Furnace Problem

I'm getting back into casting bullets after several years layoff. Having a problem with my RCBS ProMelt Furnace: I have to keep heating the discharge nozzle with a torch, sometimes after filling a four cavity mould. Once the pour starts it will keep pouring till I shut it off. Then I may have a problem starting the next pour. I don't recall having to do this years before. I have the furnace set at about 740 degrees and didn't want to go much higher because of the appearance of frosting. Am I going to have to set it higher or is there something wrong with the furnace?

I suspect that you may have some foreign matter in your melt. Flux it well making sure to scrape the sides and bottom, then skim it. Run the contents of the pot into ingot moulds. After the empty pot cools, take it OUTSIDE and wire brush the inside completely, taking great care not to breathe any of the yellow lead oxide powder. Wash it off of your hands afterward. It is fairly water soluble, that is why it is dangerous, but the positive side is that makes it easy to wash off. Make sure the spout is all cleaned out and working properly. Start again with some clean ingots. If the problem reappears, you may need to return your alloy supply to the smelting pot to thoroughly flux and skim it. As you surmised, turning the temp up won't help at all, you have to get the imputities out. It's really aggravating when you get all set up, moulds preheated, and then the spout keeps clogging. I suspect it has been the source of not a few new words in the language. Good luck.

Is the pot slow to heat up?
Could it be Coil going out of it.
Ken.

Thanks for the input. I had emptied the pot, but did not do the extent of cleaning that you suggest. I will empty it again, wire brush and flux as you suggest. Thanks

There doesn't seem to be any delay in the furnace heating up, but then the manual doesn't provide an expectation as to heat up time except for a 15 minute empty approximate heat up time to the lowest temperature setting. I will also check this at the next start up. Thanks

you might also have some zinc or copper in your mix this will freeze up a spout.

This Fall I moved my setup to my Moms carport so I could care for her while casting. The weather turned cold and the wind never stops. This new environment caused the same problem with spout freeze up that you are having.
I cut 1/3 of the side (except for about 1/2" of the top edge for strength and balance) out of a 5 gal metal bucket , and a 6"hole in the bottom. With this turned upside down over my furnace and a 12" length of stove pipe to get the fumes above my head, the problem was solved.
While the pot was able to keep the melt up to temp, the spout was cooling due to the windy cool environment. Mine is a Lyman and has always had a tendency to freeze if casting at a lower temp, but it suddenly became much worse with the move.
Even if the other suggestions solve your problem, this addition makes it much nicer to work outdoors in harsh weather. The radiant heat without the fumes is a plus, and it probably save a little on electricity to boot.
See Ya
mold maker
PS I retired last year also.