Lyman cast book, Fluxing

[fiatmom]

Forgive me if this seems too simple or redundant of a question.
I was reading the Lyman cast boolet book and they mentioned various types of fluxing, and I got confussed.
First they said to float borax on the top of the melt to prevent oxidation. Is this the same as the casting flux by Midway and others?
They also said to allow a pool of wax to remain on the top. Is the same thing?
For fluxing they recomended a little bit of wax of miraflux to stirred in.
I also read saw dust is better than wax because it removes othe impurities, and that the charred wood should be left on top.
When I used Midway flux I got a black glass, did this remove the tin?
Help me make sence of this.
Thanks
Nick

[docone31]

Fluxing really helps.
I just use Kitty Litter on top. I can toss my rejects on the pot and they melt into the pot without the tinsel fairy.
With Borax,
I have used it. The molten lead does not get hot enough to really melt the borax. It clumps on top, but it does pull the crud into it.
The black molten flux is normal. I would leave it and keep working with it. It will eventually either dissapate, or you will scoop it out.
Lead oxidises rapidly. I am pretty sure you can flux all the lead out of the pot if you kept at it.
You cannot flux an alloy apart. You will need acid for that.
I now, use Kitty Litter all the time. When it is expired, it is nothing but powder and crud.

[chboats]

I believe the reference to floating borax on top is to put a layer of no combustable material on top of the melt to prevent contact with the air (oxigen). Almost any carbon based material can be used for fluxing. Saw dust, wax, various oils, saw dust mixed with wax or oils all work some better than others. Just figure what works best for you.

Carl

[rob45]

Forgive me if this seems too simple or redundant of a question.
I was reading the Lyman cast boolet book and they mentioned various types of fluxing, and I got confussed.
First they said to float borax on the top of the melt to prevent oxidation. Is this the same as the casting flux by Midway and others?
To the best of my knowledge, yes.
They also said to allow a pool of wax to remain on the top. Is the same thing?
The intent is the same- to provide an oxygen barrier.
For fluxing they recomended a little bit of wax of miraflux to stirred in.
That's one way of doing it, but certainly not the only way. "Stirring in" is good, but the product used may vary.
I also read saw dust is better than wax because it removes othe impurities, and that the charred wood should be left on top.
Absolutely!
When I used Midway flux I got a black glass, did this remove the tin?
Most likely, but hard to say for sure. The benefit of the borax-based fluxes is that they remove impurities and provide an oxygen barrier. However,to they best of my knowledge, they are not as effective in reduction qualities.
Help me make sence of this.
Thanks
Nick

As boolit casters, we tend to use the term "flux" very loosely.
Our primary goals are:
1. Remove impurities.
2. Minimize further oxidation by providing an oxygen barrier.
3. Reduction of oxides back into the melt. A lot of those "impurities" are oxides of the valuable alloy constituents. The proper flux procedure will reduce those oxides and help maintain the alloy, usually with the use of something carbon-based.

My favorite all-purpose flux is plain ol' sawdust. It accomplishes all three of the above.

A very useful article:
http://www.lasc.us/FryxellFluxing.htm

[mroliver77]

I start with a wood stick and stir melt well then scoop off the dross. If melt acts funny I will flux with sawdust or wax whichever is handiest at the moment. O very stubborn melts I bring temp slightly above the melting point and flood with beeswax while stirring and scraping away.I like to leave a layer of ash or kitty litter on top to slow down the oxidation. I stay away from the borox and marvalux type fluxes. My .02
Jay

[fiatmom]

This is what I thought ,and have been doing. I guess reading made the process much to complicated. Its like when I read an article on long range deer hunting just before opening day. Yes you can miss a standing deer at 50 yards with a .270 Win.... after all you have to concider windage , trajectory, mirage, and slope. : )

[Maven]

"First they said to float borax on the top of the melt to prevent oxidation."

fiatmom, Dennis Marshall, a metallurgist and cast bullet authority, suggested the use of borax only when casting temperatures were at or above 900 deg. F in a bottom-pour furnace. As the Lyman manual indicates, lots of substances can be used to flux your alloy, but the one you choose may depend on whether you cast indoors or outdoors. If the latter, old candles, sawdust, etc., work very well, but smoke a great deal. If the former, Marvelux (from Brownells) is excellent (no smoke or odor), but is hygroscopic. Make sure your fluxing spoons are 100% dry (preheated) if you use it.

[geargnasher]

As boolit casters, we tend to use the term "flux" very loosely.
Our primary goals are:
1. Remove impurities.
2. Minimize further oxidation by providing an oxygen barrier.
3. Reduction of oxides back into the melt. A lot of those "impurities" are oxides of the valuable alloy constituents. The proper flux procedure will reduce those oxides and help maintain the alloy, usually with the use of something carbon-based.

My favorite all-purpose flux is plain ol' sawdust. It accomplishes all three of the above.

A very useful article:
http://www.lasc.us/FryxellFluxing.htm

You got it. There's FLUXING, which uses a "sacrificial reducant" to chemically turn oxide scum back into elemental lead/tin/whatever, there's CLEANING, which is just getting impurities like rust powder, calcium, dirt, etc. (sawdust does a good job of this for me, plus it does a good job of fluxing, too), then there's casting with a layer of borate glass on top of the melt to conserve heat and prevent oxidation.

I use borax rarely, and it's my understanding (and I do it this way) that the alloy must be freshly fluxed and cleaned with a shiny surface BEFORE adding the borax.

The Lyman manual is basic in it's explanation, there are many ways of accomplishing the fluxing process, and IMO the stick/sawdust method is best, and you can't use borax if you ladle.

Gear

One more thing, and this often gets confused: Using Kitty Litter is great for conserving heat and preventing oxidation after it's added, but it will not do much actual fluxing, so make sure you flux and skim before adding it.

[HORNET]

The waxes and sawdust only smoke until they burst into flame...that'll get your attention...

[a.squibload]

I was taught to stir in a chunk of candle or boolit lube, do you stir in the sawdust?

Always heard that you remove dirt, nothing else, to avoid removing tin, etc.?

Saw a pic here somewhere of a paint stirrer with shiny stuff on it, does that remove
the good stuff? How do I know what to remove?

Thought I knew what I was doing!

[snuffy]

I was taught to stir in a chunk of candle or boolit lube, do you stir in the sawdust?
Always heard that you remove dirt, nothing else, to avoid removing tin, etc.?
Saw a pic here somewhere of a paint stirrer with shiny stuff on it, does that remove
the good stuff? How do I know what to remove?
Thought I knew what I was doing!

It sounds like you're believing the myth that tin and the other lighter components of the alloy float to the surface. That simply is not true! What you see floating after fluxing is dirt and other things lighter than lead. That includes lead, tin, and antimony OXIDES. A perfect flux would re-combine those oxides to their metallic state.

Providing a barrier to protect the surface of the melt prevents oxidation. If Lyman DID say to leave a pool of wax on the surface, they must have been taking drugs that day. Alloy at casting temp would not have a pool of wax sitting on it very long, like less than a minute! It will smoke to beat the band, then self ignite!:holysheep Don't know what they were smoking, somebody wasn't thinking too clear that day.

Molten lead WILL hold dirt and other nasty stuff against the sides and bottom of the pot. That's why a good, solid, long handled spoon is an important tool. Scrape the sides and bottom of the pot to knock that crud loose so it can float out.

[prs]

I know that at my casting temp, there will be no pool of wax on top of the melt. I like to stir flux with beeswax and scrape the sides of the pot in the process to get the oxides to give up the black crud to be skimmed; leaving a bright surface. I cover that surface with clay grannules (oil dry) of about an inch in thickness. As I add alloy or spru waste, it sits on the clay until it begins to melt through - no splash. I occasionally reflux with a lubed black powder type boolit that I push through the clay granules and stir in under them. One such boolit seems to freshen the whole 20# pot load. If you process your lead well during smelting, there will be little impurities to add to the real dross when you re-flux. Saw dust from sappy pine, like southern pine, seems to work great too as a "cleaner/fluxer". I avoid Marvelcrud as it tends to coat my tools.

prs

[a.squibload]

Snuffy, 10-4 on oxides, I always worried about that and was careful not to remove too much!
I just read that again, if I have a lot of that stuff maybe I didn't flux properly. Will try sawdust,
or sawdust AND wax.

prs, do you use a bottom-pour? Seems like an inch of clay on top would get in the way of my dipper.
Way back when, I decided not to ever get a bottom-pour 'cause my freind's would leak and
spatter. Never figured out why. Also I'm cheap.

PS: I'm following 2 threads on fluxing, hope I'm not asking too many questions! Getting similar
answers from both, just hope I'm asking the right questions. Can't wait to start casting again,
with all the new info it seems I'll get better results!