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Hans Meevis

New "How I Do It'

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I posted a new Hidi in my website.I hope this is the right place to post. I would not mind at all posting the whole thing on this website, but it seem easier to just supply the link. Anyway, hope you all enjoy it.

Go to http://www.meevis.com/jewelry-making-class-list.htm and scroll down to the bottom, Making a Hollow Onion Pendant.

Cheers, Hans

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Hi Hans,

Got a question for you...

This x-mas I was really getting into your tutorial section and convinced myself I have to do something like it as well. So I made a fine wax model of a monkey, not to diffecult but nice...

So I thought, to make a mal I had to put it into uhhh that white stuff you know...

And than I put it upside down into the microwave to get the wax out. Ofcourse this went wrong the mal broke and the model was lost. So what's the best way to get the wax out you think???

 

And is there a way to make a mal for multiple works of silver???

Sorry for my english and thanx for answering!!!!

All the best for 2008!

Cheers Bart

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Back in the dark ages of high school art class, we burned out the wax in a little kiln, which also made the investment (plaster mold) hot and ready to receive the molten metal. I don't know what is done in "modern" times :D .

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Guest ford hallam

and Janel wins the cigar for providing the correct answer :D

 

The heating of the mould, and melting out and vapourising of the wax must be done very gradually. If the mould is heated up too quickly and there is any moisture still present ( almost always ) the water turns to gas, expands quickly and cracks the mould. The wax may also expand before it actually begins to melt out, this is another cause of mould failure.

 

There is evidence of the basic process of lost wax casting ( cire perdeu ) having been used more than 6000 years ago. The earliest process was carried out using mould materials like clay, chopped straw and animal manure ( good fibrous stuff!). Wax from bee hives stiffened with pine rosin. The whole process carried out over a charcoal fire.

 

Namaste, and take care when playing with fire.

Ford

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Thanks Ford, I'll step outside for that cigar!

 

Maybe this it too much additional information: Pots can also explode in their first firing, called the bisque (sp?) firing, which slowly drives out the chemically bonded water from the air-dried clay and begins to melt the particles of the clay together, to make it stronger and absorbent, prior to applying the glaze. The thicker the clay the slower and longer the firing, same as with plaster or other water made molding materials. When that magical point of 212°F (100° Celsius) is reached and water turns to steam, kapowie! What a mess! Should have gone slower... Occasionally a potter will reglaze an already finished and fired pot, and even though it is vitrified, water will find a way into the microscopic openings... and it dries much more slowly because there is little choice for where the water molecules can escape, so the chances of doing great mischief to the other pots in the kiln and the kiln shelves are much greater when refiring a pot. I am really glad that most of you don't need to know this!

 

There might be a correlation between organic materials which have been treated in one way or another with a water based mixture, stains, bleaches, washings... too much water soaking, and or too rapidly drying with a hair dryer for instance, could cause the material to shrink and or dry too unevenly and crack. Ouch. Finding the balance is the trick, for what ever it is we are working on when water is involved.

 

Thank you Ford for the history. I am always intrigued by how "technological" processes might have first begun so long ago. The initial, important "ah-ha!" moments, have grown over the thousands of years to become essential to us as we find our way and hone our own skills to create our pieces.

 

Janel

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The best way to remove wax from investment (refractory plaster for casting) is to place the flask on a trivet in a pot above some cool water. Cover the pot and slowly bring to a boil. The steam will remove the wax and not crack the investment. You will also save the wax to use for the next sculpture. I have done this process hundreds of times for myself and with students when I taught lost-wax casting and never had a crack in the investment.

 

Back in the dark ages of high school art class, we burned out the wax in a little kiln, which also made the investment (plaster mold) hot and ready to receive the molten metal. I don't know what is done in "modern" times." Janel

 

The plaster investment MUST be burned out in a kiln at 900 to 1200 degrees F . The temperature depends on what is being "burned out" . When you can see a dull red inside the flask it ready. The final casting temp. of the flask depends on the metal you are casting into the investment. If you try to cast molten metal into investment that has not been properly burned out it may EXPLODE!

I hope this helps,

Dick

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Hi there,

 

the best way to start with metal casting is to seek the guidance of an experienced art founder even when it comes to small scale dimensions. The tricky thing is all these techniques are sounding very easy when you read about in books but they actually are not.

 

Casting and sculpture techniques

 

Bronze casting

 

The cheapest and proberby the safest way is to carry your wax models to a professional founder. It will prevent you from failures (most times) and health damage.

 

regards, Karl

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I couldn't agree more, Karl!

 

Although I strongly believe that the artist should be involved in the preparation of the wax and of the final casting, the actual process of casting metals is an art in itself, and a professional founder will save an enormous amount of time, and money, especially for those who are not really familiar with the process. If you are willing to do all the clean-up work on the wax and casting, the actual cost of casting is usually quite small, particularly with bronze. If you are lucky, the founder will let you be around for the casting process, and with time you can pick up quite a bit of info. The founder that I use is quite open to sharing inormation, as well.

 

Phil

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Hi,

Phil is right in every way about having someone do your casting for you. Here is the foundry I use for small pieces. They are very reasonably priced and you can do all the finish work yourself. http://members.aol.com/browncasting/index.html

I had my own foundry for about twenty years. I could cast about 70 lbs. at a time. I can tell you from experience that after the first few castings foundry work becomes hard, dirty and dangerous work. Here is a picture of casting a crucible with my small furnace (25 lbs.) As you can see it is very HOT! I still have my Kerr Electric Melt furnace but never touch the thing.

post-15-1199659182.jpg

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Hi everybody,

Well I was reading in a book that I could melt the wax out by putting it in a microwave, wich didn't work...

Thing is that I like to do the complet process by myself so I will try to do it with the boiling water...

I also noticed that there was still a thin layer ofwax in the mould does this have to go as well, or will this go when I pore silver in? Does this not take away small details in the final piece?

 

This book was telling me that the weight of the wax x 11 is the weight of the silver I need for my final peace, anyone knows this is correct? I don't believe so, because when I put the 2 pieces of my mould together and pored silver in I came (a lot ) to short...

 

Believe this is becoming a very helpfull topic!!!!!!!!!!!!

Thanx you all!

Cheers bart

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Guest ford hallam

Hi Don,

 

good to see you around, it seems as though it's been a while.

 

I used to to use David Reid's ceramic shell casting procedure years ago. I met him a few times in England, he's a really interesting person. He told me about his work with microwaves at the time and to be honest I initially thought he was pulling my leg...apparently not :blink:

 

Thanks for the link, now to see if I can convince my wife to let me convert our microwave into something useful ;)

 

Namaste, Ford

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Thank you Ford for the history. I am always intrigued by how "technological" processes might have first begun so long ago. The initial, important "ah-ha!" moments, have grown over the thousands of years to become essential to us as we find our way and hone our own skills to create our pieces.

 

Janel

 

A good book on the history of many technologicaql innovations is Caveman Chemistry. He teaches chemistry by having his students replicate important ancient discovies like smelting metal ores, knapping, making soap, alcohol, batteries, ceramics, glazes and others.

 

A bit too poetic and literary for science purist but an attention grabber for non-chemists and you actually learn how to do the practical side of what can be a very abstract science.

 

At one time the entire book was available on his site http://cavemanchemistry.com now you can browse or order it in printed or electronic form.

 

David Callaghan

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For those how are able to read and understand french (I have to admit my french is more than poor) here comes a book reference. I ones had loan it from our library and I found it seems to be the most comprehensive work on the subject of art foundery. Buying it is proberbly a bit costy. ;)

 

Le Bronze d`art et ses techniques

 

 

Grüsse, Karl :blink:

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Hello Bart,

 

You really should remove all the wax from the mold before casting - your ratio of 11 to 1 for silver should get you there just fine, but remember to use at least 1/2 an ounce extra to allow for enough metal to get a dense cast. Are you just pouring this into your mold by hand? Do you have a vacuum caster or a cetrifuge? I love casting and do my own for my jewelry and beads. Should I do a tutorial on this? Let me know. Also, Bart - do be very careful when working with molten metals - poring into moist molds can at times have an explosive reaction with molten metal thrown all over the place(a miniature volcano in your shop).

 

Another note: steam divesting will not work on hard carving waxes as their melting temp. is too high.

Blessings,

Magnus

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Hi Magnus,

I use the hard carving wax. I noticed this works the best for me...

So boiled water does not work for this you say... ok, can I put the mould above a small fire?

And how do we get the last bit of wax out?

With the broken mould I trayed to get it out but noticed that with fire you burn out the details of your carving as well!

Well you just try to do everything the first time right?!

Anyway a tutorial would be very very nice!

Maybe like a (what we call...) a home garden en kitchen tutorial... (meaning a dummy one :rolleyes: )

I just pore in by hand and it seams to do just fine, I shall take a pic of my piece, it looks like it didn't work and well,

it didn't but it gives you an idear of where I would like to go to.

Just give me a day....

Cheers Bart

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Hi Bart,

 

it seems that you are full of resolution to do your own casting.

 

For centuries goldsmiths used a handtool to make centrifugal castings like this one.

 

This is a version with a ball bearing but there some with a chain.

 

You place your hot mould into it, melt your metal in the cavity of the mould and if everything is well fluid you rotate the tool. To be honest I never tried this method myself because I do not like the idea to get the mould and the molten metal as well on my head. But exercise will make the master (with curly hair). :rolleyes:

 

If your model is not too complex you may use cuttlebone casting.

Cuttlebone casting

 

There is the also the option to combine more than two cuttlebone to one mould. You can actully make quite complex piece-moulds with this method. The results have a somewhat rough surface and are in need for further refinement. In my opinion this is a very elegant method of casting....but try yourself.

 

regards, Karl

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Cuttlebone casting is fun.

 

Once on a camping trip near the French coast our kids found some cuttlebones and some fishermans lead as well. Over a campfire we made a replica of a pendant my son happened to wear. Just for fun. (Its nice to show this kind of techniques, definitly to kids)

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I while ago I bought some in a petshop and tried it out.

Well to make a mould out of it, but it's just not the thing for me. I ended up with to much dust and a crappy mould!

I do believe some can make lovely things with it, but I think you have to do to much to finish your work. When you cut it you get this wavy texture you see.

How does the finish look at your sons replica leon?

 

Bart

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Hi Bart,

 

It looked a bit crappy. But that was no problem because it was not about a finished product but about the process. Cuttlebone is best used with hard models you simply press into the bone. (My son wore it with pride, at least that holiday!) I believe we even 'polished' it with beach sand.

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Hi,

I don't mean to be a PIA but you should NOT pour molten silver into a investment plaster mold that has not been brought up to the proper temp. The inside of the mold must be a least a dull red color. You can let the mold cool a bit before casting depending on what kind of metal you are pouring. If there is any moisture or wax in the mold it will EXPLODE! I am sorry to bring this up again but you could be very badly burned and set your studio on fire. Molten metal and moisture do not mix. Allways an exception to the rule-sand casting- but that is a topic in itself.

Dick

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Ok Dick,

I believe you and will not do this again...

So if I have finished my plaster mould I leave it to dry completely and than I heat it up untill it goes redglowing put it on a string and go trick or tried? uhhh I mean I can pore my silver in???

Anyway I'm gonna wait on Hans his tutorial as well.

Thanx for pointing this out again Dick!!!!

Cheers Bart

PS I just love this forum!!!!!

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