I'm assembling some machined copper parts for my rocket project. I'm using silver solder. If I heat the parts hot enough to make the solder flow then the parts get a scaly dark almost black coating.
On the exterior of the parts I can wire brish this away, but in the interior passages I have some very fine (0.010") passages I don't want to get clogged.
Does anyone know of a chemical method for cleaning this?
Does anyone know how to prevent it from forming?
I'm using a MAPP torch in normal air, I've Contemplated getting a sand blasting box and converting it to an argon purge box, then using an oxy acelelne torch to heat it, as the box has no Oxygen.. I could also maybe put it in a purge box and heat with a TIG torch.
Would the purge box help?
Am I better off just finding a furnace brazing shop?