Craters in my ingots

[Bashby]

Hello everybody, been reading here a lot and just joined. Did a little reloading years back and just recently got interested in casting bullets. I collected a pile of range scrap and have been making it into muffin pan ingots. They are looking good to me except for the last couple stuck to the pan a bit and when I got them out the bottom looks like the surface of the moon. The only thing I did different was turned the muffin pan upside down and put it on top of the melt to keep the heat in. I guess that somehow that caused a problem. Not sure how to post a pic or if I even can yet, being a new member and all.

[RedlegEd]

Hi Bashby,
Welcome to Cast Boolits! I'll get that as well and I believe it's caused by impurities (oil or dust?) that create little air pockets when the molten lead is poured in. As long as you were fluxing and removing the dross while you were smelting to remove junk from the alloy, you should be fine. Ed

[Bashby]

Thanks for the quick reply, Ed. These arent small pockets. 250351
Lets see if this picture works.


Son of a gun!, it worked. The two on the left are like the rest, three on the right are cratered. The bottom right is cratered on the bottom. I showed the top of it for comparison.

[redhawk0]

Did you flux the pot either with a commercial flux or sawdust? Did you recombine the fluxed alloy using wax? These are important steps to getting good clean consistent alloys. The craters look like the alloy had some contaminate in it and it was what came out as your pot got low.

redhawk

[Bashby]

I have been using pine shavings for flux. They are smaller shavings I got at a pet supply. I have been adding a little wax now and then, I dont know the proper time to use it if there is one.

I am thinking that when I turned the muffin pan upside down on top of the melt the smoke from the sawdust made a film on it. I just did another batch and a couple looked good and a couple had some craters. Not as bad as the first time though.

Let me try to give a quick summary of what Ive been doing. I melted down the scrap and scraped all the dirt and coper off the top without heavy stirring or flux to get suspended dirt out. Then I learned I need to stir and flux so I am melting my ingots back down to clean further. All was well for 50 lbs or so then they came out all pitted up. I am using a cast iron skillet, hot plate, and acetylene torch to melt the lead. Stirring and skimming with a slotted spoon and dipping with a stainless ladle.
Maybe I should wash the pan with dishwashing soap or try to burn the residue off with the torch.

[Winger Ed.]

Those look like tiny steam explosions from trapped moisture.

I've had it happen when everything is clean, and moisture in the air got trapped on a cold mold when the molten lead hit it..

The same will happen, and you can see it when putting a cold, steel screw driver in the pot if the air has high humidity.
That's also a way to get a visit from the tinsel fairy.

I stir all the way to the bottom and along the sides.
All sorts of more dirt and soot will float up compared to just skimming off the top.

[redhawk0]

Here is the process I've been using.....someone add comments if I miss something.

melt your dirty metal
Skim off the garbage that floats to the surface
Stir with a slotted SS spoon
Skim off the garbage that floats to the surface
(continue above until you get very little floating)

Add 1/4-1/2" of sawdust over the surface...if it doesn't catch on fire from the molten metal, then light it with a lighter or match
Once it burns to charcoal, start stirring it though your metal making sure you scrape the bottom/sides as you go.
Skim off garbage that floats.
add a marble/pea size bit of wax to the surface....this WILL ignite on its own....start stirring in the flaming molten wax.
When if burns off you should have a very small amount of black skim on the surface, remove this.

This process should be repeated 3 times.

You will have nice clean shinny surface to your alloy when you are finished.

I've used this method for quite some time and it eliminated the pock marks and dirt that was suspended in my lead. I wasn't fluxing enough in the beginning.

redhawk

[Bazoo]

Sounds like you have some flux gas that contaminated the ingot mould when it was upside down.

When I clean wheel weights, what I do is melt them and skim off the majority of clips and dust. Then I throw in a heap of sawdust and let it char good and stir it good and scrape the sides and bottom of the pot well. Remove that mess, then repeat with wax. I think sawdust does good helping to get the particulates out.

Those are neat looking ingots by the way.

[bmortell]

looks like moisture to me too, id just make sure the mold is a couple hundred degrees every time before pouring, be better for safety too.

for flux with sawdust and wax I recommend spreading the sawdust thin on a surface and pour wax over it to make a sheet. let it cool and break it up into little flux cookies. then whenever its fully melted you can flux or whenever its been long enough that theres surface junk again. to flux throw a piece in and light it on fire, stir until the fire goes out, scoop the floating stuff up with a spoon, if its heavy at all or metallic feeling flux again until its light like black ashes then you can remove it from the pot.

[poppy42]

That’s not uncommon if it was a new muffin pan! There is a coating that is put on so real muffins don’t stick or some other such foolishness. Ya would think muffin Pan makers would know it messes with our ingots! Anyway it’s no big deal it’s happened to every pan I have and it usually burns off after a couple uses. Don’t forget corn muffins bake at temperatures no where’s near close to what we melt lead at!

[Bashby]

I heated the muffin pan with the torch to burn off the residue and it is doing fine now.

I need a better heat source for this. I spent 5 hrs today to make 75 lbs or so of ingots! Hate to spend money on that right now since I have other equipment to buy.

[poppy42]

Like I said. You don’t have to do a thing it’ll burn off on its own in a couple of casting sessions ! And craters in your ingots don’t make a bit of difference

[Ed_Shot]

Like I said. You don’t have to do a thing it’ll burn off on its own in a couple of casting sessions ! And craters in your language don’t make a better difference

+1 What he said^^^^^

[Bazoo]

I smelt with wood. It's a low cost way for me atleast. http://castboolits.gunloads.com/showthread.php?335783-Smelting-with-fire

[lightman]

Welcome to the hobby! Warning, its addictive!

I agree with poppy and the others. Its probably the coating on the pan gassing off. It won't hurt anything.

Most of us understand the budget thing. Theres nothing wrong with what you are doing now except that its slow. No reason that you can't keep doing it until you can work in buying a Turkey frier. Just remember when you increase the capacity or speed of one operation you will need to improve on the other parts to appreciate those improvements. IE, a bigger burner may need a bigger melting pot. A bigger melting pot will need more ingot molds.

Just a suggestion, get a set of metal stamps (yeah, another purchase!) and permanently mark those ingots before you get so many that you can't catch up. You will be stamping lead so a cheap set will work fine.

[Rich/WIS]

Have had that happen when using aluminum muffin tins that the previous owner had used cooking sprays on, first couple of ingots burned off the baked on spray. Won't hurt a thing.

[WRideout]

FWIW I acquired a muffin pan from the thrift store, and the first time I used it, the lead soldered itself to the pan. Upon further reading, a member here said that rust is a release agent. I left the pans out several damp nights to get rusty, and Voila! the ingots no longer stick.

Wayne

[JonB_in_Glencoe]

I have been using pine shavings for flux. They are smaller shavings I got at a pet supply. I have been adding a little wax now and then, I dont know the proper time to use it if there is one.

I am thinking that when I turned the muffin pan upside down on top of the melt the smoke from the sawdust made a film on it. I just did another batch and a couple looked good and a couple had some craters. Not as bad as the first time though.

Let me try to give a quick summary of what Ive been doing. I melted down the scrap and scraped all the dirt and coper off the top without heavy stirring or flux to get suspended dirt out. Then I learned I need to stir and flux so I am melting my ingots back down to clean further. All was well for 50 lbs or so then they came out all pitted up. I am using a cast iron skillet, hot plate, and acetylene torch to melt the lead. Stirring and skimming with a slotted spoon and dipping with a stainless ladle.
Maybe I should wash the pan with dishwashing soap or try to burn the residue off with the torch.


I heated the muffin pan with the torch to burn off the residue and it is doing fine now.

I need a better heat source for this. I spent 5 hrs today to make 75 lbs or so of ingots! Hate to spend money on that right now since I have other equipment to buy.
Bashby,
Welcome to the forum.

I use a old coleman gasoline campstove.
I can make about 500 lbs of ingots on a saturday afternoon.
You may already have a campstove laying around?
Gasoline is prefered over propane...as it burns hotter (more BTUs) and runs much cheaper per hour.
While they are $80 to $100 brand new, you can find them at thrift stores or garage sales for $5 to $20.
Also, once you use it for Lead, you shouldn't use it for cooking food anymore.
Good Luck.

[WHITETAIL]

Yes, check out yard sales,
and thrift stores.

[bbogue1]

Another alternative for fluxing is the free paint stir sticks at your friendly paint store.

[Tripplebeards]

My pewter looks exactly like that every time when I pour it into silicone baking molds to make little ignots. The pewter actually keeps bubbling and white smoke comes out if the bubbles when they pop until the pewter hardens in my silicone mold. I don’t use it anymore.