Fluxing

[joeb33050]

3.4 FLUXING
I flux seldom to never when casting bullets; commonly casting for an hour plus session without fluxing. I dip out any slushy stuff and put it aside. When done casting, I put the slushy stuff back in the pot, get the pot hot, flux and stir and scrape. What’s left is some very dense black powder stuff, which I think is oxide of some metals. I don’t know what it is. I throw it away because I never found a way to turn it back into shiny alloy.
I use Darr lube for pan lubing, and replace it yearly because I think the heat degrades it. I use the old Darr lube for fluxing.
A long time ago I asked Loring Hall, a very experienced caster and shooter at the Old Colony Sportsman’s Association in Pembroke, MA, about fluxing the pot. Loring said that he fluxed-when he did- by putting the spout of the ladle in the flux and then continuing to cast bullets. I’ve done this any number of times in the past.
I did this the other day and paid attention. Putting the spout of the hot dipper in the lube, and then putting the dipper in the pot, gave me some smoke and a little flame. Doing it repeatedly gave me a clean dipper, nicely lubed sprue plate holes, slightly lubed mold top and sprue plate bottom, no lead on the mold top or sprue plate bottom, and a generally clean-of-lead mold. There was no problem with too much lube/flux causing voids in the bullets. Everything worked great.
There were a few lumps of slushy stuff on top of the alloy, which went to the slushy stuff place; the alloy was nice and shiny.
I’m going to do this now and then, as I remember, because it cleans everything up so nicely.

[JSnover]

Thanks! I met Loring a few years ago but never had many chances to speak with him. If he says it works then it's certainly worth a try.

[jhrosier]

I have tried this and that and the next thing for fluxing over the years.
A bit of beeswax stirred into the mix works but makes more smoke than I care for.
Since I restarted casting recently and read the experiences of others on this forum, I have changed to a much simpler and nearly smoke-free method.
The best thing that I have learned here is the use of a pine stick to stir and flux the alloy.
After the first use, the stick is pretty well charcoal on the outside and smokes little if any.
I start my melt at a high temperature and stir well with the pine stick. This eliminates the slushy stuff by getting the antimony back into the alloy. As soon as this is done, I can lower the temperature and start casting. The mould is nicely preheated sitting on the edge of the pot while the alloy melts and usually I get good bullets on the second or third pour, even with iron blocks.
After about each third pour, I give the pot a quick stir with the stick.
Doing this I get a reject rate of 1% or less.

I sure wish that the information that I found on this forum had been available years ago when I struggled to make good boolits. It's still not what I think of as fun, but it is rewarding to get good results easily.
Thanks to all who have made casting work better.:drinks:

Jack

[gon2shoot]

I like the "stir with a stick" method too. Just remember to have a dry stick.
I have had pitch pockets in the wood that smoke considerable at times. For some reason it smells like singed hair. :roll:

[montana_charlie]

I dip out any slushy stuff and put it aside. When done casting, I put the slushy stuff back in the pot, get the pot hot, flux and stir and scrape. What’s left is some very dense black powder stuff, which I think is oxide of some metals.
I come before you to speak of slushy stuff.

Slushy stuff is oxides.
Both lead and tin turn to shushy stuff (oxides) at the surface of the melt where there is contact with air. Tin turns into oxides more readily than lead.
If your alloy is 20-1 tin/lead, 95% of the exposed surface is lead, and 5% is tin.
Early-forming slushy stuff contains a somewhat higher tin ratio (than the alloy) because tin oxidizes more readily. As the oxide covers the melt, lead oxidation is retarded, but tin continues.
When the amount of slushy stuff reaches problematical proportions, it is skimmed off and put in the slushy stuff place.
This slushy stuff can be expected to have a pretty high tin oxide content.
(Pretty high is a technical term, found in those glossaries which also contain terms like slushy stuff)

After the session, the slushy stuff is remelted and 'fluxed' to remove oxygen molecules and replace them with carbon molecules. The slushy stuff becomes metal (once again) and the excess carbon is left as dense black powder.

However, since the slushy stuff had such a high tin oxide content, It can be assumed that the new metal ('reduced' oxides) is not 20-1 alloy.

If the tin content of the new metal is higher than 20-1, then it stands to reason that the alloy in the bullets has less tin...except for the first ones cast...and that the tin content fell gradually as the session progressed.

Had 'fluxing' (reduction) been performed throughout the casting session, with no slushy stuff skimmed out at all, the alloy in the bullets would be 20-1...in all of them.

No...?

CM

[sundog]

That's prexactly why I use a layer of wood ash on top on the melt. Reduces slushies on the surface to almost nothing.

Ever really take a close looksee at what's going on in the pot when the heat is to it? It's constantly convecting (stirring itself) just like any other liquid would when heated. Anything that oxide's on the surface is going to be lighter and stay there - float. With the surface covered, and it doesn't take much, contact with air is reduced significantly. Whatever little bit does start to oxide on the surface, a gentle push of the ladle back into the melt and it mixes in all by itself.

Well, that's the way I've been doing it for a long time, and it works for me.

[joeb33050]

I come before you to speak of slushy stuff.

After the session, the slushy stuff is remelted and 'fluxed' to remove oxygen molecules and replace them with carbon molecules. The slushy stuff becomes metal (once again) and the excess carbon is left as dense black powder.
I certainly don't know, nor will I argue about it. I will say that the black powdery stuff is DENSE, has a high specific gravity, suggesting to me that it has in it some metal, some dense metal. I have a few ounces if anyone has access to a means of analysis. Chromatograph?

CM
Whatever it is, I have found no way to get it, the dense black powdery stuff, back into shiny metal condition.
joe b.

[jhrosier]

I come before you to speak of slushy stuff.

Slushy stuff is oxides.
.......
When the amount of slushy stuff reaches problematical proportions, it is skimmed off and put in the slushy stuff place.
...........
That is what I used to do, before I realised that the slush was likely antimony.
When I raised the temperature a couple hundred degrees and fluxed, the slush went right back into the alloy, leaving virtually nothing behind. The re-constituted alloy seems to cast well when the temperature is lowered and does not oxidize at the lowered temperature.



Had 'fluxing' (reduction) been performed throughout the casting session, with no slushy stuff skimmed out at all, the alloy in the bullets would be 20-1...in all of them.

No...?

CM

I believe that you are quite right about this. Stirring the pot with the stick after every few pours leaves a constantly shiny surface with just a bit of carbon floating that I only remove just before I shut down the pot and drain it. I bottom pour so the carbon doesn't get in my way.

Jack

[montana_charlie]

I certainly don't know, nor will I argue about it. I will say that the black powdery stuff is DENSE, has a high specific gravity, suggesting to me that it has in it some metal, some dense metal. I have a few ounces if anyone has access to a means of analysis. Chromatograph?Whatever it is, I have found no way to get it, the dense black powdery stuff, back into shiny metal condition.
joe b.
Once again, I find the need to revert to simple logic based on general knowledge, because my specific knowledge of the subject is insufficient to make a factual statement.

All living organisms 'are what they eat'...even trees. The water taken up by the root system includes a variety of elements that are not 'food', but are nonetheless present. The tree may even benefit from their presence.

Metals (such as iron and others) exist in almost every aquafer on the planet. If a tree contains metals, or oxides of metals, like iron, magnesium, lead, copper...and who knows what else...taken in with the water it 'ate', it would be reasonable to find it (them) in the 'residue' from burning that wood.

Perhaps something along that train of thought can explain the 'denseness' of the powder...ya think?

CM

[joeb33050]

Once again, I find the need to revert to simple logic based on general knowledge, because my specific knowledge of the subject is insufficient to make a factual statement.

All living organisms 'are what they eat'...even trees. The water taken up by the root system includes a variety of elements that are not 'food', but are nonetheless present. The tree may even benefit from their presence.

Metals (such as iron and others) exist in almost every aquafer on the planet. If a tree contains metals, or oxides of metals, like iron, magnesium, lead, copper...and who knows what else...taken in with the water it 'ate', it would be reasonable to find it (them) in the 'residue' from burning that wood.

Burning what wood? Do you have a chromatograph or not? Did I spaell chromatograph right?

Perhaps something along that train of thought can explain the 'denseness' of the powder...ya think?

CM
PM your address and I'll mail 11 pounds of dense black powder.
joe b.

[Bert2368]

Have you tried putting some of the dense black powder in water, does it off gas? Got any acids available?

[montana_charlie]

PM your address and I'll mail 11 pounds of dense black powder.
joe b.
It's hard to answer your specific question or comment when it is embedded in a quote of my last post. When I click on the 'Quote' button, the previously quoted material is not shown.

But the purpose of this post is to answer your question, "What wood?"

When I flux, I (like many) use a wooden stick. I used beeswax long ago, but I don't recall any of that dense powder being left behind.

I do get it when using wood.

Since you are seeing a similar powder, I assumed you had (like many others) turned to wood products for your flux...and you didn't say anything specific about what you do use.

If you don't use wood...and still get the powder...my 'guessing' must not apply.

Since it IS necessary for me to guess about the properties of that powder...you can bet I surely DON'T have a chromatograph.
However, if you wish to mail me 11 pounds of black powder, please make it Goex Express FFg.

CM

[Grampie not Grumpie]

I am new to casting boolits, however I am a retired elevator mechanic. I remember when re-cabling an elevator and pouring babbit in cable shackles we heated the babbit in a large laddle on a propane burner. The way we checked for the proper temperature was to stirr the babbit with a pine stick. When it smoked and started to "char" it was ready. We then skimed the laddle and poured the babbit in the shackles.

I do the same when I pour boolits and it seems to work.

Grampie not Grumpie

[insanelupus]

I know this will sound like a dumb question. But, when you are fluxing with the pine stick, do you leave it in the melt when you pour, or do you remove it from the melt? If you remove it, does it do like metal and have the lead just run off, or does it adhere to the stick? Also, how quickly do the sticks get chewed up? I'm curious, I've a friend who is a contractor and can get me all the dry scraps (long enough of course and then sawn into chunks) to use for this process. Stored in a heated room, they should be plenty dry by the time I wish ot use them. Just not sure how many to lay in for a casting session.

[snaggdit]

If you leave it in, it will eventually start on fire. I stir and remove. The lead does not stick on it. It also does not wear out very fast. If you start with a 3/4" x 3/4" x 18" stick, you will have many hours of stirring/fluxing before you find your fingers near the casting pot rim.