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Old 2015-08-24, 12:43am
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Speedslug Speedslug is offline
Join Date: Mar 21, 2009
Location: Winnebago, MN
Posts: 2,276

I think your 195 cfm is pushing too close to the lower safe limit for the work you want to accomplish. I think that fighting even a small wind outside would most likely over come this system.

I would first recommend replacing the ribbed flexible ductwork for straight sided hard duct work even at the cone over the torches and on the exhaust side of the fan as well.

The ribs generate turbulence in the flow and will effectively reduce the size of the ductwork by almost two inches and then you are only getting 4 inches of laminar flow.

And is there any way you could translate the 90 degree bends into sloping 45 degree angles?

You currently have 3 each 90 degree bends plus the two 45 degree bends over the torches. That generates a lot of losses that I don't think you can afford with this.

You mentioned that you have access to testing equipment.
Can you run a clamp on amp meter on the wires to the fan?
I am as much in favor as saving money as the anyone else but I have heard things about Harbor Freight equipment that are not encouraging.

I also remember some discussions on my wood working forums about trying to get 3 horse power out of a router on a 15 amp circuit breaker and that the volts and amps math did not add up unless someone installed a 20 amp breaker at the least.

This leaves me concerned that your fan may be running hotter than you would like if it is in fact pushing 2 horse power but I have to say I am inclined to think that the rated cfms on it may be closer to "hot air" than a realistic test would show.

I will be the first to state that flow dynamics is not a field I am thorough versed in.
I learned enough to know that what I planned for my own system was at least three times what I needed and I stopped studying the subject after that.
So all of the above is just my 2 cents and worth what you paid for it.

I am hoping some of our more experienced members will voice their opinions because I learn from each of these questions even when I learn I am wrong.

Good luck with it.
We have to take care of ourselves so we can take care of each other.

Last edited by Speedslug; 2015-08-24 at 12:45am.
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