loctite adhering to aluminum
loctite adhering to aluminum
(OP)
Were having issues with steel to aluminum loctited assemblies coming loose. Normally they'll withstand 40 ft-lbs. of torque, but when they fail, it's only at 5 ft-lbs.
We clean and rinse parts, and use primer and #638 retaining compound for strength. When we take the failed assemblies apart, it seems half the loctite is gone, and only residue on the trailing half of the threads remains. Is the loctite being wiped away by the threads?
Maybe the retaining compound is to viscous for threads, but when it works, it work very well. Has anyone had this type of consistancy problems?
Thanks...
We clean and rinse parts, and use primer and #638 retaining compound for strength. When we take the failed assemblies apart, it seems half the loctite is gone, and only residue on the trailing half of the threads remains. Is the loctite being wiped away by the threads?
Maybe the retaining compound is to viscous for threads, but when it works, it work very well. Has anyone had this type of consistancy problems?
Thanks...
RE: loctite adhering to aluminum
I suggest you contact Loctite, or at least seek information and recommendations I am sure can be found at their web page.
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
RE: loctite adhering to aluminum
Ted
RE: loctite adhering to aluminum
Loctite 242 has always worked for me. What Loctite are you using, and what exactly is your material?
--
JHG
RE: loctite adhering to aluminum
As others have suggested, one of the high strength thread lockers may be more appropriate.
The stated gap filling capability of the 638 product "approaches .25 mm/ .010" ".
The internal clearance of your 1-1/4-7 threads (*) can easily exceed that.
* When information is not provided in OP, I provide my best guess. Yesterday I was working with a dainty 1.25-7 thread, so what else could I assume ??
====.
As far as how/where/when to apply Loctite to the components being assembled, Loctite has something to say -
https://tdsna.henkel.com/NA/UT/HNAUTTDS.nsf/web/FB...
"For Slip Fitted Assemblies, apply adhesive around the leading edge of the pin and the inside of the collar and
use a rotating motion during assembly to ensure good coverage."
I'd think assembling a threaded part would be similar to to twisting together a slip fitted assembly.
RE: loctite adhering to aluminum
RE: loctite adhering to aluminum
Your may not be triggering all of the time.
Talk to your supplier.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: loctite adhering to aluminum
Follow the advice given above.
RE: loctite adhering to aluminum
It seems our overseas supplier is applying a corrosion inhibitor to the aluminum parts since they sit on the water for a month, so the loctite won't cure properly in the presence of nitrates. The short term solution is to wash the aluminum parts, and long term is change the type of inhibitor.
Thanks again...
RE: loctite adhering to aluminum
Ted
RE: loctite adhering to aluminum
RE: loctite adhering to aluminum
The inhibitor was not only blocking the metal ions and affecting curing, but also changing the surface tension and wetting ability of the adhesive on the metal.
...Learn something new every day.
RE: loctite adhering to aluminum
Or are you removing it yourself, now?
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF
RE: loctite adhering to aluminum
But the original post said - " We clean and rinse parts, ..."
What are the details of the apparently unsuccessful "cleaning ?"