View Full Version : Mono T 9 replacement

Pete VanderLaan
08-05-2014, 04:59 PM
For those of you who actually build furnaces, or make replacement parts and are old enough to remember Mono T 9, this is for you!

Mono T 9 was this indestructible plastic refractory that a lot of us used in the 1970's and '80's. It was withdrawn from the market in 1988 when the clay pit ran out. There was virtually no comparable replacement. For those of you who draw back from the word "plastic", that means unfired clay and you literally pound it into place with either a hammer or a pneumatic device, the latter being preferable. The product fired is indestrucible.

Peiser and I have been going around with each other since after 13 years, Mark's crown has to go and it is so complex that he doesn't think it to be a candidate for castables. We have really been scouring the mines and fields and finally Missouri Refractories company has an intelligent thinking PHD who listens and then responds and he has made a recommendation for a similar mine run about forty five miles from the old site that National refractories was using for the Mono T 9.

Mno T 9 was never particularly high in alumina. It's about 45% and the bulk of the remainder is rotted silica ( AKA Clay) at 48 % or so. It varies in the deposit. There are trace amounts of iron, titanium and alkaline fluxes in the goop, This is true not just of the old stuff but the new stuff is strikingly similar. I had thought that given the geology, there was a great likelyhood of it being just the same.

"Not so" says our Ceramic Engineer at High Temp. He said that even though compound clays can have virtually identical analysis, it doesn't mean squat. What does mean squat is the "modulus of rupture" and in both materials, if you get it good and hot, it gets really strong.

Let me show what that means: In a bonded clay or castable fired to 200F, the modulus is around 200PSI which means it can break pretty easily. From here on, I will look just at the clays. Fire to 2000F, the modulus goes up to about 1000PSI. Fire to 2750F, it jumps to over 1300PSI and once at 2910, it's amazingly over 3000PSI.

Of course the rest of your furnace just melted and went down the drain, so compromise. There is a point here in this educational little tirade and that is to fire your new furnace as hot as you can before actually putting glass in it. This works for gas units and decidedly does not work for small electric kilns which whimper and die tragically. . This is a lot of the reason why you can't make your own crucibles out of greencast 97. You actually probably could if you fired them to 2750F but you can't or don't.

Coming to the endgame here, This material super plastic A looks to be really nice stuff. The plastics have always been very cheap for what they do. Mark and I both recall $16.00 for 100lb box but that was back when we were broiling dinosaur meat on the grill. I can say that they make the best floors you could ever build. Mark is making his crown out of the stuff. Thank You Missouri Refractories Co! You can get their products from High Temp in Fenton Missouri and I wasn't paid a dime for this post. You can also go to :

Missouri Refractories
1198 Mason Circle Drive North
Pevely, MO 63070-1635
(636) 479-7770
(573) 368-7628 cell and sms
(636) 479-7773 fax
bill@morco.us or bill_headrick@hotmail.com personal
morco@morco.us company

Learn this stuff. It will save you from eternal ignorance. Tell them all that I sent you.

Victor Chiarizia
08-05-2014, 08:16 PM
i used low alumina ram for my bread oven. it's suppose to take cycling very well. true for this new ram? and it's name is plastic A? Vic

Pete VanderLaan
08-06-2014, 06:56 AM
Super plastic A. Mark is going to be ordering it I think. I could ask him to get some extra if you want to get it at the same time. It might cut shipping some.

Victor Chiarizia
08-06-2014, 07:52 AM
not ready yet..think the last plastic was a franco product. i did use mono t 9 on my very first furnace i made. pounding that stuff isn't ez so i bought an air impact and that was the ticket. v

Pete VanderLaan
08-06-2014, 08:08 AM
Smooth it's not. I could rip up my hands on the alumina chunks. It comes in fifty lb boxes with four 12.5 lb slabs about two inches thick.

Glenn Randle
08-07-2014, 08:56 AM
I remember Mono t-9 coming as either an "air-set" or a "heat set", right? Can't remember which was preferred, but seems like the heat set would have a longer shelf life.

After beating on a crown for hours & hours with a hammer I discovered that Walmart sold air hammers for about $15.... They turn " hard labor" into "play time".

Pete VanderLaan
08-07-2014, 09:00 AM
you can reconstitute the stuff. Just stand an unfired slab in an inch of water and it gradually wicks up the clay. Ultimately, it's all heat set. In sintering materials, essentially the hotter you get it on the first firing , the stronger it will be up to about 2900F in this case. 2500F would make a very strong crown.

David Hopman
08-07-2014, 12:33 PM
The air hammer works pretty well as a mold vibrator too.

After beating on a crown for hours & hours with a hammer I discovered that Walmart sold air hammers for about $15.... They turn " hard labor" into "play time".

Glenn Randle
08-10-2014, 11:09 AM
The air hammer works pretty well as a mold vibrator too.

They are handy tools. I sharpened a cold chisel and used it to carve Locust (super hard wood) like butter. The body panel cutter is a great for cutting metal roofing.

This is one of the rare times when an "el cheapo" tool is great.

Lowell Duell
08-11-2014, 06:51 PM
Mono t 9 is great stuff, I must of got the last batch in 1999 used most of it in my furnace but put the rest in a bucket with a lid and forgot about it. Pete, Good thing to know it can be reconstituted, probably dry by now.

Victor Chiarizia
08-21-2014, 06:01 AM
pete....can i get some of the super plastic. just shut down for maintenance and need to replace a few things. v