To all,
Note the following correspondence and corrections.
>However, I do not believe that your comment in regards to Super Glue being
>anaerobic is correct. The active ingredient in such glues is a
>cyanoacrylate monomer, which polymerizes in the presence of hydroxyl ions
>in water. The moisture found on all surfaces (unless the humidity is very
>low) is sufficient to quickly polymerize the thin film of glue in a joint.
>This is also what happens in the bottle cap. The entire contents of an
>opened bottle of glue will thicken and harden after several months due to
>moisture being introduced into the bottle. Uncured glue left in the open
>will do the same. I don't think that the presence or absence of air
(other
>than as a vehicle for the moisture) has anything to do with the process.
>I am not a chemist, just insatiably curious. My use of cyanoacrylates in
>building radio control airplanes prompted me to research how the stuff
>works.
>BTW, Permatex is the automotive product line of . . . Loctite Corporation.
>73, Jimmy
>Jimmy, KG2AU <kg2au@stny.lrun.com>
Original response:
Jimmy,
Awh shucks, you caught me trying to oversimplify the components of the
subject and make it easy for the multitudes to digest.
Yes, you are correct that the cyanoacrylates work on a different chemistry.
I'm not a chemist either, but have been forced to delve into these
materials to get reliable products out the door!
You're correct that most commonly recognized "Super Glues" are
cyanoacrylates. I know that I have run across several anerobic adhesives,
would have to dig deep into the bookshelf to find them!
I'd really like to make a post regarding your comments , correcting me, to
further the knowledge of the reflector subscribers. with your permission, I
will do so. <snip>
>Kurt,
>Feel free to post any or all of my message re CYA (cyanoacrylate)
adhesives
>if you think it will help others. Please note that I was referring only to
>the Super Glues, not to the Loctite threadlocks. Loctite threadlocks ARE
>anaerobic adhesives. However, several of the CYA manufacturers do make CYA
>based theadlock compounds. The ones I have used range from Loctite red to
>green in difficulty of disassembly. Please include this clarification in
>any post you make, ...
>Maybe a real chemist will come forward and help us out if I don't have
>everything right! <snip>
>73, Jimmy
Thanks Jimmy! That's what happens when I try to shrink the discussion. What
I was after, is the apparently identical behavior of the two to illustrate
the behavior. Trapping it in a confined space vs a relatively open one.
With the anaerobic one, absence of air promotes cure, with the CYA it is
confining it with moisture in a thin film.
The air is crucial to the curing of the cyanoacrylate. It is usually the
only vehicle to introduce moisture into the connection.
That's why people in dry desert climates, like my QTH will have difficulty
with cyanoacrylate thread locking compounds or super glues.
East coast and Gulf coast U.S. areas should be ok.
Side Note: This problem is identical for RTV (room temp. vulcanizing)
rubbers (I.E.one part silicones). The subject of a previous post.
Additional information:
I've been waiting for a bit to see what comments come in regarding good &
bad experience with the thread lockers. Hope to compile them by the end of
this week. Some of the comments made me realize an omission from the
original post.
The Loctite compounds are intended to be used with a primer. You can get
acceptable performance without the primer if the surfaces are CLEAN! I do
not know exactly what is in the primer (trade secret), but from its odor I
would wager it has some anhydrous isopropyl alcohol. This stuff is magic
for eliminating moisture from the surface. The alcohol readily absorbs
water. When it evaporates it takes the water with it.
Side note: If you mix 1 gallon of water with 1 gallon of anhydrous alcohol,
you end up with less than 2 gallons of mixture. This is evidence of the
chemical linking of the two, whereby, the different molecules intertwine,
resulting in a smaller volume.
Some of the comments have indicated that the "Red" compounds come apart
easily. Probably due to lack of use of the primer.
BTW, you probably won't find the primer in just any auto or hardware store.
Try an industrial supply.
73, Kurt
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