Thread: Quick and dirty Blast Gate.

I'm in the process of rearranging the workshop, that involved moving the Bandsaw and running a new 150mm ducting run for the BS and the Router table. Of course things never go quite to plan and the vertical part of the ducting was just a bit to close to a big steel upright to allow a normal blast gate to operate.

Now I needed to get something fitted and running quickly, I remembered a big beefy threaded coupling I found at the back of the shed during the cleanup, I then remembered a blast gate design that Bobl had posted and with the little I had I came up with this in a hurry.

I cut a fine slot half way through the side of the coupler, inserted the 150mm pipe and fixed it in place then remade the cut, this time cutting half way through the 150mm pipe. The two together are strong enough that no other bracing was needed. I cut and slider out of 0.97mm steel, very thin and extremely rigid.

I didn't get fancy and just cut a small 150mm sleeve to pop over the slot when I'm using the BS, in reality the amount of vacuum lost through that 0.97mm slot is not noticeable - without actually measuring it, however the sleeve sucks down and seals the slot when the DC is running, so no loss at all.

Surprisingly, it's almost as quick to operate as the other gates, it works so well and takes up so little room that I'm tempted to leave it and not build something better, although I guess I should make a proper insert to use when the gate is open and keep the inside wall of the 150mm pipe smooth. Wonder how much difference it makes with that sealed 0.97mm slot in the side when using that crude cover / sealing ring?