dimag Posted June 28, 2016 Share Posted June 28, 2016 I have acquired a bag of Cercast ht. The only info I can find says it is classified as " dense" ( kinda makes it and I kindred spirits). Assuming that it has little or no insulating capabilities, it might be good for a removable forge floor. Does anyone have any idea what the water mixture and drying time would be on this stuff and/or anything else about it. It was free to me , so the price was right. Quote Link to comment Share on other sites More sharing options...
Frosty Posted June 29, 2016 Share Posted June 29, 2016 I exercised my Yahoo Fu on the terms, "Cercast HT" and got more info than a non-professional furnace re-builder could want. This hit made my anti malware warn me and download in a "protected" inactive mode. but I looked anyway. Refractory Materials COTS Vendor Survey Appendix B It not only lists Cercast HT but all the other Vesuvious refractory products. The Greencast 94 I have in a pail in the shop and the Kast-O-Lite 97 bubble alumina I'm lusting after currently. Dense refractories have all the insulating properties of limestone IF you're lucky. The Greencast I have is the main reason the portable forge I built won't get hotter than mid orange. I only used it as the flame front but it's too thick and I don't have it backed by a good enough insulator. Cercast HT shows to be a similar product. If you want more data on what you have you'll need to exercise your Google Fu at least a little bit. I thought it was laughable easy to find out more than I wanted to know and I didn't look on the Vesuvious site. They have a vested interest in people using their product correctly so like any other refractory manufacturer I'm SURE they tell you everything you need to know to use it. You gotta look though. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
dimag Posted June 30, 2016 Author Share Posted June 30, 2016 The only casting I have ever done was with fishing lures and on several occasions I cast my fate to the winds. Both procedures garnered mixed results. I saw the NASA website on my first search which seemed to collaborate the chart on the Vesuvious site about it being non insulating but able to withstand some abuse. Neither site told me what to do with it. If they did it was in a language that I don't understand. Shortly after I posted here I added " curing schedule" to my query and got plenty of instructions on how to get the best results with Cercast. Surprisingly when the same query was submitted to the Vesuvious site it came up with 0 results. The floor on my Whisper deluxe is slowly deteriorating and I am hoping to buy some time before have to lay out the cash for a reline. Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 1, 2016 Share Posted July 1, 2016 Gotcha. I'm still swearing at the dense castable refractory liner I bought, I didn't know enough to know how ignorant I was. I had a lousy 1/2" floor in my forge and running both burners wouldn't get it above medium orange and I really REALLY need medium yellow to be happy. Just because it's a castable doesn't mean you need to ram up a cope and drag. You can make a mold or mix it thicker and spread it with a trowel. I've mixed it really thin like thin slip as a kiln wash on Kaowool. I'm not thrilled with the last one. Even with half a bucket left I'm really tempted to buy high alumina kiln shelving as a fire face over kaowool rather than mess with the stuff again. Currently I think the local guys and I are going in on a bag maybe two of "Kast-O-Lite 97" it's a castable "high alumina bubble refractory." The high alumina means HOT borax won't dissolve it and the bubbles are little vacuum filled spheres making it lighter and insulating. Though there is discussion of just how insulating it is or what the heck the thermal transfer charts actually mean and how it relates to us here on Earth. What's under the floor of you Whisper Deluxe? Flame face part of the floor that is, the part in direct contact with the flame. If it's an inch or so of Kaowool or equivalent ceramic blanket then just mix up some of that refractory about tooth paste consistency and spread a THIN layer, say 3/8" max. You have a bunch so if that isn't enough you can redo it easily enough. Let it dry, hanging a light bulb in the forge for the radiant heat speeds things considerably even in high humidity conditions. Once it's DRY fire it up gently for a first time, stop before it hits red heat and let it cool. Next firing take it to bright red and let it cool. After that let it rip she should be good as she'll get. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
dimag Posted July 1, 2016 Author Share Posted July 1, 2016 Not sure what the lining is on the NC forges. It Is board like as apposed to a blanket type material, maybe 1 1/4 thick. An NC Tool reline kit is $140 usd ,so considerably more in cad. It is actually a farrier's forge but I have modified it a little so I can heat longer pieces. I was thinking of casting a thin brick of it and coating it with ITC and see if that works. I could probably scrounge up a soft fire brick or 2 and coat that instead and save myself the hassle. Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 1, 2016 Share Posted July 1, 2016 Casting a high density refractory that thick would last forever but it'd be a terrible heat sink. I think laying 1" of Kaowool and plastering it 1/4" thick with the refractory would do you a whole lot better. Washing it with ITC-100 would help as well. I'm waiting for rigidizer to harden up so I can see how laying the Greencast over Kaowool works. It'll be a couple days before everything is done, dry and cured though. I'll post the results on Iforge though. Even if it works it's looking like a number of guys in the club want to go in on some Kast-O-Lite 97 bubble refractory. Regardless I don't have anything to lose trying the dense stuff in this way. Heck, it might work and give folk more options. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
dimag Posted July 1, 2016 Author Share Posted July 1, 2016 Rigidizer? What is that? Quote Link to comment Share on other sites More sharing options...
MonkeyForge Posted July 1, 2016 Share Posted July 1, 2016 Usually sodium silicate of something similar. It is used to coat the ceramic blanket and does 2 things: 1) Rigidize/harden the blanket so it is a bit more resistant to flame an to some degree poking, 2) inhibit the ceramic fibers that the blanket releases. (a silicate dust which is hazardous to breathe in) Quote Link to comment Share on other sites More sharing options...
dimag Posted July 3, 2016 Author Share Posted July 3, 2016 I wonder if one was to mix in ceramic blanket material with a dense castable would it become less dense and more insulative. I have some of what I think is dura blanket that is damaged. I noticed while searching for forge insulation that one supplier was selling the fiber not in a blanket but loose in plastic bags. Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 3, 2016 Share Posted July 3, 2016 The rigidizer I have available is: colloidal silica suspended in ethylene glycol and water. Unlike sodium silicate this stuff doesn't actually get hard till it's fired then it stiffens up nicely. I've had mixed results using a castable refractory ceramic blanket combination. I've tried stiffening blanket to use as a more durable higher temp fire brick replacement it's pretty questionable right now. I have used shredded blanket as reinforcement in castables and that works well. If you sift castables you'll find bits of ceramic fiber "lint" included in the mix as reinforcement. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Latticino Posted July 3, 2016 Share Posted July 3, 2016 Not to hijack the thread or anything, but one refractory reinforcement that I have used very successfully is stainless steel needles like these: http://www.newhorizonstore.com/Products/129-refractory-stainless-steel-needles.aspx. They work great, but make the refractory a lot more painful to dry mix by hand before you put the water in... As regards mixing blanket and hard refractory, I expect that it will improve the hard refractory" insulating value only a nominal amount. Remember that it isn't the blanket material that is the insulation in a refractory blanket shell, it is the trapped air in the thickness that has the radiant heat reflected away from it by the blanket material. If you fill those hollows with castable you negate that insulation. If you don't fill the hollows, you don't really have a bond, and you might as well go with the conventional layer of refractory inside the blanket. Of course that doesn't mean you can't use the loose refractory blanket material. You just need to cast a refractory cylinder between 1/2" and 3/4" thick (I like rolled vinyl flooring for molds for this - tape it together and you can easily disassemble), place it in your steel shell and pack the annulus with your loose fiber. Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 8, 2016 Share Posted July 8, 2016 Agreed, I wasn't expecting an insulating "brick" anything as good as ceramic blanket. What I need are partition walls and baffles that don't die from repeated thermal cycling like light fire brick and are not the heat sink hard brick is. The plan isn't to soak blanket in slurry it's just to stiffen it and wash it to survive my forge environment. Plans change though and due to the excellent discussions about castable refractories I believe I'll be dropping my attempts to make reasonably durable home brew partitions and baffles. I'll be buying Kast-O-Lite 30 and just casting what I need, I can afford it and it's well within acceptable performance specs for my purposes. The first cylindrical forge I made I used 2 sizes of sonotube and packed the 3/4" annulus with refractory. Once cured I wrapped it with Kaowool and used news paper and tape like a ring compressor to slip both into the forge shell. I like the idea of using vinyl flooring for mold material, wish I'd thought of it. You HAND mix the SS needles in the refractory Are YOU DAFT MAN?! Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Latticino Posted July 8, 2016 Share Posted July 8, 2016 19 minutes ago, Frosty said: You HAND mix the SS needles in the refractory Are YOU DAFT MAN?! Yes, I still have nightmares about that hand mixing. I did it dry, or course, and had heavy leather gloves, but it was still like wrestling with a nettle bush. Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 8, 2016 Share Posted July 8, 2016 You DO know the good lord gave us great big brains and thumbs so we could invent tools and NOT damage ourselves needlessly right? I talked to folk in ceramics shops back when I was trying to come up with a forge liner and there were still shops around who made their own kilns, etc. I shuddered at the thought of how they mixed SS needles, I picked up a few and poked holes in my fingers, mix by hand? SHEESH! Have you ever split soil samples? The lab needs a representative sample for any tests to mean anything so we'd have to reduce a loader or back hoe bucket full to a 40-70lb sample and bag it but without separating the material. The way you do this is by throwing random shovel fulls from the "center" of the pile on a tarp. Then you roll the material back and forth together in the tarp, sort of like the old shoe shine motion. Fold, roll a couple few times, unfold and refold at 90* roll and repeat a few times. Once mixed you eyeball center of the pile and slip the shovel handle under the tarp then lift it by the shovel handle, splitting the pile. discard half and repeat till the sample is the right size and using the tarp pour it in the sample bag. How's THAT apply to mixing ss needles in refractory? Spread the refractory on the tarp and spread the needles on the refractory, fold and roll, rotate 90* fold and roll, repeat. Mixing on a tarp is more effective than stirring and at least as effective as a proper mixer. The possible problem I see here is will needles get stuck in the tarp and be separated from the mix? (Gradation) This doesn't work unless it's a flexible surface like a tarp. the next best bet would be a cement mixer or similar purpose built device. Who would've thought working for the State soils lab and as a driller would have uses later in life? You BET I know how to take a representative sample. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Kozzy Posted July 8, 2016 Share Posted July 8, 2016 2 hours ago, Frosty said: Agreed, I wasn't expecting an insulating "brick" anything as good as ceramic blanket. What I need are partition walls and baffles that don't die from repeated thermal cycling like light fire brick and are not the heat sink hard brick is. I've never played with these refractories but was pondering---what if you (not even sure it's possible) used a significant amount of vermiculite in the admix? Vermiculite seems to, in theory, be able to take the temperatures and might give a hybrid level between the soft insulating and hard non-insulating level of coating. Mainly I was wondering if something like this could be used as the base layer and be topped with a layer of the pure refractory. As I said, I've never mixed or worked with these refractories. I've done something similar to make small pieces of lightweight concrete but the notion might be idiotic with the refractory material. In my case, I'm thinking about a forge hearth that is both reasonably insulating and has the benefits of a good refractory on top. Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 9, 2016 Share Posted July 9, 2016 Well, I just looked up what vermiculite is and it's aluminum silicate clay similar to mica or maybe a form of mica. and used for insulation and it's fire resistance. I was thinking Perlite was puffed mica and it turns out to be a form of heat puffed obsidian. Had both of those wrong didn't I? I didn't see a reference to melting temp for vermiculite but I don't have time to dig tonight. As little as I actually know about the stuff it might work, I don't know. Darn, learned something AGAIN! Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
dimag Posted July 9, 2016 Author Share Posted July 9, 2016 Vermiculite melting temp - 1330 C. 2426 F. Perlite-1260 C. 2300 F Quote Link to comment Share on other sites More sharing options...
Kozzy Posted July 9, 2016 Share Posted July 9, 2016 8 hours ago, dimag said: Vermiculite melting temp - 1330 C. 2426 F. Perlite-1260 C. 2300 F In my initial reading, I ran across a reference that pearlite starts to break down at a lower temp than that--can't remember the details though and i'm too lazy to look it back up. In the same search day I also ran across a passing reference to vermiculite being used in refractory mixes...but that was a one-liner without details. One other issue with the wild notion of a mix---the refractories only partially "cure" at room temperatures. I'm not sure you could get enough heat into a scabbed insulating version to get a decent heat cure, especially of it was topped with an inch or two of unadulterated refractory. One of these decades, I'll get around to experimenting with the idea Quote Link to comment Share on other sites More sharing options...
SLAG Posted July 9, 2016 Share Posted July 9, 2016 Have you tried heating and then microwaving the mix? Just a thought. SLAG. Quote Link to comment Share on other sites More sharing options...
Steamboat Posted August 26, 2016 Share Posted August 26, 2016 On 7/3/2016 at 3:06 PM, Frosty said: I have used shredded blanket as reinforcement in castables and that works well. If you sift castables you'll find bits of ceramic fiber "lint" included in the mix as reinforcement. Frosty The Lucky. Frosty, did you happen to test the "lint" (good term for the fibers) to see if it was actually ceramic fiber? The reason I'm asking is that a while back I separated out some lint/fibers from a castable refractory dry mix and found that I could melt the fibers with an ordinary electric soldering iron. I've since heard that sometimes a low-melt fiber such as polypropylene may be added to castable refractories, which may provide some benefits during the intitial dry-out/heating schedule through enhanced permeability. A quick online search brought up a fair number of references to the use of polypropylene in castable refractories, although I have not had time to have a close look at those sources. Steamboat Quote Link to comment Share on other sites More sharing options...
Frosty Posted August 27, 2016 Share Posted August 27, 2016 Good question Steamboat, no I didn't. So much for my thoughts about the lint stuff in commercial castable refractories. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Steamboat Posted August 28, 2016 Share Posted August 28, 2016 I may call a couple of refractory manufacturers next week and see what they can tell me about any fibers that they might be including in their mixes. If I hear anything interesting, I'll post it on IFI. Steamboat Quote Link to comment Share on other sites More sharing options...
Frosty Posted August 28, 2016 Share Posted August 28, 2016 Good deal, I'm always looking for useful or interesting info. Know any good stories? Tall tales are good. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Steamboat Posted August 28, 2016 Share Posted August 28, 2016 I might allow a few stories...mostly true...to leak out from time to time. Steamboat Quote Link to comment Share on other sites More sharing options...
Frosty Posted August 28, 2016 Share Posted August 28, 2016 I might mostly . . . believe them if they don't leak out on my shoes. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
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