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.