Author Topic: Green Twin Oscillator Cast/Build  (Read 17067 times)

MetalCaster

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Re: Green Twin Oscillator Cast/Build
« Reply #50 on: August 08, 2013, 10:12:38 AM »
Hi David-

I try and resized them to 100k or less.
More than that and they can get a bit grainly.

Thanks for the feedback.

Offline ironman

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Re: Green Twin Oscillator Cast/Build
« Reply #51 on: August 09, 2013, 09:46:01 PM »
Mine would sometimes break. Lets hope that yours are successful.

MetalCaster

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Re: Green Twin Oscillator Cast/Build
« Reply #52 on: August 10, 2013, 10:02:01 AM »
There is a bit of an art to making sodium silicate cores.

I have been experimenting with different percentages of sodium silicate, between 3 and 4 percent by weight of sand.

I have a core I made last week, and it is as hard as granite, and then another one that fractures easily.

I need to figure out how to get a consistent hardness to the core.

Too much sodium silicate and you cannot force the CO2 through it.
Too little sodium silicate and the core is too fragile.

Offline ironman

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Re: Green Twin Oscillator Cast/Build
« Reply #53 on: August 11, 2013, 08:24:10 PM »
Have you tried using a microwave oven? Gassing them can be hit or miss if they are not gassed properly.

MetalCaster

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Re: Green Twin Oscillator Cast/Build
« Reply #54 on: August 11, 2013, 08:51:07 PM »
Nope, I have not tried that.

I can't pull the core from the pattern without hitting it with the CO2.

MetalCaster

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Re: Green Twin Oscillator Cast/Build
« Reply #55 on: August 13, 2013, 11:50:59 AM »
Snap flasks made yesterday, and runner/gate arrangement glued together.
This flask will be used to make multiple molds.
The mold halves will be glued together and poured without the flask being present.

Using bound sand, so the flask is only 4" tall total height (cope is 2" and drag is 2").
The photos show the cope and drag stacked.

Pour basin will go in the blank spot along the runner left of center.

When I get the cores completed, it will be time for a cast iron pour attempt, weather permitting.
We have been getting a record amount of rain this summer.  Generally we get little or no rain for about 3 months in the summer.
It rains almost every single day here.

Offline tom osselton

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Re: Green Twin Oscillator Cast/Build
« Reply #56 on: August 13, 2013, 12:54:08 PM »
Looks like a lot to cast how big is your crucible?  That is huge I would hate to see you make a short pour. Could you split them into two halves it could still be the same mold but would ensure against a short pour you still have to fill the sprue and riser too.  I don't want to sound negative but it seems like a lot.

MetalCaster

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Re: Green Twin Oscillator Cast/Build
« Reply #57 on: August 13, 2013, 05:03:43 PM »
Tom-

Not a problem, I use a #30 for cast iron.
Brim full I think is around 100 lbs. of iron.

I will probably try and pour around 60 lbs. this time, and fill three of those molds.

I have a pouring cart almost finished.
I have hand poured with the #30, but it is a bit of a bear to handle, and for this much metal, I will be using the cart.

I saw a commercial cart online several years ago, which is where I got the idea, but I noticed that ironman uses a similar cart with great success.


Offline tom osselton

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Re: Green Twin Oscillator Cast/Build
« Reply #58 on: August 13, 2013, 06:18:08 PM »
A # 30 dam!!  going to have to call you herc !   :) well if you have to lift that much by yourself I think I would redo or make another that raises the furnace to expose the crucible then just latch on with Ironmans wheeled pouring doohicky. I just finished putting the fiber refractory in mine still have to coat it with zircon after I do my coffee. It is 11"wide and 13 1/2 tall inside so now I can figure what size crucible to get. I should weigh dad's cylinder's and get a good guess on that although the base would probably take more.
Anyways good luck with the pour!  :thumbup:

MetalCaster

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Re: Green Twin Oscillator Cast/Build
« Reply #59 on: August 13, 2013, 08:27:10 PM »
I hand poured with about 20 lbs of iron in it, but that was just because the cart was not finished.

I also have a crane for lift out.

I know someone who is using a #50 I think.
I think he is running a two man operation.

I forget my furnace dimensions, I think 15" tall.

Thanks, I am looking forward to this pour, and hoping it goes well.

Offline tom osselton

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Re: Green Twin Oscillator Cast/Build
« Reply #60 on: August 13, 2013, 08:46:49 PM »
Ok this is the one I thought was a good design 

   


it would be a lot safer.
« Last Edit: August 13, 2013, 10:40:51 PM by dsquire »

MetalCaster

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Re: Green Twin Oscillator Cast/Build
« Reply #61 on: August 13, 2013, 08:59:18 PM »
Just wear leather shoe covers, or some heavy boots.

I wear a lot of leather.

It is not that difficult to lift a crucible out of a furnace, and if you use quality crucibles, then breakage is not much of a danger either.
Special furnaces like that are just not necessary in my opinion.

And you should inspect your crucibles before each pour to make sure the are in good shape.

This is me pouring about 20 lbs. of iron.
Don't forget to put on your leather shoe covers (don't pour in lace-up shoes like I did, not a good idea if you like your feet).

   


« Last Edit: August 13, 2013, 10:44:06 PM by dsquire »