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Hello All;

 

I have a couple of boxes of brass pipefittings; and I was looking for some brass flat stuff to make guards and such; so I figured I'd melt some and pour it into a flat thing to make a plate.

Seems simple enough, right ?

Well; I grabbed a grafite crucible, put it in my coal forge and tried to melt stuff in it. And lo and behold; it did; it started to melt. But before I could add some borax, it started to like "burn" green flame; white smoke; and rather voilent. so I turned off the forge and left the place; since I know that zinc fumes are really really bad for you health. I was wearing a respirator rathed for organic and metal vapors (doesn't breathe easily). Then I remembered a frosty quote; feathery white smoke; green flame; evacuate.

But I still didn't end up pouring brass. Anyone any ideas how to overcome this "burning" issue ? Did I overheat it (to boil the zinc)?

 

greetz; Bart

 

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the box says "solid brass" in french & dutch :-) It also has these spiral cone sprayers for sprinklers. I'll attach a picture so you get the idea.

also; I was planning on making a tapered sprue in a two part oilsand casting to reduce porosity and add a teaspoon of borax before casting. 

brass.jpg

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Have you done a web search of the maker to find out what alloy they used, Bart? Most manufacturers want to make the job as trouble free as possible and if there's much machining to be done us a "free machining" brass alloy. Those usually contain lead to make it cut easily and not leave jagged surfaces and edges. This saves on time, tooling and a finishing step. LOTS less expensive. 

Yeah, you overheated it. All the material in a crucible doesn't need to be melted but burn. Borax isn't a degasser, it's flux and floats on the molten surface. You need to stir it in so it'll contact and entrap impurities and particles so they don't make it to the mold.

Casting anything but especially high temp metals is NOT A TRIVIAL undertaking and you've picked one of the trickiest and dangerously toxic alloys to learn on. 

Might I suggest you take a couple classes and try a different metal? Right now those fittings are more valuable as scrap than what they'll turn into in your crucible.

I not being mean, I'm being honest. I don't want to see anybody injured or poisoned if I can discourage a mistake.

Frosty The Lucky.

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You need to research 15% phosphor copper as a degasser. The phosphorus is a reducing agent (deoxidizer). This must be carefully measured so that enough oxygen is removed, yet a small amount remains to improve fluidity.

In addition to phosphor copper, pure zinc should be added at the point at which skimming and temperature testing take place prior to pouring. This replaces the zinc lost by vaporization during melting and superheating. With these alloys, cover fluxes are seldom used. In some foundries in which combustion cannot be properly controlled, oxidizing fluxes are added during melting, followed by final deoxidation by phosphor copper.

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  I thought you said you were going to pour it into a "flat thing" to make guards.  Oilsand can be toxic too.  I used to do a lot of casting and you really cannot be to careful.  A few whiffs of the wrong stuff can be life altering.  I may sound like a nag, but have a care early on.  It will save you some misery.

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Not sure about Belgium but i am sure some place sells them, door kick plates. My local hardware store sells them. They are thin sheets of brass, 1/16" thick (not sure of mm) , 4" W and about 12" long (75mm x 300mm) or so, but for some of the guards i have made i cut strips then glue, screw or rivet them together. I prefer screws and glue, you can grind them off and still leave enough thread to hold it all together. Or i have used 2 pieces of the brass with piece of 1/8" aluminum sandwiched between them. Makes a nice effect with the yellow brass on the outside and the white aluminum in the middle. 

Much safer than trying to cast brass.

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I smelt and cast rifle and pistol brass into knife guard shapes and then file and grind to finish. .45 brass is my favourite. I usually just put an iron cup on the forge and cram it full of brass shell casings. A pinch or two of borax and heat to liquid, add more shells as needed. I have a guard shaped dimple carved in my concrete floor near the forge for a mould.

Sometimes there will be a touch of green smoke, but it goes away quickly. I make sure to not have many contaminates in the brass because once I had water in some that I threw in the pot and the water became steam instantly and the popping wasn't fun..

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Bart, as far as I know almost all couplings are made from DZR Brass, (at least over here in the Netherlands by VHS) and that contains lead and arsenic to prevent the loss of zinc. It is used a lot in couplings that are use for water boiling.

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8 hours ago, Rhyfelwr said:

I smelt and cast rifle and pistol brass into knife guard shapes and then file and grind to finish.

where do you get the Ores to smelt? since you are smelting 2 different metals,  or did you mean melt?

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Not to mention using a dimple in a concrete floor for a mold. The guy is pretty obviously imagining how to do what he hasn't a clue. 

Be sure you have 100% PPE coverage and cleared out all the flammables within about 30' the first time you pour molten brass into a concrete mold. 

Take a casting class or better a course, you'll be more likely to do some of these things without maiming or crippling yourself. You're contemplating playing with something that can put you in intensive care for weeks or months with one small mistake say spilling a little on a concrete floor. 

Frosty The Lucky.

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My questions too,  cuprite and cassiterite?  But then the description sound like melting not smelting; so I checked the location and probably not a translation error.

WARNING getting water in a melt can result in death or "Freddy Kreuger"  disfigurement.  Casting molten metals onto concrete can result in steam explosions and molten metal being flung about the place.  I'd strongly suggest you look into using petrobond oil sand for casting or volcanic Tuffa for molds!  (I've been using my forge to melt and cast the same sorts of things for over 30 years now.)

Please note: nobody is saying not to use your forge as a heat source for casting; we're just saying please do it SAFELY!   I've spent several Holiday evenings sitting in ERs, (A&Es for the UK folk), With friends who have hurt themselves trying new things without any PPE or research...and I wasn't even in the "Hold my Beer" zone back then.  Learning the correct terminology does a lot to show folks that you are doing the proper research too.

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Question, I once found out that using a cutting torch close to concrete results into exploding concrete, was that also because of steam? Or was that just the pebbles expanding and going boom boom on me?

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Well; it melted , I think I was just rushing and heating it up too quick. (too hot).  once I got it molten, I added some more stuff, borax'd it; scooped the crud off; and cast in a pre-heated grafite mold. Worked quit well; and gives me nice barstock to mill guards and stuff.

I installed a vapor extractor (usually for welding) just in case I get strange smoke again, but it seemed fairly OK this time.

Thanks for the help guys

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1 hour ago, Deimos said:

Question, I once found out that using a cutting torch close to concrete results into exploding concrete, was that also because of steam?

Steam. Concrete is bonded together with a type of hydrated lime. Heating it much above 100c 212f cooks the water out of the structure and can cause spalling. That's steam flowing chips from the surface. If you ever want REAL excitement try taking an oxygen lance to concrete. The smoke is a vivid orange and the flying chips are in huge quantities and flying FAST. I don't know what adequate PPE is but not what we were wearing.

That's good to hear Bart. It's easy to rush brass in the melt, I've only messed it a little in high school shop class. 

Frosty The Lucky.

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Thank you, what fools we where then. We did use a cutting torch then to cut trough some steel I beams. Nobody ever told us it was more dangerous to use them on concrete then on steel. Only PPE we had where overall's and welders goggles. 

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I'm not sure if you're being serious or giving me a friendly hard time. There is a huge difference between a cutting torch and an oxygen lance. https://www.youtube.com/watch?v=CeAP1WiO1Dk&feature=emb_logo

There are different types but this one is similar to what I got some training with. Working for DOT highways we were emergency response personnel, depending on what disaster befell us. Well, I was a certified welder at one time and got tagged to learn to use the oxygen lance available to us on short notice. 

I cut some structural steel scrap and a hole through a concrete road barrier, Jersey barrier to run a cable through so it could be lifted. Building, bridge, etc. collapse type thing, we're known for earthquakes and stuff gets knocked down. 

I didn't get to wear an aluminized suit like the guy in the video though, I got leathers and a full coverage leather welding hood. NOT good enough, it roasted me like a potato and put hot concrete chips in my everywhere. 

Frosty The Lucky.

 

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  I have never used an oxygen lance, it sounds like fun.  We used to "bore" deep holes in heavey steel with air carbon arc and the slag had nowhere else to go except right back at you.    A slag glob WILL find that one weak spot or chink in your leather "armor" and burn and burn and burn.......

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Frosty, I think the language barrier is playing up again, the tool I used was a cutting torch, had to look up what an oxygen lance is and I am very glad that is not what we where using.

The I beam we where cutting was laying on concrete, we where maybe 17yo fools (the ones that are invincible and know everything) so we just fired up the torches and started cutting into the I beam, you should have seen our shock when things underneath the steel started exploding... 

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Concrete will not always spall either. When i was under cars a cutting torch was one of the best tools in the shop. Bolt wont come out, burn it out. For years i would just lay something on the floor and cut it with the torch no problem or hassle, and of course very little PPE, goggle sometime if they were not broken. Anyway i started working in one shop and went to cut something and concrete chips started flying at me. That was when i learnt about spalling, the hard way. 

My point is you can go years or even a lifetime doing an unsafe practice with out something going wrong, but it is that one instance that could very well change your life forever. Better safe than sorry.

My grandkids like to come out in the shop with me. They have hooks for each of them to hold their safety glasses on and the first thing they do is get them and put them on when they come in. Teach them young to practice safety. 

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