Questions regarding experiences with loctite & using 680 or 630 series retaining compounds as thread-lockers
John2005
Is there anyone in the forum that has used any of the 600 series
loctite "retaining compounds" as thread-lockers ?
I have tested some loctite # 262 & #2760 thead-locker on a #10-24 screw
with a small pattern hex nut having a height of 7/64". I tried black
oxide finished & stainless screws with stainless and brass nuts. After
24 hours, the strength was not satisfactory. Loctite said that the
#2760 is some of the strongest thread-locker they make & does not need
primer and even works in the presence of a small amount of oil. I did
not use primer as loctite said that the primer is already in the #2760
and advised against it's use. The screws were brand new out of the box
and appeared clean and dry.
Someone suggested using #680 retaining compound as a threadlocker and
said that it should be stronger than threadlockers. I see no reason a
retaining compound would not work as a threadlocker unless the gap in
the screw threads is too large for the retaining compound to dry
properly.
Loctite lists the # 638 retaining compound as "maximum strength" but
the # 680 has a shear strength of 4,000.00 PSI
Loctite's technical data sheets don't list the strength of each product
in the same way and it makes it very difficult to compare products.
They should just list the torque necessary to break the nut loose in
each case and provide data for large and small nuts.
This thing never gets hot and is always used at room temperature. I
just want to use a threadlocker or retaining compound to permanently
lock the nut to the screw with the greatest amount of strength
possible. It's no problem to wait 24 hours for the assembly to dry.
Loctite only recommnended using threadlockers, but someone out in the
field said they had used the 680 loc-tite as a threadlocker with
success.
What loc-tite product will produce the strongest bond and/or the
greatest resistance to the nut breaking loose and/or backing off ?
I am going to test some of the 680 and perhaps 638 retaining compound,
I just wanted to see if anyone had any experiences they could relate to
me that might help me choose the best product for the job. Perhaps a
two part epoxy would be stronger, but then I have to mix it and I would
rather use a single part product already mixed.
Thanks for your help.
John
John2005
I tested some 270, 271, 262, 2760, 638, & 680 loctite as a threadlocker
on some 10-24 and
10-32 screws & nuts. Whether the thread was course or fine seemed to
make no
significant difference as far as strength.
I tested with and without primer using black oxide finished screws and
zinc,
brass, and stainless nuts. The stainless nuts had the weakest bonding,
and
the brass nuts seemed to have the strongest bonding although the zinc
seemed
close. I let the loctite dry for exactly 24 hours.
The best bond seemed to be the 680 using a brass nut, black oxide
finished
steel screw, and 7471 primer. I think it will be plenty strong for my
application, but it did not destroy the threads when taking the nut off
the
screw, as a couple people told me it would. The 271 was also good, but
I
think the 680 was a little better, and it seemed to dry faster than the
271
using the brass nut.
The 2760 does not seem very strong at all on small screws.
I just thought I would report my findings to you in case anyone was
interested.
John