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Mikey98118

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Commercial solutions usually contain about 1100 grams of colloidal grade silica per liter of water

I bought a gallon of Cab-O-Sil fumed silica. It weighs 300 grams including the plastic bottle. I had thought the suggestion was to use fumed silica and am now thinking this may not be the same as colloidal silica and I missed a detail. Is this a different silica than is recommended for making a rigidizer solution? Thanks

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No; colloidal silica simply consists of silica particles small enough to stay in solution, when mixed into water. Fumed silica is made up of molecular chains, a few molecules long; they are, by nature, tiny enough to qualify for this use. Simply mix them into water to suit, and add a little food die to the solution, to enable you to see how well your rigidizer is doing its job.

The next question is usually "how much fumed silica to how much water." You will be glad to know that "to suit" means exactly that. If your solution ends up to thick to spritz, just add water until it will. If too little silica is present in the water, it does a weak job of rigidizing, but you can repeat the process as many times as you want. So, anyone would have to work very hard to mess up :)

So, how will you know if you get enough rigidizer on the ceramic fiber? Once you think you have enough, using the visible evidence provided by the food die, heat the insulation to red hot, using your burner. Once cool, use the touch test to decide whether you are satisfied with the result; if not, just repeat the process as many times as desired, until you are :D

 

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1 hour ago, Steven Bronstein said:

Commercial solutions usually contain about 1100 grams of colloidal grade silica per liter of water

Thanks Mikey98118 , 

If the proportions are approximately 1100 grams silica per liter of water the my 300 gram ( gallon of fumed silica) will produce approximately 1 cup of solution so I am thinking something is off in my thinking about this. I would have thought a gallon jug of fumed silica would create a lot of rigidizer but apparently not....thanks.

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AFB,

It is a one-off for most people. Since fumed silica is also used as a binder in various refractory mixes, and as binder to mix with ground zircon powder, in heat reflective coatings etc., a gallon jug isn't all that much for some people.

 

Steven,

For your use, that jug is A Lot!!! You must remember that commercial "colloidal silica" solutions are sold as full of the silica as possible, to offset shipping costs; not because the supplier supposes that their customers will necessarily use them "as is"; some do, and others don't.

So, why would a small amount of fumed silica do the job?

Because the thickness of the sheath of glass coating left on the individual ceramic fibers is only a few nanometers thick. The solution is drawn along the fibers by capillary action, leaving the fumed silica as a surface film after the water drys out. Where the individual fibers cross one another, they collect in a large enough lump to act as a weld; this is how ceramic wool is rigidized with colloidal silica (well, once it is heated to red incandescence).

So, think in terms of cups of fumed silica in a typical spritzer bottle. Do not mix up any more rigidizer than that at a time, because once mixed, the solution must be kept from freezing in your garage. If allowed to freeze, the solution must be thrown out; it will never be colloidal again.

 

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I only have a minor clarification to add here. "Colloidal" is a physical property like hot, soft, blue, etc. Not a type of material like wood, glass, Pepsi . . .  

I realize you got it when Mike described it, Steven. But it is such a common misconception I figured describing the difference could help others reading along.

Frosty The Lucky.

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Thank you Mikey, this is exactly the kind of help I was looking for. There is so much information out there and it can get really hard figuring out how to apply it. I will make up my solution and coat my kaowool just as you suggested. 

Thank you Frosty. I very much appreciate correcting the technical errors. It is the only way we can ensure real understanding and the ability to make good decisions.

I have posted previously about the kaowool bricks I make and this will improve them significantly. I had only been rigidizing the outside layer. This did help stabilize the fibers and facilitate applying the Kastolite coating but now I will more fully saturate them to add more structural integrity. Thanks again to you both for sharing your expertise.

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Trying to unify and modernize the blacksmith's jargon has been a thing of mine for years. It's easier to communicate if everybody uses the same names and terms. It's not about correcting people it's more just trying to make a common language a reality. AND for hopeless quest, this is a world wide forum and it's SOOO hard to get people who speak different languages to . . . :rolleyes:

Better still, good questions are a treasure. I tend to learn as much or more from questions I don't know the answer to. 

Frosty The Lucky.

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New to forging. I saw a guy on a video and thought, I can make one of those flame units. I made it. Now it doesn’t work.

I connected the round thingy to the tube piece. And added the gas part. Why won’t it work?

Also, I got a grain silo to use as my hot container body. I wanted it to be big enough to forge anything I could ever want to. Do you think I need to build a second fire maker?

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He'll recover in a while and if we did it right, beg us to stop.

On a sidenote I'd love to hear crickets, there aren't any up here and I miss them. 

Frosty The Lucky.

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They are great until there is just one, it has infiltrated your place, and it’s two in the morning. They chirp away until you finally get up, get the flashlight out and then they quiet down. You get back into bed, after failing to find them, just start to drift and boom, cricket. They know what they are doing.

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Don't fish? Nothing catches native Brown trout like a creeker with the hook threaded through it's wing case. There are effective live cricket traps or they're silly easy to farm. That way you have all the fish bait, lizard and bird food you'll ever need and fishermen will buy live crickets. Sometime before that the creeking will stop being annoying because it sounds like money.

I have a friend who raises Red Wigglers just like Mr. Carlson on "WKRP In Cincinnati." Earth worms are a lucrative product, my buddy makes a pretty decent supplementary income from them. Worms aren't legal bait in Alaska but they are great for soil amelioration, winters are hard on wild worms so folks buy thousands for their gardens and he won't say how many farmers who don't breed and grow their own buy.

Think about cherishing your resident money farm, you'll sleep much better.;)

Frosty The Lucky.

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  • 1 month later...

Is there any substantial benefit to using 2 layers of 1" ceramic fibre insulation instead of a single 2" layer? I've seen it recommended around this forum but the only reason I've seen is that it might crinkle slightly less.

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It's also much easier to wrap 1" into a tube than 2". 2" wrinkles and requires work and extra quantities and thickness refractory to make a smooth interior so the flame flows smoothly. 

Frosty The Lucky.

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Frosty has it right. Two one inch layers crinkle far less than a single two inch layer. Once rigidized, both layers are glued back together again. So, you gain a lot of control, when installing the insulation, with no down side. What's not to love?

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Thanks guys, I'll buy it in 1" then.

12 hours ago, Mikey98118 said:

Once rigidized, both layers are glued back together again.

So if I lay the first layer, spray it with water to butter it, spray it with rigidizer, then fire the forge up until the blanket is red hot, then do the same thing with the second layer then the layers will end up fused together by the rigidizer?

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