Best way (if any) to reattach a copper trace that has lifted?

[jimbob]

Sort of a tangent, but along the lines of what Mark H said...whenever etching your own boards or even having them pass produced, it's a good idea to have FAT traces when possible and even extra holes drilled in vulnerable parts of the circuitry...that way you can re-drill a new hole if a trace lifts or just wire right into your "backup" hole. I have seen this on multiple tube amp boards.

I second that!

[Paul Perry (Frostwave)]

And I always swear I am going to put in a couple of carefully considered 'test points' - or at least the holes for them! - and always forget, in the final layout frenzy.

[amz-fx]

Cheap superglue (or crazy glue) that you get at the dollar store is 100% Ethyl Cyanoacrylate. Methyl Cyanoacrylate is better for bonding metal, and is sometimes used in specialty superglues but you won't find it at the discount stores.

A better quality superglue will have a formula like this:

95.0% Ethyl cyanoacrylate
4.6% Poly methyl methacrylate
0.4% Hydroquinone

The hydroquinone is a free radical stabilizer that is used to extend shelf life. The polymethylmethacrylate is used to thicken the glue slightly and make the bond tougher.

Superglue will begin to release around 194°F (90°C ), so more than a momentary touch with a soldering iron will break the bond. Cyanoacrylate can cause stress cracking of some rigid substrates (like hard plastics) since it tries to hold the piece in place while the substrate expands and contracts. Not usually a problem with small areas.

Superglue depends on water or hydroxide ions on the surface to make a bond, and the best humidity for using it is around 40% to 60%. At low humidity the glue will not cure properly or it may take an extended time to make a cured bond. Higher humidity makes it cure faster but it will make the joint slightly weaker.

A trick to make superglue adhere to a surface is to blow your breath across one of the surfaces and apply the glue to the opposite surface, then stick them together. The added humidity from your breath will make a more positive bond between the pieces.

regards, Jack