Do I need a new mold?

We've had this ball-head jig mold for 20 years or more. It has always produced fine for us. However, today, we tried to pour some 1/16 oz. ball heads (with collar) and most of the pours resulted in having little or deformed collars. Trying the 1/8 oz. cavity, no problems. The 1/32 oz. no problems as well. Seemed like just the 1/16 oz. cavity gave us incomplete molds. Tried pouring the entire block with lead, no hooks, to adequately pre-heat it up. We did this several times, then we'd put in a hook in the 1/16 oz. cavity and about 80% came out not fully formed. Very frustrating! Any suggestions?

Sounds like a piece of lead stuck somewhere on the mold. Try taking a soft bristled brush and brush through the pouring gate and along the inside surfaces of the mold. You could very well have a small piece of flash which is messing up the pour - this can happen in new molds also.

Thanks for feed back. We looked at the pour spout on the 1/16 oz. cavity and it looks very clean. We even tried several blank pours (no hooks) in all the cavities to make sure the mold was hot enough. Still got a very high percentage of half to no collars on that one size. I'm thinking about taking a reamer to it - carefully by hand - to open up the pour spout?

Could try smoking that area with a candle.....the soot will make the lead fillout the cavities......Has worked in the past......

Problem solved! Had nothing to do with the mold afterall. Nothing to do with the pot either. Had everything to do with US! LOL! We were just too slow between our hook placement and actual pouring. The faster we got, the better the mold results. Apparently, keeping that mold hot is paramount. I don't remember having that kind of a problem several years ago when we last poured some jigs....but then again....we were much younger back then! ;)

Thank you all very much for the suggestions.

glad to see it worked out for you

Was going to give the same wax information but I'm glad you got it worked out.

I had the same issue with a 3/4oz mold this year. I had a 1 1/2 lb ladle that I was pouring from and getting inconsistent pours. I changed to a simple 2 oz ladle. This forced me to dip between each pour in the cavity. Resulted in hotter lead on each pour.

Next year, I think I'll just bypass all of this and get one of the pots that require zero dipping.

Meant to ask - what kind of mold is it that your pouring???

are you setting the mold on top of the melting pot to pre-warm it? i do that till i am ready i also use a map gas torch used for soldering copper pipes got to remember aluminum dissipates the heat very well like sheds it from were your heat is or pull it away to the out side of the plate.

this is all threw heat conduction between it and the air and metal. this is just like when we have a problem over heating a weld we back steel with aluminum to drawl the heat out of it quicker same reason a computer has a heat sink.

any how try heating it before you pour any thing don't over heat and warp the metal. but try to get a feel for it i do it for like 10-15 second per side of the mold before i pour it. also smoking the mold with bees wax will help.