[bruce wilcock]

if you feel you need a flux silica sand ,is proberly as simple to use just throw a light dusting on the fire as your job comes towards a full heat,a bottle broken up into dust is cleaner but you will have to place it over the job to make shure it melts,and is the one we use on big jobs if the steel in one fire comes to a heat before the other piece in another fire is ready, somthing we try to avoid,
this is the only time i might use a flux, i work wrought iron up from old chain and it all has to be welded up under the hammers without flux
i have put a small piece of wrought iron between steel if its a bit of carbon in it and its welded up well