What's causing this?

[Bushfire]

I noticed on the last batch of balls I did the bottom had these notable "wavy lines" for lack of a better word.

The balls shown are all weighing out within 1 grain of one another.

I didn't think it was a temp thing but I'm not sure?

The straight lines are obviously from where the two edges of the moulds meet. I'm not sure if anything can or needs to be done there. It's just a Lee aluminium mould for my .600 fusil balls.

 

[nhmoose]

Mold to cold , lead to cold makes a lousy fill out, ball or boolit

 

[bang]

What he said.

 

[Bushfire]

Yeah bugger, not much I can do about that unfortunately with my setup. I've not noticed it previously, mind you I did this session outside, normally do it in the shed where it's more protected from wind etc.

 

[DOUBLEDEUCE 1]

I run a few balls through the molds to heat them up to get a good cast. If the mold is left alone for too long and it cools, I might dip the bottom onto the molten lead to heat the mold again. Never really had a problem casting. Drop the balls onto a dampened thick soft cloth. Works well for me.

 

[Bushfire]

I run a few balls through the molds to heat them up to get a good cast. If the mold is left alone for too long and it cools, I might dip the bottom onto the molten lead to heat the mold again. Never really had a problem casting. Drop the balls onto a dampened thick soft cloth. Works well for me.

I do all of that other than I preheat my moulds before casting anything. I don't have any kind of furnace though. I just use an old cooking pot and a side burner on a BBQ.
I can definitely get the moulds hot, on my last 54 casting session it was too hot to the point it took maybe 30 seconds for the sprue puddle to solidify on the first ball. I think it's the actual lead that struggles to maintain the right temps.

I'm realistically not going to be in a position to prioritise buying a better set-up any time in the near future. I'm really not that phased either, I figure as long as the weights are consistent and they group well it doesn't overly matter.

 

[Daveboone]

With my Lyman molds my last batch of .54s with pure lead, I consistently had the same waves. I cant believe either my lead or mold were not hot enough, but fer what its worth...bench resting at fifty yards I could still make one hole with them, which was better than I could do with store bought Hornadys cast. I dont worry about it anymore.

 

[EC121]

Along with a cold mold and/or lead pouring too slow might can cause that.

 

[Bushfire]

Along with a cold mold and/or lead pouring too slow might can cause that.

Now that I do do. Maybe that's it.

 

[User_Dan]

Those big molds are tough to fill and maintain temp at the same time. I get the same temperature Mark's on my 660s and 690s.

 

[Brokennock]

I heat my molds on an electric hot plate next to my lead pot. If I have to do any else while in process, the mold goes back on the hotplate. The little electric pot I use really doesn't allow for heating the molds with the lead itself.

 

[satwel]

As stated above; lead too cold, mold too cold or a combination of both.

 

[rafterob]

Had the same issue outdoors. I have one steel mold and one aluminum. The steel mold was throwing nice balls but the aluminum mold would simply not do it. They don't hold the heat as well. That combine with my camp stove barely keeping the lead hot enough.

 

[akroguy]

I use a Map gas torch to help heat up the mold at the start or if I have to stop the session for a moment. Keeping a steady pace keeps the mold hot. Lee alloy molds heat up quickly. Lyman steel molds take some time.

 

[Johnny Tremain]

I preheat my gang molds on the stove, 120 degrees for 20 min or so.

 

[SciAggie]

I don't know what kind of ladle you have but that can make a difference. I use this Lyman ladle. It allows me to press the ladle into the sprue hole, then while holding them tightly together - turn them and pour the lead. I leave them "mated" for a few seconds - then move the ladle and pour the sprue.

 

[Greenjoytj]

My casting results improved greatly soon as I started using a heavy iron ladle like pictured above. Plus using an electric hot plate to preheat my molds.
With this iron ladle when thoroughly heated deep in the melt can easily fill my mold with out flaws.
The cheap light weight stamped steel spoon style ladle caused poor fill out, and the larger aluminum ladle was only a little better. Both required the melt to be at near frost creating temperature.

 

[Rifleman1776]

Mold to cold , lead to cold makes a lousy fill out, ball or boolit

Yep, too cold. But for a smoothie those should work just fine. I wouldn't use them in a target rifle.

 

[Urban Coyote]

Lead, mold temperature and the ladle, (what Greenjoytj said). I use a Lyman 20 lb electric furnace and an RCBS ladle, which is iron. My biggest issue is getting a consistent pour from my ladle which tends to clog, yes I flux often. With hot molds, either aluminum or steel, and lead I get by with minimal rejects if I can keep the ladle flowing consistently, and yes larger molds are tougher to fill. I haven't cast any .648 RB for my 16 gauge flint for some time but as I recall it took me a while to get the results I wanted.

I was recently on a casting binge, something I do about every couple years. I ran .310, .315, .353, .370, .440, .445, .490, .495, .530, .535 and .562 over the course of the past three weeks or so. It took me a day or so to get my learning curve squared away at which point I was getting really good results, low reject rate. I ran through almost all my lead.

 

[sussexmuzllodr]

When up to temps tilt your mould when you pour. This allows a better fill and less to remain behind on top of the sprue plate