When I first set up my dust collection network, I purchased some of these blast gates. The blast gates were used to control air flow by sliding the gate in a track, either allowing or blocking air flow. I closed gates to block airflow to tools not being used, thus increasing the suction to the tools in use.
At first, they worked well. Then, as dust accumulated inside, the movement of the sliding gate became impeded and the gate would not close. This meant that the blast gates were unable to effectively control air flow – their sole purpose.
What’s more, one broke. The blast gate consisted of three parts – the gate and two halves glued together. Well, the glue failed. Now, the good thing about that broken blast gate was that I was able to clean it out thoroughly and easily. Since I didn’t have any spares, I clamped it together with four C-clamps (double-sided tape didn’t work).
The blast gate on my table saw wouldn’t close completely. I didn’t think this was a problem until I hooked up my DeWalt planer. The planer’s blower used to clear chips pressurized the dust collection system and blew chips through the hoses and up out of my table saw, raising a big cloud of chips and dust.
I’m going to replace the plastic blast gates with metal self-cleaning blast gates. They cost twice as much, but I’m convinced they will be worth it.
As shown on the Lee Valley Tools Ltd. site, the design of these self-cleaning blast gates avoids the problem of the plastic ones.
Sculptural Woodwork by Chris Wong 
Thanks for the info, Chris. I never realized what the difference was between the two types. The Lee Valley model is really the one to install.
Best,
I dunno, Serge – that sawdust geyser looks pretty cool!
Chris
I have to respectfully submit that your “old faithful” table saw gate looks funny as hell!
I have the same planer and a Harbor Freight Dust collector, and between the blower on the planer and the suction of the dust collector, it’s incredible the air pressure they generate.
You could push a compact car through my system. lol
Thank you for the tip on the better blast gate and good luck.
Eric
Hi Chris,
I had the same problem with the plastic ones. I replaced all of them with metal gates, but I did not use the LV so called self cleaning gates. Mine are simple metal gates that slide a plate in or out (no extended plate with a hole in it) and have not had a problem with clogging. Also you would need extra space to accommodate the double length of the slider.
These metal gates are installed in my shop in both horizontal and vertical positions, and angles in between.
Cheers,
Peter
Further to my previous post, here is a link to the type I have in my shop. I have them for 4, 6 and 7 inch.
http://www.amazon.com/Woodstock-W1142-4-Inch-Aluminum-Blastgate/dp/B0000223YN/ref=sr_1_2?s=hi&ie=UTF8&qid=1318364469&sr=1-2
Cheers,
And here is where I actually bought them:
http://www.spiralmfg.com/gatesf.htm
Thanks for the information, Peter. Is there a slot opposite the gate so that sawdust won’t accumulate there?
Chris
Let me see if I can explain this. The plastic gates are closed on three sides, for structure rigidity I suppose. That left the rear end to collect stuff. The metal gates on the other hand are two pieces of aluminum attached on two sides only, with a slider that slides between them. You could, if you wanted, insert the slider at either end. So when you pull the slider out, the back end is exposed to some sucking airflow that clears out said back side. So they are inherently self cleaning.
I have seen them locally at places like KMS for about $12 for the 4 inch size.
Thanks for the explanations, Peter. That makes sense.
Another bonus to the LV metal gates, they can be taken part to make tool adapters. This is really good for anyone using 6″ hose unless you like tin bashing coffee cans to make adapters.
Don
Great idea, Don. You’re talking about fastening half of the gate to a tool, right? Brilliant!
That is a very big dust cloud … I’ve been thinking of making the same changes
I love the metal blastgates. I use foil tape to seal the joint between the flex hose and gate, and also to help seal the sides a bit. I leave the bottom open to clear the dust.
I haven’t had to clean them on over 5 years, and they put up with my abuse too.
Chris, I’ve been very happy with my metal blast gates. They do a great job of always making my system SUCK!