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Uni-cast 3000


Paul Kin

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Hey guys, anyone have any experience with uni-cast 3000? I talked to a sales rep at Inpro heat and he says in must be cast a minimum of 1.5” thick and recommends 1-2% needles for reinforcement. What I am wondering, arent Kast-o-lite, Mizzou, and other common castables “technically” supposed to be cast thick as well? The reason I am wondering is because it is literally half the price of Kast-o-lite and would be a very handy and affordable source for us Canadians. Here is the specs he gave me:

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A sales rep's job is to sell product, not REALLY know anything about it in a practical sense. I doubt he knows a home scale propane forge from a sidewalk. 1.5" with needles is probably the minimum in an industrial furnace, not something with about 300 cubic inch volume. The product description says it's for large cast sections, large sections have proportionally greater "structural" strength requirements for thickness. Think 10' tall x 30' long. Make sense?

The analysis looks good with 51% alumina, the CaO would be the calcite binder. It'll probably work just fine but forget what a sales rep tells you to buy, he's there to take your order. 

What you don't see are evacuated silica spheres, the bubbles in Kastolite, so Unicast doesn't have any better insulating properties than an equal thickness of limestone. 

Adding needles won't hurt and MIGHT help but if you buy Unicast apply some to a test piece and see how it stands up to a few thermal cycles. Make it a little 1" or so, larger than your opening so you can use it as the door baffle in the new forge. Yes? Make the test coupon just like the forge liner, two 1" layers of rigidized ceramic blanket and say 3/8" - 1/2" max of Unicast. Remember to butter the material BEFORE applying rigidizer or Unicast. I go into the  whys of buttering, it's important so spray things down with water before you apply rigidizer or unicast. 

We know Kastolite 30 works well in our propane forges and is a proven industrial product. I think Unicast 3000 is probably a high quality product, I've never heard anything bad about URC and I have a lot of back channel trouble shooting conversations. I'm pretty sure it'll do the dob for you just fine. I can't guarantee anything of course but I don't have any indications it won't work well. 

So, there's the crux of your decision, price vs. efficiency. Does the lower price make up for the lower insulating properties? If we're talking $20-$30 per sack go with the Kastolite, the savings in propane will pay the difference in under a year if you use it much. There's also shipping, Unicast will be heavier, the bubbles lighten  Kastolite.

Frosty The Lucky.

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Thanks Frosty! This is exactly the type of reply I was hoping for! I think I understand what you are saying also. One question though, as far as insulating values, when using 2” of wool, does the insulation value of the castable make that much difference in such thin layers? Does a 3/8” layer of Kastolite really insulate at all compared to non insulating refractories? This is something I have never really understood, Im not at all trying to argue! Its purely a question to try to understand better. 

I do see now why Kastolite may be the better deal though now that you mention weight difference. 50 lb of unicast would have less volume then Kastolite of the same weight, as it takes more material to make that weight. Therefore, Kastolite should cover more area correct? Thats how my brain is seeing it anyways haha!

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You're welcome, it's my pleasure.

It's a good question Paul and I don't mind a good argument so long as it doesn't turn ugly. 

The insulating value isn't significant to the over all forge's insulation. What is significant is how fast it comes to temperature under the burner and how well it shields the blanket from forge temps.  A regenerative furnace works by heating the forge liner and heating the work through IR, direct effects of the flame on your work isn't so much. We tend to place our work under the burner but that's because that's the hottest place in the forge. 

What is radiating the heat that CAN have an effect on your work is the surface facing it not the material on the other side. A little thickness is good as energy always takes the path of least resistance, Heat ALWAYS moves towards cold. This means the HOT material behind the flame face will conduct towards the surface as the surface (flame face) cools. 

How thick is a benefit depends on how fast you cycle cold iron into the forge as it draws energy from the furnace walls and may exceed what just the flame can support. A thick furnace wall takes longer to come to temperature but has a faster recover rate, the thick  refractory is literally a thermal battery and "recharges" cooler sections in contact. Make sense?

And yes, 50lbs. of a less dense refractory or anything measured by weight, will cover more area than denser materials. That's a BINGO. Give yourself a cookie. :)

Frosty The Lucky.

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Thanks again Frosty! This helps clear things up for me a LOT. I think haha! So being that my intentions with this next forge are axes and hammers, larger stock basically, a denser thicker floor may be appropriate. I did notice in the forge I recently built that it helps a lot to keep flipping that size material because theres always a black cold spot under it. So having some battery power would probably benefit, as well as maybe 3” of wool no? And a much smaller interior. Around 300 cu/in.

I have determined that I am ordering the wool from Inpro either way because its so much cheaper being that it is bulk and theres 2 other guys that want to split it this time. And yes it is 2600° 8# blanket Kaowool. So its not cheaper quality, its just bulk. I am very tempted to get 1 50lb bag of the uni-cast with the order to try out. Its only $50 whereas Kastolite is $100. And Im sure there wouldnt be 50% more material in the Kastolite... hmm. 

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A note of caution: Twenty years back, loads of guys were constructing casting furnaces in five gallon propane cylinders, etc. Kast-O-lite 30 was just starting to be used by our crowd, and mostly the kind of refractory you are referring to was the standard choice. Cracking was a major problem with it, and guys were going to great lengths to try avoiding cracks, with limited success.

.Most of the fellas were casting two inch thick solid walls, with chicken wire support to keep their furnaces together, once cracking showed up. I went with the Kast-O-lite 30, and never got a single crack in all the furnaces and forges build with it. 

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Oh thanks Mikey! I did not realize this. Do you think the cracking could still be an issue when used it the same way as Kastolite with kaowool? If so, maybe I really would just be better off spending the extra money. But I feel like this thread would still be really helpful to others that are looking for info on the Unicast at least. Though maybe it would be a good way to make a more heavy duty floor still?

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18 hours ago, Frosty said:

A sales rep's job is to sell product, not REALLY know anything about it in a practical sense. I doubt he knows a home scale propane forge from a sidewalk.

I have to take issue with this, Frosty. Speaking as someone who's spent more than half their life helping people exchange their money for things they value, the best salesmen are those with intimate knowledge of their product and its applications specifically to be able to help their customers get the best use-value for their hard-earned cash. There was one particularly memorable incident when I was selling furniture and refused to make a particular sale, because I knew that what the customer was looking at would not suit him in the long run. Six months later, he came back, expressed his gratitude to me for looking out for his best interests rather than pushing for a quick buck, and proceeded to place one of the largest orders we took in that year. Really knowing your product (and, importantly, being honest when you don't know the answer to a specific question, but being willing to find out) help build a relationship of trust with the client, and those long-term relationships are a lot more profitable than a quick sale.

The sales manager at my local Harbison Walker branch is quite knowledgeable about what we might call "off-label uses" of his products, and he and I have had some pretty good conversations about possible alternatives to Kastolite 30. He has sold a lot of product to local smiths and has also worked with a number of glassblowers -- including Dudley Giperson, author of "A Glassblower's Companion".

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One factor in attainable thickness that I've noticed is the size of the grog/aggregate used. It's not really practical to cast a 1/4" thick wall if the lumps are over 1/2". Sieving it can overcome this, but may make it more crack-prone due to lack of reinforcement. These castables are/were formulated by competent folk who do/did it for a living. 

Generally speaking, I find it is best to read the manufacturers spec sheets and use a product suited to the task in hand, unless you are fortunate enough to have access to one of the technical guys who genuinely knows how far outside the published spec a product will go while still getting the job done AND who is properly familiar with the finer details of the process.

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  • 1 month later...

Paul I'm interested in how this works out for you if you buy it. I bought a box of wool from Inproheat and got talked out of the unicast for the same reason, I should have grabbed it though it looks like it'd work. 

I'm going to try this Kalakast product, I'm told it's basically mizzou but more alkali resistant, maybe tough against flux....... Rep says they use it in the crematorium incinerators a lot. 

Here's the breakdown of kalakast and mizzou, they're also similar to the unicast. You can get kalakast for around $70 cad a bag from a HWI outlet/warehouse. 

Screenshot_20200519-131247_Dropbox.thumb.jpg.626b9697292a6c9bfdd1bc098b72e306.jpgScreenshot_20200519-131354_Dropbox.thumb.jpg.3b893f3e6ff300a330ee3c8de8c8f450.jpg

 

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Let me know how it works! I was thinking of trying the kalakast also. Im not entirely sure if I am going to use the unicast 3000 yet. Urc sells a lot of refractories I discovered. The uni-cast lc65sr looks interesting. High hot strength and thermal shock resistant and 64% alumina... but I believe its dense like mizzou so theres that to consider as well.

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Heres the urc refractories [commercial link removed]

theres some interesting stuff. I had absolutely no idea there was a need for this many different types of refractory!

Edited by Mod34
Commercial link removed per TOS
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I will definitely update once I try out this Kalakast. Yes there are some crazy refractories out there, HWI, URC, Morgan thermal, allied minerals, vesuvius and that's just the name not the products. 

Most of these companies make their own stuff like bubbly alumina mizzou etc. The problem is finding a supplier that happens to either stock it like the basic kalakast, unicast, loucast, house brand or get lucky and happen to call when they have a partial pallat of specialty refractory. These guys have it made up in pallets and it only has about a 6mth commercial life so the stuff gets custom ordered, if you're lucky you have a shipper that's willing to sneak a 55# bag out of a 5ton order if you get him at the right time. 

I'm not able to post a link but if you use some Google foo :ph34r: you should be able to find the

"Harbison Walker 2005 refractory handbook"

it's not really brand specific and gives a run down of different refractories. 

 

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Trevor, thanks! I’ll look it up! Im considering bringing a small inventory in so theres a local supply. Thats why I want to do some testing. Theres just no dealer for this stuff in northern BC at all as far as I can find... it would be nice to have something for us far westerners! The closest to me here is Edmonton and Vancouver. 12-14 hours away. Shipping on small quantities makes it very expensive. I would likely just stick with the tried and true Kastolite and mizzou but willing to try others!

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