30 guage pipe isn't designed for the pressure that a modern dust collection system will produce and yes, you will be at risk for collapse. There have been pictures posted in the past of this right here at SMC to my recollection. While you can get away with re-jiggering components like adjustable elbows, etc., for the straight pipe, you really want the heavier "stove pipe" which is 26 gage. It's also readily available and not hard to find. My local Home Depot carries it, although they don't carry it longer than 24". I bought 5' 26 gage snap-lock at a local HVAC supply. While they prefer to deal with "the trade", they did agree to sell it to me....money talks sometimes...and it wasn't expensive.
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The most expensive tool is the one you buy "cheaply" and often...
I used 30ga for my 3hp system. I did some testing to see if it would collapse. http://www.sawmillcreek.org/showthre...ing&highlight=
If you use he plywoid rings there there is no problem with using 30ga. I taped all my seams and connections. I have been running for about 2 years with this set up. I bought all my fittings from Menards and Lowes. The plywood rings were convent for attaching the duct. Would I do it again? Yes. The cost of my fittings,tape and pipe was less than $200 for about 100' total runs. For me cost was the main issue as I could not buy 26ga locally at a reasonable cost. 26ga would have cost me 3X more. My DC doesn't know the difference and neither do I.
Edit: Note as said in the referred thread I believe it is important to rotate the seams 90 degrees at each connection regardless of the gauge pipe.
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Last edited by William C Rogers; 10-01-2017 at 10:01 AM.
When working I had more money than time. In retirement I have more time than money. Love the time, miss the money.