pipe size questions

[kevmc]

my brother and I are embarking on building two top hats for our jet 1100 dust collectors.  just a few quick questions before we start the build

1, My dust collector has a 6 inch in with one of the adapters to make it two 4 inch pipes.  The outlet is a 5 inch pipe.  Is it useful or any good to build the top hat with a 5 inch outlet then use 5 inch pipe to the tools and then downsize to 4 inch for the tool collection.  Or is my dust collector not that powerful enough to support a 5 inch pipe.  I should not that I will likely have the dust collector on wheels and connect it to the tools with a short piece of flexible pipe.  or should I just stay with a 4 inch out on the baffle.

2.  I am probably going to use a steel drum for the collector.  a 30 gallon steel barrel is 20 inch in diameter and the 55 gallon is 24 inch in diameter.  Is there any reqiurement for how wide the baffle should be .  I would prefer to go with the smaller barrel but want to confirm that a 20 in diameter top hat will still work well


Thanks in advance.  The site is hugely helpful.

And Phil thanks for all your work on the design.  Its really awesome

Regards

KC

[phil (admin)]

The problem with 5" is finding materials.  Many people like using PVC and there is no 5" PVC.  Personally, I'd try to stick with 6", I know some people with the Harbor Freight model have done this and it has worked.  It should work with your Jet.

The smaller barrel should work fine.  As the diameter of a typical cyclone is reduced, the speed, resistance, and separation are all increased.  As the diameter of the Thien separator is reduced, the speed and resistance are increased, I'm not so sure separation sees much of an improvement, though.

Those steel drums are heavy, BTW.  Consider one of the plastic ones.  I have been emptying mine (a plastic) a lot lately, and I cannot imagine having to lift the steel in combination with the sawdust.