Sodium Silicate for Foundry Sand

[Shopgeezer]

If I try a lost wax style setup with Sodium Silicate sand and I can’t heat it to melt out the pattern maybe I could make the pattern from urethane foam and dissolve it out with a solvent. If I used Acetone and soaked the mold in it that would make for an exciting pour. I could just pour the aluminum into the mold and let the foam melt out. I think Toyota makes cylinder heads this way. Saw a You Tube on that.

 

[GreenTwin]

There are very few shapes that really require the lost wax / lost PLA / lost foam methods.

I have seen some really complex shapes removed from bound sand molds.

If you have a part with a lot of internal passages, you may be forced to use one of the "lost" methods, but even those shapes (such as auto intake manifolds) can be cast with bound sand and standard cores.

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[SmithDoor]

There are very few shapes that really require the lost wax / lost PLA / lost foam methods.

I have seen some really complex shapes removed from bound sand molds.

If you have a part with a lot of internal passages, you may be forced to use one of the "lost" methods, but even those shapes (such as auto intake manifolds) can be cast with bound sand and standard cores.

.

Sodium Silicate can take hight temperature 🌡

I have read using for lost wax.

Refractory
Water glass is a useful binder of solids, such as vermiculite and perlite. When blended with the aforementioned lightweight aggregates, water glass can be used to make hard, high-temperature insulation boards used for refractories, passive fire protection and high temperature insulations, such as moulded pipe insulation applications. When mixed with finely divided mineral powders, such as vermiculite dust (which is common scrap from the exfoliation process), one can produce high temperature adhesives. The intumescence disappears in the presence of finely divided mineral dust, whereby the waterglass becomes a mere matrix. Waterglass is inexpensive and abundantly available, which makes its use popular in many refractory applications.

Dave

 

[Shopgeezer]

Hmmm. In thinking about it I remember reading that high temperatures alone will cause sodium silicate to set without using any CO2. So maybe I can burn out the pattern just like with lost wax. Except you wouldn’t need the long complicated heating program on the kiln that you need to cure the plaster properly. Just melt out the pattern and pour the aluminum. There are a variety of 3D printing filaments intended for this use. Whacking out a bunch of cylinder heads for a radial engine on the printer and casting them that day sounds very appealing.

 

[lee webster]

The information set out in this thread proves that I have been mixing and setting my sodium silicate mix the wrong way. Next time I make a core I will follow the advice here.
Lee

 

[SmithDoor]

Hmmm. In thinking about it I remember reading that high temperatures alone will cause sodium silicate to set without using any CO2. So maybe I can burn out the pattern just like with lost wax. Except you wouldn’t need the long complicated heating program on the kiln that you need to cure the plaster properly. Just melt out the pattern and pour the aluminum. There are a variety of 3D printing filaments intended for this use. Whacking out a bunch of cylinder heads for a radial engine on the printer and casting them that day sounds very appealing.

Sodium silicate will setup just sitting on table even on your hands.

Dave

 

[Shopgeezer]

So is there any info on how much SS to add to the sand? It is a liquid so maybe it’s by weight?

 

[SmithDoor]

So is there any info on how much SS to add to the sand? It is a liquid so maybe it’s by weight?

It is by weight and it 3% to 5% .

Dave

 

[100model]

Hmmm. In thinking about it I remember reading that high temperatures alone will cause sodium silicate to set without using any CO2.

You can use a microwave oven to cure sodium silicate, I used plaster core boxes and dipped them in water before adding core sand so the microwaves would heat up the core box and then cure the sodium silicate.

 

[SmithDoor]

You can use a microwave oven to cure sodium silicate, I used plaster core boxes and dipped them in water before adding core sand so the microwaves would heat up the core box and then cure the sodium silicate.

Never tried microwaves.
Let me know how works

Dave