TopHat SketchUp Model - looking for feedback

[jgt1942]

OK I think I'm making progress with my SketchUp model and would appreciate any feedback and suggestions, if you have SketchUp please download the SketchUp file and review. I know that it is not complete and most likely I made some mistakes thus I'm open. At this point I'm just tired and need to get some sleep!

[jgt1942]

I just realized (brain damage prevented this flash) that I can install the motor/impeller and TopHat in the attic area of my garage. In the ceiling area I have about 33 inches of space between the garage ceiling 2x4 joist and the roof 2x6 joist. The insulation in my house is a foam spray and was applied to the underside of the roof. The house is a Santa Fe design and the near flat roof is highest at the front of my garage with a gentle downward slope as the roof line goes to the back of the garage.  This will put most of my duct run in the attic area. With this thought my entire design changes. In the design in the previous post I was going to use Plexiglas for the sides but this will be wasted. If I want to be cute with the design I could use Plexiglas for the bottom of the TopHat and also install Plexiglas in the ceiling below the TopHat. This would allow me to easily see the dust action in the TopHat but I will admit this maybe overkill!

I've been playing with SketchUp and came up with the following so far. Any suggestion or questions? I realize that some of the items are not exactly to scale but this will be adjusted with a better model or I just may live with the fact that it is not 100% correct.

[jgt1942]

OK I think I've completed the rough design (see below) and would appreciate feedback.  In the following I just added the parts to collect the dust from the TopHat. Rather than a cylinder I made a box that tapers down on all sides  to a 7" opening and then attached a 6" port. From there I drop down with a 6" pipe to a round tub. I could have put a cylinder at the top just under the TopHat but my space is constrained, I only have a max of about 30 inches from the bottom side of the roof to the top of the ceiling joist. If I allow

• 2" between the top of the motor and the bottom of the roof,
• 16" for the motor and impeller unit
• 4" as an estimate for the connection between the impeller input and the TopHat
• 7" for the TopHat
• This puts me at 29" which is almost on top of the joist.

Currently I have the TopHat width at almost 23 1/2" inches and the section below it must fit between the ceiling joist (I just measured and I have 22 1/2" between the joist) thus I'm in trouble with the current width. Decreasing the width of the TopHat should not be an issue, because I used square top and bottom I added a little to each side. Once I fit between the ceiling joist I can cut a hole in the ceiling, frame it in and allow whatever to extend down to the container at the bottom.

Questions:

• What is the smallest dia I can make the TopHat and still use 6" pipes? I think I'm OK with the current dia but just for backup.
• Is using a sq tapered box to catch the dust rather than a cylinder going to create problems? I can use a cylinder if the dia to the outside is no more than 22 1/2".
• The total drop for the dust from the TopHat bottom to the bottom of the container will be about 11', is this an issue?

[Dougp28704]

I don?t want to knock your idea. But I think you may be asking for trouble. I wonder if the square tapered box will change the way material falls thru the drop slot of baffle.  :-\
Maybe you should have a straight portion, at least for a few inches, before starting the taper.

[jgt1942]

The tapper was a concern and at first I thought I had a space issue and the taper would solve the space issue. Very near the end of the design last night I measured the distance between the rafters and discovered that it is 22 1/2 inches. I did include this measurement in my post but it was a last minute update and I did not really consider the possibility of changing and replacing the tapper unit with a cylinder. After rethinking (boy is this hard!) I can easily use a cylinder in that this would eliminate any possible issues with the tapper this is the route I will go. That being said following are my current plans.

• First build a unit for my shop vac. This "should be" much quicker and allow me to get a unit in place.
• I can then build another unit and just place it on top of a Brute garbage can, as others have done. This will be much faster than the attic mount.
• Assuming I still want to do the attic mount I can now pursue it at a much slower pace.

BTW Doug, I've utilized many of the ideas from your postings, great work!

[jck53151]

idk.  People smarter than me have posted that every foot of ducting reduces the capabilities of the DC.  Won't the added runs going to the attic reduce the effective CFM and therefore SP?  Are you really saving any floor space by putting it in the attic?

[Bulldog8]

  Are you really saving any floor space by putting it in the attic?

That was my thought as well. With your filter and bin in the shop area, what is the real gain by having the top hat and impeller in the attic?

Steve

[jgt1942]

The attic mount was in part to service my table saw which sits in front of my garage doors, see the shop image. However after sleeping on it (I cannot believe how much I've been thinking about this project) I've decided to first build a unit for my Ridgid shop vac and then build a second unit for the Grizzly DC BUT just use a Brute can as others have done. ALL of my tools will be on wheels because I'm limited in space, e.g. the garage (about 708 sq feet) and all the doors I have really chops up the wall space. I'm going to be using one tool at a time and if push comes to shove I can use the big DC on one tool and the shop vac on a small tool. Currently the Grizzly is on wheels and modifying the current base or just putting the Brute can on a base will work. As you suggest I'm not saving any space with the attic mount but if I install fixed pipes I run into more problems with ceiling mounts.

In the shop image I just realized I do not have the garage door rails correctly positioned, e.g. they have 9 1/2" of clearance and the bottom edge of the drive track is 5" from the ceiling thus I could not run a pipe attached to the ceiling but because I have 10 foot ceilings I could run a pipe under the rails and the pipe would not interfere with my 8 foot garage door opening.

The input I have received has been helpful! Big thanks.

[jgt1942]

OK today I went by True Value looking for a 20 gal brute can for my to use with my TopHat and Shop Vac. They did not have one in stock but did order one for $30, later in the day when I stopped by Home Depot I found the same Brute for $20 as well as the dolly for my 32 gal brute ($24). Yes I could make the dolly but the  wheel would cost me almost $24 so I purchased it as well. The 20 gal Brute is for the shop vac and the 32 gal is for the big Grizzly DC.

I also picked up a 3/4" sheet of MDF but had considered using plywood.

At Lowes I did look at the polycarbonate but it was super expensive, about $70 for a 36"x48" (this may not be the actual size) which is not long enough. Next week I'll call some local glass shops and see what I can get.

[RonS]

If there are any plastic supply or mfg companies in your area, I would check them out. You may be able to get sheet goods cut off material very cheap / free.

[jgt1942]

I'm still playing with the darn design in SketchUp using some models I had downloaded from different websites and last night I started to lay it out on some MDF. It was then I realized that the models I had downloaded while they looked great several of the dimensions were not correct. Needless to say I was bummed out and now I'm bouncing between my SketchUp drawing, the actual layout and various postings in this forum.

BTW I've checked in Phoenix (about 90 miles from where I live) and so far I've not found a good resource for the plastic but I will continue to look.

[Dougp28704]

I just about gave up on finding Lexan here in Asheville, NC. Nothing was coming up in searches. Then I searched the plain old yellow pages and found multiple places. I guess its because places like that don?t do a lot of business with general public. So, it doesn?t make sense to pay to come up on search engines.

[galerdude]

You can normally pick up drops (waste) of lexan from electrical sign shops. I'd call some and work up a deal.

[SteveP]

Just a quick note, Looking at your attic design, would you gain any efficiency by running the airflow all the same direction? Your Thien is running clockwise, and your fan anti-clockwise.