Plans for a 5 gallon top hat

[Breadman]

Hello Everyone,

I just registered on this forum this morning.

After being a wood working hobbyist for several years and only spending a couple of hours a week in the shop, I have recently become ?semi-retired? and have been spending 20 to 30 hours per week in the shop.  And suddenly the dust is starting to accumulate everywhere!

So now instead of just tolerating the dust for a few hours at a time, I need to build a better dust collection system.  My first goal is to collect most of the fine dust from my table saw and band saw.  I?ll be starting with a fairly standard top hat on a 5 gallon plastic bucket, with maybe a few minor modifications depending on what materials I can find at little or no cost.   

Here?s a few other thoughts as I start collecting materials.  First, the standard literature on dust collecting says to maintain 4000 FPM in all the inlet piping in order to keep all the debris moving in the pipes.  Apparently that is what is required to move bigger particles straight up in vertical pipes.  The disadvantage is that high velocity in flexible hose also produces high drag.  So in the interests of maintaining the highest air flow possible through my old shop vacuum I?m assuming that a lower velocity will be adequate if I can keep the inlet hoses close to horizontal. 

Second, if the top hat collects all the larger dust particles, then I can probably get by with even lower velocity in the outlet hose from the top hat to my shop vacuum.  So my plan to date is to use some 3? flex hose that I found at thrift shop last year for both the inlet and outlet.  If dust starts collecting in a sag in the inlet hose, then I?ll revert to the standard 2 ?? hose that came with my old Sears shop vacuum as the inlet hose.

Third, based on the Paretto principle, also known as the 80/20 rule, I?m assuming that a tapered opening for the outlet pipe will be almost as good as a true bell mouth entry.  So I?m going shopping at the local dollar store in a few minutes to look for some tapered plastic tumblers that I can use with the 3? flex hose from the top hat to my shop vacuum. 

And in case anyone is wondering, the outlet from the shop vacuum will go out the back wall of the shop.  The nearest neighbors are several hundred yards away, they both work during the day, and they rarely come out to this side of their house. 

If anyone has any comments, please send them in the next couple of days.  If not, I should have initial performance observations by next weekend.  No more new sawdust until I get this thing working. 

[Breadman]

First Update

I bought two 5 gallon buckets at Home Depot this morning, but they didn?t have much of anything else useful in the whole store.  I had much better luck at the local dollar stores, and picked up a whole assortment of plastic tumblers that can serve as tapered entrances for various sizes of pipe and flex hose. 

I also found two small plastic tumblers that taper down from 3? round at the big end to 2? square at the small end, actually about 1.8? inside dimensions.  I remember that a square entrance is reported to work a little better than a round one, and the taper will give the entering air stream a burst of speed just where it enters the cyclone.  Since a faster spin should help with fine dust separation, that?s probably the best place to spend a little of that precious velocity pressure. 

Also, I?ve decided to use the tops of two plastic buckets for the top hat, in hopes of further improving dust separation.  Now it?s time to head for the shop and start construction.  I note that my first post has had eight views so far, but no one has raised any objections to my modifications, so it's time to forge ahead!

[mseries]

I' m thinking about making a 5 gallon hat too so I will watch your progress with great interest, be sure to take your camera into the workshop with you and take some photos during construction,

[Breadman]

Second update

Before I started cutting I realized that I don?t really need to cut up two of those five gallon buckets to get a taller top hat.  All I needed to do is cut the first one a little longer and position the baffle farther down from the cover.  I just end up with the baffle a little closer to the bottom of the collection bucket.  If I find that the smaller space in the dust bucket fills up too fast, I can always cut up another bucket later, or maybe even find a larger container that can be kept airtight.   .

The lid and tapered outlet are all done, I?ve got the baffle all laid out, and I surprised myself by finding all the threaded rod, nuts and washers I need right here in a dusty corner of the garage.  I?ll probably go back out and finish the baffle after supper. 

After that, the tangential inlet is the only big challenge left, but that may have to wait until tomorrow.     

[Breadman]

Third update

I started off Tuesday morning by doing a little testing on my two shop vacuums.  It turns out the newer and smaller 6 gallon Shop-Vac (the brand name) seems to move just as much air as the older 12 Gallon Craftsman vacuum, and it does so while using less power (790 watts vs. 1020) and making far less noise.  So that?s the one I?ll use with the new cyclone. 

Then I did a little redesign of the tangential inlet.  It occurred to me that if a square inlet works slightly better than a round one, then a rectangular one, taller than wide, might be better still.   And I just happened to already have the near perfect way to do that, by using one of the attachments that came with the Sears vacuum way back when.  In effect, it includes the 2 ?? hose attachment, the transition from round to rectangular, and a well shaped nozzle, all in one handy piece, and the little bend at the end fits the curve of the five gallon bucket just about right.  Sears calls it a car nozzle, and they still sell it on their website at the modest price of  $6.45. 

But then the fine print says that it is only available in Canada!  After puzzling over that for a few minutes I think I figured out why.  Sears doesn?t make much of anything themselves.  They just have suppliers and marketing agreements.  The same nozzle is probably now sold here in the Excited States under a different brand name and at different stores.  If any reader recognizes this nozzle and knows which stores now sell it, and under which brand name, please let the rest of us know. 

<IMG SRC=" http://home.gwi.net/~wbasford/Searscarnozzle2.jpg "  ALT=" Sears car nozzle ">

To attach the nozzle to the bucket I cut three sides of a rectangular hole, poked the nozzle through the hole, and then attached the nozzle to the flap.  I had planned to use pop rivets, but after spending an hour searching for the pop rivet tool I gave up and used sheet metal screws instead.  Instead of using messy adhesive or caulk to seal up the small gaps, I fashioned a boot from a plastic bread wrapper and sealed it with duck tape.  If this cyclone works well, I?ll probably peel of the duck tape and apply a better sealant in a few weeks.   

I finished the cyclone late yesterday afternoon but I can?t test it until I find a suitable 3? to 2 ?? reducer to attach my three inch flex hose to the shop vacuum.  I didn?t take any photos during construction, partly because my shop is such a mess right now.  But I took a few photos outdoors on the back of the car yesterday afternoon.  Keep in mind that this is my first try and the second one will be better.

<IMG SRC=" http://home.gwi.net/~wbasford/Searscarnozzle2.jpg "  ALT=" Sears car nozzle ">
<IMG SRC=" http://home.gwi.net/~wbasford/Topcover1.jpg "  ALT=" Top cover1 ">
<IMG SRC=" http://home.gwi.net/~wbasford/Topcover2.jpg "  ALT=" Top cover2 ">
<IMG SRC=" http://home.gwi.net/~wbasford/Topcover3.jpg "  ALT=" Top cover3 ">
<IMG SRC=" http://home.gwi.net/~wbasford/Tangentialentry1.jpg "  ALT=" Tangential entry1 ">
<IMG SRC=" http://home.gwi.net/~wbasford/Tengentialentry2.jpg "  ALT=" Tangential entry2 ">
<IMG SRC=" http://home.gwi.net/~wbasford/5Gallondustcollector.jpg "  ALT=" 5 Gallon Dust Collector ">
<IMG SRC=" http://home.gwi.net/~wbasford/ShopVac.jpg "  ALT=" 6 Gallon ShopVac ">

I haven?t been able to test the first cyclone yet, but already I?m planning several upgrades for the second one.
 The next version will use a larger debris container, probably a 15 to 20 gallon steel drum.
 Instead of mounting the outlet in the bucket lid, I?ll just turn the bucket upside down and use that for the top of the ?top hat?.  Another advantage of using the upside down bucket is that I won?t have to spend any time trimming away the outside ribbing near the rim of the bucket where the inlet nozzle is mounted.   
 Instead of suspending the baffle from the top using threaded rods, I?ll support it from the bottom, thereby keeping the threaded rods out of the cyclone.
 Instead of cutting one flap where the inlet nozzle is mounted, I?ll make two flaps (the cuts will look like an H laid on it?s side) so that I can pop rivet the car nozzle on both sides.   
 
Other notes:  It?s not easy to draw layout lines on that smooth shiny plastic, so I applied masking tape on the plastic bucket about where needed and then drew my layout lines on the tape.  I tried using my jigsaw to cut the plastic and that worked OK, but my compound tin snips leave a much cleaner edge. 

[Breadman]

Fixing a spelling error for the second photo of the tangential entry

<IMG SRC=" http://home.gwi.net/~wbasford/Tangentialentry2.jpg "  ALT=" Tangential entry2 ">

[Breadman]

Success!!!

After another trip to the thrift shop I found a suitable item to serve as the transition from 3" flex hose to the 2 1/4" inlet to my shop vacuum.  The sacrificial lamb was a plastic travel coffee mugs designed to fit into car cup holders.

An hour or so later I was able to test fire the cyclone and it works well.  I sucked sawdust out of my table saw for the next half hour and got about ten liters in the bottom bucket.  I seem to have some air leakage around the top of the collection bucket, but I can apply some thin weatherstripping there tomorrow morning. 

The next project will be rigging up better dust collection on my table saw.  I have already found some good information on that, and I'll start tomorrow.

After that I need to upgrade dust collection on my old Delta bandsaw.   It's about 60 years old.  It still runs well but has nothing but a dust chute under the frame!  I haven't run across any good information on that yet, so if anyone can suggest some good links, please post them on this thread.   

[toolmantim]

I like what you did with the Spackle buckets, as I have plenty lying around my place left over from home improvement work I do for a living. Compact size and probably the easiest transition to Top hat type collectors I've ever seen. Thanks for the ideas as I'll be trying them out myself.