Call around HVAC service and furnace suppliers.  If they don't sell refractories to the public they can tell you who does locally. Fumed silica isn't something special it's commonly used in a bunch of applications. West Systems uses and sells it as a thickening agent for epoxy. Heck call outfits that install, do or repair fiberglass, like: bath tub, shower enclosures, boats, etc.

Use the  TELPHONE, talk to real people the company receptionist knows more about the business than any online contact link. Online contact links are more to opt you into the spam marketing files than answer your questions.

Fumed silica is used for all kinds of things, ceramic blanket rigidizer is a really small specialty use.

Frosty The Lucky.

1 hour ago, machinisttalk said:

I am searching for the right rigidizer product to purchase.

So, I just search for any "fumed silica"? 

There are 2 categories of fumed silica:  hydrophobic and hydrophilic.  You want hydrophilic (meaning it is attracted to and will dissolve readily in water).

55 minutes ago, Buzzkill said:

There are 2 categories of fumed silica:  hydrophobic and hydrophilic.  You want hydrophilic (meaning it is attracted to and will dissolve readily in water).

I did't know that Buzz and I need to buy some, thanks for the need to know ifno.

Frosty The Lucky.

Oddly enough I have just been thinking about rigidizer again, my first forge is running fine and has worked hard for me for a year or so but I have sourced a (free) second hand water heater and am considering building a larger and longer unit.

This will of course need fresh insulation so hope I can find that tub of silica I bought last year 

The link has been removed but I am pretty sure it is the same product, I got mine form a marine supply store who sell it as a thickener for epoxy I believe.

2 hours ago, Buzzkill said:

There are 2 categories of fumed silica:  hydrophobic and hydrophilic.  You want hydrophilic (meaning it is attracted to and will dissolve readily in water).

Thanks

For anyone who is wondering if they need rigidizer, I suggest reading this thread.

 

On 4/30/2018 at 1:16 PM, EnglishDave said:

Oddly enough I have just been thinking about rigidizer again, my first forge is running fine and has worked hard for me for a year or so but I have sourced a (free) second hand water heater and am considering building a larger and longer unit.

This will of course need fresh insulation so hope I can find that tub of silica I bought last year 

The link has been removed but I am pretty sure it is the same product, I got mine form a marine supply store who sell it as a thickener for epoxy I believe.

It can also buy purchased cheaply through eBay; shipping charges are also cheap because it is so light.

I am making a foundry and would ask how much Cab-O-Sil M5  would I need to purchase for a beer keg foundry?  I am in process of creating my forge with a standard keg, will use kaowool for the insulation and then the cabosil m5 as a rigidizer, sprayed on.  Thanks

I would advise you to either plan on an extra layer of ceramic fiber blanket (three 1" thick layers), or to forget your plan for employing an aluminum beer keg. At 400 degrees  aluminum will lose all its tempering, and become less than entirely suitable as a forge shell. Thus, additional insulation is advisable to keep the shell cooler.

I am about to build my next forge and was wondering this same question if someone can enlighten me as to what I have read. If I understand right your definitely need rigidizer for the wool but if you line the frame of the forge with kaowool and then put 100 HT on top of it would this be the same as rigidizer since it hardens and would keep the flame off of the koawool? I definitely don't want the fumed silica but I was thinking this would work because I did a work around on my first forge where I used the hard bricks (non insulating) I took Kaowool and lined the outside of the bricks with it and haven't had an issue that Ive noticed with the kaowool fuming since the flame doesn't come into direct contact with the wool.

Rigidizing locks ceramic fibers together where they touch one another, creating endless little joints. Among other things, this stiffens the springy blanket into rigidity; it is like turning a sponge into a foam block, Thin seal coatings--all of them--need something rigid behind them; not something spongy, to back them up.

Mikey98118 I understand that part I should have specified a little better. I am not talking about a thin layer. I was planning on doing a steel frame bottom 12'' square x 4'' high then filling it with 2'' kaowool and then 2'' of ITC 100 ht. I know I could just do the refractory by itself but was thinking with the wool lining under it would be even better insulation. My plan is to to a botton like that then the walls and top would be a separate piece that can just sit on top of the bottom an it would be line the same way. 

Once the cabosil fumed silica is sprayed onto the ceramic blanket, does it need to be cured before the refractory is applied? Can anyone advise on how to cure?

Welcome aboard Matt, glad to have you. If you'll put your general location in the header you'll have a better chance of hooking up with members living within visiting distance. Lots of answers can be location specific as well.

Yes, you want to do a heat cure up to dull red temp. You can do it with a Bernzomatic type soldering torch or with the forge burner. If you use the forge burner be careful not to get it too hot, orange heat is pushing it. All the cure does is melt the silica rigidizer and make the bonds where fibers cross permanent. 

Remember to butter the ceramic  blanket before applying the hard refractory.

Frosty The Lucky.

I used a commercial heat gun to cure the rigidizer in our build.