Dust collection routing outside

[Guswah]

I'm completely new to this stuff.  I have a large General dust collector in my woodworking shop, but I found my way to this site because I want to convert it to two-stage.  The commercially made cyclones are really expensive, and I would enjoy making my own cyclonic unit based on the Thien design(s) -- unless someone tells me why I shouldn't do this for a DC system.

I would like to locate my 6" main metal collection pipe outside in an eave and feed it from three or four ports that pass through the wall.  This is mostly to save space since I have cupboards and shelving that already occupy the upper corners.  The collection pipe would terminate in the far corner and re-enter the indoors into the Thien cyclone, where obviously the dust receptacle resides.

I noticed a few comments that mention the loss of heating/cooling when there is external venting.  My venting is indoors, but I'm interested in what experienced people might say about the passage of air to the cold outside and then back indoors.  Does that sound like a recipe for humidity issues or some other trouble?

[WayTooLate]

Guswah -
You have come to the right place.  Search these posts for lots of great ideas and success stories of converting all types of DC units. 

As far as your inside/outside issues go.  When in operation, the air moves too fast to be affected by the differences inside/outside.  What may be more significant is the uninsulated duct as a permanent opening through your walls.   Depending on the climate you live in, the differential may be a greater consideration.  I would be certain that your openings are sealed and moisture protected per your local building codes and climate considerations. 

Check out what other people have done and I am sure you will be pleased with your results.
- Jim

[alan m]

i dont see any issues extraction wise . condensation and damp could be a problem . if i was doing it i would box off the pipe outside and insulate around it.

[tommitytomtom]

What Alan M said. Use a high R value insulation. especially if you are in a cold environment. Condensation will be an issue.