[photo-3d] Union case repair

[E R Swanson <ers@xxxxxxxxxxxxxxxxxxxx>]

I'm afraid I don't know what a Union Case is, but repairing plastics or
metals with adhesives really depends upon a number of factors. Type of
plastic. Load bearing. Potential shear (e.g. vulnerability to angular
stress). If the plastic is meltable with an organic solvent cement, then
that's the way to go, because it's analagous to welding. You have to be
very careful because the stuff is nasty, and it cal also leach out
elasticizers out of the plastic behind the repair. Epoxy is a good bet for
other plastics, and it has better shear strength than the cyanoacrylates
(superglue). However there are exoxies and there are epoxies. Fargo
Enterprises should have just about anything you need. Unless you need a
flex quality in your careful re the 5 minute epoxies that you get at Home
Depot-- these adhesives tend to stay slightly rubbery. A good superglue
with a spray accelerator can be excellent-- if shear strength isn't a
major issue. As with epoxy, there are all sorts of superglue flavors--
viscoscity factors, etc. And superglue has a shelf life. Never buy
superglue at Home Depot, get it from Fargo or a Hobby Store. It can also
be used where shear strength is an issue if you make a reinforcement piece
of plastic or metal. In some cases it's best to use a dremel and cut in a
space for a metal or plastic brace. Thin reinforcing metal is available at
hobby stores. If color is an issue, you can get black superglue from
Fargo. Surfaces should always be clean, and free of any adhesives used for
earlier repair attempts. Never rough up a fracture being fixed, but
sometimes roughing up larger surfaces that bond is a good idea. Sometimes
not. Depends upon the adhesive and the nature of the repair. Lastly some
plastics cannot be fixed, except by exotic techniques like sonic welding,
though I've faked it with heat. Risky...

Elliott