J. Phil Thien's Projects

Ok, I know the general concencus is to use 2 45deg bends together to make a 90 so that the transition is more smooth and open, but I would like to quiz you guys on the following...

I'm not to sure what kind of storm water pipes you guys have over there, but here in Australia, the 100mm (4") pipe bends have a smooth transition along the inner and outer radius for the 90deg but the 45deg only has a smooth radius on the outside, the inside is not a radius, but rather the 2 45deg planes meeting at a point.

So, with this in mind, would it still be better for airflow to use the 2 45deg units to make a 90deg turn, or just use the single 90deg piece yeilding a tighter radius but a smoother path?

Hey guys, I'm the new kid around here so first off a big hello to you all and cheers for sharing all your designs!


I'm chasing some information that may help me design my intended seperator a bit better. At present I have a 1HP DC (pssibly looking to upgrage to a 2.5HP unit with a bigger impeller in the future). I know that this isn't the most powerful of units on the market, but it is what my current budget and space constraints allow for. Having a bit of a play around in the shed last night, I made a rough attempt at a cyclone by cutting some holes in a 20L fetta cheese bucket and duct taping some 100mm piping in place. Although it leaked like a sieve, it still pulled a huge ammount into the bucket as opposed to the DC itself.

What I need to know is if there is a magic number so to speak in terms of the diameter of the seperator vs inlet/outlet piping size? ie will it be any more or less effiecnt pending its size? I have a lot of offcuts in my shop at present that are 450mm (or 15") square, so a seperator of that diameter is looking mighty tempting!

Any advice would be greatly appreciated, cheers.