I was watching YouTube videos about various melting furnaces (and pouring ingot molds) and saw something in one that I had never seen before (and thankfully had never experienced)…It was quite startling and sobering…the molten silver pour hit the mold and…splattered…exploded…and shot out all over the place!..in the blink of an eye!! (I don’t think the operator was injured in this instance…)…there was almost nothing in the mold, so I am assuming it all splattered out!
(I would love to know the proper technique and safety information…all comments welcome)
(this convinced me that I need to get leather gloves and a leather apron at the very least, I think?!)
Since I had never seen this happen before, I thought I would share it here…as an example for why it is important to take proper safety and protection measures when pouring an ingot…!
I would love to hear any recommendations for safety and protection items and measures, that are used by members, when pouring an ingot.
I had a coworker, who was wearing a tank top, have the moist air in the ingot mold become trapped under the molten gold. It superheated and popped. A large glob of gold landed in the hollow of her shoulder and collar bone burning her severely.
The fix is to tip the ingot mold slightly by propping it up on tweezers on one side The result is you can pour down one side of the mold rather than covering the opening entirety with molten metal, trapping the air beneath.
You also need to prep the ingot mold by heating it with the torch until too hot to touch. Most then use a little 3 in 1 oil to aid with release. The oil should smoke a bit. Others use wax. The idea is to remove moisture and keep the metal from wanting to freeze up immediately.
I like to do this all on a large soldering pad with a casting torch under a hood.
Like anything else, it’s easy after you do it a few hundred times.
The top of the crucible had cooled by the third pour. As evidenced by its darker color. It seemed to me that when the molten metal hit the cooler part of the crucible it spattered.
H2O and or the mold too cold. Crazy dangerous thing to do. It kills me to
see stuff like this on U tube. They need to know that this is very
dangerous and have the video flagged.
-Jo
so, I was wandering thru Harbor Freight today, perusing belt sanders, when I remembered that I needed leather gloves and an apron for the ingot making…
the leather welding apron didn’t look like it covered a whole lot up top…then I got to thinking that perhaps I could wear my old leather shirt…it is like a suede/ split leather…not too thick, not too thin…then I could maybe wear better fitting leather gardening gloves, rather than the large, unwieldy leather welding gloves…
Julie- I f you pre oil, heat and pour your ingot right you will not need a
leather apron or gloves. I’ve been pouring ingots for 47 years. Last week I
poured 8 in one morning. I’ve never ever worn a leather apron or gloves.
The only heat protection I need is on my hands when I un screw the ingot
mold. Then I usually just grab a heavy towel to handle the hot mold.
Have fun and make lots of jewelry.
-Jo Haemer www.timothywgreen.com
Had to jump in here and ask you to please use caution with pouring ingots! I had one explode in my face just once, in 1994, and will never forget the pain of hot gold catching my hair, skin and clothes on fire. It was a mixture of karat gold scrap melted into a nugget for in-house refining, and led to the decision to let a refiner take care of this hazardous work. Leather apron and gloves are a must!
In the nature of things…I too, let my refiner do the dangerous stuff, I
never do any casting, I pay a simple fee for his services…safety is so
terribly important. I even have my jeweller do my soldering. As a ‘setter’
I keep my bench clean
of the things I don’t want to have explode on me…“Gerry, the travelling
setter/instructor!”
I pour ingots every day, several times a day. I always where protective eyewear. And no fleece or flammable clothing. But that’s it. I always preheat my steel ingot molds—mostly open face. On rare occasions, when I’m impatient, metal will explode out. But it is not catastrophic. And at the risk of seeming foolhardy, I don’t think that the video is startling at all. It was fairly minor explosion considering the amount of metal being poured. Please understand that I am not advocating sloppy safety procedure…
Thanks for your insight! I guess as a newbie to melting and pouring (and forging and rolling!) ingots, seeing the metal splatter out so suddenly was unexpected and startling to me, as I still have some lingering molten metal anxiety to work through…! and it was actually (what I would have previously considered!) the rather benign metal mold that was the culprit! I had my attention focused on the metal and have not been giving due respect to the mold!
The YouTuber did appear to preheat the molds, before pouring, but apparently it was not long enough through the whole pour…I was not knowledgeable enough to observe that his preheating process was insufficient…
It was a good lesson for me to see how/ that this can happen, and what it looks like…and how to avoid it and to protect myself from potential burns!
Many years ago I poured an ingot but wasn’t happy with the result so i reset the mold, melted the gold and went to pour again without pre-heating. The ingot mold (the type mpandfamily posted) had cooled enough to gain moisture and then sent 12 grams of 22ct gold raining from the air and over my workshop.
I was unharmed as the small granules from the gold explosion had solidified and cooled instantly, some even landing in my hair…
Expensive mistakes are the ones you learn from the most!
You might first do some melts in open trenches carved into a charcoal block as was suggested… Small amounts and no pouring required. An easy way to get used to working with molten metal.
Another tip is to stand your mold in a high walled baking tray to catch any little bits of metal that may escape.This will save you money as the metal is easily reclaimed also stopping it melting something it shouldn’t.
I was surprised at the mold heating technique when I first watched the video–it was only for one minute and appeared to be done with propane only (no oxygen)—nowhere near hot enough! Also, he ‘heated’ only the depressions. I don’t know what kind of material the molds were, but if they were iron/steel, the heat would have dissipated into the heavy bases. You would need a lot more time with a lot stronger (higher) heat to get the entire mold sufficiently hot. I was actually surprised the first 2 pours went as well as they did…
I thought it might be relevant to repost here a post I recently posted on another thread:
“For small melts, you can’t beat charcoal blocks! Iron molds require a lot of heating. I have recently been melting 14K scrap in a groove in a charcoal block even without borax (!), and it comes out fine. I do flame the pieces in alcohol/boric-acid beforehand. The big advantage to the charcoal block is that you don’t have to pour–you can melt the scrap right in the groove!” I always used a Mini Torch with oxy-acetylene with the rosebud tip. Now that I recently switched to propane/oxy in my MiniTorch, I use a #7 tip. With acetylene I always did use borax.
Video doesn’t play on my iPad, so can’t comment on it, but I have experienced some pretty strange things when casting molten metal into ingots. Don’t over grease the mold with vaseline/oil etc. A light film only. I preheat the mold always prior to the pour and then set it up so that it’s getting heated at the same time I’m melting my metal. Tilting it slightly makes a huge difference in the success of the pour. Get your crucible lip as close to the mold as possible and pour in one fluid motion when the flux has your metal swirling like water. I have a melting furnace. I rarely use it as I feel I lack the control that I have with a smaller crucible. I find that if I’m vacuum casting the furnace is the way to go as it handles more metal. I ALWAYS wear safety glasses. Anytime I am dealing with hot metal, hammers, chemicals, etc the glasses are on my face, no exceptions. I also wear a leather apron when casting. My casting table is waist height and so I make a seal between the table and my lower body in the event that metal does spill over, it’s not going on my feet. I don’t wear gloves, there really isn’t much call for that, your hands should be well away from the action, I do put on a pair of ratty old leather work gloves when removing the ingot. Do not quench the mold, it cools down quickly enough on its own. The one time I had a metal explosion was when I stopped paying attention for a split second and the torch tip ended up going into or to close to the metal and it blew the flame out. I had molten metal embedded all over plastic table I was using for casting outdoors, not my usual fireproofed table. I somehow didn’t get hit by any flying metal, but it was a good wake up call not to be distracted when you’re casting. Casting is not difficult or dangerous when done correctly and keeping moisture out of the equation.
