Thread: I need an opinion on the dust stuff sold by Beyond Tools - all the way over in WA

A couple of things to consider.

Those 6" gates are inserted into the ducting or flex so they end up constricting the air path down to <140 mm diameter - this might not seem like much but it all adds up. It's better to use gates that go over ducting so the air path retains the full 150mm all the way - unfortunately not many of these around but they are a doddle to make.

The more flexible the ducting (like PU) the greater the losses. Not sure exactly why but its probably a mix of 1) being more easily able to flex the pipe to smaller angles and along the same lines the air travelling thru the duct causes vibration which causes more turbulence. Fewer losses are obtained using the stiffer PVC flex than the PU - the effects are quite dramatic.
Air flow calibration measurements

OTOH sometimes you have not choice to use a very tight bend which is when the PU stuff comes in handy.
Whatever you use keep the use of flexy as short as possible.

Thanks very much for responding, Bob.
I have read all your archived stuff here over the last year or two and understand much more about dealing with dust than I ever though I would need to - though when it gets into the maths on airflow my eyes glaze over.
My first dust installation, before doing any reading, was like a training wheels one and the errors annoy me.
I understand the imperative to limit the use of flex and stuff like opting for, say, 2 x 45 degree bends vs 1 x 90 degree one.
And it makes sense that gates fitting inside the PVC will limit the airflow.
Now, when you say it's a doddle to make good 6 inch gates, I bet you have a preferred design you can point me to. I have been mulling this over and know a bloke near me who has a cnc to cut the perfect holes I will need.

Thanks again,

Scott

Originally Posted by scottbr

I understand the imperative to limit the use of flex and stuff like opting for, say, 2 x 45 degree bends vs 1 x 90 degree one.

depends on which 90º bend is used.
at post 32 and 35 in the same threads as the flexy dats.

Now, when you say it's a doddle to make good 6 inch gates, I bet you have a preferred design you can point me to. I have been mulling this over and know a bloke near me who has a cnc to cut the perfect holes I will need.

Blast gate gallery

Thanks again Bob.
Yep, I saw that mention of the more gentle 90 degree curves being better than the tighter ones.
I'm wondering whether 2 x 45s would still be better if space permits?
I knew there would be a gallery of blast gates. I take photos of mine when I do them.