After seeing the discussion on cupronil, I want to know if it MUST
be sprayed, or can it be applied with a brush? Can the item be
dipped in the flux? Why spray...is it a cost issue, or does it
affect the function of the flux?
You can absolutely apply it with a brush. I've been doing it for
years. In fact, in my opinion, spraying it on is wasteful.
What's most important is to be sure the piece is very clean before
applying the Cupronil. If it's not, you'll see spots where the flux
didn't cover and those spots will fire stain!
What I do is heat the piece a little, apply the Cupronil and dry it
with the torch. If I don't see a white powdery substance covering all
the metal (with no little spots), I repeat until I do.
I see no reason why you couldn't dip an item except that you'll have
no flux where the piece was being held by the tweezers. Also, if the
the item is heated first, the flux may spatter when you dip. Now that
I think about it, the latter may be a deal breaker, but try it and
see. Just be careful!