All about Metal casting

I’ve thought about using some of that dense green foam that florist stick flowers in. It might give you a nicer finish. But how would you shape it? My hand skills aren’t good enough to make the pattern for a pencil holder look good. I would have to use a CNC. In the foundry, pattern making is always the biggest hurdle.
Foundry is a great process for making LARGE number of pieces cheaply. For ‘one only’ projects CNC is usually better.

Btw, I like having that Southern Bentonite in there, because it makes the sand flow into the mold better. A little of it burns out when the hot metal hits it, so you have to add some as you use the sand over and over.



The high density foam that is sold for house insulation will make a smoother finish, BUT, being higher density it robs more of the heat from the metal.
This video has some helpful info.


If you are going to do CNC drawing, lost casting using PLA plastic might be a better route. You 3d print what you want in PLA then it works as a lost cast process.

that being said some of the DIY type CNC tables say they do foam, as well as plastic. You can make PLA from like cornstarch and something on the stove. our it into a chunk, then cnc it on a table, then lost cast it.

There are quite a few options at least.

On a side note, I got my “foundry” working. It worked with charcoal but it took a bit too long to get going for a demonstration for the kids who wanted to melt cans, and I ran out of time because it rained everytime I planned to do it. I needed to clear up space so I cheated and used a propane heater torch for burning garden weeds and such off ebay. Then added a hair drier for extra air. I got rid of a bunch of cans, I have like 10lbs of aluminum blocks now, and the dross probably has a pretty high content as well.


Forgive me, I don’t know if I have seen this before or not. But this is funny.


I was expecting from the name this was going to be some kind of joke.
But wow, it works.

The bread not only insulates, but ti will scavenge Oxygen.


Glad to hear you got your foundry going. Natural gas is cheaper than propane and makes higher temperatures. Agua Das has this woodgas producer that he uses to fire his furnace to melt bronze. Now, that would make a nice demonstration.


Recently I have been doing a little copper melting using a “cheap Chinese Induction heater”.
I have several videos on the subject, but here’s one:

I know I could melt that much material faster with my blacksmith forge, but this way there’s no flame and nothing else gets heated except for the coil cooling water.

Pete Stanaitis


There are a few video’s from canadians like that. Homemade high tech.

Thank you, and I am happy I did too. I would have to pipe NG outside, and I would probably need permits and crap. I actually got the propane tank from a curb find. The torch is for another project I haven’t gotten done because of the rain. lol

I am wanting to do a woodgas version. I forgot about the dasifier, and that was probably all the information I have seen on it bundled up into one spot. thank you. It actually reminds me of Matt’s. The ejector is the key component, and I suspect any properly sized gasifier will work.

I do actually have a metal coffee can, and some extra 1" pipe. hrmm …


Carbon makes for higher temperatures because hydrogen strips off more heat form the off gases of combustion.
By volume its probably cheaper to use propane and it is cleaner, but at the risk of some of that stray hydrogen finding its way into your metal.

Where I work we use Inco flash technology to melt our metal a long with Bessemer converters .
When the Sulphur content of the feed is low we inject some natural gas to add fuel.
In the old days of the reverbs and blast furnaces coke was used.
The introduction of Oxygen injection did a couple of things, it reduced fuel burn and increased both smelting speed and the quality of the product.
Natural gas could have been used on the old air blown furnaces, but the amount of heat stripped off by H in the form of H20 would have cost more money than carbon…

Outokumpu built and industrial scale system to use wood for copper smelting.
This was in the 1940s and if memory serves it was used to make gas to co-fire a flash smelting unit in Sweden in the war years.

What burns 40 litres of diesel and hour, emits sulphur dioxide in its exhaust, needs a crew of 5 men plus a foreman to operate, is a big as a bus, kills 5 men a year, and cuts an apple in three pieces?
A Vale mining company fully autonomous machine for cutting in apple into four pieces…


That is neat. and safer then the flame. It would be excellent for smaller melts and more valuable metals. Currently the aluminium cans I am keeping outdoors and not breathing fumes because they are coated in plastic. They go poof and shoot out a flame when the oxygen and vaporized plastic catches fire unless you squash them first.


This may be true. I’m just reporting what I’ve experienced personally. I started out using propane and switched to NG. Melt time was reduced ~20 minutes to 18 for a #20 crucible and I was able to melt copper tubing fairly quickly. It would take about an hour before, basically not doable with propane. Most of the commercial foundries in the Denver area use NG.
We are allowed to have a natural gas barbecue around here, so I just used a flexible hose and other equipment that would be used for a NG barbecue. Not too sure whether a permit is required.


Natural gas is cheap.
Cheapest fuel around dollar for pound you can through a lot more BTUs for the same amount of money using gas.

Added later
Cleaner too!
Less stack emissions using natural gas, no ash to dispose of, no heavy metals released…


Wood is even cheaper… :slight_smile:


okay, i am distracted trying to find cheap materials for the k-bond recipe materials from
recipes - Made From Scratch - Gingery Machines Wiki I need to stop so this is kind of a personal/public note.

Organo-bentone is basically bentonite treated with a cationic emulsifier or surfactant aka
Bis(hydrogenated tallow alkyl)dimethylammonium bentonite. It can be formed from a mixture/reaction (haven’t figured out exactly how yet) of bentonite mixed with bis(hydrogenated tallow alkyl)dimethyl chloride (kao product name QUARTAMIN 2M2HTE for applications Used in softener formulations in textile industry, other applications are in hair conditioning, antistatic agent and organoclay intermediate.)

Which according to
also known as:
Quaternary ammonium compounds, bis(hydrogenated tallow alkyl)dimethyl, chlorides, reaction products with bentonite; Bis(hydrogenated tallow alkyl)dimethyl ammonium bentonite salts; Clayamine #4; Clayamine ARO; Clayamine EP; Clayamine EPA; Dimethyl dihydrogenated tallow ammonium chloride reaction product with bentonite; Dimethyl dihydrogenated tallow ammonium chloride, reaction product with bentonite; Quaternary ammonium compounds, bis(hydrogenated tallow alkyl)dimethyl-, chlorides; Quaternium-18 bentonite; Tixogel VP; Quaternary ammonium compounds, bis(hydrogenated tallow alkyl)dimethyl, salts with bentonite; Quaternary ammonium compounds, bis(hydrogenated tallow alkyl)dimethyl-, salt with bentonite; Di(tallow alkyl) dimethyl ammonium bentonite; [ChemIDplus] Baragel 2000; Bentone 120; Bentone 34; Bentone 760; Bentone 910; Bentone ER-10; Bentone TPG; Carbo-Vis; Modofied bentonite; Organically modified montmorillonite clay; [IUCLID] Claytone II; Alkyl Quaternary Ammonium Bentonite; [Southern Clay Products MSDS]


Yes on a small scale.
Forrest disappear at industrial consumption levels…
At one time the Amazon was being turned into charcoal to make iron.
With the Fascista in power in Brazil these days deforestation has increase 270% this year


Not exactly sure if that is true or not. Only 4.7% of our iron ore/steel products come from Brazil (it includes iron ore and processed goods). I -could- see it being true, if Mexico, canada or china is importing it to make car parts destined for the US market. Those countries represent about 100B in parts imports, and Brazil is 1.5B.

I don’t totally trust Greenpeace. They were overrun by communists in the 80s.


It is surprising to me that the NG heated your work faster than propane. I’d have thought the exact opposite to be true.:

This article is typical of those comparing the energy in NG to propane::
Provided that 1 cubic foot of propane contains 2,516 BTU and 1 cubic foot of natural gas contains 1,030 BTU, it is accurate to say that propane contains over twice the usable energy content per cubic foot (2.44 times more)

I wonder if there wasn’t a problem with burner optimization, when you changed from NG to propane,

Pete Stanaitis


Can you back that up with a citation or two?

If anything I think Greenpeace was infiltrated by corporate and government interests, now they are pretty tame.


This seems pretty factual at least how I remember the events unfolding even if you don’t agree with the conclusions of the editorial. There were a few other events like trying to stop us military exercises by saying they were out trying to save the whales. I am also being a bit lazy and not digging out articles.

The one part that struck me the most out of the article is the New Economic Order section. And how they tried to kill the norwegian economy. The same attacks style is going on against the US auto industry right now especially GM. Who is the world’s 3rd largest automaker. You never hear people attack Toyota or VW, who are #1 and #2.

I also suspect they haven’t stopped their shannigans.

Just saying they don’t have much if any credibility in my mind.


Hi Sean,

I have to disagree. VW was haevily attacked for defraud of the real driving emissions of their diesel-cars. The US government fined them, and in Germany the trials are going on.

I just read today that this strong increase of deforestation on brazil has mainly to do with agriculture - they cut down the trees for soy and cattle farming to increase soy-bean and beef exports.