<p>The PTFE liner should be in contact with the nozzle. Normally, they are cut about half a millimetre too long, to ensure that good contact with the nozzle is made. I used these throats for several years before I switched to an all-metal hot end. If you take care to tighten the nozzle with the hot end at the highest working temperature that you intend to use, you should have no problems with leaking filament.</p>

CC BY-SA 4.0
2021-10-31T01:16:53.720Z
2021-10-31T11:00:06.317Z
2021-10-31T11:00:06.317Z
Mick
<p>I have an Anet A8 clone printer. I see the throat tube is different on each end. I'm trying to ensure I understand which end should go up and which should go down. To me, it appears (from the photo below) the one on the right is the proper orientation (teflon down, metal up). Is this correct?</p>
<p><a href="https://i.sstatic.net/gju30.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/gju30.jpg" alt="enter image description here" /></a></p>
<p>There are a couple of reasons I ask this question. First, I had the teflon oriented up, and one time the teflon pulled out of the tube while I was pulling the filament out after a print was finished. Secondly, I recently experienced where melted filament was leaking from between heater block and the throat tube right after I replace the tube and nozzle. This was with the teflon down. In this case I think I didn't have the tube tight enough in the heater block (tightened against the nozzle) so there was room for hot filament to ooze out and up past the tube.</p>

CC BY-SA 4.0
2021-10-31T00:29:59.810Z
This design just makes no sense to me.
R.. GitHub STOP HELPING ICE
<anet-a8>
Which way should the throat tube be oriented?
Pᴀᴜʟsᴛᴇʀ2
# Which way should the throat tube be oriented?

(Asked by: username_0 on 2021-10-30)

I have an Anet A8 clone printer. I see the throat tube is different on each end. I'm trying to ensure I understand which end should go up and which should go down. To me, it appears (from the photo below) the one on the right is the proper orientation (teflon down, metal up). Is this correct?

[![enter image description here](https://i.sstatic.net/gju30.jpg)](https://i.sstatic.net/gju30.jpg)

There are a couple of reasons I ask this question. First, I had the teflon oriented up, and one time the teflon pulled out of the tube while I was pulling the filament out after a print was finished. Secondly, I recently experienced where melted filament was leaking from between heater block and the throat tube right after I replace the tube and nozzle. This was with the teflon down. In this case I think I didn't have the tube tight enough in the heater block (tightened against the nozzle) so there was room for hot filament to ooze out and up past the tube.

**Tags:** anet-a8
> **Comments:**
> **username_1**: This design just makes no sense to me.  

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## 1 answers

### Answer by username_2 on 2021-10-31. Score: 2 | Accepted answer

The PTFE liner should be in contact with the nozzle. Normally, they are cut about half a millimetre too long, to ensure that good contact with the nozzle is made. I used these throats for several years before I switched to an all-metal hot end. If you take care to tighten the nozzle with the hot end at the highest working temperature that you intend to use, you should have no problems with leaking filament.


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