wall 6" line throughout for my main run? Would I lose too much suction power, etc.?

All Blast gates will be 4" after which some will be reduced to 2 1/2" and 1 1/4" because of the equipment. My Radial arm saw will have the 1 1/4" on the dust guard above the blade and a 4" collector area at the back of the saw.

Total main run will be no more than 30 feet and I plan on seven 4" Blast gates so I don't have to change out hoses all the time. Just open the correct gate. - L A Z Y - :)

[Rick Potter]

First of all welcome to the creek. Lotsa nice people here, and no shortage of opinions, so here's mine.

If the intake on the DC is 4", it will probably be best to keep the main ducts at 4", make them short as possible, and even use one drop for more than one machine with quick bell connectors. This way you will have less drops, less loss, less money.

Rick Potter

[Mitchell Andrus]

Welcome to the 'Creek. You'll want the velocity of the air steam to stay high. I'd stick with 4" on a 1hp system. 6" will likely cause heavier particles to drop out and close the pipe down to about 4" anyway.
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[Cliff Holmes]

Keep in mind that a 6" pipe has a cross section that's 125% larger than a 4", so the airspeed in the 6" duct will only be 45% of whatever your DC can pull through the 4" inlet. Since you want to keep the airspeed at 4000 feet per minute (to keep larger chips from dropping out), you'll need to get 9000 fpm (102 mph!) at the inlet. And that's assuming 100% efficiency in the ducting, which of course isn't possible.

[glenn bradley]

Welcome Al. I believe you've gotten the drift already; a 6" pipe of any length would hold more air than that machine is designed to move. I have had the same machine for about 5 years. Due to my tool positions I was able to build a manifold of sorts right next to the AP400 that gated 3 short runs to 3 machines, all within 10 total feet of duct run. That length was still a bit much and performance was hit but, not too bad.

I added an American Fabric Filter oversized 1 micron bag up top and went solid on the lower bag. This improved the DC so much that I kept the machine when I got my cyclone installed. It still only services one machine at a time, via a 4" hose (as designed) but has no trouble keeping up with my jointer or planer. I a quick connect fitting on the end of the hose and move it from machine to machine as required.

[Al Deutscher]

Hi guys,

Thanks for the great information. I thought, what you guys said, might be the case, but I had to run it by anyway. I had this way-out dream that when I upgrade DC's, I wouldn't have to upgrade the piping again. I guess I can forget that idea. It's better to know now than get mad at the new DC when it doesn't perform up to standards with the 4" piping.

Thanks again guys. Life is so much better when a person has good answers to work with.

Al