Smelting good cast bullt alloy Sprews and Culls

JWFilips

Well-Known Member
I have about 150 lbs of Clean cast bullet alloy spews and culls from cleaned ingots I smelted 2 years ago and have been using.
I like to run my pot with clean smelted ingots and do not add spews back into my pot.

I would like to re-smelt these sprews & culls and re-clean the alloy and make new fresh ingots but I have a question on "depletion". Do I need to add more tin ( or anything else) to the sprews to get them back to where the original alloy was? or is the depletion factor negligible? The highest I ever run my pot is 730 deg
Thanks
Jim
 

Brad

Benevolent Overlord and site owner
Staff member
I don't think it is an issue. Linotype does deplete over time but think about it, that stuff was remelted daily forever. How often was it replenished?

Don't over think it Jim. I use sprue to refill my pot before finishing for the day.
 

JWFilips

Well-Known Member
The reason I don't add sprews back in the pot is I dislike having to stir & srape the pot for oxides. You can tell the difference in that if the bottom of the pot feels sticky when you are scraping it. With fresh clean ingots that is seldom felt!
Not saying that is bad it is just something extra to worry about
 

Brad

Benevolent Overlord and site owner
Staff member
Much has to do with surface area. Sprue has farm more surface area per unit weight than an ingot. That surface area is covered in oxide.
I flux my pot well before each session so it isn't an issue. Using a Rowell ladle helps too.

Remelt in a smelting pot, flux well with sawdust, and make new ingots. They won't differ from what they were last time around.
 

JWFilips

Well-Known Member
Thanks Brad,
I only bottom pour at this time....Maybe some day a Ladle will be in my future!
 

JSH

Active Member
I dump my sprues and culls into a metal 5 gallon bucket. When it's heavier than I want to tote, I use them for the initial fire up of the pot at the next session.
 

Chris

Well-Known Member
I'm with brad... I just toss them back into the pot at the end of the day. Any oxides clean up with the first flux of the next melt.
 

Ian

Notorious member
Yup, just toss them in the pot. If they were clean to begin with, all you need is a small blob of wax to recover the oxides once it all melts.

The problem with oxide occurs when you add them back while casting; they sink to the bottom to melt and deposit their non-melting oxide skins there where it sticks to the surface tension of the molten alloy on the BOTTOM of the pot and it gets wicked into the spout, then you get dross inclusions in your bullets. Starting cold with a pot full of sprues lets them float to the top as they melt where you can reduce them and carry on.

BTW, most of the time I throw the sprues back in while I cast, but stop and stir and skim periodically. I only do this to extend the available alloy to me because my furnace is so small and I can only use about 12 lbs of alloy at a time with consistent pours and temperatures.
 

RicinYakima

High Steppes of Eastern Washington
Starting cold with a pot full of sprues lets them float to the top as they melt where you can reduce them and carry on.
This is the prime reason I empty my pot at the end of each casting session. I can clean the bottom and side of the pot, and start with all the left over sprues, flux and add clean ingots.
 

fiver

Well-Known Member
I won't say what I do.
but I think I'm maybe going to actually empty my pot and sort of clean it.
it's only been like 20 years since it's been emptied.

like Ian say's you don't need to get all carried away with a whole fluxing routine for the sprues.
all they need is the oxides reduced back into the mix.
some fire and some stirring will do the job just fine.
skim the junk off after smushin it against the side of the pot.
 

RicinYakima

High Steppes of Eastern Washington
Fiver, just remember most of the stuff on the pot is water soluble, but are metal salts and toxic. FWIW, Ric
 

Ian

Notorious member
Toxic as heck. I've heard of people cleaning their casting pots with a wire cup brush and drill, but not me, not unless it was all very wet. A good way to clean the sides of the pot is let the alloy get down to about 1/4" on the bottom and build a big sawdust fire on top of it, like dump a whole handfull of shavings in there and torch it off when it starts smoking really good. When it's burned down the sides will have just black carbon on them and it wipes right out with a damp rag when things cool off.
 

fiver

Well-Known Member
I need to look at the needle and seat it has started dripping intermittently.
it's only had like I dunno 3 metric butt ton's of lead through it.
 

quicksylver

Well-Known Member
I take a break every once and a while when I'm casting...that's when I throw the sprues back in the pot and lightly reflux the mix...I guess I'm not spotting the problems if there are any..
Ah!!.. Ignorance is bliss:rolleyes:
 

Ian

Notorious member
I need to look at the needle and seat it has started dripping intermittently.
it's only had like I dunno 3 metric butt ton's of lead through it.

Five seconds with the rod on a drill and dab of 400 carborundum paste on the seat and she'll be good for another few metric butt tons.
 

Kevin Stenberg

Well-Known Member
My cut sprues go into a high sided sauce pan on an electric hot plate. Next to my pot. By the time they are melted my pot is ready for a refill. I leave a layer of sawdust and a little candlewax to clean the sprues as they melt.
And when pouring the remelted sprues they pour through the layer of ash with no problem.
 

KHornet

Well-Known Member
My sprews all go in the pot, particularly if I am doing a large qty of
bullets. If only one pot, they go in as the pot cools, and are the
start of the next pot the next time I cast. I agree with Brad, and I
think it is easy to over think this issue.

Paul
 

popper

Well-Known Member
My sprue go into the souce pan and then into the pot when the pot gets low. Usually don't even flux, bottom pour Lee. I dumped 6# of my soft yesterday through the spout for muffins. Spout is nice and clean now. Melted ingots of isocore today and added 4# of dross. Doing my normal CuSO4 thing and the crumbly dross disappeared. Nice full pot of clean alloy now, ready to cast some for the 308W.
 

KHornet

Well-Known Member
I am not by any means as scientific as a lot of guys on this forum when
it comes to alloy. However, as long as what I cast shoots to my satisfaction
I really don't care that much.

Paul