Covering silver wire for use as a speaker cable

Why would you be contemplating using silver and copper? If you can afford it, use silver only. It has the highest conductivity.

Willoamp, The silver wire I have is about 26 gauge.
The thought of using copper was to be able to add more gauge.

Here's a basic "rule of thumb" for estimating wire gauge needed when combining gauges. There's a chart for this somewhere.
Every time you double up the amount of silver, the effective wire gauge goes DOWN 3 steps.

If you double-up on 18 ga., the effective total gauge is now 15. Double up again (4 - 18 ga. wires), and it is now 12 ga. effective total.

Add two eight ga. wires together, and it becomes 5 ga. effective total.

So in your case, doubling two 26-gauge wires is now 23 guage. Four runs of 26 guage would now be 20 gauge, and so forth...

Has anyone made progress with bare silver speaker wire? Any news about the need for a cover? Any other news?

Sabai, check out Tempo Electric cables. They use an oversized teflon tube so as to minimize contact to the wire itself. They also recommend no terminations but if you want, they use what they feel are the best ones out there and they raise the cost of the cables considerably.

I have a set and they're really good.

All the best,
Nonoise