Spikes on my boolits....(groan)...what now?

[centershot]

I'm not new to casting, started about 35 years ago, got out of it for a time and now I'm back in again. But, I've never had this problem before. I've got metal flowing into the vent lines on my mold, the boolits come out with little spikes attached to them from the vent lines! I'm ladle casting with a Lee 20 lb. electric pot and a RCBS ladle. I briefly ventured into the bottom pour world some years back but was discouraged by the "Drip-o-Matic" pot. Enough of that! This time I went back to ladle casting but with an electric pot instead of a gas burner. My molds are new production Lyman 429667 and 311041 (the problem molds) and a couple of Lee molds that give no trouble. The Lyman molds repeatedly create spikes. I'm running WW + 2% tin in the 44 and WW + pure with 2% tin in the 30 cal. The 30 is a much larger problem in this regard than the 44.

I should say that the 44 mold was fine until I beagled it. Both molds seem to be OK around 700 deg. but it's difficult to regulate temp with the dial on the pot. Is this a temp problem, or should I alter my alloy in some way? Like I said, I had no problems like this back in the old days. Any advice is appreciated!

[nhrifle]

Which mould are you using and what is it made of? I have never used brass moulds so I can't speak for them, but with my aluminum moulds, and especially with the smaller boolits, I can get lead to flow into the vent lines when the block's temperature is excessively high. Maybe try slowing down your casting rate a bit, and also check to make sure the sprue plate isn't completely sealed to the tops of the blocks as this would hinder top venting.

[Hannibal]

Might I add to carefully inspect your mould/moulds. Tiny bits of debris can get in between the mould halves and cause you considerable grief. Also, look at your alignment pins and hold your mould up in sunlight/strong light and look for a gap between mould halves. Once you have identified the reason your mould halves show light between them and correct that condition, I suspect things will get much better.

[centershot]

Well, the problem molds are both Lyman's, as I mentioned in the OP. They are steel molds (cast iron?), as are all Lyman molds. The sprue plate swings freely, of it's own weight, without excessive play. The heels are well filled out, I would think that area of the mold is sufficiently vented. I'll try running a little slower (cooler) and see if that makes a difference.

[country gent]

How are you pouring and from what ladle? A pressure pour with a big ladle and high temps is a solid formola for spikes. I pour bullets in the 400-550 grn wieght range in brooks lyman and old west moulds. The Lumans when up to temp and 725* alloy and the fitted spout of my ladle will fin or spike due to the wieght of the full ladles pressure forcing lead into cavity. My sprue plates are vented to allow over pouring also. It may be a combination of technique, temp, and the days conditions. A thermometer is a plus so as to know what temp you are at.

[centershot]

Yes, I've checked to insure the blocks aren't held open by debris. Of course, when the vent lines fill, I have to remove the lead with a soft bristle brass brush. As long as the mold is at casting temp it only takes a couple swipes with the brush to clear the vents. Yes, I use a lead thermometer, 700 seems to be as hot as I can go w/o problems. I use an RCBS ladle; I turn the mold on it's side, insert the spout into the sprue hole and then rotate to the vertical position, hold for a second and then remove the ladle.

[Pilgrim]

Mould + melt (some combination of the two) are too hot. It's flowing into the vent lines before the melt has a chance to set up. I'd try a colder mould first, then try the melt a bit cooler. Look at it this way...you are getting complete mould fillout for sure!!

Try pouring the melt into the mould FIRST before you do anything else. The pressure of the added melt in the ladle is also forcing the melt into the vent lines.

Pilgrim

[RED333]

Mould + melt (some combination of the two) are too hot. It's flowing into the vent lines before the melt has a chance to set up. I'd try a colder mould first, then try the melt a bit cooler. Look at it this way...you are getting complete mould fillout for sure!!

Try pouring the melt into the mould FIRST before you do anything else. The pressure of the added melt in the ladle is also forcing the melt into the vent lines.

Pilgrim

I am going with this.

[44man]

I had that with a few of my molds. A mold with vent lines that align at both blocks can do that. I started venting only one block instead of both and it is enough.
If it makes a good boolit otherwise, I use my thumbnail to remove the spikes from the boolit. Does no harm.

[Cmm_3940]

I recently had that problem with a new Lyman steel mold. Holding the closed mold up to a light showed that one of the alignment pins was sticking out too far. A couple of taps with a roll pin starter punch fixed the problem.

[Gtek]

I think I would light check, then run a razor blade at a 45 around faces and up to pins just to me me feel better. Would not be the first Lyman I've heard of with carry through around pin holes. How big is the ladle? Maybe slowing pour flip or reducing volume in ladle reducing head pressure?

[country gent]

Try filling the ladle only half full or even a little less to reduce pressure of fill. Some molds pefer beieng poured into the stream maybe a 1/4" above the moluld. This only leaves the sprue for pressure on the bullet. A little experimenting with a clean mould will show what it wants. At work to much pressure on the "Shot Tube" and we had every vent and line filled. The rcbs ladle holds a fair amonunt of lead and makes form more pressure on the hot casting

[centershot]

Mold and melt temp and pressure - never had these problems when I was using my moms gas fired canning stove in the garage,way back when. Seems like the more we try to control the beast, the more it fights us (LOL)! OK, you guys have given me some things to work on, thank you all for your input, I really appreciate it!

[44man]

Too hot can do it too. I find a mold at 500* will make perfect boolits right off. As the mold reaches melt temps you can get different results. Slow casting pace a little. The Ladle will make better boolits in any case. I am the strange old guy that never got bottom pour to work as good as a ladle.

[GLL]

I also use an RCBS ladle.
Try pouring a few dozen without touching the spout to the mold and see what happens ! Pressure pouring at high temp often causes the problem.
If that does not work try cutting the tin to 1% and try again without touching the spout to the mold.

Jerry

[gnoahhh]

I swore off of pots and ladles years ago, and never regretted it. (Of course, I always avoided Lee bottom pours and stayed with Lymans.) Whenever I start getting fins on bullets, I back the heat off a scinch, or switch to different mold for a while.

[centershot]

Well, it appears that a combo of temp control, both melt and mold, and pouring without the ladle touching the mold is just the trick! Thank you for your assistance!