When soldering, I understand there is a powder that can be mixed to coat the metal. This will keep the solder from wicking past the coating.

Anyone know of this product and can explain better how it works, and where to get the stuff?

yellow ochre

Most jewelry suppliers carry it, and it works by contaminating your flux. Paints on really easily

[Edited. Do not use correction fluid unless you have excellent ventilation. It turns out that even the water based stuff produces nasty fumes when burned. My apologies.]

As far as I know, these things work by preventing the solder from wetting the underlying metal. Cleanliness is the key to good soldering; these are just reliable ways to make parts of the base metal dirty.

Edited October 30, 200916 yr by MattBower
safety

I much prefer the yellow ochre to the Wite-Out crap. Let the yellow ochre dry, I use a hair dryer on low to accomplish this.

I use a welders soap stone. I works for solder and brazing. Just draw the boundry with the soapstone and solder will not cross.

brad

Here's a link to fluxs and products that prevent the flow of solder etc.
Have not personaly used these products but have used yellow ochra for hard silver soldering.
http://www.riogrande.com/MemberArea/SearchPage.aspx?page=GRID&category|category_root|126=Soldering+Equipment+and+Supplies&first_answer=241

Glen I use yellow ochre as well. The product does a great job for me.