What sealant should be used

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Spikeysonic
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What sealant should be used

Postby Spikeysonic » Fri Mar 10, 2017 5:06 pm

been told I need some form of sealant, thread or ptfe sealant on the throat screw threads on the hot end but there seems to be many with different heats and some appear to be glues (Don't want to permanently lock it.

Can you guys recommend the right ones to use for Raise 3D 300 degree c printers and which to avoid that are available in the uK. Ideally with links or photos please

Jetguy
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Re: What sealant should be used

Postby Jetguy » Fri Mar 10, 2017 5:51 pm

No, no sealant on the planet will seal the threads of the extruder. Whoever told you that was dead wrong.
The nozzle must seal to the thermal barrier by how they are screwed into the heater block.
The thermal barrier tube AKA throat screws in from the top of the block. The nozzles screws in from the bottom.
In the middle of the block they tighten against each other. That is the seal.
Last edited by Jetguy on Fri Mar 10, 2017 6:30 pm, edited 1 time in total.

Jetguy
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Re: What sealant should be used

Postby Jetguy » Fri Mar 10, 2017 6:12 pm

https://www.raise3d.com/pages/instructi ... assembling

Again, while they show and list high temp silicone, this has never been something I recommended to the group and does nothing- less than nothing to seal against leaks. It cannot. realize that because the filament is only 1.75mm in diameter and the extruder feeder can push with a few pounds of force on that, that the hydraulic pressure inside the hotend system is minimally several hundred pounds per square inch and easily could reach 1k PSI. Silicone or any other sealant under temps of above 200C, and pressures over 500PSI- nothing short of a metal on metal deformation seal is going to seal against that.

Again, if the filament is 1.75mm diameter, then Area=Pi*Radius Squared.
1.75mm diameter is 0.875mm radius (1/2)
0.875mm = Area of 2.41mm
1 square inch = 645.16mm
645.16/2.41= 267.70 ratio
So for 1 pound of pressure pushing the filament into the hotend and nozzles results in 267.70 PSI
Anything over 4 pounds of push by the extruder results in over 1K PSI inside the hotend and specifically at this joint between the nozzle and thermal barrier where this is liquid plastic.

That's why sealant is not going to do anything meaningful and is a step that can be removed.
Last edited by Jetguy on Fri Mar 10, 2017 6:32 pm, edited 1 time in total.

Jetguy
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Re: What sealant should be used

Postby Jetguy » Fri Mar 10, 2017 6:30 pm

If you insist on exactly following the instructions and adding sealant- then use automotive high temp rated silicone based sealant.
https://www.amazon.com/Permatex-81160-H ... B0002UEN1A

Again, it does nothing for actual sealing, If you don't get the assembly correct and the nozzle and thermal barrier are not tightened against each other inside the heater block- no amount of sealant or type of sealant will stop hot molten plastic from leaking out of the threads and making a huge mess.

Ari
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Re: What sealant should be used

Postby Ari » Sat Mar 11, 2017 12:04 pm

The raise3d hot end assembly instructions refer to high temperature silicon grease (not a sealant). Presumably this is to make it easier to release the threads of the throat tube the next time it needs to be removed.

Jetguy
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Re: What sealant should be used

Postby Jetguy » Sun Mar 12, 2017 6:31 pm

While the instructions say the word grease, I assure you that in the 7 V2 hotends all straight from Raise 3D, that is not grease. It is in fact some type of sealant and it's dried hard in the threads when you take these apart to adjust the nozzle. In fact, if you Google the label on the tube of adhesive- NOT GREASE- used in the pictures, it's https://www.aliexpress.com/item/Kafuter ... 31485.html

Again, I'm saying avoid adding anything. Just about everything you do add burns, chars, and degrades under the heat. It has no possible way of actually sealing anything under the pressures present. In fact, some things you could put there would be more prone to stripping out the threads in the heater block than others.
Last edited by Jetguy on Sun Mar 12, 2017 6:44 pm, edited 1 time in total.

Jetguy
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Re: What sealant should be used

Postby Jetguy » Sun Mar 12, 2017 6:43 pm

Kafuter 611 Polymer liquid sealant Non-toxic glue Silicone Rubber Adhesive sealant
Product features:
With high polymer synthetic rubber as main material, with reinforcing agent,antioxidant and solvent refined.
No particles of white sticky paste; easy disassembly, convenient repairing again; adhesive after curing elastic; have good seismic sealing performance;resistance to various engine oil, gear oil, gasoline, diesel oil and water media

Properties and Uses:
Wipe moisture sealing parts and oil; glue evenly coated on sealed surfacesor threads; normal open about 5 ~ 10 minutes; closure sealing surface,tighten the bolt assembly; such as the sealing gap is bigger, to be used in conjunction with other gasket.

Scope of application:
Automobile, motorcycle engine cylinder pad, oil pan pad, pad into the exhaust manifold and the gearbox, also for thread locking and sealing.
Attachments
1_30ca4145-74ff-4619-a4bd-19a82932a5d3_large.png
Kafuter611.jpg
Kafuter611.jpg (11.19 KiB) Viewed 2702 times
5_26a9ed82-fc03-4562-acbd-5fb279699e4a_large.png

itsawhatchamacallit
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Re: What sealant should be used

Postby itsawhatchamacallit » Tue Jul 09, 2019 6:59 am

I've been thinking about doing this since early 2018 because the Ender 3 is notorious for jams, and after enough times of my Ender 3 hotend loosening itself and causing major heat creep jams, I'm sick of it. The hotend with this thing is a nightmare. After looking for sealants for awhile, I finally came across McMaster-Carr which makes several very capable thread locker / sealant products that easily surpass any of the force requirements mentioned above.

Several options that look promising:

(best) Extreme-temp thread locker with 2000 cP viscosity - up to 2100F

(better) Non-hardening thread sealant paste with PTFE - usable up to 500F and 10,000 PSI

(good) Medium strength high-temp threadlocker paste (probably not the best, but maybe it'd work?) - up to 600F



Naturally I want to try the extreme temp threadlocker because it seems to check every single box to be optimal for the application of 3D printing, as it's made specifically for fine-threaded hot metals under pressure. I think it would be great to be able to essentially glue and seal in a properly installed nozzle and heat block as it will never drift again, and ideally there wouldn't even be a microscopic gap left for melted filament to find it's way into and screw things up. As long as you didn't do something stupid with a tool while removing it, you'd be fine. The only downside is the extreme temp locker is about 5x as expensive as the pastes, which causes me to wonder... would either of the first two would do adequately? The PTFE sounds like it could be a really good self-lubing type of experience as dry PTFE spray does a bang-up job of keeping filament moving. I'm probably going to spend a stupid amount on the extreme temp just to lock in a couple of hotends, but it's the idea of such a seemingly perfect medium to fix a really annoying problem that doesn't technically even need to be there that attracts me to it.

Thoughts?

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jetdillo
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Re: What sealant should be used

Postby jetdillo » Fri Jul 26, 2019 8:25 am

itsawhatchamacallit wrote:I've been thinking about doing this since early 2018 because the Ender 3 is notorious for jams, and after enough times of my Ender 3 hotend loosening itself and causing major heat creep jams, I'm sick of it. The hotend with this thing is a nightmare. After looking for sealants for awhile, I finally came across McMaster-Carr which makes several very capable thread locker / sealant products that easily surpass any of the force requirements mentioned above.

Several options that look promising:

(best) Extreme-temp thread locker with 2000 cP viscosity - up to 2100F

(better) Non-hardening thread sealant paste with PTFE - usable up to 500F and 10,000 PSI

(good) Medium strength high-temp threadlocker paste (probably not the best, but maybe it'd work?) - up to 600F



Naturally I want to try the extreme temp threadlocker because it seems to check every single box to be optimal for the application of 3D printing, as it's made specifically for fine-threaded hot metals under pressure. I think it would be great to be able to essentially glue and seal in a properly installed nozzle and heat block as it will never drift again, and ideally there wouldn't even be a microscopic gap left for melted filament to find it's way into and screw things up. As long as you didn't do something stupid with a tool while removing it, you'd be fine. The only downside is the extreme temp locker is about 5x as expensive as the pastes, which causes me to wonder... would either of the first two would do adequately? The PTFE sounds like it could be a really good self-lubing type of experience as dry PTFE spray does a bang-up job of keeping filament moving. I'm probably going to spend a stupid amount on the extreme temp just to lock in a couple of hotends, but it's the idea of such a seemingly perfect medium to fix a really annoying problem that doesn't technically even need to be there that attracts me to it.

Thoughts?


I'd avoid PTFE/PTFE-related compounds on any part of the hot-end, esp. if you are printing with high-temp filaments. Just about any guide that you read about "How to print with PETG" or "How to print with Nylon" will tell you to use an all-metal hot-end because the PTFE in regular hot-ends will break down and outgas at the temps needed to print those materials. I would imagine PTFE grease would behave the same way.


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