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JB Weld versus Loctite for grubscrews

fafrd

Solar Wizard
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I’m getting ready to install 20mm SS M6 grubscrews into my EVE 280Ah cells and am down to the last detail of whether to use JB Weld or Loctite to secure the threads.

So I’m asking those members who have experience with both whether there is any disadvantage to using JB Weld over Loctite that I am overlooking?

I understand JB Weld will make a permanent installation and that the grubscrews can only be be removed by stripping out the threads while Loctite makes non-destructive removal possible, but I am not interested in ever removing these grubscrews once installed.

A higher priority for me is strength of the installation especially in the presence of worn threads. The top 3 aluminum threads of my terminals are visibly worn from just 4 insertions/removals of SS bolts with light force (by hand) and one terminal is pretty much stripped over the top 3 threads from being torqued to 4Nm / 35 inch-lbs.

So I want to use these threads only once ever again and have as strong a connection as possible the the 3 pristine lower threads on the worn remains of the upper 3 threads.

I believe JB Weld will be better for an ‘as-strong-as-possible’ permanent installation but appreciate any heads-up of JB Weld is inferior to Loctite for reasons other than the one already listed (removal).

If anyone has already used JB Weld to secure M6 grubscrews into the M6 aluminum threaded holes tapped into 280 Ah LiFePO4 cells, I’m interested in any tips and especially in any regrets.

I understand the holes should be well-cleaned first, so any advice on the best way to clean the threaded holes would also be appreciated...
 
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I use JB weld for a lot of things I don't think it would be particularly good for your purpose. While you can thread it it isn't all that strong as a thread and it doesn't conduct electricity. I suggest that you repair the threads with something like a heli-coil and if necessary use loctite on the repaired thread.
 
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Hilicoils would be so much better.
I'm going to try locking my studs in with permanent threadlocker.
People say you can't remove them without heat. That must add pull out strength to the threads.
 
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Hilicoils would be so much better.
I'm going to try locking my studs in with permanent threadlocker.
People say you can't remove them without heat. That must add pull out strength to the threads.
fyi I have never found any of the permanent thread lockers really permanent. I was trying to find something so I could secure a backup generator as part of a system to at least slow down a thief. Nothing actually held if I use my impact wrench with enough patience. It was disappointing....buuut, do you have a product in mind that you have tried? My attempts were just the typical off the shelf consumer grade stuff.
 
I use JB weld for a lot of things I don't think it would be particularly good for your purpose. While you can thread it it isn't all that strong as a thread and it doesn't conduct electricity. I suggest that you repair the threads with something like a heli-coil and if necessary use loctite on the repaired thread.
I specifically did not ask about Helicoil because it is far more trouble and I’m saving that as a fall-back option in case JB Weld or Loctite using remaining threads fails.

I’m not concerned about conductance through the fastener - surface conductance through the Aluminum terminal ‘doughnut’ is sufficient for me.

If you are saying the use of JB Weld will not be any greater than just using the remaining threads (with Loctite to eliminate rotation if needed), that might cause me to skip the JB Weld and just Loctite in my grub screws into the remaining threads.

But seeing the wear on the upper 3 threads makes me think epoxy or JB Weld or something to harden into the remaining space and eliminate any play / movement on the grub screws from the partially-worn upper 3 threads would be a good idea...
 
Oh, I have had decent luck keeping bolts subject to vibrations or expansion in place using a toothpick inserted into the hole with the bolt. Seems to add just the right amount of grip to reduce loosening. And it won't add so much bulk that the thread might strip. My thoughts for the ones I'm building as to use the toothpick with a drop of Loctite or even JB Weld, just a drop...
 
Others have had luck using JBWeld. It is a matter of your choice whether you want helicoil or JBWeld.
As I (just recently ;) said, JB Weld seems much less involved than Helicoil, so I want to use either JB Weld or Loctite to try to salvage the remaining threads and save Helicoil for a fall-back / recovery action in case thus first less-involved attempt fails...
 
Hilicoils would be so much better.
I'm going to try locking my studs in with permanent threadlocker.
People say you can't remove them without heat. That must add pull out strength to the threads.
I thought you were going to try JB Weld???

Perhaps I misunderstood.

When you say you are going to use ‘thread locker’ do you mean into existing aluminum threads or into Helicoil?

And what is threadlocker? Is it different than JB Weld and different than Loctite?
 
Oh, I have had decent luck keeping bolts subject to vibrations or expansion in place using a toothpick inserted into the hole with the bolt. Seems to add just the right amount of grip to reduce loosening. And it won't add so much bulk that the thread might strip. My thoughts for the ones I'm building as to use the toothpick with a drop of Loctite or even JB Weld, just a drop...
It’s not really loosening from vibration I’m concerned about. My battery will be in the basement and never moved after installation.

My main concern is salvaging the remaining aluminum threads (the lowest 2 threads are pristine / unused) to secure 20mm SS grubscrews as strongly as possible (ideally able to take a nut tightened down with 4Nm / 35 inch-lbs of torque).

Have you used JB Weld in threads before? Why ‘just a drop’?
 
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It’s not really loosening from vibration I’m concerned about. My battery will be in the basement and never moved after installation.

My main concern is salvaging the remaining aluminum threads (the lowest 2 threads are pristine / unused) to secure 20mm SS grubscrews as strongly as possible (ideally able to take a nut tightened down with 4Nm / 35 inch-lbs of torque).

Have you used JB Weld in threads before? Why ‘just a drop’?
KK, gottcha!! Salvaging the threads is for sure a tough one and yup a more permanent product is def needed. I mentioned just a drop because it will still hold but also be easier to break loose should you ever need to remove it. Also it should interfere less with conduction? I don't know about the conduction because I've never used it in an electrical connection just mechanical connections.

I learned a lot from you guys here about the weak point of these batteries...the aluminum bolt holes. I sort of wondered about it but dismissed it without really thinking about it...so thanks for sharing this info. My install is going to be in the RV meaning vibration will be a concern for sure.

I think your idea with the JBW is a good one and if it fails you can always drill it out, retap, install a coil and go back at it...
 
I thought you were going to try JB Weld???

Perhaps I misunderstood.

When you say you are going to use ‘thread locker’ do you mean into existing aluminum threads or into Helicoil?

And what is threadlocker? Is it different than JB Weld and different than Loctite?
I still might try JB weld. I change my mind a lot. And I know helicoils are strong as hell
 
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KK, gottcha!! Salvaging the threads is for sure a tough one and yup a more permanent product is def needed. I mentioned just a drop because it will still hold but also be easier to break loose should you ever need to remove it. Also it should interfere less with conduction? I don't know about the conduction because I've never used it in an electrical connection just mechanical connections.

I learned a lot from you guys here about the weak point of these batteries...the aluminum bolt holes. I sort of wondered about it but dismissed it without really thinking about it...so thanks for sharing this info. My install is going to be in the RV meaning vibration will be a concern for sure.
I’m pretty sure once you gain some experience with these weak aluminum threads, that any concern with ever needing to break loose a grub screw after it has been properly installed will be out the window in about 10 seconds flat...
 
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I’m pretty sure once you gain some experience with these weak aluminum threads, that any concern with ever needing to break loose a grub screw after it has been properly installed will be out the window in about 10 seconds flat...
hehehe, yeah that sounds pretty true for sure!! :D
 
I still might try JB weld. I change my mind a lot. And I know helicoils are strong as hell
Well I’d been planning on waiting for your report back on JB Weld before going that route - sounds like I’ll either have a long wait or need to be the guinea pig...

Helicoil seems a lot more involved, more expensive, and always an available option (as long as the grub screws can be removed).

So my plan is to try to salvage the threads that are there to hold grub screws, torque busbars down to 30 inch-lbs or hopefully 35 inch-lbs, and check electrical performance.

If it fails or the performance makes it clear I need higher torque, maybe time for Helicoil, but if it performs well-enough, I’ll be good to go...
 
I’m pretty sure once you gain some experience with these weak aluminum threads, that any concern with ever needing to break loose a grub screw after it has been properly installed will be out the window in about 10 seconds flat...
just a thought....have you considered installing studs rather than bolts? if they get permanently secured you can then have lots of freedom should you ever end up needing detach a cable. I know you mention you are doing a permanent install I'm just thinking aloud here based on my past misadventures in bolt tech.
 
just a thought....have you considered installing studs rather than bolts? if they get permanently secured you can then have lots of freedom should you ever end up needing detach a cable. I know you mention you are doing a permanent install I'm just thinking aloud here based on my past misadventures in bolt tech.
I thought so made that clear in my lead post - yes, I want to install threaded stainless ‘posts’ (grub screws) once and forever.

That is the reason I don’t care about removal after glueing into the aluminum threads - battery can be disassembled by just unscrewing the nut holding down the busbar against the terminal...
 
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oh I'm sorry I read too quickly...oops!! I do that once in a while...you logic makes total sense...
 
Well I’d been planning on waiting for your report back on JB Weld before going that route - sounds like I’ll either have a long wait or need to be the guinea pig...

Helicoil seems a lot more involved, more expensive, and always an available option (as long as the grub screws can be removed).

So my plan is to try to salvage the threads that are there to hold grub screws, torque busbars down to 30 inch-lbs or hopefully 35 inch-lbs, and check electrical performance.

If it fails or the performance makes it clear I need higher torque, maybe time for Helicoil, but if it performs well-enough, I’ll be good to go...
helicoils aren't expensive. And I bet one could be installed without even removing the cell from the battery.

I am fairly sure I pulled out another one today with 40 inch pounds. I stopped and screwed the stud in all the way then got it to hold 25 inch pounds. I'm so pissed. Lucky I have lots of cells to play with.

Less than 40 inch pounds isn't right for this purpose. If I can strip them with 40 then I guess I should try 30 and even that might strip one.
 
oh I'm sorry I read too quickly...oops!! I do that once in a while...you logic makes total sense...
if you are new to this domain and planning to purchase some new 280Ah LiFePO4 cells, my advice to you is purchase 20mm SS grub-screws and Loctite before your cells arrive, install them into your virginal terminal threads first thing when they come out of the box, and only ever exercise those threads a single time.

I hand threaded down busbars only 3 times using a Philips screwdriver on bundled SS bolts and was exceedingly careful and gentle in doing so (low current so didn’t really care much about resistance of the connections).

The upper 3 threads (of 5 total) of all of those terminals are visibly worn far more than I would have expected.

Mentally, imagine you are screwing a bolt down into threaded clay - it’s really not that different.

Sp I will never again use new threads for insertion & removal (using bolts instead of grub-screws).

The new unused threads should be strung enough to hold a grub-screw down (once & forever).

But as soon as you start unthreading, you are taking some of that soft aluminum thread with you...
 
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