When casting with my Lyman 385 grain RN mold the multiple bands on the boolit do not seem to fill out completely. They appear very rough and grainy, while the nose is nice and smooth. Other molds I use with the same techniques and alloys do not do this. Does this relatively large bullet require something different in its use when casting? My .459 push thru sizing die only touches the front driving band when used. Any suggestions would be appreciated.
probably need to scrub it out with Comet and a toothbrush to get it REALLY clean.
Bill
If it was easy, anybody could do it.
What Bill said + check the vent lines to make sure there clear. The not filling out of the bands between the base and nose and being grainy is a sighn of uneven mold temp(hot spots).
You didn't say how you are casting this boolit, what I have found is the large heavy caliber boolit in most cases needs to be pressure cast and/or use a ladle.
If the mold is new or used very little, it may require a break in period.
Calamity Jake
NRA Life Member
SASS 15704
Shoot straight, keepem in the ten ring.
That is not that heavy a boolit.
I suspect the mold is being run too hot. Even a small tumble lube .44 boolit will do that if too hot.
The rough and grainy nose is usually caused by turbulence from dead center pouring the alloy in the sprue hole and insufficient over pour onto the sprue plate. This happens whether the mold is either too hot, too cold or just right if you have sufficient turbulence. The poor band fill-out is caused by low temp of mold or alloy or oil in the mold or a combination. Start eliminating things step by step and try a different pour method for your pour. The ideal pour has a short flow length of 1/8 to 1/4 inch from the nozzle to the sprue and the stream is poured half the diameter off center to the sprue hole to cause the sprue funnel gate to swirl the flow into the mold. Vents are to let air out when metal goes in but turbulence splash will block them off and negate vent function. Pouring with a good swirl does not require mold vents at all and bullet quality will be better. The round nose related to that bullet length actually causes more turbulence than a flat nose would so the mold is sensitive to pour technique and a good swirl is important, Tilting the mold about 5 degrees along with the off center short flow pour will give maximum swirl for the fussiest molds. That is a persnickety good skill to develop for excellent casting.
Gary
Last edited by onondaga; 12-02-2010 at 11:51 PM.
I am fairly new but have worked through tons of issues with 45/70 and 40/65 boolits, 405s, 410s, 475s, 510s, 535s, and others.
In my case, unfilled bands always means not hot enough mould heat. Get the mould hot enough, even too hot and then, if necessary, let it cool while casting until the bands come out sharp and clean. I know, someone said the mould was too hot, not too cool.So good luck
but too cool a mould is always my issue with failed multiple band fill out.
As to size, what alloy, temp., etc. That would help in diagnosis.
The Dude abides.
Excellent, Onandaga! I tend to do the same thing on the rare occasions I ladle-cast because it is difficult to spiral the alloy into a large mould with a bottom-pour with any consistency. Same goes for long, skinny boolits, too. The process is difficult to describe but you nailed it.
I'd say the issue with some shiny places and super-frosted edges is both the mould is too hot, and too cold. In other words, uneven heat distribution. Most of my large boolits have the same issues at the beginning of a session, especially the 457125 which has really deep lube grooves and narrow driving bands. Keep casting and it will even out after ten or so pours.
Gear
What I have done is, use a hot plate to heat the mould.
Beer is proof that God loves us and wants us to be happy!
Ben Franklin
Place your mold on a hot plate to preheat it and make sure you flux your alloy to remove the impurities. If you are using wheel weights cast at 800 degrees or over to insure proper fill out or if using pure lead make sure you use enough tin to make the alloy flow at a lower temp. There are different alloys for various applications and they all require a different temp and mix to flow correctly. It also depends on the size of the mold and the materials it is made from.
Why do you think it is necessary to go "800* or over" with WW metal? Anything over 750* drosses out tin at an exponential rate and renders it totally ineffective for aiding fillout. 675-700* is all that alloy needs for good fillout with minimal drossing or tin burnout. MOULD temp is the key here, get the mould to the temp it needs to drop good boolits, and maintain the alloy at the temp that is best for the particular alloy (the more tin and/or antimony=lower liquidus temp=lower preferred pot temp, down to as low as 600*, pure lead may need to be cast at temps over 800 due to its high "surface tension").Originally Posted by wilddog45
Gear
Well said Gear!
Get one of BRP's 420 molds and ladle cast.The mold I got from him works better than others I've tried.Big 45-70 boolits are a little harder to get perfect fillout.I like aluminum molds and the venting on his molds work great.Like what was said above you can cast at 700 degrees if the mold is hot enough and you keep a consistant pace.His 3 cav in a 4 cav block works just right with 420 grain 45-70 boolits.
Absolutely not !! There are safety issues with melted lead. There are two types. One is what I'd call the obvious physical risks, like splashing onto skin or into eyes and the like. The other is lead poisoning from fumes, which are cumulative in the body, and undetectable because the fumes are colourless and odourless. There are no fumes at normal casting temperatures. Fuming starts at about 900. 800 is close enough to the danger area to be avoided. In any case, it is way above temperature needed for good casting, even for pure lead. I cast all bullets at 600 because that's the lowest my pot will go, and that's too hot for the heavy bullets. As a commercial caster I have to get top quality with virtually zero defect, so this is not guesswork or casual opinion without basis. I am constantly amazed at what is offered as good advice.
Gentlemen,
I have a (preheated) Lee 6-cavity Tumble-Lube mold, vented, bullplated and Lee-mented, the simply will not cast at under 740, or 750 in cold weather. Period.
You can lecture, call me an idiot, call it unvented, I don't care, but this one particular mold WILL NOT run under 740 even when preheated to crazy temps.
If you're talking steel or brass molds, well yeah, I got a bunch of them I can cast at lower pot temps, with a proper preheat.
Oh, and I agree, 800F really isn't necessary, at least not for anything I've tried.
-HF
I give loading advice based on my actual results in factory rifles with standard chambers, twist rates and basic accurizing.
My goals for using cast boolits are lots of good, cheap, and reasonably accurate shooting, while avoiding overly tedious loading processes.
The BHN Deformation Formula, and why I don't use it.
How to find and fix sizing die eccentricity problems.
Do you trust your casting thermometer?
A few musings.
Gee I'd like to see a video of how you cant get the 6er to work for you. Could be a number of reasons. Unexplainable problems usually point to alloy. Pre-heating the mold doesn't pre-heat the sprue plate very much at all and it is the sprue plate getting the heat sucked out of it by the massive aluminum heat sink mold block that leads to the thermal problems most of the time. That is particularly true with a slow work cadence.Try really over pouring big puddles along the entire sprue plate at least for the first 10 pours. See if that helps. You can judge this yourself by counting how many seconds it takes for alloy to solidify on the last sprue you pour. If it is less than 4 seconds, something is not hot enough. At 740-750 the tin in your alloy has gone to the top and you are casting very pure lead through your bottom pour pot. of course it has to be hotter with the purer lead plus antimony and the purer lead doesn't cast as well formed bullets because the tin is gone. The antimony may be the only thing left in your alloy with the lead at 750. that doesn't help casting quality and will make your boolits look cold with unsharp edges where they should be sharp because of low tin. More heat will not correct that very much. more tin and a lower temp will.
Heat the sprue plate with a propane torch evenly before you pull it off your warmer or heat the mold sprue plate down on the warmer. You can also do a hardness test on the poor quality boolits you cast and check that the tin is gone by the BHN number to verify the overheat of your pot. Measure the drop bullet BHN against your ingots. If there is a way for you to verify your thermometer, the problems you are having is a signal to check that too.
You haven't mentioned really, really cleaning your mold either. Some casters switch to a ladle for 6ers and the problems you mention go away immediately. You need a big ladle for those if you try that--more than twice the volume of the entire pour for the 6 and include puddle volume---a big ladle. If you pour two little ladles full or one medium ladle full and just have enough to fill your mold, your alloy is cold from the ladle sucking the heat out of your metal. Get a big ladle that is over half full after your pour.
I'd say start over. degrease and scrub the snot out of your mold. Use new metal that you are sure of the tin content and get your sprue plate really hot. Then 675 should be close with a 6er. Mold lube application is an art. most people use 90% more than they need and put it in the wrong place. Handle Hinge and guide pins only. If you need to lube the sprue plate hinge, disassemble for that. I occasionally scribble pencil on the mold top and sprue funnel gates too. Graphite from pencil is an antiflux and works well for that and the guide pins in a pinch too.
That is not a lecture either. I hope your bullets get better than mine and you get better helpful tips than mine too.
Gary
the multiple bands on the boolit do not seem to fill out completely. They appear very rough and grainy, while the nose is nice and smooth. 4296
What you describe is what I've had happen when the mold gets TOO hot, drive bands "burned back" for lack of better terminology.
Charter Member #148
[QUOTE=onondaga;1080539]Gee I'd like to see a video of how you cant get the 6er to work for you.
Actually, I get it to work just fine. Above 740F.
Yup. Which is why I finish the preheat sprue plate side down. I've mentioned this in another thread. Ah, here it is:
http://castboolits.gunloads.com/show...60&postcount=4
Yup the big aluminum mold loses heat while I'm working with it, particularly under 50F ambient.
Yes, that matches the advice I gave in this thread:
I'm sorry, Gary, but this is purely bogus. Lyman 3rd edition has some good articles about melt non-separation, but for further evidence, I'm not getting BHN12-14 boolits out of "very pure lead" from the bottom of the pot. I'm not even losing much to oxidation at the top, since I put some charcoal up there first.
hehe... you're talking to the king of cheap tin here.
I used to do that, I find the electric heater more convenient. I preheat mold side, at 1/2 power, down, then flip it over a couple of minutes on full power right before casting. That and 740F on the pot and everything comes out great.
Same BHN.
Who knows, my thermometer might be "on" at boiling water and way off over 500F. If that is the case, it really doesn't matter, I just record what works and go with that.
Sorry, I only mentioned Lee-Menting, bull plating, and, uh, some other things, but yes, I soaked in paint solvent and then scrubbed down with Simple Green, soap and water, stiff bristle brushes, that mold has been cleaned more times and with more cleaners than I can remember. Anyway I don't fool with it any more, I just cast with it, perfectly. At 740F, at least, 740F indicated.
OK I have to confess, I have a couple of ladles I've never used. But now that I've found how to cast with the bottom pour, I'm not sure I see the point.
I appreciate your concern, but I'd say not. That mold works great at 740F and above, so I'm not going to mess with it.
I'm in complete agreement there, from hard experience.
No problems, Gary. I've had an interesting ride, figuring out which molds like what. I have a Lee 6 Cavity 44 310gr that will mold at most any temperature. The TL groove likes a little more tin and a lot of heat, so that's what I give it. It's the only one of almost 20 molds. It works so I don't mess with it any more.
-HF
I give loading advice based on my actual results in factory rifles with standard chambers, twist rates and basic accurizing.
My goals for using cast boolits are lots of good, cheap, and reasonably accurate shooting, while avoiding overly tedious loading processes.
The BHN Deformation Formula, and why I don't use it.
How to find and fix sizing die eccentricity problems.
Do you trust your casting thermometer?
A few musings.
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