Emerald
spending too much on rocks
Member since August 2004
Posts: 417
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Post by Emerald on Nov 8, 2005 16:00:50 GMT -5
Here are two pics I just scanned of pieces I learned to straw cast while in my Silversmithing class last week. I'll be trying this again just as soon as I get a crucible. If all goes well, I will cast alot of my scrap silver and hopefully, get a few pieces that I can add a stone to. Each one is unique....nifty eh? I was just sooo excited about trying the technique that I just had to finish them out. They look really cool and are quite 3d!   |
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Post by Cher on Nov 8, 2005 16:35:42 GMT -5
I've seen info on doing that somewhere on the net, it's pretty cool way to make really individual pieces.
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Post by parfive on Nov 8, 2005 21:40:25 GMT -5
Emerald - They look very interesting. How about a quick description of 'straw casting'.
Rich
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Post by rockyraccoon on Nov 8, 2005 22:54:28 GMT -5
emerald i need to see closer! the 2nd one looks like it has a little candle on the side.
kim
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Post by LCARS on Nov 8, 2005 23:46:59 GMT -5
Yes, tell me more about this "straw casting" you speak of...
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Post by Cher on Nov 9, 2005 8:20:45 GMT -5
They take a bunch of straw from a corn broom, bind them together and soak them thoroughly in water. Then molten silver is poured into one end and as it runs down between the straws the silver forms the different shapes. PS .... Here's a link to pictures of how it's done. groups.msn.com/FineWire/broomstrawcasting.msnw |
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Post by docone31 on Nov 9, 2005 8:44:34 GMT -5
Another trick, is potatoe casting.
With a piece in investment, burn out the piece. Using the flask as the mold, melt a puddle of silver, or gold.
Instead of using a centrifugal caster, keep the silver liquid, and take a cut potato and mash it onto the silver. The steam from the potato forces the silver into the mold.
I have found that capable of producing better detail in some cases than spin casting.
Another interesting casting form is bean casting.
Do the same thing with beans instead of the straw.
Good polish on the cast piece.
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stefan
Cave Dweller 
Member since January 2005
Posts: 14,113
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Post by stefan on Nov 9, 2005 10:49:19 GMT -5
how freakin cool is that- I think even I could have fun burning that stuff up!
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Emerald
spending too much on rocks
Member since August 2004
Posts: 417
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Post by Emerald on Nov 10, 2005 7:00:06 GMT -5
I'm ordering a crucible thingee so I can do straw casting again. I'm inviting all my sons best friends over from college and making them each a pendant for Christmas. In return, they have to give me a hand casting. (You should have someone present to give you a hand while doing the pouring. Or at least, to put you out when you catch yourself on fire *snickers*)
Sorry I missed out on describing the process. Cher, a GREAT example you sent us...almost exactly what we did.
We used good ol' Georgia "pine straw" ....the longest strands you can find and the bundle was as big around as a clenched fist. (Larger than what was show in the photos from the above article) It was bound with a wide heavy rubber band. They were soaked in water for almost a week. We poured about 5.00 worth of silver with each cast. (small handful of scrap silver)
I heard of using split peas, navy, pinto other types of beans. I was told when using the beans, sometimes you get voids that you can set stones in. I never heard of potato casting...I'm extremely interested in that!
Doc, I'd love to pick your brain! I'm thinking of taking a casting class, but since I can't afford the tools for it, (centrifuge, vacuum system, kiln for burn-out) the straw casting and other methods seem to be the best way for me to try casting in lieu of lost wax method. Any suggestions or books on learning old-style methods of casting...I'm very interested and all ears!!
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Emerald
spending too much on rocks
Member since August 2004
Posts: 417
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Post by Emerald on Nov 10, 2005 7:05:18 GMT -5
Doc, on the investment, is there a "home" way to burn out the wax? Torch, oven...other way? I need a poor man's method. :-)
I was interested in casting even when I was a kid. My dad used to work for the steel mill near Chicago and he worked right along where they were pouring the car sized ingots. I always thought it was neat! Once, we went in for a tour and got to see them do a pour. Absolutely amazing....hot and stinky process! Silver is much nicer and far more manageable I say!
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Post by docone31 on Nov 10, 2005 8:26:55 GMT -5
If you want to do a burn out. Get a clay flower pot. Line the inside with aluminum foil. Use the extra for an aluminum hat.
Get a Coleman propane single burner stove for camping.
I use soup cans for the flask, investment I purchase.
Light the stove, put the flask upside down on the stove so the wax does not drip on the burner, put the flower pot on the stove, go away for a while.
To cast.
Take a tuna can. Screw it onto a wood dowel. Where the sprue is, make an hole to melt the silver. I do it before I burn out the wax, that way the pieces of investment drop out of the mold rather than messing up the cast.
Take either a potato, cut in half, or use the tuna can, with pieces of paper towel wet.
Melt the silver untill it rolls, flux, keep heating. Take the potato, or the tuna can, and press it down on the flask.
No more steam, chuck it into a bucket of water.
Polish.
Enjoy.
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Emerald
spending too much on rocks
Member since August 2004
Posts: 417
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Post by Emerald on Nov 10, 2005 8:58:22 GMT -5
Doc...
You're the best...
I have all the materials at hand except the investment. I actually have made a few pendants out of wax that I want to cast. You betcha I'm going to try it!
I figured there was a "home" method for burning out the wax! Damned expensive "lost wax" method....your first born is required to afford it! If there's a will...there's a way!
I probably won't be able to try it till I get out from under my last teaching assignment (painting) It's going to take me at least a month or two to prep for 60-70 students. Teaching in Vegas end of February for a week and everything has to be shipped by early in January!
Now you know why I'm giving up painting. I'm a far more impatient soul and the thought of painting 14 hrs a day simply gives me a headache! (and back-ache) I'd rather cut/polish rock, wear mineral oil, wear my fingers down on the grinder and have the black silver crud under my nails than to suck up sawdust and paint all day long! (I think menopause is talking!)
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Emerald
spending too much on rocks
Member since August 2004
Posts: 417
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Post by Emerald on Nov 10, 2005 9:04:44 GMT -5
Oh...btw....
I once donned the notorious aluminum cap....my son (he's 23) broke into a fit of giggles. It's a LONG story...but he loves it....and thinks I'm nuts in a good way.
When we do the straw casting, I'll be sure and have him take photos. Rest assured, in your honor, I'll be wearing the "safety gear" (aluminum cap)
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Post by xenaswolf on Nov 10, 2005 9:14:27 GMT -5
Ok since some of us are totally clueless what ya'll are talking about...sprue, investment, burn out etc etc, I vote you must all take pics and show us  |
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Post by Cher on Nov 10, 2005 9:16:32 GMT -5
Helen, you know how when your tumbling, you end up with all those little bitty pieces of polished rock. Could that be used for casting? That would be a good place to use those tiny polished stones then.
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stefan
Cave Dweller
Member since January 2005
Posts: 14,113
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Post by stefan on Nov 10, 2005 9:25:31 GMT -5
way too cool- I have a question? what is lost wax method?
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Post by hermatite on Nov 10, 2005 9:29:31 GMT -5
Okay...call me crazy...but it just hit me. Here's what we need to do. We all need to move within about ten miles of each other so that we can borrow quipment...exchange ideas...give each other shoulders to cry on when our rocks break...and just generally create a massive rock artist movement the likes of which will not be equalled on earth! YES?  YES??? it could WORK! we can do this people!!!!! |
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Post by hermatite on Nov 10, 2005 9:30:03 GMT -5
;Dahem..too much coffee this morning...sorry.
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Emerald
spending too much on rocks
Member since August 2004
Posts: 417
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Post by Emerald on Nov 10, 2005 9:58:05 GMT -5
Lost Wax Method...
I'll give you the abbreviated version from a total newbie.
Carve a design in wax....add a spruce (a channel to pour the silver into)
Poor in investment material and let harden (this is REALLY abbreviated)
Burn out the wax
Pour your casting.
You lose the original wax model when you burn out the wax. It forms a hollow within the investment material that you can pour your silver into. Once you pour the silver, the investment mold is useless. So it's a one shot deal. You can still make a silicone or latex mold of the original wax mold and make duplicates before you use the piece in the investment. On intricate designs, you have to force the silver through the mold (centrifuge) to completely fill the design before the silver solidifies. Doc's Potato technique may well be just the ticket for the centrifuge challenged silversmith. (me)
I used to make molds for ceramic jewelry...and the processes are quite similiar, (except for the centrifuge part) Though with silver, you have the ability to create far more detailed castings.
I'm sure Doc has a more articulate way of describing the process.
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Emerald
spending too much on rocks
Member since August 2004
Posts: 417
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Post by Emerald on Nov 10, 2005 10:03:09 GMT -5
Lol Hermatite!
Sure you're not in menopause too? (I hate it... it makes me incredibly emotional, philisophical and down right cynical at times. Forgive me!)
Though...an OD of coffee can do it too....but it's somewhat worse! It causes me to jump on my soapbox, flail my arms while I rant about my current state of affairs!
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YES??? it could WORK! we can do this people!!!!! 
