You're absolutely right. Titanium printing lasers are at 1070nm. Very close to what this machine was giving off. Each material will take a different nm.

Adding black will work.  I thought sla printer immediately when I saw this on styro piro. There is an arduino open source sla project.
You will need argon for allow type metals like Ti and aluminum.  

Be overly carefull with this!
Metal Powder can ignight into a fire you wont be able to put out.  You will need argon. Look up how not to burn your house down first! Ti and mg powder is no joke.

I suggest you look into titomic. Cold spray deposition as well!

If I recall correctly, StyroPyro was able to point the laser right at his skin with minimal effect because it's designed to only couple with darker pigments. I wonder if that will mean you have to stick to darker metal powders, or perhaps have to somehow tint the powders to get them to heat up enough to stick.

Just a thought, looking forward to seeing progress. Keep us posted.

Yes. I believe this have to do with the lenght of the pulse. On flickr [Andrew Harmon] seems to have manager to wed metal with longer pulse. So I will follow that road, remove the Q switch and lower the capacitor voltage or the capacity to see if it help