Tinsel Fairy visit

[00buck]

Howdy Pards

I decided to smelt some wheel weights yesterday.. it has been cold and damp for the last couple of days and yesterday it had stopped raining and was nice.

I had some ingot molds I made out of angle iron that I keep in the garage..along with my other lead melting stuff.

Got my melt skimmed of clips and fluxed.. dipped my ladle into the melt and it started to spit and bubble up.. the ladle was cold.. so I floated it on the melt to warm it up.

Started to pour ingots and Whoosh!! Jumped right out of my mold!! The metal was not wet.. but must have been damp. I heated them up with my torch and could see the moisture coming out on the metal. I was lucky.. it missed me.

Shut down my burner and cut grass instead..

Next time I'll be sure to heat my tools up and drive any moisture out before I start.

Be careful out there..

[D Crockett]

00Buck there is a way to melt wet ww safely and it is very simple to do you just melt them in a empty pot with no liquid lead in the pot that way the heat will evaropate the mosture on the ww D Crockett

[00buck]

The moisture was in the metal of the ingot molds.. not the wheel weights.

They were not wet.. just damp from the air. I could see moisture coming out of them when I put the torch to them.

I guess the wheel weights could have been damp too.. I started with the pot full and the burner would have driven out the moisture. If I threw another handful of weights into the mix.. I guess that could have been bad too.

I'm pre heating everything from now on..

Just wanted to share.. we cant be complacent

[chboats]

I have several RCBS and Lyman ingot molds that do that every time if I haven't used them for a while.

Carl

[Jim]

I preheat my molds by laying them across the top of the pot about 5 minutes before I'm ready to run off the pot. I try to get 'em so hot, I need gloves to handle 'em.

[I'll Make Mine]

I guess the wheel weights could have been damp too.. I started with the pot full and the burner would have driven out the moisture. If I threw another handful of weights into the mix.. I guess that could have been bad too.

As you note, the heating before the alloy starts to melt would very thoroughly dry the wheel weight that started in the cold pot. The ones thrown in after melting, by contrast, could very easily have ejected most of the contents of the pot (and that, most likely, wouldn't have missed you).

One simple rule: if an object is below the boiling point of water, it might have water on or in it, so never pour lead into anything that hasn't been preheated at least to the point a water drop sizzles on the surface. For an iron ingot mold, if you dampen your finger (don't lick it, not when handling lead) and tap it on the surface, and don't hear a "hiss" (like testing an iron, if you're old enough to have learned to iron shirts before they were all durable press), it's not hot enough to be reliably dry.

[00buck]

I had two strikes on me so I stopped and cut my grass instead

Three strikes and youre out.

Just wanted to share my mistake.. Ya'll stay safe

[xd4584]

The moisture was in the metal of the ingot molds.. not the wheel weights.

They were not wet.. just damp from the air. I could see moisture coming out of them when I put the torch to them.

You will always get moisture out of any metal when you heat it. That wasn't the cause. There had to be a drop of water in the mold. Even aluminum will sweat out moisture when you heat it. I have been a welder most of my life up until 2 years ago. Any and every piece of metal that was required to be per heated sweated. Cast iron is probably the worst.
I have all my casting equipment outside. I have never had an occurrence like this from pouring molton lead into a mold that was not pre heated

[00buck]

Yep.. there was water in there somewhere..

I'll be pre heating my molds and tools from now on.

Be Safe

[I'll Make Mine]

You will always get moisture out of any metal when you heat it. That wasn't the cause. There had to be a drop of water in the mold. Even aluminum will sweat out moisture when you heat it.

When you turn your torch on a piece of metal and see moisture "sweating out", that's not coming from the metal; it's coming from your flame. Every combustion torch produces prodigious amounts of very hot steam as a combustion by-product (along with carbon dioxide and carbon monoxide); when that steam hits metal at room temperature, some will unavoidably condense, just like steam from a kettle onto a cold spoon. If you put the same metal, in the same condition, into an electric oven, you'll see no moisture come out -- because there isn't any "inside" the metal. Metal that's a little damp from weather conditions has moisture on the surface, not inside (cast iron being the only possible exception, due to the surface porosity that, in cooking, takes up oil and seasons the pot).

The surface porosity of cast iron, however, can "hide" enough water to cause some trouble even if the stuff looks and feels dry; the cavity of a cast iron ingot mold can easily trap the equivalent of two or three drops of water, which will be underneath the lead if you pour in a cold mold. Not a good setup...

[John in WI]

I'm glad to hear you dodged the boolit.

I didn't realize that cast iron could hold dangerous amounts of water. I knew it was pretty porous stuff (that's why you "season" your pan with hot oil--to clog up the pores) but I don't have any cast iron molds (yet).

Thanks for the safety reminder.

[xd4584]

When you turn your torch on a piece of metal and see moisture "sweating out", that's not coming from the metal; it's coming from your flame. Every combustion torch produces prodigious amounts of very hot steam as a combustion by-product (along with carbon dioxide and carbon monoxide); when that steam hits metal at room temperature, some will unavoidably condense, just like steam from a kettle onto a cold spoon. If you put the same metal, in the same condition, into an electric oven, you'll see no moisture come out -- because there isn't any "inside" the metal. Metal that's a little damp from weather conditions has moisture on the surface, not inside (cast iron being the only possible exception, due to the surface porosity that, in cooking, takes up oil and seasons the pot).

The surface porosity of cast iron, however, can "hide" enough water to cause some trouble even if the stuff looks and feels dry; the cavity of a cast iron ingot mold can easily trap the equivalent of two or three drops of water, which will be underneath the lead if you pour in a cold mold. Not a good setup...

Thanks for enlightening me. I was always told you pre heat metal to get the moisture out so it doesn't cool to fast and crack. Live and learn.

[KyBill]

I have had the WW problem before add a WW and molten lead jumps out of the pot . I do then now 1 pot at a time pour into ingots . Let every Thing cool down start over again .
( Use a little Pam Grill spray on Iron tools and pots when finished but still warm seals the pores very well ) I use it on every thing but the Molds

[I'll Make Mine]

Thanks for enlightening me. I was always told you pre heat metal to get the moisture out so it doesn't cool to fast and crack. Live and learn.

Preheating, in a welding context, has nothing to do with moisture (at least not inside the material), and everything to do with avoiding warpage and cracking due to differential expansion. Weld cast iron without preheat, and it's likely to crack near the edge of the zone heated by the weld process. Weld on curved body metal, and you'll get a dimple where the heated metal deformed due to restriction by the surrounding cold sheet, then flattened out the curve when the shrunk area cooled. Weld angle iron, and you have to use procedures like intermittent welding to avoid warping the finished part due to heating one edge but not the other. Proper preheating with prevent all these problems.

KyBill, you've got what I'll be doing when I smelt or cast: melt what will fit in the pot, pour it, then let the pot cool before starting again with another charge of scrap or ingots. I'll also be preheating my ingot mold at least to the point where a drop of water sizzles immediately (i.e. well above boiling point, so water can't remain on the surface or in the pores).