John: Carbon may be the enemy of platinum, but the carbon left behind
by the cyanoacrylate when it burns will disappear long before the
platinum approaches welding temperature. As you know, platinum will
not normally oxidize, so no flux is needed for welding.
Problems occur when you try to weld on a platform of carbon that does
not burn away completely, like a charcoal or graphite block. I have
never had a problem with using glue on platinum.
I should also mention that I do not like the gel form of
cyanoacrylate. I find it to be too thick. I use the more liquid type,
and use it very sparingly.