Hotend Hack for the CB3 to prevent picking up Ooze and brown droppings.

Our customers and we had some troubles with the CB3. One of them is that a lot of Ooze has been picked up by the bottom of the hotend. As that's not a very smooth surface, it's a great container for that dry ooze produced by stringing and such.
When a certain amount is picked up, the Ooze will be burned and will fall somewhere in your delicate print, causing brown spots.

Hotend Hack for the CB3 to prevent picking up Ooze and brown droppings.
Hotend Hack for the CB3 to prevent picking up Ooze and brown droppings.
Hotend Hack for the CB3 to prevent picking up Ooze and brown droppings.

As I have been told by CraftUnique the hotend design won't be changed, that made me excited, as that's the point I feel alive. Hacking stuff!

And for this, the hack is pretty simple: just flip the silicone cover upside-down. By that the bottom of the hotend is protected by the silicone cover and not being able to pick up Ooze again.

Hotend Hack for the CB3 to prevent picking up Ooze and brown droppings.

Only the nozzle itself can pick up Ooze, but for that I used our P3d Apollo nozzle. That's coated and less likely picking up Ooze. Shameless advertising to be found here.

Of course the silicone cover won't fit completely after flipping it upside down: you have to make some incisions for the heater and -if wanted- the grub screw for the fastener of the heater and thermistor. I used a stanley blade to do that.
As they are already pretty tight in the heaterblock, I left the fastener for the heater/thermistor out.
Nevertheless: if you want to turn back to the original state: that won't be a problem: the cover still works unless some small cuts in it.

Hotend Hack for the CB3 to prevent picking up Ooze and brown droppings.

It's unclear how much turns the nozzle has to be loosened out of the heaterblock. With E3d it's only half a turn. Craftnique seems to turn it a couple of times. Anyway; that's good as by that the silicone cover slips a little under the nozzle to fit nicely.

To be sure i taped on top of the heaterblock some Kapton, to limit radiation of heat to the heatsink.

Hotend Hack for the CB3 to prevent picking up Ooze and brown droppings.

After long PETG prints I have no black hotend anymore, and -more important- no brown droppings in my prints anymore!

E3d
BTW: in stead of this hack you can exchange the heaterblock of CU by the heaterblock of E3d, as they are compatible: the heater and thermistor of CU fit in it too. E3d has already a slicone cover that protects the bottom of the heaterblock.
As I don't know the effect of radiation to the heatsink with that as well: also put some Kapton layers on top of it.
Yes i sell those as well. But you can buy that E3d stuff everywhere.

Hotend Hack for the CB3 to prevent picking up Ooze and brown droppings.

Hotend Hack for the CB3 to prevent picking up Ooze and brown droppings.


We have some adapted E3d hotends available as well for the CB, CB+, CB2 and CB XL. By that you can set the print temp to max 300 degrees Celcius in stead of 260 degrees. You can also print flexible fillament.

Hotend Hack for the CB3 to prevent picking up Ooze and brown droppings.




Enjoy! Bart

June 29, 2018

Bartaar Bartaar
Service partner
1663 posts

0 replies

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