Making zinc ingots

[konsole]

On my Coleman 2 burner stove it certainly takes a little while to get up to zinc melting temperature, but it does get there eventually. I'm not a bullet or fishing weight caster, just someone who has fun melting metal into various shapes. So out of the 200 pounds of wheel weights I sorted through, I found about 10 pounds of zinc weights. After doing some melting with the lead weights and throwing the steel weights aside, I decided it would be fun to melt the zinc down since it melts only slightly higher then lead. With all the lead I melted I just put a mini steel bread loaf pan on the stove, made sure it was nice and level, melted the lead and skimmed off the junk. The solidified lead ingot fell out of the pan easily, however after doing this with the zinc weights the zinc ingot seemed to bond to the bottom of the pan. I'm not sure if it bonded to steel itself or just bonded to the black hardened material at the bottom of the pan that was left over from making the lead ingots. To get the zinc ingot out I had to hacksaw the steel pan in two and I could see where the ingot had fused to the bottom of the pan.

I want to use the mini bread pan as the melting pot because I can get it nice and level and I like the finished size and shape of the ingot, but after having to hacksaw the zinc ingot out of the first bread pan, I don't want to try it again and have to take out the hacksaw again. I like using the setup of having the mold be the melting pot also, so I don't want to use a cast iron pan and ladle combination, so please don't tell me about using separate melting pots and molds unless its the only way this will work.

Why did my zinc ingot stick to the steel pan? Some sort of reaction between zinc and steel, that doesnt happen between lead and steel?
Obviously an aluminum melting pot isnt smart, so what other materials can I use as a melting pot for zinc?

[konsole]

Upon further research I think what may have happened is the molten zinc did react with the steel and bonded to it via galvanization?

The bonding only occurred in places of the pan that I had scraped to remove excess buildup after making the lead ingots. The scraping probably got down to the bare steel and provided a clean steel surface for the molten zinc to bond to.

If thats right then it seems steel cant be used as a zinc mold.

[SciFiJim]

The only time I have cast zinc ingots, I used a teflon lined aluminum muffin pan that I had previously used for lead ingots. They dropped right out.

[40-82 hiker]

Ask ShadyGrady. He molded cannon balls with zinc.

On my Coleman 2 burner stove it certainly takes a little while to get up to zinc melting temperature, but it does get there eventually. I'm not a bullet or fishing weight caster, just someone who has fun melting metal into various shapes. So out of the 200 pounds of wheel weights I sorted through, I found about 10 pounds of zinc weights. After doing some melting with the lead weights and throwing the steel weights aside, I decided it would be fun to melt the zinc down since it melts only slightly higher then lead. With all the lead I melted I just put a mini steel bread loaf pan on the stove, made sure it was nice and level, melted the lead and skimmed off the junk. The solidified lead ingot fell out of the pan easily, however after doing this with the zinc weights the zinc ingot seemed to bond to the bottom of the pan. I'm not sure if it bonded to steel itself or just bonded to the black hardened material at the bottom of the pan that was left over from making the lead ingots. To get the zinc ingot out I had to hacksaw the steel pan in two and I could see where the ingot had fused to the bottom of the pan.

I want to use the mini bread pan as the melting pot because I can get it nice and level and I like the finished size and shape of the ingot, but after having to hacksaw the zinc ingot out of the first bread pan, I don't want to try it again and have to take out the hacksaw again. I like using the setup of having the mold be the melting pot also, so I don't want to use a cast iron pan and ladle combination, so please don't tell me about using separate melting pots and molds unless its the only way this will work.

Why did my zinc ingot stick to the steel pan? Some sort of reaction between zinc and steel, that doesnt happen between lead and steel?
Obviously an aluminum melting pot isnt smart, so what other materials can I use as a melting pot for zinc?

[konsole]

Hes not responding. What aboout using a ceramic bread pan? From what I have read ceramic can handle very high heat, it just doesnt handle fast temperature swings as it will crack. So its not a good idea to use it as a mold without preheating it, but since I am using it as the melting pot as well as the mold and it will see gradual up and down temperatures, then it should work. I know it can be fragile but I don't plan on carefully moving it until after the zinc has solidified.

I wonder if it insulates the zinc from the heat source too much though?

[RogerDat]

The purchase of a $10 stainless pot and $3 ladle so you don't have to melt in your mold might change your outcomes for either zinc or lead ingots.

Think about it soldering and brazing depend on getting the metals being joined hot enough that the joining metal can bond with it, your mold is just as hot as your zinc. Maybe that is why the "joined".

[konsole]

but when I used the steel bread pan to melt lead the pan was just as hot as the lead and the lead didnt stick to the pan after solidifying.

Since dipping steel into molten zinc is a common way to bond (galvanize) the zinc and steel together, then thats probably what happened. The zinc didnt stick to parts where there was still some sort of coating left on the inside of the pan, but on a few spots where the coating was probably scraped off from cleaning was where the zinc and steel bonded.

If I was going to get into smelting on a larger scale then I probably would get a larger melting pot and ladle combination, but I don't shoot and I don't fish so the ingots I'm making are simply fun ways of melting metal and making whatever shapes I can think of. I want the bar to look clean and be uniform in weight and dimensions, and thats near impossible when pouring with a ladle.

[RogerDat]

I should have said the "correct temperature" rather than "hot enough" lead solder won't bond if the metal is too hot. You can solder wires, pipe or sheet metal but only if the metal and solder is at the right temps. Otherwise the solder just rolls off.

You heated the pan to a much higher temperature to melt zinc. And the Wikipedia article on hot dip galvanizing this line sort of leaps out "The steel is dipped into the molten zinc bath and held there until the temperature of the steel equilibrates with that of the bath." Since you heat the pan to the same temperature it is exactly what you are doing. http://en.wikipedia.org/wiki/Hot-dip_galvanization

Lead and zinc are different so it is reasonable to expect them to have different properties.

As for pouring clean and uniform umm how do you think bullets are poured clean and uniform? The molds need to be hot but not as hot as the lead being cast. People use a damp sponge to keep the mold from getting too hot if they pour that fast.

I do know it takes some practice and re-melting the mistakes but it is certainly possible to pour clean and uniform ingots. Have seen them, and once in awhile I have made them. Don't know if this applies to zinc but seems like a small cheap pot and a bent ladle might be a more direct route than ceramic bread pan. It is a free country and experimentation is a lot of the fun of casting and hand loading.

I purchased a pot recently for $6 at the salvation army that would easily handle your 10 lbs. And used it to melt lead on a single burner Coleman stove. And those ingots turned out fairly shiny and uniform even though that was not my goal. I was more concerned with uniform weight and clean than anything else. Some tin would have pushed that lead into totally smooth but I wanted to keep it plain for mixing with other alloys.

http://castboolits.gunloads.com/show...=1#post2795453

Note the pans and bent ladles. Cheap stuff. The green bag is my old one burner stove. Man that thing has seen a lot of country. And caught fire in every US time zone! It is a total PITA to get burning without paste to pre-heat generator.

[40-82 hiker]

Hes not responding. What aboout using a ceramic bread pan? From what I have read ceramic can handle very high heat, it just doesnt handle fast temperature swings as it will crack. So its not a good idea to use it as a mold without preheating it, but since I am using it as the melting pot as well as the mold and it will see gradual up and down temperatures, then it should work. I know it can be fragile but I don't plan on carefully moving it until after the zinc has solidified.

I wonder if it insulates the zinc from the heat source too much though?

If you're worried about it cracking, why not worry about all of that 800 degree zinc going everywhere? If you don't know, don't go...

[RogerDat]

If you're worried about it cracking, why not worry about all of that 800 degree zinc going everywhere? If you don't know, don't go...

Good point! Experimentation is all well and good unless you forget it's molten metal and mistakes or going out on a limb have consequences.

[konsole]

The ceramic bread pan did crack into 4 pieces and that was after having the pan on the stove for only about 5 minutes. Luckily I was testing it out with just a zinc penny scratched down to the zinc. I know zinc melts at only about 150 'F higher then lead, but a coleman gas stove seems to really struggle melting zinc larger then a few ounces. It can melt a single zinc wheel weight in about 10 minutes and you can keep slowly adding zinc wheel weights that will melt, but starting with a dry pot and trying to melt a 5 pound zinc ingot and the stove couldnt even start to melt it after 15 minutes. I put the 5 pound zinc ingot on a cast iron pan and after 15 minutes of not even seeing the melting start I shut the stove off. Also I think its going to be too much of a pain trying to figure out what setup will prevent the zinc from sticking to the pot/mold. Seems like metals that melt in the 600-700 degree area is about the most that the coleman gas stove can handle effectively. An ideal pot setup on this stove might just barely be able to handle zinc with any reasonable speed.

[RogerDat]

The metal melting both uses up and evens out the distribution of heat, not surprising that ceramic bread pan cracked. With dough in it the dough would have moderated and distributed the heat. With a penny in it not much to moderate or distribute the heat.

Don't know if this will help with zinc but I had some heavily oxidized lead, I was having trouble getting it to melt so I hit it with a propane torch to push things along. Found out afterwards that oxidized lead is harder to melt for some reason but the torch helped it along nicely.

[shadygrady]

i get my zinc an mold real hot with no problems 1000f +

[konsole]

I did a complete cleanout of the Coleman stove and threw the ingot and pot/mold on the stove again. This time the 5 pound zinc bar melted fully in about 15-20 minutes. Really really benefits from having as much surface of the zinc getting the most heat from the flame. Since the mini loaf pan fits snuggly around the bar, there was no heat loss from air circulation around the bar. I'm still waiting for the bar to solidify and most likely will have to hacksaw the loaf pan off again. Good thing these mini loaf pans are 0.99 cents at the local donation store.

[konsole]

surprise surprise this time it fell out of the pan with only a little more effort then the lead ingots. 5 pound 11 ounce zinc ingot ....nice
I liberally coated the inside of the pan with silicone lube before melting, and maybe that helped maybe not.

There she is...

[SciFiJim]

Looks like a nice door stop. Or maybe a toe breaker!!

[konsole]

The lead ingots I made are about 1/4 " shorter and weight 8 pounds. This zinc ingot weighs about 5.5 pounds. So if this zinc ingot was the same size as the lead ingot it would be about 5 pounds. 5 out of 8 is 60%, also lead weighs .40 pounds per cubic" and zinc weighs .24 pounds per cubic".

.24 out of .40 is 60%, aint science fun?

[zuke]

Bring it to the scrapper's and see what they'll give you, then ask for that much in lead.

[konsole]

Bring it to the scrapper's and see what they'll give you, then ask for that much in lead.

nah thats my paperweight / desk decoration

I like zinc, melts low enough, super hard, not much related to potential toxicity, and its kind of fun enjoying a metal that most people hate (reloaders anyway)

[Defcon-One]

It is .409! So, if your gonna use two decimal places then you've gotta round up to .41. That is science, and it is fun!

I smelt my Zinc in a cast iron dutch oven. I do 30 lb. batches and just let it set up in the pan after fluxing and skimming out the clips, etc.

One huge, hard ingot.

DC-1