Liquid metal style epoxy like JB weld etc

[mobile chicane22]

Looking to repair an M8 thread that's about 30-40 deep, the bolt it contains is not structural just used to adjust chain tension so no real load on it.

Would using the appropriate aluminium putty such as this work ?

https://sylmasta.com/product/superfast-aluminium-s...

I'm thinking fill the knackered void completely with the stuff then letting it cure then drill and tap as required, Google AI suggests a maximum torque of 15NM for any swing arm bolt.

Anyone done this before how did it go and what product did you use ?

[thebraketester]

Is drilling and tapping up to an m10 not an option?

[E-bmw]

thebraketester said:

Is drilling and tapping up to an m10 not an option?

Much better idea if at all possible.

[shtu]

A helicoil-or-similar thread insert is going to be a much better repair, and isn't especially expensive.

A -very- quick look on ebay found 24mm length inserts, which sounds like plenty for your needs.

edit - as above, going up a size is another option, though that does leave you with an aluminium thread rather than the steel of an insert. Either is better than a glob of epoxy though.

[ARH]

shtu said:

A helicoil-or-similar thread insert is going to be a much better repair, and isn't especially expensive.

A -very- quick look on ebay found 24mm length inserts, which sounds like plenty for your needs.

This every time.

[mobile chicane22]

Up sizing to M10 and or helecoil are unfortunately not options due to the location of the hole.

I'll be purchasing some of the above linked epoxy's and doing a test piece on a similar hole on some scrap piece before comitting to it

Edited by mobile chicane22 on Thursday 4th June 11:42

[mobile chicane22]

mobile chicane22 said:

Up sizing to M10 and or helecoil are unfortunately not options due to the location of the hole.

I'll be purchasing some of the above linked epoxy's and doing a test piece on a similar hole on some scrap piece before committing to it.

also I believe the part I am going to re thread is actually 30-40mm deep

Edited by mobile chicane22 on Thursday 4th June 11:42

[mobile chicane22]

Actually looking at it helicoil may work if I can get a 150mm + long drill bit of the correct size

[Ritchie335is]

Look up Time-serts, much better than heli coils.
If you do need to use a chemical metal, JB Weld is thought to be the best from what I have seen.

[xstian]

Ritchie335is said:

Look up Time-serts, much better than heli coils.

Agree, although they are rather pricey, but worth it compared to a botched heli coil.

[Arnold Cunningham]

Ritchie335is said:

If you do need to use a chemical metal, JB Weld is thought to be the best from what I have seen.

Of easily available stuff, I agree. I compared lots of specs when I had a tricky job a few years back and JB Weld was the best commonly available stuff I could find.

[catso]

JB weld is as good as this kind of stuff gets but I wouldn't trust any glue/adhesive/putty repair to hold a thread in anything other than cosmetic.

Either use a thread insert or fill the hole with weld and re-drill it, IMO.

[Krikkit]

Ritchie335is said:

Look up Time-serts, much better than heli coils.
If you do need to use a chemical metal, JB Weld is thought to be the best from what I have seen.

Not necessarily: https://youtu.be/jknMrFOGMOQ?si=CoeG88C1IaZ-_umH&a...

Both are more than capable of being stronger than an originally threaded aluminium part.

mobile chicane22 said:

Up sizing to M10 and or helecoil are unfortunately not options due to the location of the hole.

Can we see the part?

[catso]

Krikkit said:

Ritchie335is said:

Look up Time-serts, much better than heli coils.
If you do need to use a chemical metal, JB Weld is thought to be the best from what I have seen.

Not necessarily: https://youtu.be/jknMrFOGMOQ?si=CoeG88C1IaZ-_umH&a...

Both are more than capable of being stronger than an originally threaded aluminium part.

Indeed, and also more durable if bolts are removed/loosened regularly - As an example, Ducati fit inserted threads into their cylinders to hold timing belt tensioners rather than thread directly into the aluminium for this very reason.

See the 4 tensioner rollers (also M8 threads) on the cambelts here;



I doubt the threads would last very long if they were directly into the heads.

[Ritchie335is]

catso said:

Krikkit said:

Ritchie335is said:

Look up Time-serts, much better than heli coils.
If you do need to use a chemical metal, JB Weld is thought to be the best from what I have seen.

Not necessarily: https://youtu.be/jknMrFOGMOQ?si=CoeG88C1IaZ-_umH&a...

Both are more than capable of being stronger than an originally threaded aluminium part.

Indeed, and also more durable if bolts are removed/loosened regularly - As an example, Ducati fit inserted threads into their cylinders to hold timing belt tensioners rather than thread directly into the aluminium for this very reason.

See the 4 tensioner rollers (also M8 threads) on the cambelts here;



I doubt the threads would last very long if they were directly into the heads.

One way to overcome this is to use a stud and nut rather than a bolt, so the thread is only under tension and less torsional forces when tightening and loosening.