What consistency for rigidizer ?

[Cyrilak]

Hello all, I bought some fumed silica and it is to my understanding that I just need to mix that with tap water to make my rigidizer for my kaowool.  What consistency should it be? I read somewhere where someone was using a spray bottle to disperse it so it must not be that thick? Thanks In advance.

[stockmaker]

This has been discuss before on the forum, but may be hard to find so let me give you what I remember.  I have used fumed silica on two forges, so I have some experience, but not much.  The bottom line is there is a wide range of mixture you can work with from thin to thick. If it is thin put on a lot, if thick use less.  You want the rigidizer to soak into the ceramic blank through capillary action so thin may be better at least for the first coat.  I found that putting it on with a brush was better/faster, I took more than I expected.  If you have time you might want to do a 2" square piece of blanket and see how rigid it is after a day or two.    For me I found that one coat was enough, but I put on several coats all at one time.  The wetter you make it the longer it takes to dry, mine took a couple days, don't top coat with refractory until it drys, you will just slow down the entire drying cycle, and loose track of how dry your rigidizer is, don't ask me how I know that.  Hopefully others here on the forum will have more on this subject for you. 

[Cyrilak]

Thanks for the help, it must be somewhat forgiving then if it's been mixed in different ways, I was planning on curing it with my burner to decrease the drying time