Fluxing Question

[Bisley]

When I resumed casting, I bought a 2-lb bag of pine shaving litter / bedding for flux. Having read so much about it, I put my chunks of candle wax away. My procedure is to get the melt up to temperature, then add enough pine shavings to form a layer 1 inch thick. I stir these in, forcing them under the led until the lead stops bubbling around them. When that happens, I stir, skim, and start to cast.

One observation: If I flux without adding the old sprues back to the melt, the pine shavings seem not to generate as much bubbling when I force them under the lead melt. When I add and melt the old sprues, I seem to get greater bubbling.

One question: Am I purging the lead of oxygen as I flux this way, with more oxygen introduced to the melt by adding old sprues, and that causes the bubbling, or is it residual moisture in the pine shavings?

Or should I just go back to tossing chunks of dead candle into the pot? Here in greater suburbia, I generate less attention with pine smoke than wax smoke.

 

[358156 hp]

Here's a link to one of our marathon (not really) fluxing & ladle casting threads. This one has a couple of Brads videos on fluxing with wood shavings, and a side trip on ladle casting with a Rowell ladle. There are more, and I'll find them eventually. I've forwarded the fluxing video to countless (at least three or four) people who have asked me about fluxing lead alloys. I'm not trying to evade your question, I just wanted to to have access to the information that helped me out when I had the same questions.

https://artfulbullet.com/index.php?threads/fluxing-and-ladle-casting.2715/
https://artfulbullet.com/index.php?...-forms-on-the-top-of-the-melt.604/#post-10172
And Glen Fryxell, from Ricks site:
http://www.lasc.us/FryxellFluxing.htm

 

[Brad]

A couple points. Try not to push wood under the surface too much. It WILL leave bits behind suspended in the melt that will eventually end up in bullets. As long as the wood will still burn it will also off gas when exposed to high temps. Those gases will bubble to the surface.

I like to let the wood begin to char a bit so I know it is dry. I then Use a spoon to dump lead over the wood chips the ignite them. I continue the dump and stir as the wood burns. I sometimes add a bit of wax to extend the burn time. Once all flame is out I begin skimming the ashes and stuff. I also stir vigorously to create up current to help bring bits suspended in the melt to the surface.

 

[CWLONGSHOT]

I also like the “smell” better but DONT like the deposits left in my alloy. I went to a candle stick. Cheap at HD. Just give it a stir a couple times and It’s nicely fluxed. Sometimes it’s amazing what I pull outta a pot.

Good lucK

CW

 

[ChestnutLouie]

Will any kind of sawdust be OK? hardwood or soft pine? fine grain or large flakes?

how is sawdust different than Franklin Arsenal Fuxing compound?

Thanks
Francis

 

[Brad]

Fine grain. Pine would be excellent.

The Frankfort Arsenal stuff looks a whole lot like Marvelux. No way I would use that stuff again. It attracts moisture when cold. It also does an excellent job of removing stuff from the melt. Sadly much of that stuff on the surface when the pot hits temp is tin or antimony oxides we want to keep. Using a reducing agent helps get them back into the melt.

Want to really get people going, ask for an opinion on Marvelux.

 

[Bisley]

I used Marvelux thirty years ago when dad bought some. I had to use candle wax after the Marvelux to clean the lead. That was with a plumber's furnace capable of 1,000 degrees, but I tried to keep it around 750 when casting, after Dad bought the thermometer. Wax or pine shavings for me from here on in.

 

[Matt]

I don’t know the reason that sawdust works but I feel it’s the best way to flux. I use a heaping tablespoon in either of my 20 lb pots. I let it start to char and begin to push it to the melt and stir and scrape the sides and bottom of the pot. As stated earlier you won’t believe the crap that surfaces. I’ve had gas checks show up from rejects that I have remelted but it took fluxing to release it. (You can see the surface tension of the melt change too. )
Scrape the crud off the top and put it something that won’t melt or burn and give the sides and bottom another scrape. I used Marvelux 40 years ago and it just made a mess and seemed to rust everything it touched. Haven’t been impressed with using bullet lube ( messy, smelly. and expensive) nor paraffin for mess and smell. I don’t think hardwood or softwood matters. I just grab whatever is in the collection box under my table saw. I flux once for a bottom pour pot until I add metal and then reflux. The little bit of ladle casting I do requires more fluxing to get good billets my experience.

 

[Joshua]

When I add new ingots I crumble up dried leaves and add a 1/2 teaspoon sized piece of wax. I let the carbon do it’s work, absorbing the junk that we don’t want in our mix. Scoop out the ash and charcoal. From then on I only use wax to get the oxide layer back into solution. It ain’t fancy. It also seems to work just fine.
I have substituted dry grass clippings/straw and bacon fat/old cooking oil, this also works just fine.

Side note: Over a hundred years ago the first arc welded tanks were made with a pine backing board and bare electrodes. The burning pine board gave off CO2 and shielded the weld root from oxidation. Who knew pine was so popular in the battle against oxidation!
JM

 

[Winelover]

Anything organic will suffice. Use what's cheap. In my case, sawdust for smelting. Clean ingots, introduced to the pot, at the start of a session (2-3 hours), get a pea sized ball of Carnuba Red.............because my Star sizer leaks periodically. I ladle cast, anymore, with a #2 Rowell. Floating it between pours, it just about covers the whole surface of the melt, in all three of my furnaces. Keeps oxidation in check, so I don't need to flux again................ even though I return sprues to the pot, after every pour.

 

[ChestnutLouie]

Saw dust it is

 

[JWFilips]

Two Documents that have helped me over the years are attached below!
May be they can be a help

 

[fiver]

when you add the sprues back in they have oxidized over. [that's the color change you see on the surface]
so you do have more oxides to deal with.

 

[trapper9260]

I use ground up corn cobs. For my fluxing , I use to use bee wax but found that the corn cobs did not cost me anything since I had a farmer ground some up for me and I also use it to tumble my brass for the 2nd time for clean the lube off the cases after I size and deprime the cases.

 

[dannyd]

In Florida hard to use sawdust because of moisture so I use a wood paint stick.