anyone do any metal casting or smithing?

[Kevinkris]

so ive been beating around the idea of getting into a bit of metal smithing for fun and i built myself a pit foundry. i fired it up today using just some dried wood i have stacked in the back yard and by my estimate i managed to get the temperature up to around 1400 degrees (conservative estimate) ; this is considering the glow of the steel i placed inside. because im only interested in casting copper and bronze right now its still not hot enough for that.

with that said i can get to my question. i know that i can get it hotter just by using charcoal instead of wood but will it increase it to the 2000 degrees i will need to get it to melt and the excess i will need for casting? or will i need to consider better insulating materials?

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[Redcap]

I have a little Johnson 900 furnace and do a little casting on occasion. I'm afraid I have no suggestions for the way you are doing it, though I have done aluminum with a good rocket stove.

 

[Swedish K]

just out of curiosity - have you tried coal? don't even know where you can get it around here but remember back in the 80s in CO we would go pick up a trash can full of coal and add a lump to the fire in the wood burning stove - burned much hotter and lasted longer than the wood.

Oh - and you can irritate the "environmentalists" while you are at it....

 

[Kevinkris]

i understand coal to be the best for doing it but with the proper kiln you can smelt iron with charcoal, i wouldnt even know where to get any coal. i guess i could use the magical google machine to locate some though. i have only fired it up once at this point and i could have used some of the charcoal i have to try it out but i buy the higher priced stuff for the grill and i didnt want to burn it just to try out a hole i lined with blocks, earth and ash . i think for a first attempt it did well and if i had let it burn for about 30 min longer i may have reached about 1800 degrees (which is still not hot enough) but i didnt want to use up all of my fire wood just yet either.

i think this weekend ill give it a shot with some charcoal to see how it goes with a longer burn and i think it may work but im still a little skeptical. being a pit furnace means i will have to let it burn a bit longer to get the higher temps because of convection but the ground i made it in stays dryer that most of the lawn too. i think i will be starting out with simple things like broad heads and small knives before i make any bigger attempts so it if works with charcoal it will be good enough for a while. im mostly just trying to see if anyone here has any experience with copper or bronze smelting so i wont have to join another forum for some tips.

 

[Rick4070]

You might consider a propane furnace, there are many videos and tutorials on Youtube.
You can get a coal/coke fire hot enough to forge weld steel, around 2,300 deg. or so, and a propane forge/furnace can get that hot too.
You will probably need a forced air source with both coal and gas, and with wood.
Charcoal is another option, along with an air source.
Copper melts at around 1980 deg., and broze at somewhere around 1830 deg., or so, both can be melted in a charcoal/coal/coke fire or a gas furnace/forge.
For a coal source, try looking up a local blacksmithing shop.
An air source can be something as simple as a hair blow dryer, or a shop vac set up to blow rather than suck, with a simple gate valve to control flow.
Try your charcoal, but also try some sort of forced air.

 

[Kevinkris]

yea, im using an old hair dryer that i have used in the past for drying spray paint, its pretty good for it too. it has hot and room temp settings as well as 2 speed options. as far as propane, im just not sure if imm really going to enjoy the new hobby enough to invest in the needed equipment just yet. it seems to be much better than solid fuels because it will help remove impurities as opposed to adding some but at this point its a no go for current financial conservation.

 

[Rick4070]

I hear you on the financial part, for sure.
My first coal forge was an old car brake drum, some scrap plumbing parts, and a cobbled together blower made out of a car heater motor and a 12 volt car battery....
Search around for tutorials on building your own forge/ casting furnace burner.
The regulator for the propane can be one of those cheap ones for turkey fryers, etc., no need for a spendy regulator.
A 20 lb. propane bottle for a gas barbecue will put out enough gas volume for a simple furnace, and used firebrick can be used for the furnace.
A crucible can be a pipe cap.

Flux can be 20 mule team borax.
Really, it CAN be done on the cheap, and still stay safe, by searching around a little.
My propane forge used an old steel tube off of a tank of some sort, about 12" in diameter, and about 18" long, lined with Kaowool refractory blanket, a 20 lb. propane bottle, an old acetylene regulator, (same left hand threads as a propane bottle,) various pipe fittings, a ball valve, and an old tank type vacuum cleaner, with the hose in the blow end, and a light dimmer switch to control how fast the air came out.
With that set up, I could bring steel to welding heat, and beyond.
The most expensive part was the Kaowool refractory blanket.
Besides, it's kind of fun scrounging around for stuff and making something that can turn steel all sparkly and white....
(which is MUCH to hot for welding BTW, if it gets that hot, it's not good...)

Also, here is a link to a really good site:

www.backyardmetalcasting.com

Scroll down to "home built propane burners," there is a good homemade burner there, I built one following the directions, and it really works, although I turned out a "nozzle" using cast iron rather than the sheet metal one he describes.
Give the site a look see, there is LOTS of good info there.

 

[U201491]

so ive been beating around the idea of getting into a bit of metal smithing for fun and i built myself a pit foundry. i fired it up today using just some dried wood i have stacked in the back yard and by my estimate i managed to get the temperature up to around 1400 degrees (conservative estimate) ; this is considering the glow of the steel i placed inside. because im only interested in casting copper and bronze right now its still not hot enough for that.

with that said i can get to my question. i know that i can get it hotter just by using charcoal instead of wood but will it increase it to the 2000 degrees i will need to get it to melt and the excess i will need for casting? or will i need to consider better insulating materials?

What are you doing for a bellows or air flow. Needs plenty of oxygen and good insulation to get up that high. Coke or coal as fuel .
Coke will produce twice the heat as coal.
Here are some things that might help.

http://railcraft.wikispaces.com/Coal+Coke+(Fuel)

http://www.iforgeiron.com/topic/17352-coal-vs-coke/

 

[BoonDocks36]

A couple things from someone who has cast professionally.

Your method of heat deduction, spot on.

What is sadly missing is your source of Oxygen. Yes, I know your shooting in air, but How Much Air is my point!!!

Every body who wrote you spoke ~volumes~ Pun intended, about their Air Source!!! THE clue, which was Not noticed was: AIR CONTROL.

You probably need at least three hair dryers as you spoke of, to get your heat out put, IOW. hair dryer is not the final way to go...

A furnace is a ratio. Of:

FUEL.

Fuel containment.

Air Enrichment

CONTROLLING all of above, to get to needed heat levels....

IOW, you can make a very small containment system, to pour an ounce of gold for example. The containment system, here called a crucible, will receive the heat Into & Onto the gold.... Not the same as a forge, but the crucible is built to withstand 4-5 K heat Fahrenheit. The gold does not need that much, the Containment system DOES.

HEAT: Sterling Silver melts at 1640 *F What then is its casting heat ????

Answer: casting temp must always be ABOVE melting temp. No Jeweler would ever take a scientific reading. It is Not Needed!!!! Needed, is awareness of the difference of melted, and Flowing metal. IOW, at just molten, the very action of moving the metal Away From its heat source, will Solidify your chosen metal. Regardless of its properties.

Non Ferrous, in the copper families all have similar flow patterns.

Aluminum has its own characteristics, Commonly cast precious metals are fairly uniform in flow dynamics, UNTIL you add in the other precious metals: add Platinum to Gold for a white Gold alloy and you have changed its formulation out of the Periodic Table of Elements, (see copper, silver & gold... And how they relate in the PT Elements!!!

So recapping from a different view, your burning area requires more Air, or Modification to control the heat. Consider:

A Two Cubic Foot area can be spread out, with less hight, Or it can be Very Narrow, and Tall. The proper dimensions are fixed, crudely speaking, to how that Air is injected into Onto the Fuel ... Am I making sense here???

After that, your crucible is your concern, a cast iron or steel pipe cap, of 3 - 4 inches diameter is a cheap but formable container. Which reminds me, How much metal do you want to be able to pour, at once ???

This was not yet mentioned, and possible for good reason. But it is subjective to the topic.

I have cast common red Bronze, in as small a pour as .5 ounce, and as large a pour, as over one Pound. Both are unique casting needs, IOW. They are not the same pour!!!

I will say with that, the coarsest of casting definitions have been given... I started casting in 1968. My last casting was 12 years ago. I am getting set up,to start Red Bronze again, as I have Fifteen or so pounds to work, straight from the factory where it was alloyed, in Portland. Never retouched.

That is important!!!! In fact I made it its own Paragraph!!!

Now, one might ask, why I have not been casting since Twelve years prior.

I learned a dangerous, vital lesson in that shop I had set up.

REMOVAL of all, Exhausting of ALL smoke is vital.... Nay, It is only important,if you wish to consider the continuation of... Breathing. Period. End of that sentence. Full stop!

The moment you mentioned Copper, I cringed. My lungs felt an absence of Oxygen ... Unless, until you Study the alloy formulation of the Copper you intend to cast... Respect for your lungs is VITAL

I can not write that loud enough. And Red Bronze is mostly "copper" in the above paragraphs intentions.

Copper will kill you faster than Lead Will, unless the lead is moving at 700+/FPS I mean say, out of a 45Colt, a 1911, etc..... You push lead faster, by alloying, or putting a copper plate on the bottom, and then you could return to Copper Kills...

But I make to much with the pun's... Please, look up the common elements, in copper alloys, see where it states Arsenic? Ask why Arsenic...

Look up Arsenic Free Copper, as an alloy, see why... They are very related in the Periodic Table of Elements, and hence, very hard to separate.

OK, class, your home work is this: how do I stay Alive, while casting non ferrous metals, in the field of Bronze Casting. Extra credit will be given for understanding, and designing on paper, a melting forge, for a volume pour of One Pound, Red Brass. Fuels can change, Air must change with the fuels, Yes/No ????

Class dismissed.

(Truth, I did, in fact teach this subject, at Butte Junior College, as a Student/Assistant to the Professor, who said: "OK, you bugged me enough, here is you silver casting shop, But Remember, I told you, I no nothing about metal casting" ... I took the class, because I needed One Unit for a full schedule. I informed the Professor, that I had at that moment, a full shop at home, and been casting Three Years. His reply: "You just earned an A grade in this room" I taught, the current Love if my life: Jewelry, Smithing & Casting, to include making ones own Sterling Silver Wire, from an ingot... That there is Fun!!!!)

philip
In the Boon Docks, with half of that equipment still in my possession... Plus more, added 12 years ago

 

[Kevinkris]

air volume isnt something i thought i should be so concerned with, i will definitely have to do a bit more research on that. as far as the work environment i have constructed the furnace in one of the most open areas of my yard, both for clear walking paths and probably the best place for open air. the furnace itself has an interior that is just under 1 sq ft and seems to be pretty well insulated for being constructed with only materials from my yard though i do think it will take me longer to get temps high enough even with better fuel and air flow. my crucible is improvised, being a small stainless steel cup. i chose it because i dont have $100 to buy a real crucible and it is light enough that i will be able to grab it with just a regular pair of pliers. i wont be casting anything at this point heavier than maybe a few ounces at most, for the sake of practice and safety while i learn. it is also how i was judging the temperature. being as it has thin walls i will likely have to reach 2100-2200 degrees to do any casting because it wont hold the temp for very long but casting small will help me get by for the time being i think (or hope).

i do have some experience with metals including welding, forming, solder smelting and ive been exposed to plating, i have to say from all of the info ive been taking in, creation like this is an animal all of its own. i suppose running the solder pot i was similar in some ways but the machine was incredibly easy after i leaned how to rebuild it over the course of a year but it was not for casting other than reclaiming ingots for recycling. i find it surprising that more people dont realize copper is far for harmful than lead though, on top of the free radicals it produces, its highly carcinogenic as apposed to lead which is just slightly radioactive and only truly harmful in fine particulates. cyanide is the one that scares me though because it smells wonderful

 

[BoonDocks36]

I had a case of Cyanide poisoning Once. Yes, I lived through it!!!!

The odds of living through cyanide poisoning are very slim: Mine: I was mixing a cyanide solution, used by commercial Jewelers, to cleanGold.

First, fresh water, then drop One cyanide "Pill" into water. The pill is really about the size of a small walnut, large acorn...

It is very powdery. Instant dissolve. ONE drop, from a splash, landed upon a open cut on my skin. Five hours later, in the Hospital... They still pulled a cyanide reading in my blood analysis. Me, one very lucky man, Had there been actual Blood in the cut, I might not have been so lucky....

Remember, for Any Metal you cast, look at the Periodic Table of Elements, it is Not Rocket Surgery (who here on this forum started saying Rocket surgery, instead of science, I read that, Loved it, keep stealing the line) ...

The metal elements are within several "sections", I do not recall the proper term, but within the section are other elements, that are close to "equivlance" of the molecular weight... That is why they are harder to separate!!!

Look at gold mercury. They mix easily, and then you burn off mercury, leaving higher quality gold... Old times method to assay... But Mercury will get you Killed!!!

Darn nation, it seems everything that is Fun, will get you killed!!!! As a young boy scientist, I used to play with Mercury, knew not to touch my lips while playing with it, and wash like crazy afterwards....

Good luck on your forge, look into an "end Cap" for a larger crucible... Not much money... Use a Dremel to wipe out threads... Drill a couple holes for a wire handle... You'll figure it out you sound like the kind of Educated Worker who does!!!!

Next step, how to make a a good mold... Patterns and all.... I have taken my precious metals casting towards a newer method for me:

Delft Clay, used like "sand cast" work, but the clay is very minute grained, unlike casting sand. Reusable. But expensive.

I'll link to it, after I re-find the URL....

philip,

In the BoonDocks, I would write my resume' but It is unbelievable... Truth is sometimes that way!!!!

 

[Rick4070]

BoonDocks36 raises some very good points, we don't want our new hobby to kill us, do we?
As for air/oxygen, the link I posted has a burner that uses no forced air source at all, just the action of the propane shooting through a #57 drilled hole, along with the tube described will make a burner hot enough for a small furnace.
A turkey fryer regulator with hose assembly, a ball valve, and some various pipe and pipe fittings make up the burner.
It is simple to build, I built mine because I want to set up a small furnace to melt silver, we use silver bearing epoxy here at work, it is 70% silver, and we just use a dab or two out of a package, I have around two pounds of the stuff...

 

[U201491]

I had a case of Cyanide poisoning Once. Yes, I lived through it!!!!

The odds of living through cyanide poisoning are very slim: Mine: I was mixing a cyanide solution, used by commercial Jewelers, to cleanGold.

First, fresh water, then drop One cyanide "Pill" into water. The pill is really about the size of a small walnut, large acorn...

It is very powdery. Instant dissolve. ONE drop, from a splash, landed upon a open cut on my skin. Five hours later, in the Hospital... They still pulled a cyanide reading in my blood analysis. Me, one very lucky man, Had there been actual Blood in the cut, I might not have been so lucky....

Remember, for Any Metal you cast, look at the Periodic Table of Elements, it is Not Rocket Surgery (who here on this forum started saying Rocket surgery, instead of science, I read that, Loved it, keep stealing the line) ...

The metal elements are within several "sections", I do not recall the proper term, but within the section are other elements, that are close to "equivlance" of the molecular weight... That is why they are harder to separate!!!

Look at gold mercury. They mix easily, and then you burn off mercury, leaving higher quality gold... Old times method to assay... But Mercury will get you Killed!!!

Darn nation, it seems everything that is Fun, will get you killed!!!! As a young boy scientist, I used to play with Mercury, knew not to touch my lips while playing with it, and wash like crazy afterwards....

Good luck on your forge, look into an "end Cap" for a larger crucible... Not much money... Use a Dremel to wipe out threads... Drill a couple holes for a wire handle... You'll figure it out you sound like the kind of Educated Worker who does!!!!

Next step, how to make a a good mold... Patterns and all.... I have taken my precious metals casting towards a newer method for me:

Delft Clay, used like "sand cast" work, but the clay is very minute grained, unlike casting sand. Reusable. But expensive.

I'll link to it, after I re-find the URL....

philip,

In the BoonDocks, I would write my resume' but It is unbelievable... Truth is sometimes that way!!!!

You can case harden with peach pits. They contain cyanide.

 

[Rick4070]

You can case harden with peach pits. They contain cyanide.

You can case harden steel with charcoal, bone charcoal, charcoal made out of beans, cherry pits, wrap the part in old leather, and coat with clay, etc. too.
We used ground up charcoal briquettes at the shop I worked at first, and then went to using Ebonex bone char.
We got a nice case, about .010" to .015" thick, depending on soak time and quenched in cold water.
Colors were good too, although we weren't after colors specifically.

 

[BoonDocks36]

BoonDocks36 raises some very good points, we don't want our new hobby to kill us, do we?

Thanks Rick!!! I was still ill from Saturday when I wrote that, and I did get some funnies into it, but All Metal under Heat should be examined carefully... My sister was a renowned Stain Glass worker... I mean side light panels for Double Door entries, and her price on the work, $4500.00 typical cost, only delivery there, she did not install !!!!

But her lungs are damaged by the acid core solders she used, with just "A Fan, to blow the smoke away from her" she had to stop doing a creative and high quality job, and Great Pay.... For lack of an exhaust system....

As for air/oxygen, the link I posted has a burner that uses no forced air source at all, just the action of the propane shooting through a #57 drilled hole, along with the tube described will make a burner hot enough for a small furnace.

I will admit, I did not go to your link, but will, Now... The reason was the OP was trying to go the "natural" working forge fuel methods....

A turkey fryer regulator with hose assembly, a ball valve, and some various pipe and pipe fittings make up the burner.

YES!!! It takes very little money, for set up in Propane, Good Will type stores or second hand stores our Are Friends in that!!!

I think more $$$$ should, would, Could be spent on the refractory materials, the Heat Reflective barriers to keep the heat organized upon the crucible.

In my first post, though not mentioned, I was referring to a Centrifuge Casting crucible. Their design Centuries old, allows all heat to be reflected back towards the heat, and also provides the "Excess Heat" I mentioned, to go through a complete cast, molten metal, to Flowing Metal, and CAST!!!

I lost count of the Hundred upon Hundreds of centrifuge casts that I have done, prior to The Need to go to Vacuum casting.

That machine, with a 220Volt Vacuum Pump, pulling more than 27 "pounds" of vacuum... I can not remember the actual unit, but IIRC, total vacuum is 30# ??? It sucks the flowing Bronze, & its smoke when you do the cast, both methods are dangerous, but the centrifuge is limited in Volume, by the Super Increased $$$$ of the machine.

If you recall, Ruger made history, when they started doing centrifuge cast frames. And for good reason!!!!

A side effect of Centrifuge Casting is:

The gravitational effect upon the Still Molten Metal (lost Wax casting is ~Different~ Than all other casting styles, in that it needs the Mold to be At Molten Metal Temperature, and Because of that, the Molten Metal is actually Compacted, via 7 to 10 G's of force, while still in that Important Molten Stage!!!!

Under Scientific Casting Procedures, it is possible to actually determine end cast weight, which is Metalurgicaly Different, than a simple pour cast into say A sand mold, or even a Vacuum cast!!!

IOW, the method above, produces a cast More Dense, than normally possible. Very useful in such things as a Gun Frame, which is only One nice factor, the other being it provides a cleaner cast surface, which needs Very Little Machining and in fact, if you look into the Non-Critical areas of a Ruger, you will see they leave them completely un-machined, with No negative effects, for the fire arm user, and of course saves Cost!!!

It is simple to build, I built mine because I want to set up a small furnace to melt silver, we use silver bearing epoxy here at work, it is 70% silver, and we just use a dab or two out of a package, I have around two pounds of the stuff...

I have Two feelings about that.... Total Envy, & please take care of Exhausting those fumes!!!

Again, referring to the Kabillion kinds of works I have ~done~ I have commercial work, in Epoxy Paints.

I am sure you are Already Aware, of the chemical reasons that Epoxies Work, and the various Two Part chemicals used in the entire EPOXY industry...

Just understand, BURNING said products will Require a more intensive Exhaust System, than you might think, even the Second time Through... (Measure twice Cut once type thinking)

You might even consider how to make a low cost "Scrubber" upon your exhaust system, to pull out the particulates, so as to not have them in your immediate atmosphere!!!!

At this point, I am only speaking from awareness, not actual practice... But If it were Me (envy, envy, envy....) I would study up on the scrubber systems that are possible....

For instance, a Blower (vacuuming your exhaust) Sucking the fumes, through a water trap.... See "Rainbow Vacuum cleaners" for the idea....

Good Luck on salvage of that silver, with such a small loss (burnt off epoxies) your final product should be near 999 Fine... But even if it were 900 Fine, that is Coinage Quality Silver, and is great barter!

After you get ingots, consider developing an actual weight Factor, ie: 1/2 Ounce & One Ounce sizes...

Need more info, feel Free to PM me... It truly is my "One Love" over Jesus Christ, that is....

I don't even like Gold as much as I like Silver, only in its Metallurgical aspects... Silver is in my Blood!!!!

philip

 

[BoonDocks36]

Taku, I had heard about the Peach Pit/cyanide thing... Uuhh I think I'll pass though, I believe the cyanide ~Lightening Strike~ Back when I worked for Mr. Gig Parker, Tacoma, WA should be a "One Time Only" experiance...

Like Rick stated, there are many case hardening products, I bought one from Brownell's last fall,used it twice, and had good results, but I just don't even like the word Cyanide!!!

Yours,

philip

 

[Rick4070]

BoonDocks36, I did do a very small melt using my oxy/acetylene outfit and a stainless steel cup, along with a little anhydrous borax for flux.
I did it outside, standing upwind and yes, there was quite a bit of smoke from the epoxy.
I'm thinking along the lines of making some sort of system where the smoke is recirculated through the burner, perhaps in a pre-heat sort of procedure, to burn as much of the fumes as possible.
I like the idea of a water bath, where the fumes are bubbled through the water, I'll think more on this.
Oh, and I got a nice button of silver out of the small melt that I did!

 

[Kevinkris]

a lot more info here than i thought i would find.

 

[U201491]

a lot more info here than i thought i would find.

What kind of things are you wanting to cast ?
If it is just decorative, there is a simple thing called woods metal that will melt at around boiling temperature or less.
For measuring chambers, forming dies and other internal shapes sulfur melts and holds tight tolerances when it solidifies.
I used to match rifle chambers to custom dies for match rifles using sulfur castings.

Also there used to be small forges made from heavy steel that were shaped like a round bbq with a hand cranked squirrel cage fan for forging horseshoes and farm implements. We used one for years on the farm. They may still be available out there.

 

[Rick4070]

Taku, I'm pretty sure that Kevinkris Wants to get into casting copper and/or bronze.
Yes, coal forges like you describe are still out there, mostly at farm auctions, or perhaps for sale through some of the blacksmithing sites.
I have one myself, a Champion Forge and Blower Works, it isn't exactly a squirrel cage, but uses an impeller that is hand cranked.
I did a lot of work with it, but as soon as I made a propane forge, I really didn't use it much anymore, good coal was hard to find, and I never used charcoal much. Also, propane was much cleaner to use, and it was easier to do forge welding with.

Kevinkris, Yep, there is lots of us firearms folks with some knowledge about other things that are somewhat related to firearms, I worked at a custom gunshop that made front and rear sights, scope rings and bases, bottom metal, and other parts for sporting rifles. That is where I learned about case hardening some of our parts, and also heat treating some of them also.

Most of the little I learned, I mostly remember.