To continue this stub on the subject of defroster repair, I'll mention some very old and possibly not relevant experiences. I have not attempted this repair on any Volvo.

In the 60's when printed circuits were just coming of age in industry, a vendor marketing to consumer repair shops, e.g. TV/radio repair, GC Electronics, provided small quantities of chemicals to help with the maladies of the new technology. One such chemical got famous. It was called Print-Kote Solvent. The solvent was marketed to remove another product intended to suppress arcing and moisture intrusion, called, ah, Print-Kote. But its "fame" is as an effective universal non-polar solvent, which I guess, if I remember the smell, was toluene.

Then they supplied a silver powder in suspension called Silver-Print, to repair circuit traces, but it was not so popular, because most circuit traces could more easily, effectively, and permanently be repaired by tacking a piece of wire over the broken portion. I can guess the outrageous price of this stuff now is not entirely due to a rise in silver prices, but lack of demand. Who ever buys a second bottle?

There are a few uses for this metal in suspension, one of which is exactly what you are doing. One gently polishes the defroster/defogger line around the break, masks it, and brushes on a few coats of copper or silver in suspension. I did this to a car long ago, and had temporary success. I say temporary because the breaks I were repairing were not due to an ice scraper, but simply the loss of the original metal across the entire grid. Fix one spot and another opens up when current is applied.

A friend uses this to fix modern keypad contacts which wear out, such as those you find in your TV remote control. In spray form it is used to create RF shielding in a plastic housing.

If you do manage to reclaim the defroster grid in your Volvo, please write it up. It is the alternative to replacing the rear window, which for any other reason never needs replacement.
--
Art Benstein near Baltimore

Sometimes, the good you do does you no good. -Dr. Phil's way of saying no good deed goes unpunished.