Release agent question

Home enthusiasts discuss their Foundry & Casting work.

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jscarmozza
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Joined: Mon Mar 03, 2014 5:09 pm

Release agent question

Post by jscarmozza » Fri Jan 25, 2019 4:24 pm

I would like to make a core using sodium silicate and harden it in the core box to pick up some fine details, can anyone recommend a release agent?
Thanks, John

Harold_V
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Re: Release agent question

Post by Harold_V » Fri Jan 25, 2019 4:54 pm

Hmmm.

Keeping in mind I have no experience with what I'll propose, is it possible that you could use silicone spray in the mold before ramming the sand? Seems that would discourage the resulting core from sticking.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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ChipsAhoy
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Location: Arizona

Re: Release agent question

Post by ChipsAhoy » Fri Jan 25, 2019 5:39 pm

We use CRC silicone spray in our core box to release sodium silicate and sand core hardened with CO2. Our core box and patterns are 3D printed with 175 filament.
IMG_20190117_120809_1.jpg
IMG_20190121_103914.jpg
IMG_20190124_121519.jpg
IMG_20190121_120324.jpg

jscarmozza
Posts: 309
Joined: Mon Mar 03, 2014 5:09 pm

Re: Release agent question

Post by jscarmozza » Fri Jan 25, 2019 6:34 pm

Thanks guys, I'll give that a try.
John

P.s. Nice work Chips!

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ChipsAhoy
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Location: Arizona

Re: Release agent question

Post by ChipsAhoy » Sat Jan 26, 2019 8:02 am

Wish I could take credit for it, but I am a student in this group, so I do help a bit. This is part of the castings for a hit & miss engine.

jscarmozza
Posts: 309
Joined: Mon Mar 03, 2014 5:09 pm

Re: Release agent question

Post by jscarmozza » Sat Jan 26, 2019 8:59 am

I still make my patters the old fashion way, out of wood. I'm amazed at the power of the 3 D printer, but I just don't want to make the investment in time and money to learn CAD and purchase the all equipment, besides, this is my hobby, if I was doing it as a business it would be a different story. That being said, you have some really nice patterns and cores, stay with it and learn how. Keep up the good work.
John

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ChipsAhoy
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Location: Arizona

Re: Release agent question

Post by ChipsAhoy » Sun Jan 27, 2019 4:39 am

If you use it, let us know how the silicone spray works with your wooden core boxes.

Harold_V
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Re: Release agent question

Post by Harold_V » Sun Jan 27, 2019 5:30 am

While not the topic at hand, I have not great memories of the time I made a pattern and finished it with shellac. The foundry that did the casting used the Furan process, which fused the mold to the pattern. You're wise to be concerned for that reason.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

jscarmozza
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Joined: Mon Mar 03, 2014 5:09 pm

Re: Release agent question

Post by jscarmozza » Sun Jan 27, 2019 1:44 pm

I'm not familiar with the Furan process, can you explain it Harold...reason being, I still use shellac to finish my patterns.

Harold_V
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Joined: Fri Dec 20, 2002 11:02 pm
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Re: Release agent question

Post by Harold_V » Sun Jan 27, 2019 5:01 pm

Furan is one of the chemical processes that result in a hard mold. Like hardening with CO2 and sodium silicate, the mold is far more rugged than green sand.
While I am aware of the Furan process, I know little about it. I do know that considerable equipment is required for its use. It is reconstituted after use and used repeatedly. It's likely well beyond the ability of the home foundry.

I used shellac on the form I used to pour my tilting reverberatory, and that was a mistake, too. Had I greased it, maybe it would have been fine, but it, too, fused to the refractory. I damaged the furnace trying to get it out and ended up burning it out. A sad day for me, to say the least. Here's a picture of the form, and the resulting furnace, which was used in my precious metal refinery.
Tilt furnace #3.jpg
The furnace was cast with a low temperature external liner (using the galvanized form), then the interior liner was placed, using the wooden form. The interior liner was 94% alumina. This furnace had to withstand excessive fluxing on a continual basis, as it was used to recover values from waste materials. It operated for hours on end, and worked like a champ!

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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