[cadman]

Originally Posted by sagacious

I think you nailed it: humidity. Low humidity during winter, plus with pouring high-volume, you go through the lead before entrained lead oxides and surface oxides build up to a deleterious point.

As the summer day wears on and the temp rises, so does humidity.
As the humidity rises and time passes, the melt eventually develops a significant amount of surface oxide, as well as entrained oxide. (You know when you get that hazy grey scum on the melt, and you stir it back in, and the melt surface is shiny again? Well, you've just stirred in all those oxides so they can cause lots of problems. Better to flux the melt and just remove the bad stuff. )

You pour 100 jigs. As humidity increases and time passes, more oxides form and collect in the melt until it becomes sufficient to prevent good pours. You stop and start over again when the humidity is low, and everything is back to normal........... until the humidity rises and enough time passes.

The soution to directly address this problem is, of course, fluxing the lead. Maybe fluxing twice, if you had a frustrating pouring session and you want to be sure. Flux early, flux often.

So, as my gramdma would say, "the proof of the puddin' is in the tastin'!" Next time you pour when the humidity is high, flux the lead once every hour, or more often if you're adding a lot of lead ingots per hour. Try that, and get back to us. Should be, "problem solved!"


Or get a de-humidifier! Better yet, just flux early, and flux often!

I would need a big de-humidifier in my garage.......Thank You for your wealth of knowledge, your insight and all of your help. If you ever need any help down the road PM me.