Canuck Bob
Active Member
I was hoping for an education on using top covers for my propane bottle ingot pot and Waage ladle furnace? Kitty litter is often mentioned as well as thicker sawdust. Combining top cover and fluxing is of interest as well.
Techniques for top cover for cleaning and casting pots?
- Thread starter Canuck Bob
- Start date
fiver
Well-Known Member
with a ladle your kind of stuck making a bit of oxidized alloy.
kitty litter helps keep the alloy from forming the oxide layer it but as you oxidize everything dipping the ladle in and out it builds up.
the kitty litter will kind of just mix in with all the silver dross and you end up stirring it all in and scraping it out when you burn the oxides back into the alloy.
now the carbon.
it does the same thing but your dipper will push it down under the surface and once it's in there it's hard to get the little carbon atoms back out again.
probably the best thing to do is to just push the oxidized alloy to the side then dip and ladle.
every now and then squish the alloy against the side of the pot.
after a bit I generally end up scraping it off and saving it in a stainless bowl then re-melting it and reducing all the oxides back down when I get like 20 lbs of it, burning everything off and reclaiming what I can and just throwing the gunk away.
the goal when casting is to use the best alloy to make the best bullets and maintaining a constant pace.
kitty litter helps keep the alloy from forming the oxide layer it but as you oxidize everything dipping the ladle in and out it builds up.
the kitty litter will kind of just mix in with all the silver dross and you end up stirring it all in and scraping it out when you burn the oxides back into the alloy.
now the carbon.
it does the same thing but your dipper will push it down under the surface and once it's in there it's hard to get the little carbon atoms back out again.
probably the best thing to do is to just push the oxidized alloy to the side then dip and ladle.
every now and then squish the alloy against the side of the pot.
after a bit I generally end up scraping it off and saving it in a stainless bowl then re-melting it and reducing all the oxides back down when I get like 20 lbs of it, burning everything off and reclaiming what I can and just throwing the gunk away.
the goal when casting is to use the best alloy to make the best bullets and maintaining a constant pace.
Paul Gauthier
Active Member
Kitty litter is not a good choice it will crap up the sides of your pot in short order, and you don't get clean lead from a crappy pot. And as Fiver said with a ladle it can be pita.
358156 hp
At large, whereabouts unknown.
I have taken to spraying my ladles with Midway "Mold Prep" to reduce the dross "beard" a bit. The oxide dross you generate sticks to, and builds up on the ladle, the less lead that sticks to the ladle seems to help reduce oxidization to a point. After a few uses I bead blast the ladle again, and recoat it. To my knowledge, there is no other practical use for Mold Prep except to reduce the sizing of the mould cavities, and make bullets slightly out of round.
I must be doing something wrong, I get no dross/oxidation buildup either on the ladle or on top of the pot while ladle casting. Can't imagine why it would unless maybe the pot temp is way too high. I keep the ladle in the melt while not pouring and give the melt a quick stir before bringing it up full of alloy.
An oxygen barrier on top of the melt is for bottom feeders, I wouldn't even try it ladle casting, could only lead to frustration and inclusions in the melt. Anything you use, sawdust/kittie litter, is much lighter than lead and floats but when you force it under the surface of the melt while fluxing or with the ladle the lead is dense enough to hold some of it in suspension, at least for a time.
An oxygen barrier on top of the melt is for bottom feeders, I wouldn't even try it ladle casting, could only lead to frustration and inclusions in the melt. Anything you use, sawdust/kittie litter, is much lighter than lead and floats but when you force it under the surface of the melt while fluxing or with the ladle the lead is dense enough to hold some of it in suspension, at least for a time.
RicinYakima
High Steppes of Eastern Washington
FWIW, I watch the temperature carefully as I heat the pot. When it is at liquidous, fully liquid, ladle casting can be done at 70 degrees over that temperature. If bottom pouring, I need at least 100 degrees to keep the liquid warm down through the nozzle at the bottom. This is where the "art" part comes in.
I make ingots in a 40 pound cast iron crucible. Since I can only cast 24 ingots at a time, it doesn't get heated much over just enough to flux with sawdust and beeswax to get clips, iron parts and gunk out. Once that is gone, and have most clean metal, the ingots are cast. They are clean enough for me to do a final fluxing in the casting SAECO pot or RCBS bottom pour pot.
I make ingots in a 40 pound cast iron crucible. Since I can only cast 24 ingots at a time, it doesn't get heated much over just enough to flux with sawdust and beeswax to get clips, iron parts and gunk out. Once that is gone, and have most clean metal, the ingots are cast. They are clean enough for me to do a final fluxing in the casting SAECO pot or RCBS bottom pour pot.
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358156 hp
At large, whereabouts unknown.
For me, a lot depends on the mould I'm using. I cast hotter with my brass moulds, and have decided that I really don't appreciate brass moulds at all. They're so... moody. I started out with Lyman/Ideal iron moulds, and still get my best results with them, undoubtedly because of long experience with them. My point is that I run some moulds either hotter than normal out of necessity, or around the 720 mark when I can, but in my view there are a number of variables that I'm trying to address. I have a 2 cavity MP mould that I got in early December that I ended up giving up on until the weather warms a bit. I wasn't able to get the mould to cast reliably in a moderately cold garage, even when warmed before use. The sprue plate temp was a constant issue, and I couldn't get the temps of the hollowpoint pins in sync with the sprueplate temps. So there it sits.... on the shelf.
Canuck Bob
Active Member
Thanks, there have been times I regret not going with a bottom pour. Watching vids has revealed them as handy and real bullet producers. The other issue is no understanding of the realities of Pb, SN and Sb alloy loss while casting. It seemed to be almost impossible to use top cover with a ladle casting furnace thus prompting this question. It seems that top cover is a little more common for ingot runs with larger pots, wrong?
If a caster just ladle cast a pot full of good alloy, say 94-3-3, how much would the alloy be affected over a large run of 30 cal 170gr bullets from that pot. I understand temp control is important and best when as low as the mold likes. If the bullets are not affected enough to change the accuracy potential over a run of bullets then ladle pouring works for me without the added headache of top covers and such.
If a caster just ladle cast a pot full of good alloy, say 94-3-3, how much would the alloy be affected over a large run of 30 cal 170gr bullets from that pot. I understand temp control is important and best when as low as the mold likes. If the bullets are not affected enough to change the accuracy potential over a run of bullets then ladle pouring works for me without the added headache of top covers and such.
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I don't think alloy changes enough over the run to matter. This is assuming you aren't running the pot way to hot and adding to the issue.
One advantage to a ladle like the Rowell #2 is that you can pour enough lead into and onto the mould to keep mould temp up even with a lower pot temp. I was running my pot at 725 but have since tried 700 and now 675 with equal results. With a bottom pour I wouldn't be able to do that as either the spout would tend to freeze up or mould temp would suffer.
One advantage to a ladle like the Rowell #2 is that you can pour enough lead into and onto the mould to keep mould temp up even with a lower pot temp. I was running my pot at 725 but have since tried 700 and now 675 with equal results. With a bottom pour I wouldn't be able to do that as either the spout would tend to freeze up or mould temp would suffer.
RicinYakima
High Steppes of Eastern Washington
What Brad said! Bullet casters tend to be a thrifty bunch, so dislike losing metal to oxidation.
fiver
Well-Known Member
you can run some pretty low alloy temps and still make very good bullets.
even in my bottom pour pots I can get down to 675 easy I just need to increase my casting rate a little.
I can do 650 if the alloy has enough tin in it.
your not going to start oxidizing the tin until you hang out at around 750 and just let the pot sit there.
the ladle going in and out of the alloy is keeping everything stirred up just fine.
all your getting is a skin of stuff on the top and that skin is keeping other alloy from oxidizing anyway.
I just keep pushing it out of the way.
if it builds up I mush it then take it off and reclaim it later.
that's just how I do it, and it works for me.
even in my bottom pour pots I can get down to 675 easy I just need to increase my casting rate a little.
I can do 650 if the alloy has enough tin in it.
your not going to start oxidizing the tin until you hang out at around 750 and just let the pot sit there.
the ladle going in and out of the alloy is keeping everything stirred up just fine.
all your getting is a skin of stuff on the top and that skin is keeping other alloy from oxidizing anyway.
I just keep pushing it out of the way.
if it builds up I mush it then take it off and reclaim it later.
that's just how I do it, and it works for me.
Rcmaveric
Active Member
I also use a bottom pour pot. I don't use anything to cover. I also normaly have to run the melt around 900* to get the bases to fill out good. I can go lower on iron or smaller caliber molds but gets iffy on good bases around 750-800*. I tried adding tin and it doesn't help me, but turning up the heat it does. Once you get a layer of oxide on the melt it wont go any farther than thin layer. I think of it like stainless steel, it develops a thin layer of oxide to prevent the rest of the metal from corroding. Fluxing makes it all mix back. I have wooden trays around me and bullets go in one and sprues in another. Once the sprue tray is full the pot will be 2/3 empty. They all go back in. Its all fluxed together. It helps keeps the alloy more consistent that way. If you try to scrap the corroded/oxide layer off without fluxing you just be skimming of your valuable tin. That shinny straw like color or yellowish tinge floating in there in the melt is the corrosion layer. Pure lead has pretty purplish color.
With your alloy i would just run it how i can make it work. That oxide layer is going to happen regardless of what you do. The higher the temp the quicker it happens. Nature of the beast. Just let it happen to save the rest of your alloy. Once you get the hang of it and find your circadian rhythm you can add an extra mold. Then you keep your mold temps more stable and help you make nice shinny bullets. Don't be afraid of frosty bullets either. They shoot just as good. Personally i think consistent mold temps are better and controlling the melt temp helps control mold temps in a way. Since i run so high, two mold are a must for me if i want shinny bullets. Single mold will make me have frosted bullets
Once you add your sprues back its a good time to cull your bullets for visual goodness. Then just add them back as well.
With your alloy i would just run it how i can make it work. That oxide layer is going to happen regardless of what you do. The higher the temp the quicker it happens. Nature of the beast. Just let it happen to save the rest of your alloy. Once you get the hang of it and find your circadian rhythm you can add an extra mold. Then you keep your mold temps more stable and help you make nice shinny bullets. Don't be afraid of frosty bullets either. They shoot just as good. Personally i think consistent mold temps are better and controlling the melt temp helps control mold temps in a way. Since i run so high, two mold are a must for me if i want shinny bullets. Single mold will make me have frosted bullets
Once you add your sprues back its a good time to cull your bullets for visual goodness. Then just add them back as well.