Need some help with definitions and terms of fluxing etc.

[Jim..47]

This was posted in a closed thread and if you can interpret it for me sure would be great. By the way, I'm asking a lot of questions cause I need to learn so much and have a short time to do it. :smile:



Wax is good for reducing the tin back into the mix.

My process is to use wood and wax when schmelting. Reduces the tin back in while "cleaning" the alloy.

When casting I will start to add wax or wood shaving dependent on how quick the surface starts to turn yellowish. No yellow no tin no sense fluxing

What I want is to have this interpreted into plain old english as I'm not familiar with those terms.

Also, please advise me if its possible to remove the tin you just added by using a poor fluxing procedure and what procedure you should use to avoid this.

Thanks again for all the help guys.

[jmort]

Flux when you smelt and reduce your alloy when casting.
http://www.lasc.us/Fryxell_Book_Chapter_4_Fluxing.htm

[btroj]

Ok, as we use the term fluxing it means doing two things.

One, we need to reduce oxides of lead, tin, and antimony back into the melt. These oxides are valuable to us, we don't want to lose them. This is done by anything that burns on a low order, a smokey flame. This produces lots of carbon monoxide which is a great reducing agent. Wax works as does pil, bullet lube, wood, or anything that burns.

Two, we want to remove I purifies such as non desirable metals like aluminum and calcium. We need something that is capable of adsorbing those impurities. Something like activated carbon does an excellent job of this.

What we see used like wax does job one but fails on job two. A substance like Marvelux is decent at job two but is horrendous at job one as it actually removes the oxides we want to reduce back in.

Something like straight activated carbn, like used in fish tank filters, will adsorb the impurities but doesn't reduce the oxides.

What we need is something capable of doing both. Something readily available. What we have that fills bill perfectly is finely divided wood. Sawdust, small animal bedding, wood plane shavings, pretty much any finely divided wood. As t shoulder and burns it is reduci the oxides. After it is charred it works to pull impurities from the melt.

Don't just put wood on the surface and stir. Use a ladle or spoon to dribble and pour molten lead thru the surface layer of flux. This takes time, possible many minutes. Follow with a good stirring to bring everything to the surface and skim the debris from the surface. What you want to avoid is actions that push lots of wood and ash beneath the surface, it can Enco w trapped there and become an impurity in a bullet or clog a bottom pour spout.

It it isn't rocket science but it is critically important.

[RayinNH]

Can someone interpret what Brad just wrote :kidding:.

[btroj]

PM Cbrick or Geargnasher, they can!

:-P

[Jim..47]

Thanks btoj. It looks like I'm going to learn a little metallurgy here. Much appreciated.

[cbrick]

Also, please advise me if its possible to remove the tin you just added by using a poor fluxing procedure and what procedure you should use to avoid this. Thanks again for all the help guys.

Kinda possible, you'll never get it all out but the percentage could be lessened in two ways. First is oxidation and skimming it off. Second would be by using a flux such as Marvalux or as I'm fond of calling it, Marvacrap. Marvacrap is not a reducer but it is a good flux, it will remove tin and/or antimony right along with the stuff you do want removed.

By either method tin and antimony percentages could be lessened.

Rick

[geargnasher]

Jim, go here, skip to post #39: http://castboolits.gunloads.com/showthread.php?266575-What-kind-of-flux-do-you-prefer-and-why

Short version, I consider cleaning alloy to be up to three different operations chemically and physically:
1. Cleaning non-metallic trash/dirt/sand/whatever (scrape, stir, police it off the surface with a spoon).
2. Reducing (opposite of oxidizing, requires chemical reaction to take place) oxides. We want to save our tin, antimony, and lead oxides, but get rid of the rest, so "selective reduction" is the key. Fortunately, those three metals reduce more easily than other contaminating oxides, so it's not difficult to properly reduce...just use any grease, wax, oil, or organic matter like clean, pine sawdust.
3. Fluxing....Flux means "flow". Dissolved/alloyed metals like zinc, calcium, aluminum, etc. are considered impurities to us because they impede good flow and casting properties. They can be "fluxed" out, or removed, only in their oxidized state via aDsorption by activated carbon. Activated carbon is easy to make as it is a byproduct of the combustion of the carbohydrates/lignins in sawdust.

Depending on the condition of the stuff you start out with, you may need to only do one, two, or all three of the above. The order is important depending on what needs done, for example if you skim before you reduce, you'll throw away good oxides. If you flux with a dedicated flux agent like Marvakrap, you'll remove ALL the oxides, good and bad. If you reduce with grease/wax/oil and don't agitate/skim, the non-metallic contaminants remain.

The hands-down best and foolproof thing to do is dump a generous layer of dry sawdust on top of your alloy, ladle the alloy up and pour through the sawdust repeatedly, try to expose every drop of metal to the burning, charring mat, then stir/scrap the heck out of it and skim the surface clean before all of the sawdust has turned to grey ash. Rinse and repeat.

Gear

[Jim..47]

Great help geargnasher, you just answered a lot of my questions. I'll check out that other thread.
Thanks a bunch.