Questions about dust collection planning

[mojoel]

I'm in the process of setting up a new workshop (about 25' x 25' in an outbuilding), and want to plan for a DC system. I've always just hooked up a shop vac to the tool I was currently using, but would like to do a central DC system in this shop. I've read lots of threads on this and other forums about DC systems, but I've never seen anybody refer to a book or website that explains the things you need to consider in laying out the DC. I'd like to avoid some of the mistakes I usually make when I jump into a project I don't really know much about. Any help would be muchly appreciated. Thanks, Joel

[LarryG]

The standard.

Bill Pentz will tell you way more than you will ever want to know about dust collection:

http://billpentz.com//woodworking/cyclone/index.cfm

Pentz has some rather severe personal respiratory problems, so he takes what many consider an extreme approach to his subject. Also, his site is dense with information and can be a little (or a lot) overwhelming. But he knows his stuff. You can bet the mortgage that the info you seek is there, somewhere.

[mojoel]

Whoa baby! I just spent some time looking at Bill's site, and while its interesting, I can't believe many hobbyist woodworkers put than much effort into designing a DC system. While I appreciate his health concerns, I'm likely as not going to be smoking a cigar while I'm in my shop, so obviously I'm less concerned about keeping the air perfectly healthy than I am about keeping sawdust under control and keeping the shop fairly clean. Are there any basic rules of thumb to use in laying a system out so that its reasonably efficient?

[cgallery]

There are books on the topic, I'm sure I've seen 'em at Woodcraft and/or Rockler. Maybe also check your local library or Amazon.com for titles. I also know that my local woodworkers club (of which I'm not a member) has a library of books they loan.

Thanks,
Phil

[JR]

Are there any basic rules of thumb to use in laying a system out so that its reasonably efficient?

Use solid pipe for as much of the system as possible. Leave higher-resistance flexible hose, if necessary, for the last little bit to connect the machines.

Install a blast gate for each machine, located as near the main run as possible.

Use the largest diameter pipe for the backbone that you can afford. I use 4" pipe in my 12'x20' shop. You might want 5" or even 6" in yours. Step down to smaller diameters for branches and to 2-1/4", if necessary, right at the machine if possible.

Plan on a dedicated 15 or 20 amp circuit for the DC. They're power pigs.

I get it on the cigar, I really do, but consider a 1 micron or better filter mechanism. The fine particles floating around your shop are not going to improve your chances of avoiding lung problems. It's a small upgrade price compared to the total project cost.

Have fun,
JR

Oh, I forgot, use wye connectors, not tees. Use long radius elbows, not short. The main objective is free-flowing volume of air, unimpeded by turns, ridges, constriction, etc.

[rickd]

hi mojo,

i know how you feel - i read bill pentz' site and it scared the heck out of me too - looked to me like nasa preparation for a space launch

anyway, i agree with everything jr said - completely. i installed my dc system about 6 weeks ago and i did it exactly like jr said - 4" pvc pipe runs, blast gates connected near the main run to each machine, wye connectors, limit the 90 degree elbows and short runs of flex to each machine. mine works just great.

here's a picture of my dust collection setup - it might help you visualize what i'm talking about:



hope this helps a bit - good luck.

[mdutch]

While I appreciate his health concerns, I'm likely as not going to be smoking a cigar while I'm in my shop....

Aw man, you're missing the second best part of having your shop in an Outbuilding!!!

[JimD]

I have a 1hp Delta DC with upgraded bags. It works pretty well in my irregularly shaped 400 Ft2 shop. It is a little weak for the planner. I have a blast gate at each machine. I have solid 4 inch PVC drain pipe - the thin walled stuff sold for use in your yard, not your house running through the ceiling to get close to the machines. I use flex pipe as the final connection. I have about 10 feet going to the BT and to the planner. For the BT that is not a problem but it is undoubtedly part of my issue with the planner.

To the good suggestions from JR, I would add that the pipe diameter is partially a function of your DC size. I do not think I would have adequate velocity with bigger than 4 inch pipe with my little DC. I would also add that the little plastic blast gates are prone to plugging up and you can make better ones from wood scraps. Locate the DC somewhat centrally to minimize pipe runs. FWW had an article where they considered DCs of 1 1/2 hp as portable and unsuitable for a fixed installation. My experience with a 1hp DC is inconsistent with that. I think a 1 1/2 or 2hp DC should be plenty for your shop. You need to plan to use either the better 1 micron bags or a cartridge filter. I also have a homemade air filtration device (a modified box fan with a electrostatic furnace filter) located near the DC to get the fine dust that comes out of the bags. A remote control would be nice but if you put an outlet on 2 or three light switches controlling the DC you can minimize the walking. Since I have to open and close blast gates anyway, the walking for the DC switch actually is not too bad.

Jim

[vaking]

Penn State Industries offers ductwork planning service for $100 but the price may be refundable if you buy your DC and parts for ductwork from that place. Here is the link:

http://www.pennstateind.com/store/ductdes.html

[meika123]

If I remember correctly, Grizzly has a booklet that explains pretty well the basics of laying out your duct work for the DC. I think I may have a copy here. If so, I'll scan it and email it to you, if you so desire.

Dave in NC

[mojoel]

Thanks for all the feedback guys. What about grounding? It seems I read somewhere that if you use plastic ducts, you need to ground to avoid static buildup. Is this an issue?

[mojoel]

Oh, and Dave, if you can lay your hands on that Grizzly pamphlet, and its not to much trouble, I'd appreciate seeing a scan of it.

[fischermh]

A friend of mine is building a shop next to his house. He is going to run all the dust collection in the floor before he pours the cement.

[jdoolitt]

There is a great book by Sandor Nagyszalanczy called "Setting Up Shop" in which he has a great section on Dust Collection. Highly recommend this book. In fact - I think Sandor has a separate book just on dust collection - but the sections in Setting Up Shop are pretty complete. He covers everything from using a central DC, to portable chip collectors, shop vacs, air filtration devices and shop ventilation.. all of which can play a part in DC solutions.

I am towards the end of setting up my DC in our 3 car garage. I used a lot of the advice gathered on this site and others and the book noted above. I have the HF DC, ran 4" S&D pipe, used S&D fittings and the HF accessory packs (2) to get my central DC mostly setup. Mostly? Well -- I ended up spending a lot of time, energy and $ on fittings to complete the system.

G'luck with your shop setup --

joe

[LCHIEN]

Principles of Dust collection

If you read Bill Pentz's site then you should have a good grasp of the principles of WW dust collecting.

One you need good filtration
two you need adequate velocity to keep the particles suspended
three you need adequate CFMs to keep the velocity
and four you need adequate diameter ducting to reduce pressure loss from restrictions to keep the CFMs up to keep the velocity up.
and five you need to reduce an or all other restrictions possible to keep the pressure loss down and CFM loss down.

So that means you need as much CFM as you can afford, as big and smooth ducts as you can get. And 0.5 to 2 micron bags or canister.

Duct grounding is largely a myth, it won't explode or catch fire. You may get a static shock once in a while. To reduce chances of that ground the machines but forget grounding the plastic ducts, the electrical capacity is so low as to present no real hazard even if it does shock you.