microwave smelter

Step 8: How not to

You've watched the video, you saw the inferno. That was caused by double-whammy of not paying attention and using inappropriate materials being used. Using insulation is sound, provided it's rated to be used in high-heat situations. In my effort to keep things accessible and open I chose to use a rigid-type foam building insulation. Bad idea. The heat from the crucible in combination with the duration I had set caused a corner to the foam to ignite. I shut off the microwave and waited to the flame to die out, but it was only getting worse. Fearing a backdraft if I opened the microwave door, I risked it anyway. Yup, huge fireball.


We were able to get our cameras running just when the flames died down from reentry temperature to just immolation inferno. 
The lesson here is to use just bricks to create the hearth and wait the amount of time required to to the job effectively, without trying to accelerate the process with insulation.

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Science can be messy and dangerous, so be safe and have fun!

Comments

[67spyder]

I applaud Mikeasaurus for including the failure as well as the success. Sometimes we learn more from failures. Plus it will stop someone else from from trying it.

[lasersage]

All these people worrying about lead poisoning and yet nothing about the fumes from the building foam :)
I'd be more concerned about breathing that.

Have any of you ever read
http://www.gizmology.net/stovetop.htm

there is a fantastic article about smelting Zamak. Its Zinc, because of its low melting point, with Aluminium (and a touch of copper) dissolved in it.
Makes for a very useful alloy for casting, but can be made at relatively low temperatures.
The next candidate for microwave smelting?

[bonpierce]

You do realize this contains LEAD right? Lead is a carcinogen whether it is being melted or held in your hand a a charm or around your neck as a necklace.

You don't want long exposure of any kind to this stuff. Seriously.

[weesuzi]

hiya folks Safety is a myth, risk is the reality. Paracelsius said " The poison is the dose" in the 15th century. As abinger says below, risk/dose increases with, time exposed and the ability of the product to get into your body due to its form (gas, fume, mist, powder, pearls, bricks...its pretty hard to inhale a brick). Spoken by someone with 16 nuggets of mercury amalgum in his gob(mouth) I feel Ok about it. Loook at it this way Acetic acid /vinegar pretty much the same chemical different concentration use one in the lab and a lower concentration use it on your chips(french fries) Whisky....like drinking it ...but don't want it in my eye. Same chemical same strength different risk. Phosphoric acid used as a disenfectant sanitiser in breweries, used as a main ingredient of Coke...okay bad example. As a safety professional( and ex lab tech with 30 years behind the bench) I genuinely appreciate people's need to communicate safety ideas and protect their web community friends. High five hazard spotters! But educate yourselves to the risks not just the hazards. Google EH40 and you will find the UK occupational exposure standards for all controlled chemicals and peruse the Health and safety executives website at www.hse.gov.uk all info free and usually pretty practical. I would love to write a safety bible for this site but where would you start and end..ohh yes Asbestos to Zoonoses (an A to Z of not so common sense) Bout ye.

[terpodion]

Lead isn't a carcinogen. It's a toxic, heavy metal - a poison. That's different. It isn't going to hurt you unless you ingest it, either by eating it, chronically getting lead paint (which isn't sold anymore) on your skin or by inhaling the fumes after it reaches it's vaporization point which is a whole lot higher than it's relatively low melting point. If one were to smelt lead every day, there would be danger. One time isn't dangerous if you are the least bit careful.

[aristide202]

Do you remember good old time of tetraethil lead in gasoline ? I guess some of that stuff is stil spread all around

[samurai1200]

So why is there this huge push away from it for consumer (and most other) electronics?

[SIRJAMES09]

AMEEN!

[terpodion]

Because it if it ends up in landfills it contaminates the water table. Of course, every public waste disposal site that I know of keeps electronic junk out of the landfill and recycles it properly but because it once did end up there; politicians created the legislation to eliminate lead in all forms. Makes for good campaign bragging rights. "Senator Jones drafted legislation to eliminate lead and protect our children."

[paqrat]

I think too there is a certain paranoia about lead. This paranoia is, in part, spread by certain legislators who, in an effort to look as though they are actually earning their salaries, play up the supposed dangers of "demon Lead" and pass legislation against it. If the web site I looked at earlier is correct, easy flow silver solder contains cadmium which is definitely something you don't want to breathe the fumes. I have read cases of jewelers killed by melting cadmium and breathing the fumes. I have yet to see anything about anyone dying from melting lead. If melting lead was that dangerous plumbers should have been dropping like flies before legislation banned it in plumbers solder. I believe the effects lead has on the brain and nervous systems of immature humans is the main thing we must be careful of when dealing with lead and that is more likely to incur through ingestion.

[gladiator327]

Then why do we still use Lead Acid Batts for vehicles?

[static]

Lead Acid batteries are still being use for vehicles because an all around substitute hasn't been created. The hazards of using them have been mitigated to a large degree on both the manufacture, and consumer end. The salvage price for lead has always been constantly high enough that persons in the know, never sent them to the land fill. The high deposits we see now on new batteries is to keep the ignorant, and lazy from sending them to the landfill.

[skrubol]

Also, due to the large deposits encouraging battery exchanges, something like 98% of car batteries are recycled.

[terpodion]

Because there is no acceptable substitute. It's pretty much as simple as that. No other type of battery can stand up to the thousands of cycles of charge / discharge, put out as much current and withstand the environmental conditions that vehicles are subject to. At least not in that price range. How would you like to have to pay $350 to $700 for a car battery (installation not included)?

[skaar]

i've read that iron acid batteries are better for lifespan and resiliency, but they're low capacity. now ni-mh could be used, they have low size, high current and capacity. at least acid iron could be built at home.

[samurai1200]

This is a good point. It's easy enough to find "Lead Free" solder these days (Sn-Ag-Cu), people should just use that if they plan on handling their ingots (as a paperweight, etc) created here.

[yogadavid]

Lead free solder was used in a lot of volkswagons, xbox, and pretty much everything else where the environmentalist went on a rampage to get rid of lead. that is why you get the red ring of death in an xbox and your airconditioner in your volks wagon. Especially in deisel. Environmentalist did not think ahead about all the crap going into a landfill because it can't stand up to any heat and or vibration.

[static]

Would appear that not all lead free sold alloys are created equal. Who knows exactly why they weren't properly researched by manufacturers, or those specifying manufacturing specifications prior to their use? This is not the first time a change(for any reason) in manufacturing methods created problems, and it will not the last. Of course it's all the fault of the environmentalists.

[canucksgirl]

You realize however that lead-free solder is actually worse for you.

[wocket]

Certainly is. Always read the material Data Staftey Sheets about any of these things.

[samurai1200]

*citation needed.

[canucksgirl]

I had originally heard about a Danish study through a television program, so I had to do some quick research to get you facts you can read yourself.

Heres a pdf from a company called OK International, who is a global supplier of soldering products. In it they reference the study and explain the results. Obviously being a supplier, they have no reason to manipulate the results either way...

[icyfyer]

While I find the linked PDF interesting, I can't give it much credibility because of their inability to correctly quote the name of the largest occupational safety organization in the US. It seems like a miniscule detail, but they're making a lot of claims, and citing a lot of other works, not to have done their research, or at least proofread the work before publishing.

[canucksgirl]

Yes, I see too that they referenced OSHA incorrectly as OHSA.
I only chose this source because (someone here wanted me to back up my statement and) Ok Int. references the Danish Study that I had heard about from a TV program.

If anyone wants to read the full Danish Study for themselves they can read it here.

[chamunks]

Wow thats really quite the paper I said to myself I'm just going to skim it than I got to the end and was like wow that was informative. I reccomend that to anyone who wants the real scientific answer to whether or not LeadFree Solder is More harmful to you. Which apparently it is.

Que instructable about making an effective deskmounted airfilter for your soldering station.

[canucksgirl]

I'm glad you found it informative. Too often people just assume that lead-free means safe and they use it without proper ventilation, doing god only knows what to their lungs...

In fact, an Instructable member has already made an inexpensive air filtration system that was intended for use with soldering.

You can see it here.

[chamunks]

Well thats handy, I dont exactly work in a production environment where I'm soldering ALL day. But this is good to know I also was under the same assumption.

I've been using this stuff the "Special Blend" at Sparkfun, http://www.sparkfun.com/products/10243 enjoying it quite a bit I will definitely look at that Ible though I do really appreciate my lungs. :)

The area I work in is a pretty open area but its probably still insufficient.

[canucksgirl]

If you read the MSDS, it has basically the same ingredients and warnings as other non-lead solders. What I would be concerned about is two statements;

1. Prolonged inhalation of fume may result in lung complications.
2. This product may contain lead. (So much for being lead-free...)

It's important to read it if you haven't already. :)

[static]

Actually the MSDS is not a datasheet for the Sparkofun product. The data sheet is for Indium solder products that Sparkofun lazily points customers to. Early on the data sheet states the warnings concerning lead apply to those Indium products containing lead. The datasheet is usable, but you need to know what it is you are looking at, and how to apply it to the Sparkofun solder product. A thousand lashes of Ann Landers wet noodle for Sparkofun, for confusing people about their products.

[79spitfire]

And once again we have the perfect examples of why no one wants to try or create anything new or different!

Great job for having the cahonies to try something 'out of the box' (or microwave as it may be)

As to the insulation I would suggest trying to score some refractory bricks, they can be had at ceramics suppliers, and cut easily. You may have some luck chatting them up, and getting some fractured or broken ones to cut up.

I'm not a fan of using solder, as much of it can contain fluxes, and it can be pricey. Old (lead) tire weights can be used. Silver might be another possibility, but also can be pricey.

Before we have ANOTHER tirade about how bad lead is, please keep in mind that lead has been used for casting for thousands of years, and while it is very toxic when ingested, or inhaled, simple safety precautions will protect a casual hobbyist.

Remember it is YOU who is responsible for you safety, not someone who is trying (at his own risk) to create something new!

[bryan3141]

the solders used for making stained glass windows are guaranteed flux free. There's also a "silver" lead free solder available at any stained glass shop (I use it if I'm making something for an expectant mother or a baby's room). It melts a little higher and solidifies fast enough that it's hard to pull a proper bead with it, but it's not completely outrageous in price....usually sold by the pound.

If you're soldering or melting lead-containing alloys, please remember to get your blood tested at least once or twice a year.

[Aeryk1]

I remember reading about using microwaves to melt metal back in 1966, yes, back in prehistoric times, before the laser much less the microwave oven. By changing the frequency of the microwave, you control what is heated by the microwave. Our microwave ovens are adjusted to the wavelength of the water molecule, distance between the oxygen and hydrogen atoms in the molecule.
While it may be beyond the oven's internals, if one could adjust the frequency, you might be able to reach higher temps.

[jimvandamme]

Water is polar, meaning that the molecule isn't symmetrical. So in an oscillating electrical field at the right frequency, they all flip back and forth furiously and generate friction among themselves.

The other way of loading a microwave cavity is by bulk resistivity. When you put a conductor in the field, it runs current from one end to the other and short circuits the field. When you put a semi-conductor in the field, it conducts a lot but has some resistance across it. If you know your Ohm's Law, you know that there's a point where you maximize the power transfer to a load from a generator. If the resistance is too low (good conductor), your power is shorted out and your load doesn't get hot. If it's too high (an insulator), it doesn't get hot because no current flows.

The silicon carbide has about the right amount of resistance to heat up. Unlike the polar resonance effect in water, this effect occurs at any frequency, including DC. So you can measure the resistance of the material with an ohmmeter. The resistivity changes with impurities, but it's in the 100 ohm-cm range, and is used for high-power resistors.

[SIRJAMES09]

there are too many things that can go wrong in this instructable....lead is deadly, silicon is equally as bad....I can not & will not support this instructable.

The risk to life and/or limb is too great.

They need to pull this instructable.

[adam 101]

"all it takes to kill a show forever, is to get one episode pulled. If we convince the network to pull this episode for the sake of Muslims, then the Catholics can demand a show they don't like get pulled and then people with disabilities can demand another show get pulled and so on and so on, until Family Guy is no more - it's exactly what happened to Laverne & Shirley. " -- Cartman

Take this quote and reapply it to Instructables. I think you will see why a site cannot pull this instuctable. As soon as it is pulled then nothing can stop people from pulling any instructable that may be deemed to dangerous of has the potential of being used for illegal ends. Next thing you know the site is empty and user-less and the DIY community is devastated.

[SIRJAMES09]

I suppose you're right....

My apologies.

[adam 101]

Don't be too sad, we all make mistakes. I was just in a trolling mood.

[adam 101]

and I get a little upset about internet censorship.

[ContraptionMaker]

SirJames, no one is saying you HAVE to do this. The risk is your choice. If you think it is too dangerous for you then don't do it, but don't stifle others for trying something new. One thing about silicon, if it is so dangerous why do they make cooking utensils and cooking pans from it.

[hcaa]

You're mistaking silicone for silicon.