EAlger Posted November 12, 2016 Share Posted November 12, 2016 My forge build will be used to heat treat tool steel for wood turning tools. The forge will be about 125 cu-in heated with a Frosty 1/2" T-Burner. Insulated using 2 layers of 1" Kaowool and rigidized. The kaowool will be treated with Plistex. I suppose the use of a floor would be well. My reading in this forum gives info for High Alumina Shelves. For my limited use of the forge, I'm open to alternative materials? 1, Mullite Shelf material? Quote Link to comment Share on other sites More sharing options...
Frosty Posted November 12, 2016 Share Posted November 12, 2016 I"m not familiar with Mullite so I looked it up. I can't say from the formula. it's listed as porcelianite in a number of descriptions. I know flux can be hard on kaolin clay "porcelain" but there are any number of those too. I just can't say, I guess it'd depend on whether the balance between Al and Si is resistant to hot flux. I do know that high alumina kiln shelf is resistant to flux and tough as nails. You shouldn't have any trouble getting either cut at a tile shop for a couple bucks. I know kiln shelf is supposed to "cut" like glass or tile by scribing and snapping but I've never done it. Your forge sounds like a good design. Please post pics when you get it fired up. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
EAlger Posted November 12, 2016 Author Share Posted November 12, 2016 Thanks Frosty for replying. My forge is going to have limited use. I didn't think far enough ahead about the floor. What I read in this forum about the use of floors seemed pretty casual so I didn't think too much about it. My Bad... Even if I managed to get a piece of high alumina shelf from the internet, I'd have to travel 60 miles to Denver to get it cut. I need an alternative solution that might last the couple of dozen firings of some small pieces of tool steel. Ed... Quote Link to comment Share on other sites More sharing options...
MonkeyForge Posted November 12, 2016 Share Posted November 12, 2016 Maybe look for a pottery supply place nearby. If your forge is small you can get leftovers for cheap. (I could but on the other side of the pool) They can be cut with a masonary saw or as I did by scoring with the diamond wheel on the Dremel and then gently tapping a cold chisel along the score line. also keep in mind if your forge is going to be small, get the thinner shelf so it takes up less of your chamber's volume. Quote Link to comment Share on other sites More sharing options...
EAlger Posted November 12, 2016 Author Share Posted November 12, 2016 MF, no pottery supplies nearby us. Must go 60 miles to Denver. Masonary blades and diamond wheels for the Dremel I have. At 81 years, my nerves aren't what they use to be so cutting with a chisel may be fun. I can find kiln shelves on the internet OK. The problem is to the shelf cost there's a $ huge packing and shipping fee! Quote Link to comment Share on other sites More sharing options...
Latticino Posted November 12, 2016 Share Posted November 12, 2016 For a limited use forge I would recommend a light casting of either 1/2" thick Mizzou or a high alumina refractory like Greencast 97 if you can't source either high alumina kiln shelves or high alumina split hard firebrick. Quote Link to comment Share on other sites More sharing options...
EAlger Posted November 12, 2016 Author Share Posted November 12, 2016 Latticino, thanks for the info. HighTempTools.com has both Missou and Kast-O-Lite 26 and 30 in quantities I could use. Not sure that these materials might also be used to cast a couple of bricks/blocks to shield the forge openings? Ed... Quote Link to comment Share on other sites More sharing options...
Latticino Posted November 12, 2016 Share Posted November 12, 2016 Kast-o-lite is an insulating refractory that would be better for making doors out of. Check the thermal transmission value. I don't remember, but I believe that last time I checked it transmits almost 4 times as much heat as an equivalent thickness of refractory blanket. Not as big a deal for the doors as there you are mostly trying to contain the IR, but I would still plan on at least 2" thickness of casting. Of course, you are planning on making a rather small forge, so should be careful regarding adding too much thermal mass. I've never personally used it for a forge floor, so can't recommend specifically, but it certainly will be better than just the blanket insulation.. Mizzou and Greencast are "hard" refractories (like hard brick) that would do better for flooring reinforcement IMHO. For that a thin casting will work well (1/2 - 3/4"). You should also consider casting some hard refractory opposite your burner port, if that isn't the floor already. Good luck and remember to post pictures when you get it up and running. Quote Link to comment Share on other sites More sharing options...
EAlger Posted November 13, 2016 Author Share Posted November 13, 2016 Latticino, thank you. The floor would be opposite the burner port as I have it set about 20 deg off vertical with some adjustment available. HighTempTools can provide 5 pound bags each Kast-o-lite and Mizzou so I may do that. Ed... Quote Link to comment Share on other sites More sharing options...
wpearson Posted November 13, 2016 Share Posted November 13, 2016 8 hours ago, EAlger said: I need an alternative solution that might last the couple of dozen firings of some small pieces of tool steel. Ed... Plistex should last that long. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted November 13, 2016 Share Posted November 13, 2016 I have not seen any answers that trouble me, even the Plistex. Quote Link to comment Share on other sites More sharing options...
timgunn1962 Posted November 13, 2016 Share Posted November 13, 2016 If you are primarily looking to Heat-Treat tool steel, many of the "normal" difficulties might just go away. The difficult thing tends to be getting a combination of flux-resistance, resistance to physical damage and adequate insulation at the high temperatures needed for welding (2300 degF plus). Often, a composite structure is used to provide the overall combination of properties needed: a kiln-shelf floor, resistant to flux and physical damage, over Kaowool blanket for insulation, for example. Your temperatures are likely to be much lower (Austenitizing temperature is around 1500 degF for most Carbon steels) and flux will likely not be involved. If you are not going to be heaving big, heavy lumps of hot stuff into and out of the forge every minute or two, there is likely to be less need for resistance to physical damage. Plistix over rigidized blanket may well be perfectly adequate for your application. I have actually used unrigidized, uncoated Kaowool in forges without any major issues. The health hazard is not to be ignored, but trying to be realistic I use a forge relatively infrequently and the measures I take to avoid the risk of inhaling Carbon Monoxide also contribute towards reducing the risk of inhaling ceramic fibres. As potential risks to my future health go, Ceramic Fibre seems to be a very long way down the list. To be honest, the biggest difficulty I think you'll face is getting the temperature low enough and even enough with a chokeless burner. You have said you'll be using tool steel, but that covers a range of alloys. Many of them need to be held at Austenitizing temperature for several minutes and this is usually the difficult bit. Quote Link to comment Share on other sites More sharing options...
EAlger Posted November 13, 2016 Author Share Posted November 13, 2016 Thank you all who have written informed and interesting things. I'm at the entry point of my learning curve in this subject. All ideas and suggestions are welcomed. I've always bought the best tools I could afford and taught my boys to do the same. I made a couple of uninformed starts in this project. However, finding this forum totally changed my thoughts about the building process. I mentioned that I felt that my forge use would be limited but if any of my past experiences prove helpful, I must build something that would prove worthy. When I built my first canoe, I bought the tools. Now I'm on my 4th. Who needs 4 canoes? I'm most grateful for the knowledge I've assimilated so far. Keep your thoughts coming. I'll post pictures when I'm finished. Ed... Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted November 13, 2016 Share Posted November 13, 2016 Tim's post changed my mind about what size forge you would be best suited with. I had thought that a coffee-can forge would best suit your stated need, but now I'm thinking helium balloon refill cylinder size (same size as Freon cylinders) would serve better; keeping forge temperatures down low enough isn't a usual problem on this list Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted November 14, 2016 Share Posted November 14, 2016 Most anybody doing tile work in your area would have a diamond saw that will cut kiln shelf. Fort Collins is not a small town---my daughter recently graduated from the University there and I got to visit. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted November 14, 2016 Share Posted November 14, 2016 Cutting kiln shelf is easy. ink mark the cut line, and use a cutoff disk in an angle sander, saw, or rotary tool to lightly score a line all the way around the shelf; then, repeat, going a LITTLE lower into the cut, when the shelf cracks in two, the break is forced to follow the scored line. Quote Link to comment Share on other sites More sharing options...
EAlger Posted November 15, 2016 Author Share Posted November 15, 2016 Thanks all for the suggestions on cutting a kiln shelf. I wouldn't have a problem cutting, I think. My problem was the $$ getting the shelf material. One internet pottery supplier wanted $168.50 to handle, crate, and ship a $45 shelf... That's probably an extreme. To go to Denver is a 140 mile round trip in traffic and I'm not up to that anymore. When the Mizzou arrives, I'll try and cast a floor and see how that works. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted November 15, 2016 Share Posted November 15, 2016 None of the 21 places listed in the Fort Collins yellow pages under pottery and pottery stores would sell you a shelf or even piggyback your order onto their next one? Quote Link to comment Share on other sites More sharing options...
EAlger Posted November 15, 2016 Author Share Posted November 15, 2016 I didn't call all the listed stores in Fort Collins, but the many I did review held pottery making instruction classes in homes and barns. Perhaps I wasn't diligent enough in this regard. Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted November 15, 2016 Share Posted November 15, 2016 FWIW, I got some broken pieces of kiln shelf from a pottery store that gives classes and sells knick knacks - as opposed to a pottery supply store. I gave the lady 10 bucks for 3 pieces that were big enough for me to cut to the size I wanted. It's worth a quick phone call or stop if you're in the area. The worst thing that can happen is they tell you no and you wasted a few minutes of time. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted November 19, 2016 Share Posted November 19, 2016 So, "make lemonade." Use an exceptionable high alumina semi-insulating castable refractory, like Kast-O-lite 30 to form a good enough floor, and move on. Quote Link to comment Share on other sites More sharing options...
EAlger Posted November 19, 2016 Author Share Posted November 19, 2016 My Mizzou and Cast-o-lite 30 and 26 came in the mail and I'm waiting for the temperature to get above 30. My plan is to cast a Mizzou floor and cast a couple of front bricks. I saw your append, Mikey, about your thought of using layers of Cast-o-lite 30 and 20 for a brick. Need to do some welding on the legs. The snow came in and interrupted my progress. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted November 20, 2016 Share Posted November 20, 2016 You could always use some of the time building a wooden form for the casting(s)...after all, the forge is going to make your art studio toasty warm; a nice feeling on those cold winter days Quote Link to comment Share on other sites More sharing options...
Frosty Posted November 20, 2016 Share Posted November 20, 2016 Minor tip here. A while back someone who's identity slips my dented mind suggested using scrap linoleum for mold forms. Refractories and such won't stick so it releases easily without having to oil or wax the mold. The local outfit who installs flooring usually has a dumpster full of scrap linoleum and other stuff. In the day I never bought carpet to glue to the inside of my pickup cab. I came home with a roll of scrap large enough to carpet a decent closet. It is of course take or leave it but orange shag just was soooo coool in the '70s. Anyway, scrap linoleum is THE stuff to make forms from, or so I'm told. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
EAlger Posted November 20, 2016 Author Share Posted November 20, 2016 Frosty, I have some linoleum; might give that some thought. Mikey, the floor is probably not a problem. I'm planning on trying to cast front bricks, the lower one would have a 3" W x 2" D notch in a 4-1/4 x 3 x 8 brick. I've lots of material to make forms. The upper brick; 4-1/4 x 3 x 8. (Using your Kast-o-Lite layer idea. As an outside layer, I could add some Perlite mixed with Sodium Silicate I have.) Does the face of Kast-o-Lite 30 cast brick need a wash? Ed... Quote Link to comment Share on other sites More sharing options...
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