Hard to fill out moulds

[Rex]

What makes a mould hard to fill out? I have a few moulds that give almost no culls and one Ideal 2 hole that has a really high percent of culls. The front driving band doesn't fill the shoulder out square. The bottom band below the crimp groove isn't always great. I use the same alloy and casting temp with all of my moulds. I've even run this one up close to 800*, washed and scrubbed the blocks with break parts cleaner. I almost give up on this one. This mould is a 357466.

 

[Brad]

Venting, design, block material all play a role.

If it was easy would we do it?

 

[Ian]

Vent lines plugged combined with not having perfected the fill rate/flow/angle that it likes.

 

[RicinYakima]

Do you have an experienced caster who can coach you in person? Watching computers are worthless.

 

[Brad]

I’m not exactly the most experienced but I am the second closest person to Rex on this board. 358156 HP is roughly an hour closer.

Rex lives on the edge of the middle of nowhere.

 

[Rick]

My first "guess" is mold temp. From your description it sounds like your trying to cast with an improperly warmed mold. They re all different, what one likes another may hate but poorly filled out bands is often cured with proper mold temp. Assuming of course it's a clean mold to start with.

 

[fiver]

my ideal's don't even have vent lines they have to vent out of the top of the mold under the plate.
I pressure cast the single cavities with my bottom pour set to dribble.
and pour from a ladle into the doubles.

 

[RicinYakima]

Since I ladle cast, pour a very large sprue and have a fast pace, it is hard for me to judge what others do. I normally cast at 100* over solidus and four casts per minute with my single cavity iron moulds.

 

[CWLONGSHOT]

Improper mold venting is my guess. (As mentioned)

Also as mentioned, I too have a few early Ideal molds with VERY few vent lines that do exactly same (before I adjusted)

Adding a vent line to the top of the mold at the spure can help base fillout but wont help grooves or driving bands.

Pressure filling (with bottom pour pot) is also my solution when I want to use these molds. (Mostly I leave them put up all
Oiled in mineral oil)

I suppose a handy sort, with a milling machine might ad a fe vent lines for ya. But probably easier to find a modern replacement for that old mold. It will have good venting.

Good luck

CW

 

[Bret4207]

Are you using a BP pot or a ladle? I find a ladle allows me to easily vary my technique to fit what the mould seems to want. Spout to top plate contact, slight air gap, big air gap, off center from 4" high, whatever it takes. Also, you say you "ran it at 800"- the alloy or mould? MOULD temp is key usually, not alloy temp. Cast fast until it gets to temp.

 

[Rex]

Bottom pour pot and that may be my problem with this mould. My 358477 has cast thousands of bullets with almost no culls, the 358156 also, the 358429 is almost as good. The 358477 could be my favorite bullet and the revolver's also, wish it had two holes but what else do I have to do anyway. I pre-heat the blocks on a hot plate before casting but will try running it a little hotter before I start. I can always live my life quite easily with the 477. Thank you for the suggestions.

 

[STIHL]

I have a couple of Ideals and Lymans that have issues as you describe and its always mold temp for me. As you I use a hot plate, and it just doesn't get them to the temp they need to be. Hence why I am working on a toaster over type mold warmer. I have a 358-156HP mold that casts great but it has to be hot before the bands and GC shank will fill out nicely It took 20-30 cycles the last time I used it to get it dropping keepers. Plus I will have 1 cold block the other up to temp, one side looks perfect, the other side horrible, it is all corrected with getting heat into the mold.

Disclaimer: I am far from an expert and this is just my .02 cents worth.

 

[Rick]

Disclaimer: I am far from an expert and this is just my .02 cents worth.

I'll donate . . . Make it .04 cents.

 

[Rex]

Your .02 cent thought is probably just about right on the money. Thank you.
Rex

 

[Matt]

Mold temperature and cadence seems to be an issue with some molds. A hot plate will help with the mold temp and reduces the frustration of casting 30-40 bullets before they start to fill out. Sounds like your alloy is fine but I’m always ready to add 1% or so more tin via solder to help certain molds. Some molds need to be warm enough to drop frosted bullets to have good fill out. Good fluxing also helps, it seems to change the surface tension and mold fill out properties. If it’s a venting issue loosening the sprue plate might help. Ben has a tutorial on venting the top of blocks. I’ve only had to do this once, but it made the mold fill out. I’ve never found that “pressure” casting with a bottom pour helps. The pressure changes as the pot empties. I’ve found that a large sprue frequently helps and that’s easy to achieve with a bottom pour furnace. I have one mold that requires the handles to just be closed with a little pressure. My usual death grip causes rounded driving bands……. Part of the fun is to understand what your molds need to perform.

 

[358156 hp]

Mould temp and...... the flow of your alloy from the pot, coupled with the distance the alloy has to drop to the mould. I used to hate bottom pour, and stuck exclusively to the ladle. I became a pretty decent ladle caster, but bottom pour continued to annoy me. One day I noticed that the lead stream from the pot seemed to break into droplets by the time the stream reached the mould so I raised my mould guide above the point of separation and things got better really quickly. Then I adjusted my flow, and most of my problems cleared up entirely. All I needed to do from that point was a little fine tuning. I still use the ladle a lot for 1-2 cavity moulds, but 4 cavity and up are all bottom pour now.

 

[seagiant]

Hi,
I would just get a better mold.

The only commercial molds I use anymore are RCBS.

MP, NOE, LBT,...Mo better!

 

[Rex]

Seagiant, I think you may be correct. I have a 358477 that casts a great bullet though it is a one holler. I like it and my 686 likes it and I have a pile of them as I don't have an abundance of primers to set them off with.

 

[Qc Pistolero]

Casting is a lovely hobby.Must be because it is so exacting!
OP:each mould has it's own preferences;nature of the blocks(steel,alu or brass).
Dimension of the blocks compared to the volume poured into them
casting temp(as an example,one of my custom made mould(Accurate)will have a 20%reject rate at 710*F while the same mould with same lead/tin mix will have a 4%reject rate at 750*F
Hope this helps!

 

[Jeff H]

Vent lines plugged combined with not having perfected the fill rate/flow/angle that it likes.

re. "rate/flow..."

And.... bottom-pour with a wallered-out spout. Both of mine have been cleaned so many times that they now have over-sized orifices.

Try casting with half a pot and see if it helps. If not, at least you know the orifice isn't enlarged. That's a good thing, because the new pots' parts won't fit the old pots.

My 357 moulds don't like that excessive flow, but my 44 moulds seem to be OK with it, even though the sprue holes are the same size, velt lines clear, etc.

I'll fix it eventually, somehow, but don't look to LEE for help. Had an engineer get a bit snotty with me, thinking I was fishing for a free replacement pot instead of listening to the question I asked. Bottom line - the new LEE pots' parts wont fit the old LEE pots. "You'll take the deal we offer or wait just like everyone else" was his reply to my query as to whether I could PURCHASE a new inner pot and make it fit an older unit.

The "deal" was that they'd sell me a pit "wholesale" but I had to pay shipping on both, which was beside the point because t hats not what I asked.