How much fluxing

[shootinxd]

Say I wanna cast 500 boolits and have to refill my pot a couple times,and dropping my sprue back in as I go.How many times should I be refluxing?I try to return my sprue back in before it cools too much so my temp stays up.And how much wood shavings should I be using?[smilie=s:

[ku4hx]

The simplistic answer is to reflux when you need to. Which is likely not the advice you're looking for. But it's basically true as fluxing is one of the "it's an art" aspect to casting.

My casting sessions usually run about 25 pounds of alloy and I generally flux at the beginning and then again near the halfway point. I say "25 pounds" because I cast boolits of ~120 to ~300 grains and boolit counts vary greatly.

What I finally discovered long ago was to work hard at smelting really clean alloy. There was a time when fluxing in my pot got me a sizable amount of dross each time. Starting with really clean alloy now has pretty much fixed that problem. But, even though I'm a bottom draw sort of guy now, I use my ladle to remix the alloy quite often sweeping it from top to bottom and back in an attempt to keep things mixed. It's all sort of like VooDoo and I do what I was taught to do and what works for me.

Back when wife and I were active bikers, I always put my left glove on first. Kept me from crashing and that made me very happy. Same with fluxing, two times per session makes me happy.

[Calamity Jake]

I bottom pour just about everything, the only time I flux is just after the melt comes to the casting temp I want and then it is just a stur with a stick, when I add metal to the pot I stur again.
I keep 1/4" layer of kitty kitter on top of the melt it keeps the heat in, acts as an oxidation shield and a flux when adding back the sprues.

[Shiloh]

I flux as needed, usually a couple of times per pot.
I've fluxed with sawdust, wood chips from a planer, old and scrap lube, as well as Marvelux.

Shiloh

[waksupi]

When you see the lead start to cling to the sides of your pot, is when you need to flux. What makes it cling to the pot, also makes it cling to the inside of the mold, making it more difficult to get a nice boolit.

[runfiverun]

i probably flux about every three pots full.
much like mentioned above, getting the alloy clean to begin with.
keeping temps in check,and oxygen barrier on the alloy.
i put the sprues back and add warmed ingots as i cast.
i don't get all worked up about it unless i see a big ball of gunk on top of the alloy.
i will stir the melt and scrape the sides of the pot with a paint stick at least once a session though.

[geargnasher]

If you bottom-pour and clean alloy, just use a little sawdust at first and scrape the sides of the pot and stir the alloy well but gently with a stick. Leave the sawdust alone, don't overheat the alloy (maintain about 100 degrees over full-liquidus), and you shouldn't have to do anything other than scrape the sides of the pot and stir with the stick again once or twice before it's time to refill.

When it's time to refill, I scrape the sides clean again, police the ash layer with the stick, and skim the surface clean with a spoon before adding more alloy. After the alloy is refreshed, repeat first paragraph.

Gear

[williamwaco]

If you bottom-pour and clean alloy, just use a little sawdust at first and scrape the sides of the pot and stir the alloy well but gently with a stick. Leave the sawdust alone, don't overheat the alloy (maintain about 100 degrees over full-liquidus), and you shouldn't have to do anything other than scrape the sides of the pot and stir with the stick again once or twice before it's time to refill.

When it's time to refill, I scrape the sides clean again, police the ash layer with the stick, and skim the surface clean with a spoon before adding more alloy. After the alloy is refreshed, repeat first paragraph.

Gear


Ditto.

This is exactly what I do. - Except scrape sides AND bottom.


.

[stubshaft]

When my ladle starts to gunk up I add flux.

[geargnasher]

Scrape bottom with spoon, sides get scraped with a stick. Too many times I've made a drip-o-matic out of my pot by scraping the bottom with my stir stick and it left ash trapped under the melt.

Gear

[Three44s]

Gear is dead on about just using a spoon on the bottom!

As far as adding sprues etc. ........ I prefer to wait and add them later and at once when I am refilling the pot.

Let the sprues accumulate because insecant adding of dabs of metal can only serve to pull something evil back into the body of your melt.

The cleaner you can keep the melt below the surface and down towards your bottom pour valve (everything else equal) the fewer reject boolits you'll have to re-run.

Pulling those sprues out also distracts from a good artful sequence and timing on pouring good boolits ....... that's what I am there for. A few degrees of re-heat on some sprues VS. re-heating more reject boolits ........

As a matter of practice, I like to break down my WW's in one melt and the re-melt those once poured ingots and re-flux in a second melt. Then those ingots are the basis for whatever alloy I then chose. Most of the time (revolver loads) I am running WW's with a small amount of tin added. That can be added right before I cast as long as I have a good "head count" on how many ingots of clean WW alloy I am running.

Three 44s

[snuffy]

Adding sprues back into the pot agitates the surface of the melt, creating more oxides. Second thing it does is take time, interrupting the cadence needed for production. Third thing it does to me is get me burned!:mad: Those pesky little droplets of hot lead produced when the sprue goes kerplop into the melt!:sad:

As for fluxing, I do it whenever I add metal to the pot. I usually roost the ingots on my hotplate so they're preheated. When the lead level falls below half way on my 4-20, then it's time to add the sprues back in as well as enough ingots to bring the level back up to full. Then a flux with stearic acid, skim off the crud, then back to casting. The mold has kept up to heat on the hotplate, so not much of a break in involved.

One note to add, the use of a PID at this time helps in the recovery back to temp. The PID allows full power right up to when it's within 10 degrees of set temp. The lee thermostat will cycle on-off all the way from where it starts to recover. Say I'm casting @ 700 degrees. Adding preheated ingots and cold sprues will drop the temp 100 DEG. It seldom takes more than 5 minutes to recover. Long enough to get the drop zone cleared of already cast boolits, hit the latrine, get a drink, or put the dog outside.:bigsmyl2:

[jonk]

Depends. When I initially smelt wheelweights and whatever else I'm putting in (usually a little 50/50 solder, 1 lb per 10 of wheelweights), there's enough grease and dirt on them to do a pretty decent job as an initial flux. Just to make sure, after scraping off the clips I dump a teaspoon of marvelux in (I usually smelt about 50 pounds at a time). Stir, let stop bubbling, and scrape.

This might not be super pure and clean but it's reasonably so going into my pot in the basement for final use. As such I have a 10 pound pot, and usually flux once at the start with either lube or sawdust, then add a little cat litter, and not again that session. I might do a few test bullets to see how things are before adding the litter and flux again if needed.

I don't add sprues back during casting, they all get knocked onto my cement floor if I'm water dropping, or on one side of the towel if air cooling. As such, they often get little water droplets on them for the former, or are too hot to handle if just on a heap on the towel.

How often to flux? Well... if you're getting good fill out and release at the start, and start to get crummy fill out, then it might be time to flux.

[Longwood]

Scrape bottom with spoon, sides get scraped with a stick. Too many times I've made a drip-o-matic out of my pot by scraping the bottom with my stir stick and it left ash trapped under the melt.

Gear

I tried the stir stick but they quickly get rounded on the end and don't scrape the bottom or corner of the pot very well plus I kept seeing pieces of carbon in bullets.

I used the belt sander to make flats on the end and one side of a soup spoon that I put a wooden handle on. Scraping the sides, bottom and corner with it and using sawdust works way better than all I tried before.

[williamwaco]

Scrape bottom with spoon, sides get scraped with a stick. Too many times I've made a drip-o-matic out of my pot by scraping the bottom with my stir stick and it left ash trapped under the melt.

Gear


Absolutely.

I always assume eveyone knows what I am thinking. (Only my wife seems to be successful at that. )

I scrape both sides AND bottom with a spoon.

The spoon has been ground down to have a flat side and a flat bottom so a straight edge is always doing the scraping against the walls of the pot.

.

[prs]

Snuffy, a layer of clay granules will prevent the splash, will float the spru waste while it slowly melts, will act as a barrier to the atmosphere, and droppong spru onto the clay is no slower than dumping them in a bread pan or such. Since the spru is already plenty hot, it conserves the energy it would have taken to re-heat it. I do not think the clay acts as an effective flux, but mix some saw dust or such with it and you get a double benefit. I generally flux throughly at the befinning of use of a full pot and again every 10 minutes or so since I cast hot. A 20# pot does not last me much longer than the 10 minutes with two 40 or 45 caliber 6 cavity moulds going in tandem.

prs