Fluxing - head spinning

[GregLaROCHE]

I’m following as a casting nubie, and have a question. Does it matter what kind of sawdust? Or can I just empty my chopsaw and use it?

Sawdust from your chopsaw should be fine. Just make sure it’s dry. I’ve even used Quaker Oats when I didn’t have sawdust once.

[bluebird66]

Thanks for the information.

[Cast10]

When you get to casting, save the dross you pull from the lead you just made...it's obviously pretty clean so the dross is oxidized tin & antimony & traces of other stuff.
I use wax in the pour pot to stir the oxidized metals back as best I can, then pull the dross, drop it in a coffee can or appropriate container and then re-seal the surface with another generous button of wax. That'll seal the pot surface from oxidation as you cast, it forms a nice carbon black crust in the pot on the surface of the melt.

Don't be dropping your sprues in the pot as you cast or it'll break your carbon seal and the melt will oxidize much quicker. Save them till your ready for a break and refill of the pot.

After enough casting you'll accumulate a lot of dross, tin & antimony rich dross...



When you make another ingot pot of lead, put the bucket of dross in with the lead your processing, you will be amazed at how much of the pour pot dross you reclaim & it'll sweeten the tin percentage a bit also.

Great idea! I was wondering what I would do with it. Thanks!

[44MAG#1]

I would say if his head was doing 10 RPM when he first posted it is now doing 100 RPM.
Occam's Razor.

[Ural Driver]

Some great info for us newbies. Don't remember who told me, but I use one of those wooden paint stir sticks. I grab several every time I go by a paint counter and keep a good supply on hand.

[country gent]

as important as the fluxing is how you stir it when fluxing, Working the melt up and thru itself then down and thru itself scraping the sides and bottom.

[Cast10]

I would say if his head was doing 10 RPM when he first posted it is now doing 100 RPM.
Occam's Razor.

More like 2500!

[B R Shooter]

I only use bees wax to flux. I can't see the logic of using saw dust and mix that into the pot, when the idea is to get as much foreign matter out in the first place. But others do it, just I don't. Country gent's post above is important. Once your flux, you need to not just stir, but to scoop from below, raise to the top, let it mix again. Scrape sides, let all the foreign stuff come to the top.

[crackers]

I put the range scrap in the pot, skim it and pour the mold. What the flux?

[Jsm180]

If your head isn't spinning fast enough yet, this should run the r's up some.

http://www.sixguns.com/crew/simplefluxing.htm

[Cast10]

If your head isn't spinning fast enough yet, this should run the r's up some.

http://www.sixguns.com/crew/simplefluxing.htm

Yeah! I read this and it’s “deer in headlights”!

[whisler]

Clear as glass to me but then I studied a lot of chemistry.

[waksupi]

There is a reason to use a stick to stir the lead. Do you really think that you can overcome the specific gravity of lead, and stir sawdust appreciably under the surface of the melt? If you could "capture" the sawdust and force it to the bottom, it would work, but it is just extra work to come up with something to do it with. Sawdust will capture what floats to the top, but that is usually your tin, which you have gone to pains to put INTO the alloy.

Once the melt is clean and you are ready to cast, a handful of kitty litter on top of the melt will help maintain pot temperature, and prevent oxidation that people usually skim off.

[Land Owner]

^^^^^^^

Sir, I just had the experience of "bubbling up" from within my 20# pot. I poured liquid alloy (melted spru) from an adjacent 10# pot of the same alloy into a partially depleted 20# pot. The surface 1/2" depth of the receiving 20# pot was smoldering and blackened sawdust, which, after nearly filling, I stirred around and scooped the dross off.

A quarter sized portion of the clean surface of the nearly full 20# pot began a slow "bubbling" as something "boiled up" like a spring will "well up" in a still water course. I had never seen "bubbling" in a melted alloy before and it was disturbing. Turned out, after more stirring, it was still burning sawdust that had been "sunk" by the added melt and bubbles of smoke were rising out of the depths of the 20# pot.

[oley55]

I don’t put as much effort or propane into melting to make ingots as I used to. I only use sawdust now and save the bee’s wax for the casting pot after a good fluxing of sawdust.

Thinking how that works, less propane so you must be rubbing sticks together, but that seems like a lot more effort!

[waksupi]

^^^^^^^

Sir, I just had the experience of "bubbling up" from within my 20# pot. I poured liquid alloy (melted spru) from an adjacent 10# pot of the same alloy into a partially depleted 20# pot. The surface 1/2" depth of the receiving 20# pot was smoldering and blackened sawdust, which, after nearly filling, I stirred around and scooped the dross off.

A quarter sized portion of the clean surface of the nearly full 20# pot began a slow "bubbling" as something "boiled up" like a spring will "well up" in a still water course. I had never seen "bubbling" in a melted alloy before and it was disturbing. Turned out, after more stirring, it was still burning sawdust that had been "sunk" by the added melt and bubbles of smoke were rising out of the depths of the 20# pot.

I would bet some stuck to the side of the pot when the level was low. As for the bubbling, where did it come from? You had a hot pot, and were pouring from a hot pot. There should have been no moisture present. Maybe some resin boiling out of the sawdust?

[Land Owner]

I got the impression that it was smoke from still burning sawdust, but it could have been resin. Hadn't thought of that. Was plenty of it in the Cedar sawdust to begin with. Definitely not moisture. Hot pot to hot pot.

[Capt Keith]

Just stirring it with a dry stick works better to get down under the surface, where you need it.

Doesn’t it burn the stick?

[Capt Keith]

Thanks Greg!

[CoolHandMoss]

I’m following as a casting nubie, and have a question. Does it matter what kind of sawdust? Or can I just empty my chopsaw and use it?

I am no pro but I would suggest tending toward dust on the finer side and avoid walnut.