Overhead Blast Gates & Blast Gates Version3 & Restructure of Ducting

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Project by Holbs posted 12-09-2016 05:54 AM 3404 views 9 times favorited 8 comments Add to Favorites Watch

So the saying goes “I love it when a plan comes together”. I started a restructure of my 2 car garage wood shop this summer. To do that, I had to take down my ceiling mounted 6” HVAC ducting to install some new electrical runs, and ceiling drywall. I knew I wanted overhead blast gates upon re-installation, which in turn meant re-doing the ducting all together because the duct would be 10”-16” away from the wall to give room for the overhead blast gate. I also ensured I had 6”x4”x6” wye’s at strategic locations for future overhead table saw dust collection booms & arms.
Overhead Blast Gates I made 4 of these. They came out pretty well. In the 1st picture, I forgot to insert the spacers at top & bottom of the outside plates but you get the idea. And they function perfectly with maybe 0.2% leakage due to a 12” spacing between the top/bottom nut & bolts. Made with scrap 3/4” plywood.
Regular Blast Gates These are my 3rd version of blast gates. Previous version was using 6” PVC sewer & drain pipe with construction glue to hold them. But found out, any jarring or accidental knocking of the blast gate and the PVC would come loose. So I took all 10 apart, made the 6” hole wider to accept 6” HVAC duct, brad nailed each piece of 6” HVAC duct to the frame with 8 nails, added rubber bands to the back end of the slider to eject debris when closed. Why do the rubber band trick/trial run? Most blast gates have a 6” hole and then another 6-8” blocking material for a total of 12-14” slider, either left/right or forward/back. I did not want to take up that space so my slider is just 7” or so. I siliconed the blast gate, and this time I affixed them to the wall with brackets (I did not do this before so when I pulled the slider out I had to use two hands: one to hold the pipe and other to push/pull slider).

-- The Carpenter Bee is derived from the Ancient Greek word wood-cutter "xylokopos/ξυλοκὀπος"

8 comments so far

View mafe's profile


12075 posts in 3506 days

#1 posted 12-09-2016 12:52 PM

Super cool and simple.
Best thoughts,

-- MAD F, the fanatical rhykenologist and vintage architect. Democraticwoodworking.

View Roger's profile


21006 posts in 3221 days

#2 posted 12-09-2016 03:07 PM

Looks like a nice setup

-- Roger from KY. Work/Play/Travel Safe. Keep your dust collector fed. [email protected]

View kocgolf's profile


396 posts in 2595 days

#3 posted 12-09-2016 03:33 PM

Nice overhead gates. Really easy to use.

View helluvawreck's profile


32086 posts in 3283 days

#4 posted 12-09-2016 08:10 PM

This is very creative. Nice work.

helluvawreck aka Charles

-- helluvawreck aka Charles,

View Holbs's profile


2213 posts in 2446 days

#5 posted 12-10-2016 01:03 AM

Thanks guys. I did not come up with the idea of an overhead blast gate :) Nor it’s engineering design.
For those wondering how much I spent on my 6” HVAC ducting… just keep in mind, I did not buy everything at once over night. I purchase 5’ sections here or there with wye’s & elbows over 2 year period. I started out like everyone else did: shopvac, dust deputy, and hose. Also, you can find the majority of ducting and pieces in the trash when business’s do a suite remodel or such for free!
Someone PM’d me and asked why I added 6” spiral flex duct at the top of my 5 drops. For 3 reasons which I have learned over the past 2 years: 1.) to give flexibility to move the down pipe over a couple inches here or there depending on where my electrical or machine sits 2.) is incase of editing the down pipe itself, I can easily pull it down and work on it off the floor 3.) final reason: incase I have to edit the entire ceiling run for any reason, I can easily dis-assemble sections
And nobody has commented about my regular blast gate design. I thought it’s ingenious with the rubber band ejecting backend :) Which usually means, since I thought of it, that it will fall apart or something.

-- The Carpenter Bee is derived from the Ancient Greek word wood-cutter "xylokopos/ξυλοκὀπος"

View woodbutcherbynight's profile


5966 posts in 2826 days

#6 posted 12-10-2016 03:59 AM

That is a very impressive system. I thought I was doing okay with my 2 1/2 clear pipes and cheap plastic gates. LOL. I know cabinet shops that do not have that large of pipes for DC. Excellent work.

-- Live to tell the stories, they sound better that way.

View bushmaster's profile


3669 posts in 2699 days

#7 posted 12-10-2016 04:28 AM

A great idea. There is always room for an improvement and you proved it.

-- Brian - Hazelton, British Columbia

View Daiku's profile


232 posts in 3324 days

#8 posted 12-10-2016 03:43 PM

It may not have been your design, but you got me thinking about my alternatives. I’ll be setting up a new shop soon and I hate the commercial gates I have now, they’re always clogging up.

Thanks for posting,

-- Cal Noguchi -

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