Well fsck a duct, I’m building a new duct by Addidis. He took my j-head adapter and modified it to mount a Budaschnozzle duct! Good stuff 
Unfortunately I totally underestimates how big that light hulahoop was. BAh.
LOL, It’ll be fiiiine with some carpet tape. (I hate that stuff! It sticks like stink on a skunk)
Will a duct like that even flow? I’ve not been able to get any air flow out of ducts because the backpressure is so high that those little fans just can’t push any air.
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There is airflow, it’s not a crazy amount though and you can tell there a lot of back pressure. Though in my experience crazy amounts would cool the extruder too much. I think it will move enough air for it’s purpose.
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I can’t speak English
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Yeah the thinking was too much air would have a worse effect than too little. I learned something while trying to center mine and failing, right as it melts, the air it blows gets considerably warmer. You would think this would have ruined my day but the results were rather exceptional. Blowing hot air at it is WAY better than cool air. I’ve decided to see about working it into a design. Thus far the problem is to get hot air you need to enclose the heat sink so you will probably need a mechanical door to vent the hot air either down to the print or away . This is because you need to run the fan 100% of the time if you enclose it. But cooling all the time, even with hot air is probably not good.
Blowing hot air to cool PLA you are saying?
I have only printed ABS (But i do know PLA would melt at the ideal temp for ABS to be ‘cooled’)
Ah, that makes more sense, You cool the ABS a little bit with a fan? I’ve only used a fan on PLA.
What temp are you using for ‘hot’?
Ive been experimenting with bridging. I lothe support material. I find blowing on it most effective, probably because Im full of hot air 
The fan makes it pop and crackle and it just cools too much. Bad things ensue. Curling , cracking, layer seperation etc.
With that fan duct I saw about a 25-30% increase in successful bridging in the little bridge test piece. This was with the backed up duct , powered at 15 % (it cuts on at 30). So ultra slow fan helped bridge, hot air from me worked even better but i nearly fell over.
When it melted it was actually uncomfortably hot. I realized it melted because of hot hot it was. Id say 100F + but I didnt check. Figure you’e printing at 230C, perhaps half that, 3/4 of that. Basically preheat it with the heatsink.
I’d been trying to figure out how to run the air for cooling past my extruder motor to cool that and give the air a bit of a boost. Not enough for the temps discussed here.
The printer I am building out now has a case and will have a heated build chamber. Recirculating that air may be a good plan or even just feeding the fresh ‘hot’ air right to the work area may be a good idea too.
Yeah I meant to utilize the heat coming off the hot end heat sink. If you are printing at 230 that exhaust would get considerably warm given a slow fan speed. Smaller temperature difference would cool it slower. Which is what I think ABS needs.
http://en.wikipedia.org/wiki/Acrylonitrile_butadiene_styrene says the glass transition temp is about 105c. So, I’d say steam-burn temps would be good.
Just need to get the ABS under that 105c quickly so it ‘freezes’ where we want it.
I am wondering if a hair dryer would be the right ‘cooling’ tool for us now? use some aluminum flex duct to get the air where we want it?
Yep or a surface mount rework station (hot air). The actual temperature will be somewhat lower than the 105. The idea is to get the right temperature to drop it TO 105 . The larger the temperature difference the faster it will cool. so it is some math with how fast you are printing, and at what temp, black for instance is 230 C and the glass transistion temp. The constant is what temp you want to leave it at.