What part fan duct do you use?

Laser8302

I have tried several part cooling ducts from thingiverse, with my 5050 blower fan it seems I always get a thermal protection every time. I've had to back down my blower fan to 40% during printing so it doesn't cool the thermistor too much and cause the print to fail.

Here's some of them I've tried:
https://www.thingiverse.com/thing:2789066 <- Large and small, both caused thermal shutdown
https://www.thingiverse.com/thing:2745997 <- melted after first print (I used ABS, bed was at 100C...)
https://www.thingiverse.com/thing:2753286 <- was too heavy and started to sag/drag across prints if I had the block above 230C

Some I'm going to try:
https://www.thingiverse.com/thing:3113423
(I can't find the 2nd one I'm going to try for some reason right now...)

For reference, this is the cooling fan mount I'm using:
https://www.thingiverse.com/thing:2847620

Samuel Pinches

Option C: add silicone sock to heater block

Der_Muck

@Samuel Pinches
I used the silicone sock but it blocks the air comeing from the fan duct because it makes the heatblock bigger with its size. So it would be better to adapt the fan duct and make it about 1.5 -2mm lower. The air would than blow again normal to the nozzle.    A copper heatblock is more temperature stabile than the aluminium one does. 

@Laser8302
I would never use a radial fan down at the hotend. Think about, you allready cool your heatblock down. A sign of tooo much cooling. It should only cool the printed filament down so it doesnt deform.  If you cool that much, you must heat up the hotend even more to get the printed area hot again with the extruding filament. If you dont do that, you get veryyyy bad layer adhesions.  You can try several break tests do see that effect.
So its not about to cool the shit out of the printed part, its more to find a balance of cooling and let it be a little warm. So you can reduce the printtemperature to a normal level. That solves stringing problems to. To cold prints cause stringing and to hot ofcause to.
At the cold end you can cool as much as passible, that expands the lifetime of the lower linear bearing. 
I have a 40x40x10 fan for the hotend and set it to max. 80% thats enough. 

And yes, with ABS prints, it can be that the fan duct melts. So most people just unscrew the fan duct. Using a silicone sock for ABS it makes the heated mass on the hotend bigger so you have a huge heating element down there, it heats the coldend even more and melts everything down. I tested that myself allready. So the goal is to keep the heated mass as small as passible to save the other parts from the radiation heat.

Nothing beats my metalhard 3000 but that is a crazy project of mine, just try using the blowhard 3000 or the scorpion ducts. They are perfect, you see that yourself because of the shut down. Just turn the blower down and you will see, a radial fan is just to much for the use of a fan duct fan. 

ThingsNSchtuff

I use the scorpion (your third link). I printed it with ABS and gave it a vapor bath for extra strength to help withstand the heat, and supported the front sides with super glue and a tooth pick to give it a little extra rigidity. Seems good so far after about 40 plus hours of prints at varying temps of 205-235C. i do have one slightly melty spot on the opposite side of the thermistor, but it has not impacted the printing capability yet. If i end up needing another one, i will probably print a few at a time just in case. Maybe the next one will even be higher temp/quality filament than amazon basics abs.