Another newbie with questions

[jgt1942]

spes - following is an image of my converted Grizzly (2 HP unit) with the Thien Top hat. I like the idea of using plastic for the side thus I can easily see when I have a problem, twice I have overfilled the Brute can. While the unit seems to work without issues as I move to the next phase (see below) I may be on the edge of being too small.

I suggest using a 20 gal Brute, a full 32 gal is heavy for us old folks.

As you can see I have a portable unit but after using it for about a year I'm going to install fixed runs. Moving it around the shop and connecting to a port on a tool has proven to be a royal pain for me. (for new effort, see http://www.jpthien.com/smf/index.php?topic=1168.0)

The collection you get with the Thien is about 99%+ thus I personally don't think you gain much by adding additional filters on the exhaust.

I used a 4" port on the input of my Top Hat and don't see any issues, however the advice by retired2 is right-on.

[retired2]

spes - following is an image of my converted Grizzly (2 HP unit) with the Thien Top hat. I like the idea of using plastic for the side thus I can easily see when I have a problem, twice I have overfilled the Brute can. While the unit seems to work without issues as I move to the next phase (see below) I may be on the edge of being too small.

I suggest using a 20 gal Brute, a full 32 gal is heavy for us old folks.

As you can see I have a portable unit but after using it for about a year I'm going to install fixed runs. Moving it around the shop and connecting to a port on a tool has proven to be a royal pain for me. (for new effort, see http://www.jpthien.com/smf/index.php?topic=1168.0)

The collection you get with the Thien is about 99%+ thus I personally don't think you gain much by adding additional filters on the exhaust.

I used a 4" port on the input of my Top Hat and don't see any issues, however the advice by retired2 is right-on.

A 32 gal is not only heavy, but by the time I transfer the contents to a trash bag, I've spilled half the drum contents on the floor. 

[Colin]

I am a complete newbie here and have been lurking around for the last few days looking at stuff.   I am thrilled to find this site because I like doing things myself.  Everyone's stuff looks pretty cool and my hat's off to Phil for starting this project in the first place and then sharing it with everyone.

I am planning to build a separator that sits in a garbage can for space reasons and because it looks easier.  Not lazy but not a lot of time either.

Here is what I am planning.

• The DC is a 2 hp King Canada dust collector with 4in inlet.  1200 CFM is the listed flow but we know that is likely high.


• I plan to use a 4" corrugated hose rather than piping because i simply don't have the space to run the piping the way the (small) work shop is set up. When I need it I will uncoil the hose and run it to the work.


• I plan to use a 16 inch dia by 29 inch high galvanized garbage can which is 25 US gallons.  It has corrugation on the sides. 



• I want to to collect fiberglass dust created by grinding fiberglass surfaces to clean them up for final assembly.


• I will be using 3" ABS plastic fittings because the hose fits on the hub well.  This will mean a 3" ABS 90 will be used to turn the intake flow to the Thien baffle.


• I am reasonably good with fiberglass and have made baffle out of fiberglass.   If I make a mistake I pour another one out of the can, throw in some chop and I have a new one.  Its about 1/8 inch think

Questions.

• Is the fiberglass baffle an okay material? If not I have some 16 ga stainless steel I can cut up but this stuff is a bit hard on tools and hard to cut.


• I have ground the corner of the 3" 90 hub on a bit of an angle so I can turn it towards the outside.    I assume this is the correct thing to do because it forces the flow to the side immediately.  How much should I turn it out.  1/2 the diameter of the hub?


• I can make the inlet elbow be tight to the top or drop it down.  Which is better and if I drop it down how much.  It looks like this is what Phil did ...  .  The 90 is 3" ID but the hub is 4" OD.


• I can make the inlet elbow touch the top of the baffle and from Phil's original design again it looks like this is what he did.   I read somewhere here that that was not a good thing and that there should be some clearance underneath. How much?


• Because I mostly want to trap dust I will initially make the drop slot only 3/4"


• The can has corrugation on the sides.  I would have liked to have use a plastic one because it would be a bit bigger but they all have reinforcing shapes on the side at the handles and are not smooth shapes.   Are the plastice ones okay?  Do the reinforcing shapes interfere with flow and separation? Is my current can too small for the size of DC?

Any help is greatly appreciated.   Thanks.

Colin

[jdon]

Okay, Colin, there are more experienced and wiser heads in this forum, but until they jump in, I'll make a few comments based on what knowledge I've picked up along the way.

1. I think a fiberglass baffle would be fine- in fact probably better than a lot of builds. Ideally, the thinner the baffle the better, esp. at the baffle opening. Many builders bevel the bottom side of the baffle slot edges (the top surface should be entirely flat). The drawback of a thin baffle is that it might need support, typically by hanging rods or dowels from the top lid.

2. The air entering the separator ideally flows smoothly around the outer edge, so the best way is to have the inlet as close to the edge as possible, with the entering air tangential to the circumference. (BTW, this is a major argument for a so-called "top hat" collector, which sits on top of the waste container- it allows entrance from the side, rather than the original design, with an internal inlet 90 degree bend inside the separator). If you angle the inlet opening toward the outside, make sure that air flow isn't likely to "ricochet" off the side- that is, that it isn't at a big angle.

3, 4. If you must go with a 3" inlet, I'd position it near the top, rather than the bottom. As I understand it, the more time the air flow can spend circulating around the outer edge of the collector (before being sucked up the outlet in the center), the better the dust separation. With the inlet at the top, the air flow has a chance to spiral down the edge, theoretically allowing a longer path for separation.

However, the air flow should hit the baffle in the solid section: the 120 degree section without the slot. If the inlet sits low- right on top of the baffle, the solid section begins right about at the inlet. If the inlet is higher, with air flow spiraling down the edge, the ideal placement of the solid part of the baffle is more complicated.

5. 3/4" sounds good- narrower slot traps smaller particles, but is more likely to clog with large pieces of debris (wood shavings from a planer, for example). If you're dealing mostly with small particles (dust), go with a smaller slot width.

6. IIRC, I've seen some threads here suggesting that corrugation may actually improve separation. Size-wise, however, a 16 inch diameter collector sounds a little small for a (nominal) 1200 cfm collector. If you're willing to invest a little more effort, I think you'd get better performance by making a top hat separator to fit on something like a 32 gallon Rubbermaid Brute container. Plenty sturdy, and allows a 21" wide separator. With that, you can go with a 4" inlet; the 3" inlet will really constrict air flow.

Check out retired2's thread for a lot of information, particularly on design and build of a top hat collector.
Final caveat: the above suggestions may be completely bogus! I hope that smarter contributors will confirm or refute. Good luck! John

[DennisCA]

As I understand it, the taller the better the separation, same goes for diameter (or was that less resistance). So for simplicitys sake a  transparent or semi transparent separator is useful, then you can see where the stream of dust goes and place your baffle accordingly.

[scowine]

This is probably a silly question, so I'll ask it....why not put the shop vac motor assembly onto a larger collection container, such as a 16 gal drum, redirect the inlet and put the baffle directly underneath the shop vac filter? Would this not eliminate the need for a separate collector? I built a 5 gal separator that really doesn't work