Al Lorona wrote:
Has anybody noticed that Super Glue (cyanoacrylate clear liquid glue) just
doesn't seem to work any more? I remember when it first came out that it
used to bond anything and everything. Lately, seems that I can't even fix my
son's toys with it any more.

Latest failu Just tried to glue a small 12V DC fan for a PA with it and
the bond came apart the next day pretty much by itself.

Al W6LX

FWIW, I've found a product called "Plas-T-Pair" to work in a lot of
cases where "super glue" won't. Also, I've been using LocTite 444 "Tak
Pak" alpha cyanoacrylate for other things, as it seems to work better
than the thin mass-marketed superglues. LocTite 712 accelerator makes
it set up quickly. In addition, any joint with stress (esp. tension)
on it I'll augment with reinforcement of some sort. Lots of things
work: embed a little scrap of cloth in the joint, drill mating holes
and put in a peg made from wood dowel stock, or threaded rod (a cut-off
machine screw, for example), or roughed-up steel wire, or even copper
wire. Even wrapping sewing thread (or small steel wire) around the
joint (if the geometry lets that work, so the thread crosses the joint
multiple times) works wonders. Apply the idea of reinforcement
creatively and you'll pretty much always get a much stronger repair.
Even embedding chopped-up fiberglass in the glue will help. Hint:
superglue alone is probably going to be fine in compression, so long as
it's not subject to shock or excessive mositure, but in tension, it can
benefit a lot from some help, especially if it adds reinforcement where
the glue joint to the original pieces becomes shear instead of simple
tension--i.e., adding pegs in holes.

From your post, I'm not sure just what part of the fan you were gluing.
If it was a broken blade, I'd expect to need to be very careful with
the repair because there's a lot of stress on the blade when the fan is
running, and adding mass will imbalance the blade if you're not
careful.

Cheers,
Tom

Al Lorona wrote:
Has anybody noticed that Super Glue (cyanoacrylate clear liquid glue) just
doesn't seem to work any more? I remember when it first came out that it
used to bond anything and everything. Lately, seems that I can't even fix my
son's toys with it any more.

Latest failu Just tried to glue a small 12V DC fan for a PA with it and
the bond came apart the next day pretty much by itself.
============================
Super glue (cyano-acrylate) works on the basis of 'exclusion of oxygen'
at the joint ,hence it can often be used effectively for rejoining
broken crockery.

With plastic the break surface is often less 'crisp' especially when
interfered with by tools /sandpaper. Hence an expoxy type of glue is
then more appropriate .

Some plastics can be jointed by hot glue dispensed by a hot melt gun
provided it is done carefully and there is a reasonably large jointing
surface.

Polystyrene can be best (re)jointed with polystyrene glue as used for
model making , or acetone (nail polish remover) when the material at
the joint is dissolved locally by the acetone (a solvent).


Frank GM0CSZ / KN6WH