Homemade rigidizer?

[Gijotoole]

As titled. I ordered a gob of supplies from Mr Coe and am eagerly awaiting the arrival. I can't afford the $90 on blanket rigidizer, so... Any ideas? I understand the real stuff to be about 30% silica or something, but what can I use that will "get me by" while coating the blanket with the refractory? I thought about a really thinly mixed refractory, and then going over it again with the thicker mix once it's hardened. You're all much more experienced than I am.

And smarter.

And better looking.

And stronger.

And (pick something else).

[timgunn1962]

I'm fairly sure it's Sodium Silicate (Water Glass). It has a number of uses and sources. I think Rutlands produce a floor sealer that is liquid Sodium Silicate, for example.

 

Thin refractory might work, but I tend to find the solids stay aon the surface and the liquid soaks in, giving a very thin rigid layer.

 

I took to mixing China clay powder and Zircopax with rigidizer to give a thin suspension and sloshing that on as a sort of poor mans ITC100. Seems to work reasonably well.

[Frosty]

Kaolin clay (porcelain) is a high alumina ceramic and resistant to fluxes. Mixing it as a thin slip and just soaking the Kaowool or equivalent then letting it dry before firing will rigidize the stuffins out of the blanket. WE started mixing our own home brew high zirconium kiln wash, 70% zircopax and 30% kaolin clay. So far the home brew is working just fine in my forge.

 

Frosty The Lucky

[DavidTodtman]

Hi Frosty.  I presmue I can get kaolin at the local ceramics shop.  Is zircopax also to be found there?

 

Thanks,

David

[Frosty]

On 2/17/2014 at 9:10 PM, DavidTodtman said:

Hi Frosty.  I presmue I can get kaolin at the local ceramics shop.  Is zircopax also to be found there?

 

Thanks,

David

Yes, kaolin is carried by most any ceramics supplier. Zircopax is a brand name of a zirconium silicate used in kiln washes. I'm sure better inventoried ceramics suppliers will carry kiln washes and many have high percentages of zirconium flour.

We settled on Zircopax plus and went in on a few lbs. With shipping it came to less than $4.00/lb. Admin may kill me for posting this but just Googling Zircopax plus will put you in touch with suppliers. Here's the link to the outfit we bought from.  Zircopax Plus (sold per lb.) - Axner Pottery Supply

One of the tricks to getting ITC-100 or the home brew to work properly is getting it hot enough to vitrify the kaolin as it acts as the matrix holding the zirconium in place. We ain't gonna get a gas forge hot enough to vitrify zirconium, it vitrifies somewhere above 3,000+c  the kaolin is the glue.

Frosty The Lucky.

[Gijotoole]

On 2/17/2014 at 5:34 PM, Frosty said:

Kaolin clay (porcelain) is a high alumina ceramic and resistant to fluxes. Mixing it as a thin slip and just soaking the Kaowool or equivalent then letting it dry before firing will rigidize the stuffins out of the blanket. WE started mixing our own home brew high zirconium kiln wash, 70% zircopax and 30% kaolin clay. So far the home brew is working just fine in my forge.

 

Frosty The Lucky

I'll try a little thin mix for the blanket. I'm using 2" of insulating so:

make the first round with plain old blanket, cut a bit long so it "stuffs" into place, then I'll soak the inside layer in a really thin mix of the kastolite 3k to help harden the blanket, stuff it, then spread the thicker mix onto the blanket once it's dried in place. Frosty, what do you recommend as the mix ratio, half the prescribed amount? 3/4? i'm chomping at the bit to get this stuff in and get to burning.

As always, thanks for helping a lost soul in Germany with no supplies...

[Cary Brief]

On 2/18/2014 at 3:37 AM, Frosty said:

Yes, kaolin is carried by most any ceramics supplier. Zircopax is a brand name of a zirconium silicate used in kiln washes. I'm sure better inventoried ceramics suppliers will carry kiln washes and many have high percentages of zirconium flour.

We settled on Zircopax plus and went in on a few lbs. With shipping it came to less than $4.00/lb. Admin may kill me for posting this but just Googling Zircopax plus will put you in touch with suppliers. Here's the link to the outfit we bought from.  Zircopax Plus (sold per lb.) - Axner Pottery Supply

One of the tricks to getting ITC-100 or the home brew to work properly is getting it hot enough to vitrify the kaolin as it acts as the matrix holding the zirconium in place. We ain't gonna get a gas forge hot enough to vitrify zirconium, it vitrifies somewhere above 3,000+c  the kaolin is the glue.

Frosty The Lucky.

hi frosty - tiring to do this right and safe. Building my forge per the zoeller instructions using a 5 gallon metal can.  Bought 1" kaowool and have two layers in.  Started reading about putting the Itc 100 and found out I needed rigidizer.   Wondered about using a slip of DE. Or west marine's colloidal silica but can't seem to get clear information.   Trying to do this on a budget - so can u suggest the best/ correct /safest way to rigidize the wool b4 coating with itc100?    Thanks much Cary 

[Frosty]

The best thing to use is a commercial rigidizer. Since writing that last post I've tried "duplicating" ITC-100 with kaolin clay and zircopax but it doesn't fire like I expected. Talking to folk who use kilns regularly I found out ITC-100 doesn't really fire either except in high fire ceramic kilns.

I'm now experimenting with the castable refractory I use to line my new gas forge as a replacement for kaolin clay. I can't say as yet how it works.

Right now my short answer is buy the commercial rigidizer. I have no experience with colloidal silica or sodium silicate. The reading I've done regarding either of these two components used for kiln liners indicates they're used primarily for glass kilns.

Silicates are soluble in caustics and if you're going to weld in your forge the fluxes all contain borax in one form or another. Borax at welding temperatures is highly caustic. That's why it dissolves holes in fire brick, ceramic wool, etc.

Frosty The Lucky.

 

[jcornell]

The main purpose of the rigidizer is to keep your kaowool from flexing too much.  ITC-100 on kaowool will flake off rather quickly if the kaowool is not made stiff somehow.  So, I use rigidizer, soaking it into the wool.  Then I fire the forge, making it stiff, then I coat the inside with kaolin and zircopax (I buy from the same supplier as Frosty).  It's not bullet-proof, but it's reasonably durable.  From time to time you will need to paint another layer of wash as the old stuff chips, cracks, flakes and wears away.

 

J

[Vito]

Hello everyone,

I'm just about to purchase some kaolin china clay and zirconium silicate from ebay to lay some fibers down

Now, I've been through all the lining threads and have collected some valuable knowledge and information, although I have never seen quantity numbers written. I'm not interested in ratios but quantities of each individual powder in order for the brew to work. I've seen that Frosty exposed a ratio of 70:30 of which the 70 part is zirconium silicate.
BUT Frosty also noted that the mix doesn't fire up like he expected to. I can imagine that zirconium silicate won't fire because we won't reach anywhere near that kind of temp in our forges but kaolin should, shouldn't it? 
Also, I haven't noticed what you guys use to bond these two powders and turn the brew into a ''managable'' form which can be applied onto wool. Is anything wrong if I use sodium silicate to liquify the mix instead of water? I'd imagine that it should be even better than it would be if we used water (besides maybe making it more ''sensitive'' to caustic fluxes?). 
I intend to first soak the wool with sodium silicate (it shouldn't penetrate more than quarter of an inch I'd imagine as that stuff is quite thick) and after it dries and hardens, apply that brew on top of it. 

Now, to clarify my point a little bit:

I'm interested in:
-what you guys think about my plan,
-how much (by weight) of each individual powder do I need to make a mix which will suffice for lining one ''medium'' sized forge.

Thank you very much.
And again, I apologize upfront for maybe missing something out and asking it all over again.

All the best, Vito

[KRS]

I don´t think "medium sized forge" is a proper unit of area. Measure the surface you need to treat and maybe then someone can help you

[Vito]

Yes, I have predicted that would be an issue. The final firing chamber should  end up at about 10-11inches in length, with a 8'' diameter (2r)

Sorry for letting that exact measurements out.

[Frosty]

I'm not finished trying to find something that works as a matrix to keep the zirconium silicate on forge walls. sodium silicate is popular but I'm not fond of it if you plan on doing any welding. Silicates dissolve in caustics, that's why sodium is used to dissolve silicates and make sodium silicate. Borax is probably the most common ingredient in forge welding fluxes and at welding temperatures it's very caustic. This property is what causes flux to eat holes in refractory liners.

My next experiment is to mix the castable refractory I'm using to line my new forge into a thin slip and use it as the matrix for the zirconium silicate. I haven't tried it as a stand alone but it seems to be holding up in my shop forge so far.

Frosty The Lucky.

 

[Mark Thomas]

Sure would be nice to see this Thread get some more updates after a couple of years.. It seems it stopped way too soon.. 
Maybe some of you guys Frosty, Gijotoole, timgunn1962, jcornell,  have tried some other mixes, can verify they are good/bad/Ok/Ok but need something better,  or have seen or read of anything since then that you think might work and want to try?
As new to this part of metalworking, I was really frustrated when I was trying to decide what I needed to use to build my first Blacksmith forge, (Now interested in building a Melting Furnace, so will use Forge as both names) so, I tried something that I was told would not work.. Three years later and I wish it hadn't, I would not still be working with my test prototype...Ha.. Same thing with my belt grinder.. Ha.. 

Several things interest me on this post... 
1) Sodium Silicate as a Rigidizer..  I know many have used this and it works for rigidizing the blankets.. Not sure to what extent when compared to other products (Colloidal Silica which has basically suspended glass beads which obviously would work at least a little better and might possibly have a higher temperature rating), or other products.. Sodium Silicate has a melting point of 1,990 ° degrees F, so, you would not want to stop there if you want to protect your blanket. 
2) Frosty, From your Previous comment: Mixing a thin slip Kaolin clay (porcelain) and just soaking the fiber blanket then letting it dry before firing will rigidize the stuffins out of the blanket.
I am assuming that you used Sodium Silicate/Colloidal Silicate/Calcium Silicate as the liquid binder to make the slip?
How has that held up over time?
Also: We started mixing our own home brew high zirconium kiln wash, 70% zircopax and 30% kaolin clay for top coating the fiber blanket.. I would assume to be used as the hot face?
And again wondering what liquid you used as a binder? 
How has this held up over time?
jcornell mentioned in his post that he used the same Zircopax/Kaolin clay, and said, not bullet proof because it chips, cracks, flakes and wears away and needs recoating from time to time. 
This got me thinking.. Frosty probably had a more rigid blanket before coating with the Z/K mix than Jcornell.. But, it seems Frosty had just tried this back in Feb of 2014 and had not had sufficient time to make a good judgement..  
It would be interesting for you two guys to discuss the wearing of your Z/K mix now, and see if they basically worked out the same, or possibly Frosty had better luck because of his more rigid blanket (I am assuming it was more rigid) at this point.
I have not built anything with fiber blanket, only seen it and touched it, and it does not seem to be something that would expand and contract at a high rate, or expand and contract once rigidized more than the rigidizer itself which would expand and contract at the same rate.. Of course, if the rates are different, could cause the fibers of the blanket to break loose too..  My thought here.. If the flakes and chips coming off have fibers sticking out of them, how many, and did it break away from itself, or the fibers, or did the fibers break and come off with the mix.. Might give us an idea of what to try next.. 
3) Along the same lines..  Frosty made this statement: Getting it hot enough to vitrify the kaolin as it acts as the matrix holding the zirconium in place. This is what makes me think that Frosty did not use the Sodium Silicate.. It's melting point being roughly 2000 degrees would not be difficult to make it bind the products.. Here is where my understanding is lacking.. I have heard that mixing liquids/solids like this, that the mix basically averages out, rather than the lowest melting point being the weak link, but, something very interesting and important to know in trying to figure out a best mix.. Anyone care to share or speculate or give some idea on that thought/subject? 
If that is true, the Sodium Silicate would become the binder at that point and possibly solve that problem of keeping it together, but, not vitrifying it, or possibly victrifying it (I don't think it would work like that, but, it may surely work up to the point lacking vitrification.. 
One reason I think this might work, or something that might be added to make or change the binder from just Sodium Silicate that melts at roughly 2000 degrees to something much higher.. Wiki has a nice article on this product.. https://en.wikipedia.org/wiki/Sodium_silicate  Under the subtitle Refractory Use,, it talks about using Sodium Silica, mixing it with Vermiculite dust to create "High Temperature Adhesives".. Since Vermiculite melts at about 2100F and Sodium Silicate 1990F by itself and is considered an Adhesive by itself, it seems that mixing them might even create something higher than either of them by themselves. I was unable to find a High Temp Adhesive made with the two to verify it's melting temperature, but, they described Sodium Silicate as an adhesive, and then described it as a "High Temp Adhesive".  Wondering and thinking.. 
If nothing else, might be able to add an amount of vermiculite dust to the Z/K mix to make it more like a high temp adhesive, which would seem to hold together better and may reduce cracking/chipping, etc.. 
What is we added some Aluminum Oxide to that same mix. It's melting point is 3762 degrees F. 
4) One last thought.. One of the main problems we have as Hobbyists is finding something that works in a Back Yard Foundry,  "AND",,, is available for Purchase in a quantity that would be usual for building a forge/furnace/foundry.. I find that to be the next large problem.. I can buy something for say $2.00/lb if I buy 100lbs and only need 10lbs, but, if I buy 10 lbs, I have to pay $6-$7 a pound for it plus shipping.. Then next problem is having to buy this from there and this from there other.. 
I think there are lots of products that are easily available in small quantities at good enough deals to put a smile on your face, if we just start thinking about it from that perspective.. 

I am researching a bunch of things.. Maybe I will have some answers/suggestions before too long, instead of questions.. 
Fiber Blanket Rigidizer: Wouldn't it be cool if you could use something directly on the Fiber Blanket that would take pouring Cast Iron directly on the material?
There are materials out there just like that, and  for about $2.00 a pound.. Is it designed for Rigidizing a Fiber blanket? NO.. Not.. Will it? Sure.. 
What is it designed for? Coating the surfaces of moulds prior to pouring the molten steel/iron on top of it.
How about a 3100F Castable Refractory that cures in 12 hours and is rock solid, and can be used as a patch system (hot face patch)for existing forges/furnaces for $3.00/lb
Probably could be used to cover the fiber blanket after rigidizing,, if you didn't as the guy who was selling it to you.. Same thing with the Rigidizer I mentioned above.. 
How many of you took days or weeks to cure a refractory, and followed instructions to the "T", and still had the stuff crack and pop off within the first or second use, using these expensive products we are using.. Makes me say.. Try something else.. Can't do anything worse.. 
Cheers.. 

[Binesman]

Rigidizer is fumed silica+water personally i do about 30/70 ratio.

Hardface best i've found is matrikote 90. The internet sells this at a very reasonable price.

 

[Jasent]

For rigidizer I also use fumed silica. 1 cup to one pint of water and a few drops of food coloring for tracer. Has worked well for me sofar

[Gijotoole]

I use kast-o-lite 3k which I originally got from the internet. I made the first coat pretty thin, more of a slip than a mortar and then laid it on thick for the subsequent coats. I ended up not needing a rigidizer after all. I’ve fired both of my forge builds within a day or so of the final layer and have never had an issue. I did find that the first batch of k3k from the internet was really hard - really really hard - to cut through when I wanted to adjust my burner approach angle. The second forge that I built, and use now, was with k3k that I got from the internet. I recently built a PID controller for the T-Rex burner and had to drill a hole for my TC; cheap dewalt bits went right through. I have no complaints, though. The forge gets crazy hot crazy fast and I haven’t witnessed any damage to the chamber. The $70 in controller parts holds it within 3*C. I have the list of parts I used, for those of you who use an atmospheric burner and want a temp controller.

[Mikey98118]

On 6/15/2015 at 7:12 AM, jcornell said:

The main purpose of the rigidizer is to keep your kaowool from flexing too much.  ITC-100 on kaowool will flake off rather quickly if the kaowool is not made stiff somehow.  So, I use rigidizer, soaking it into the wool.  Then I fire the forge, making it stiff, then I coat the inside with kaolin and zircopax (I buy from the same supplier as Frosty).  It's not bullet-proof, but it's reasonably durable.  From time to time you will need to paint another layer of wash as the old stuff chips, cracks, flakes and wears away.

What he said times three!!

Silica rigidizer does many good things to ceramic wool, but the most important thing is to freeze it in place, so that your hot face layer has a stable surface to rest on.

[Mark Thomas]

Ok.. Let me try this again.. I posted a link to a short video and lost my last post.. Ha..  
Matrikote looks like a good Rigidizer. Someone posted a 10 second video proving that here: 
https://youtu.be/vsi32OIXo7c 
But, it's melting point is either 1560F or 2500F depending on whether you have a oxidizing or reducing atmosphere. 
At 2500, not too much of a problem, but, an accidental overheat could cause more than a burnt piece of mild steel at 1560.. 
I read the temp data here on the pints.. The quarts do not have this same info: 
link removed
I was hoping to find something up near 3000 degrees that could be used for forge or furnace.. Going to rebuild the forge and make a furnace. Would be a better deal for me if I bought material for both jobs when you consider shipping, etc.. 

Frosty.. How did your mix of Kaolin and Zircopax work out? One of your last posts said you were trying it or going to try it... Did you ever get there.. 
I lost my original post and my notes after I submitted it, but, someone else also uses this mix above and wasn't having great luck with it..

Or,, Anyone ever used or know about this Zircon W product here which serves as a Rigidizer and Hot Face at the same time? 
This fella melts a lot of cast iron.. 
https://youtu.be/MgsU5EibFbA?t=4m54s
This is actually a coating that is applied to a sand mould in a large foundry after the sand is hardened but before the molten steel is dumped in on it.
I would say that it must be rated for at least 3000 degrees.. 
They stopped making the product.. I'm sure there is a replacement for it.. Just have to find it where you don't have to buy 55 gallons of it at a time.. 

Or: 
This fella I think has a good idea.. He mixes Sodium Silicate(Waterglass) with Aluminum Oxide Blasting medium to make a hot face material. 
I don't know if it would be considered in the IR (Reflective Category), but, it is interesting for sure.. 
I asked how it had worked out over time, since I have not used any of these materials yet, but, no reply.. 
It is sure something that I am going to play with though.. I have a 50lb box of Aluminum Oxide on my porch that UPS just dropped off.. 
I like the fact that you can make items with this "and" make a hot face with it... I am guessing that it might make a nice 3/8" forge floor.. Not sure if it would hold up to flux, etc, but that will be interesting.. 
https://youtu.be/vQN7EqGMTuo?t=3m37s 

[jcornell]

You're confusing rigidizer (which only makes the kaowool stiff) with a kiln wash or reflective coating.  I've been using Kaolin and Zircopax for years now - my forge walls glow brightly, showing that the heat's being reflected.  It's a consumable item - you'll need to "repaint" the inside of your forge every so often, depending on how much you use your forge.  The exciting research is the zircopax and veegum mixture.  I'm still waiting for a report on that.

[Frosty]

Mark: You're confusing 3 different things. Rigidizer as J says stiffens ceramic blanket refractory. Kastolite and other water set castable or plastic refractories make the hard inner liner or "Flame Face" that withstands the mechanical and thermal erosion of normal forge use. Lastly are kiln washes that provide a final layer to reflect IR and shield the liner from chemical erosion most common in gas forges is borax welding flux.

I haven't messed with kaolin clay in a long time and IIRC reported it didn't work any better than ITC-100. Our use in a forge is NOT what ITC products were designed for. The kaolin in  ITC-100 can't vitrify in  a typical forge environment and remains chalky so the wash rubs off.

I'm not sure where you're getting your information but it's kind of scrambled if you've been reading here. For instance you're asking me about experiments I did years ago, like that's how I line a forge now. My most recent forge liner was 1/2" of Kast-O-Lite 30 over two 1" layers of Kaowool, washed with a home brew of zircopax and sifted kast-O-Lite.

My next one will be different. 

My best advice is find a proven set of plans and follow them. Do NOT mix and match.

Frosty The Lucky.

[Mark Thomas]

On 11/6/2017 at 12:54 PM, jcornell said:

You're confusing rigidizer (which only makes the kaowool stiff) with a kiln wash or reflective coating.  I've been using Kaolin and Zircopax for years now - my forge walls glow brightly, showing that the heat's being reflected.  It's a consumable item - you'll need to "repaint" the inside of your forge every so often, depending on how much you use your forge.  The exciting research is the zircopax and veegum mixture.  I'm still waiting for a report on that.

Yes... I do find it confusing, but, I do understand the difference between the 3..
I am having problems posting for some reason.. I see now that this post didn't go out, so, let me try it again.. 

Seems a Rigidizer makes Kaowool stiff.. I agree.. Some use Sodium Silicate, some use Colloidal Silicate (Sodium Silicate with Glass spheres as a thickener). Some take it a step further, and use Sodium Silicate liquid, then, thicken it with Glass spheres like Cabosil, etc.. for the second thicker coat, some just use Matrikote, some use various other substances. 
I would think a good IR coating on top would make the forge more efficient, so, would like to incorporate those properties also if possible. 
I found this post several times.. Read over it many times.. Seems it ended prematurely, and that was the reason I wanted to open it up and see how some of these things you guys were trying worked out.. 
Frosty: That is why it appeared I was suggesting you were still using it.. I asked, how it worked out, since it was a 2014 post..
Got my answer in your last post, at least your opinion.. I think it also agrees with jcornell.  But, he is more satisfied with recoating from time to time to keep things IR, more effective.. 

Matrikote is a Reflective IR coating, but, it also stiffens the Kaowool.. I'm not sure, but, I think it would fall into both categories.. 
In the case of a fiber blanket, it would Rigidize and provide a Reflective coating.. 
Here for an example of Rigidizing.. And, it's white, so, signals some reflective property (I know only usually, but, in this case it actually is);.. 
https://youtu.be/vsi32OIXo7c 
According to this text and Wayne Coe, also IR properties
link removed 
 This material reflects radiant heat back into the furnace or forge to achieve high temperatures quickly and efficiently. 
is a low cost alternative for ITC-100 for coating ceramic blanket material such as Kaowool 
There is only two problems with this mix.. 
1) This material is rated for temperatures of up to 2500 F in a reducing atmosphere, and up to 1560 F in an oxidizing atmosphere.
Which might cause a problem with the coating if you were going to do some forge welding and your phone rang.. 
2) This material should NOT be applied over fire brick, refractory cement, or metal.
So, doesn't work very well, if you want a multipurpose material that works for several situations, or happen to want to use the same properties for different function.. (Forge or Furnace). 

I am willing to try anything, since it seems like no one has found the "Perfect mix", and may never find it, but, it might be one thought away.. 
I am not a chemist, so, have to work very hard to even guess which component adds which properties, etc.. 
Like, I am not sure if the Kaolin or Zircopax adds the reflective properties.. Or if Aluminum Oxide would or not.
I also understand what is used in Commercial forge/furnaces may not fit our uses.. But, some of the stuff is quite interesting.
I'm not sure if this Zircon W is reflective or not, but, it is surely not designed to be a rigidizer for a fiber blanket, but, according to Luckygen1001, it works very well as a rigidizer.. And, he just told me that he rebuilds his hard worked cast iron melting furnace about every 5 years.. 
The Zircon W is a mould coating. Used to coat the sand mould just before pouring molten metal into it.. 
But, if you ask the suppliers,,, "No, it won't work for a Rigidizer", you need Rigidizer and something else, both in 5 gallon quantities.. 
But, obviously it will and does, and in his opinion, works better than their combinations.. That is my only thought and reasoning for suggesting thinking outside of the box.. 

I was curious to find out the results of your testing and see if you guys had tried anything different.. 
I really want to try this Zircon W, which has been replaced (at least at one large smelting company) with Zircon Mould Wash TSCR2  from the reseller link removed , or ASK Solitec 903 from ASK-Chemicals,   but, the smallest quantity is 5 gallon pails(65lbs).. It is an Alcohol based liquid.. Shelf life = 6-8 months sealed to 12 months..  But, it is only $2.00/lb, so not bad, but, probably only need 1 pint, and, won't be using more of it, for maybe 5 years, so the rest is a waste..  
It Dries Hard,, but applies at the Consistency of Paint.. and can be Thinned with Alcohol.. Best part about it is, it can be quick fired and quickset and on to the next project phase.. 
Our main problem is finding something that EVERYONE or Most or Many agree that works great... Then,, all of a sudden, having to buy it in 5 gallon pails goes away.. 
There are enough second hand vendors that would pick it up, if there were a demand for it. The link removed.
For Example: 
If we were looking for something to coat the bottom of our forges for flux and temperature resistance.. 
What if I said, I have never used this, but, a commercial Furnace company, www.bradken.com uses it and thinks it is the best thing since sliced bread.. They only pour 100 lbs up to 5000 lbs pours.. Must know what they are talking about.. 
PLASTECH 85P - Flux Resistant  
It is a rammable product... But, 50lb bags.
Called Plastics used for Coating the Bottom of the forges.. 
Maybe Covering the bottom of the forge, or bricks with this Plastic.. 
85% Alumina, phosphate bonded. DRIES ROCK HARD AND FLUXES WON't TOUCH IT. 
link removed.
I copied and pasted this comment from this site somewhere: High alumina AND phosphate bonded! Now we're talking flux resistant refractory.. 
But, each of us would probably only need a pound or two.. 
If someone did buy this, and used it, and was able to get it to others or distribute it, and we had 4 or 5 or more people saying, "YEA,, this stuff works",, we might  have others reading about it and wanting it also.. Then, the supply problem would probably go away.. That is my main point..

I think in order to find something like that, you would have to think outside of the box, find products that work for multiple uses and situations, and a product easy to apply and easy to cure (which would reduce the error factor and anyone who used it would not have to be lucky to get it right), and would probably go over very well. 

Lets just say, Zirxopax/Zircon W is IR and does a good job for a minute. 
How to build a Forge.. Lay Kaowool inside the forge, get your 1 pint bag of Zircon W replacement, mix it with x amount of water and paint it on, until it fully coats the fiber blanket... 
Fire up the forge, and heat it until it glows, then, let it cool, and you are ready to start using as normal..
Now, if you want to make your forge flux resistant, mix the 1/2 pint bag of Plastech85 (I had found one vendor with two products, now, looking at my notes, I need to call again), apply it and wait 12 hours and you are ready to fire and use the forge as normal.. 

How many people, including myself, have used a "Premixed Furnace Cement" to avoid over wetting, etc, and followed the instructions to the "T", erroring on the side of caution and still had their work after weeks, blister/crack/peel..  All I did was add one more product to the "Do not use" list.. 
I am trying to convince myself to buy $300 worth of product, to use $50 worth, so, I can find prove there are much better ways that most will agree with to use.. 
But,  I am leaning toward this mix... 
Outer Ramable mix: 
Perlite/Sodium Silicate/Chopped strand Fiberlass
Hot face: 
Sodium Silicate/Aluminum Oxide/Chopped strand fiberglass,
Only because, I can get it in the  quantities I want, and, it seems it works, and is relatively inexpensive..
Would be nice if this guy would answer questions on his Youtube video post where he used this same mix without the fiberglass strand added.. 
The Outer Ramable mix: 
https://youtu.be/vQN7EqGMTuo?t=1m45s
and the same video, the Hot Face
https://youtu.be/vQN7EqGMTuo?t=3m37s  
Looks like this could be used for a refractory floor, or to make bricks, etc.. I wonder if the Aluminum oxide would make it reflective?
It's a shame the way I see it.. I know there are better ways to do this.

Thanks for responding...
When I get time, whichever way I do it, I will do some extra testing and playing around with whatever I get and post something that others can review and see.. and go back and post my comments after using it for a couple of months..
I surely might spring for the replacement of the Zircon W,, just because it has a history of working over a 5 year period, and, is quick, and easy for those who don't mind spending the money on a fiber blanket.. If I do, I'll post something and offer the rest of what I don't use to anyone else who wants to buy and try it.
Cheers.

Edited September 10, 2020 by Glenn

[Jasent]

I don't see how it can reflect IR if it's covered in  refactory.  Also refactory can "reflect" threw re-emission.  I would think that if you use too thick of a rigidizer your filling some of the air voids and there for reducing insulation property's. You want it stiff so it doesn't shrink too much and give a sturdy base to support refactory. 

[Mark Thomas]

I think you are referring to the Hot face of Sodium Silicate, Aluminum Oxide Sand Blast Abrasive, that is in the video, plus, I suggested adding chopped strand fiberglass, because he spread a very thin mix and I think I would rather have a thicker mix. Instead of maybe 1/8" in the video, more like 1/2 or 3/4" thick.. That is why I suggested using Fiberglass strands.
If you notice,,, he mixes a clear/blue tint Sodium Silicate with a white Sand Blast abrasive, which ends up a light gray mix, but, dries white after firing...
If you notice in the video, exactly here and a minute or two later in the video: https://youtu.be/vQN7EqGMTuo?t=3m37s  
He mixes the two, then, makes a dough like consistency, and makes some small chunks to fire it to test to see if he has too much water or not.
If you watch the flame when he is firing the little chunk,,, something strange is happening, if you look at the flame.. You see this 2 times within several seconds of the video..

I don't know what you would call that, but, if someone said "Reflective Properties", I surely would not argue with them... That is what it looks like to me..
At 4:32 in the video, he shows you a little hand made crucible he made with the material.. Looks pretty hard to me... Then, at 4:36, he puts it in the hot forge, or, it was already in the forge, I can't tell, it was wobbling like he just put it in there, but, he could have just adjusted it.. Either way, it is glowing, which appears to be reflective, but, I don't know what reflective is.. Note also that at this point, the forge is finished and already has the "Cement" or the hot face installed. The side of the forge is also glowing. Remember, he is using a very small burner made from a torch tip normally used on a 1lb propane cylinder he discusses later in the video..
I have not used a IR product yet.. But, it looks different than using a hard brick to heat something sitting on top of it. In that section of video, you can see the outside of the forge "after" it has been coated with the hot face he calls Cement... I don't see any signs of cracking, but, that doesn't tell you anything over time either, and he hasn't responded to my question about how it has held up.. But, it sure looks like the little crucible he made would survive.. Just saying.. If we pay attention,, there are simple things out there that do what we want them to do..
I don't think the 2lb to 150ml clear mix is hiding the aluminum oxide in this case.. But, I could be wrong..

Shame.. I have 50 lbs of 70 grit Aluminum oxide abrasive, but, it is black, not white.. Would it glow the same? I don't know, but, I'll let you know.. My gut tells me it won't be white, but, it will glow the same as the one in the forge.. And, with a melting point of 3762 degrees F, you sure have a hot face that will hold the temp.. Could he have mixed it thinner and put a first coat on a fiber blanket, and then followed up with a thicker note and made a very, very, rigid "Rigidizer" for a fiber blanket with a high heat resistance,, possibly reflective and could be used for making bricks, coating the floor of the forge, etc?? Sounds like Multi Duty to me, and for the price that you would have to pay for Rigidizer, the, IR, you would be glad to have on product to do both, and other things also.. Maybe someone who reads this has already tried it or has time to try it quickly and holler back.. I am very busy and trying to line up several projects that I can jump on when I get to that point. I want to make another forge and make a furnace, and would like to be able to use the same materials if I want to, or use an addition to the furnace to get some better insulation.. That might be a Perlite Refractory on the outer, fiber blanket on the inner and a 3/4" hot face over that inside the forge..

Just some brain candy for those who think there are better alternatives out there for their builds..
Thanks for your reply.. Each time I reply, I seem to learn something else, find something I didn't see before, etc..

[Jasent]

I'm talking about metrikote as a rigidizer.