Jim, do not wory about using 4" accessories with your 6" system.You will still pull the same volumn, just a higher flow rate.

 

Mike,

I disagree with you. To move the same amount of air through a 4" pipe as through a 6" pipe, the velocity would have to be 3^2*PI/2^2*PI = 9/4 as fast. Thus air with a 6" speed of 4000 ft/min would have to travel 9000 ft/min.

Drag in air varies with the cube of the velocity, so the drag is (9/4)^3 = 11.4, meaning that one foot of 4" pipe would take 11X as much pressure drop to move the same amount of air as in a 6" pipe. Said another way, using 6' of 4" hose would equate to 66' of 6" pipe.


With dust collectors we only have about 9"-12" of vacuum to deal with, so the result is less air. If I was using a shop-vac that could draw 80 or 90" of vacuum the effect would not be so pronounced.

Sorry about all of the technojargon, Mike. I had a class in HVAC design back in engineering school... in the dark ages.. B.C.... Before Computer.

I've just been researching on from what I"ve learned from Bill Penz of fine dust and shop safety. Its a really good site from someone who explains his medical problems due to dust in a technical manner and isn't trying to sell you anything. He also offers free plans for a built-it-yourself cyclone dust collector based upon his findings. I used to not be bothered about picking wood-b**gers the day after woodworking but I'm trying to change as I've become AARP-qualified!!

I may need to make my own or use 2 ea 4" runs if I decide I need the extra air.

Jim

One thing though.. it can't collect more than 100% of the dust; if 4" does it, it does it!! I just want to ensure enough volume to get the fines too.

 

Hi Jim

You can always use the floor sweeps and sanding hoods with just a little bit of rework

Grizzly.com® -- Online Catalog

==========

 

Hi Jim

You can always use the floor sweeps and sanding hoods with just a little bit of rework

Grizzly.com® -- Online Catalog

======

 

I don't worry about the big chips. Those can be picked up with a vacuum or broom and dust pan. It's the fine dust that does the damage... thus the term "Dust" Collector, not "Chip" collector. It takes a high CFM to keep the small particles air borne to get to the collector. The bag needs to be at least .5 micron or smaller to catch the really bad stuff.

 

Hi George

My system will do both,,the dust and the big chips, one bag on the top side for the dust and one on the bottom for the big chips,,,it will suck up 2 x 4 chips easy.. I will now and then need to pull off the hoses to pull out the big 2 x 4 chips...

========

 

This outfit, Nosawdust sells some. Model number 426 is a 6" universal flange that could be modified and used for just about anything.

I have an old Delta DC with 30 gal. barrel on wheels. It has a 4" hose with the exhaust side ported to another 4" hose instead of a bag or filter. Most of the chips and dust stay in the barrel with only a little fine dust out the exhaust hose. Since there is no back pressure on the exhaust side, it functions very well. I run the exhaust hose to the outside of the shop area, resulting in no worry about the fine stuff.

 

Hi Lance

Thanks that's a great link

http://www.nosawdust.com/index.htm

========

 

yep, it sure is...

 

You're welcome. Their prices for dust collection accessories seem to be lower than the mainsteam woodworking suppliers. Here's a router dust port for comparison: Dust Collection Dust Ports - nosawdust.com

 

Lance,

That's exactly the kind of thing I was looking for, except for a 6" hose connection. The 426 is a 6" flange but with a 4" hose connection.

Bob,

A little bit of rework and some more POWER! ...arg... arg... arg...

With that big sanding hood, 10" hose and the grizzley 10hp DC you could dang near suck a *basketball* through a garden hose.. and that Harley wouldn't stand a chance!

Jim

 

Jim,
I need to learn to read the original post a couple of times, I guess.

If 6" is what you're looking for, couldn't you use some of these HVAC fittings instead of paying 10x for the wood-working variety of galvanized tin?

 

Lance,

This is exactly what I am looking for. Thank you!!

Jim

 

Hi Jim- Try the link in this thread to get more info on dust collection:
http://www.routerforums.com/shop-safety/15087-dust-collection.html
This guy has more good ionfo on his site than any I've seen.
rstermer

 

rstermer,

I have Bill's site bookmarked and have read most of what's there. He gives a good commons sense approach to dust collecting. It is his advice that has led me to asking about using the native 6" hose coming out of my Jet DC1100A instead of necking down to 4" whenever possible.

Jim