J. Phil Thien's Projects

Thank you for the response, R2.  I guess what I'm looking for is the first person who built their own pre-separator side-inlet Thien tophat, regardless of whether they constructed the tophat from scratch or used a collector ring cannibalized off of a dust collector.  I also wonder who first used a clear sidewall on the tophat.

Just curious about the beginning and evolution of the tophat design.

I am looking for just a small amount of 6" flex hose to allow raising and lowering the tophat above the can, using it as a straight coupler between sections of hard duct, both on the inlet and outlet.  I really don't want to buy 10 to 25 feet just to get such a small length.  If anyone has any that you would be interested in selling me, please PM me.  Thanks.

Zane

On the lateral, the dust collector side of the lateral would be 6 inch, the overhead blade guard side would be 4 inch, and the table saw cabinet side would be 4 inch.  As you said, I can reduce the blade guard port down to a smaller size if wanted/needed.  I am going to talk to my local HVAC fabricator to check a cost comparison of 26 gauge elbows vs. big box store 30 gauge elbows.

Keep in mind, that is a 4 inch coming out of the side of the lateral to the overhead blade guard, AND a 4 inch coming out of the end of the lateral to the underside of the table saw.

Quote from: retired2 on February 03, 2016, 01:23:53 PM

How far is the lateral for you table saw from your DC?

The lateral should end up about two feet up, an elbow, and six foot across from the dust collector.

Quote from: retired2 on February 02, 2016, 10:48:05 AM

<snip>

You would help your system a lot by eliminating as much of that 4" pipe as possible (to the table saw)

<end snip>

I will have a lateral directly above the table saw blade with a 4 inch diameter drop to an overhead blade guard.  I have been advised by one person to also drop the horizontal that will eventually end up at the under saw collection to 4 inch at that lateral.  Another person advised that even if I kept the horizontal at 6 inch, to reduce it to 4 inch for the vertical drop to the saw cabinet to keep up air velocity. And yet another person advised keeping it 6 inch all the way to the saw cabinet.  I'm so confused...

R2, thank you for your reply.

The hidden agenda behind my question is regarding the wye's and elbows only, not the pipes (6" mains and 4" drops).  I am content with getting 26 gauge pipes from a local HVAC fabricator.

I will be using a Harbor Freight 2HP (optimistically) dust collector with the impeller replaced with a Rikon impeller, and a Wynn filter replacing the top bag.  I am planning on a double height (12") tophat over a 32 gallon Brute can.  The longest run in the shop would probably be to the bottom side of the table saw, about 12 feet of 6" with one elbow, and 15 feet of 4" with two elbows (approximate lengths).

BTW, I have a 6" bellmouth waiting in the wings for the outlet of the tophat (purchased from Spiral Mfg.).  The outside diameter of the flange on the bellmouth is out of round.  The pipe portion is perfectly round.  Should I try to grind the flange to round, or will it matter? 
Also, the diameter of the pipe on the bellmouth is exactly the same as the 6" duct pipe.  Instead of trying to crimp the bellmouth, I am thinking about making a 9" long, three vane air straightener to insert into the outlet, and use it as a "splint" to tie the bellmouth and the pipe together, using foil tape to seal the seam. Thoughts?

I have read that 26 gauge is the minimum to use for ductwork.  Does that apply to fittings as well, elbows, wyes, and laterals, or does their construction make them sturdy enough at 30 gauge?  Has anyone here ever experience a 30 gauge fitting collapsing under vacuum?

I found the part in the white paper that said good things about the three vane design.  Has anyone found a reference as to how long the vanes should be?  If I can't find any documentation, I think I'm going to try vane length equal to duct diameter.  Also, do you think there would be any advantage to putting vanes both at the output of the separator and at the input to the impeller housing?

JeffQ, what thickness would you recommend for the PETG?

Quote from: retired2 on August 29, 2011, 02:42:01 PM

<snip>  There were two things I was trying to accomplish with my baffle design and both created construction problems.  The first was to avoid having a ledge along the outside wall of the drop slot.  Of course, that meant there couldn't be any dado to hold the bottom edge of the plexiglass. <snip>

Has having a ledge along the outside wall of the drop slot been shown to cause any problems?  It would seem that having a dado for mounting acrylic or poly both top and bottom (and inletting the two ends of the plastic) may alleviate the need to have any screws penetrating the plastic.  I'm slowly getting the stuff together to build my own tophat, and this is one of the aspects that is making my head hurt!

Got the HF dust collector, the Wynn filter is on order, as is the impeller from Rikon and the bellmouth from Spiral Mfg.

I'll be changing the inlet plate on the HF dust impeller housing to accept a 6" inlet.  My plate will be made from 3/4" MDO, and I hope to use a 3/4" roundover on the 6" inlet hole to give me a mini-bellmouth at that point.  In hindsight, I should have ordered two bellmouths, one for inside the tophat and one for the inlet to impeller housing.  Ordering two at once would have made the shipping cost a lot more reasonable per unit.  Maybe I'll get a second bellmouth someday, but more likely, once I get this thing working, I'll just leave well enough alone.

I have a 4"x10" to 6" Round End Register Box that I plan to use to transition from a ceiling drop from the 6" main trunk to the tophat.  Not as elegant or smooth a transition as R2's, but compact for my application (very small workshop).  Internal tophat hat height planned to be 10" to match the register box.

Regarding the bottom of the tophat, planning to layer it, top layer would be either 1/8" or 1/4" hardboard with the 1-1/8" drop slot. The next layer down would be another layer of the same thickness hardboard, but with a 2-1/4" drop slot.  The bottom layer would be 3/4" MDO plywood with a 3-3/8" drop slot.  All this layering is for the purpose of stiffening the baffle while maintaining a thin edge on the drop slot.

Would 6" flex hose work as a coupler for 6" duct pipe?  If so, anyone know where I can get short lengths? I only need to make two joints, tophat to impeller assembly, and trunk drop to tophat inlet.

Regarding air straighteners in the outlet of the tophat to the inlet of the impeller housing, I'm thinking of a very simple 3 vane (think of a Mercedes emblem) assembly.  Any info or thoughts on how long this would need to be to be effective?

Also, I believe it was somewhere in this thread someone mentioned polyester as an alternative to acrylic or polycarbonate, but I don't recall that comment being developed further.  Thoughts on whether this is a viable alternative, pros and cons?  Is it available as a clear product, cost comparison, etc?

Sorry for the random stream of consciousness in this post...
There's just so many details to look at!  And I'm trying to look at all of them before I make my first cut.

Hi!  Maker of fine sawdust here.  Weekend Dust Warrior.  Just got myself a Harbor Freight dust collector for Christmas.  Getting the stuff together to make a tophat for a Brute trashcan.  I've got a Wynn filter ordered, and plan to order a Rikon impeller soon.  Planning to open the inlet to the HF blower to 6".  Wanting to see what I can do to make the transition from the output of the HF blower to the inlet of the HF collector as efficient as possible.

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