(M) Posted January 25, 2018 Share Posted January 25, 2018 Hello all, looking to build a propane forge. I have my 3/4" t-burner built, and im confused as to the order of how to proceed in construction. This is how i understand it. I have not decided on a shell yet, but somethinf that will give me a final volume of 350 cubic" for knife and machete-making as well as for general forging. Step 1: cut kaowool( 2 1" sheets) Step 2: dry-fit it in the forge body and adjust as necessary Step 3: remove kaowool, spray on rigidizer Step 4: let dry? Step 5: trowel on castable refractory? Step 6: apply thin layer of itc100 Step 7 allow time to dry Step 7 fire multiple times to solidify? Step 8 add kiln shelf as work rest Not looking for a Lamborghini forge but something economical to build and efficient on propane in the long run. I do need it to get to welding temps for working with tough steels like HSS and so i can get to forge welding and maybe damascus one day. Please enlighten me. I have looked through forges 101 etc so i somewhat understand the underlying concepts but i am confused as to the construction process. Thanks in advance Quote Link to comment Share on other sites More sharing options...
Frosty Posted January 25, 2018 Share Posted January 25, 2018 You have it about right as described. I recommend you use a kiln wash other than ITC-100 it's way too expensive and not as effective as products made for forges and similar furnaces. Wayne Coe carries Plistex and Metricote in smaller quantities for reasonable $. No good reason to buy a quart if a pint will do the job, he'll help you determine how much you need. He's good people. His site has proven forge plans and he sells most anything you'll need in reasonable quantities. When I buy Kast-O-Lite 30 it comes in 55 lb. sacks or not at all. Guys in the local club usually split a bag. HSS is problematical to forge especially forge welding. O1 is a better choice till you get experience. Iforge has a pretty huge knife and blade community with thousands of posts in their sections. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
(M) Posted January 25, 2018 Author Share Posted January 25, 2018 Thanks! I just talk about the hss cause i got a whole bunch of horizontal mill cutters from my school machine shop so i wanna use them some day. I plan to head to the specialty metal store to pick up some of whatever strikes my fancy of the tool steels they have. I have already made one little knife out of a pipe wrench (more grind than forge) , and attempted to beat around some leaf springs. I'm lucky to have a specialty metal store nearby! For the castable refractory i think i can buy some "imperial" brand stuff in reasonable quantities. Has anyone heard of it? I also have a well supplied pottery supply store nearby so i'll pick up my rigidizer and kaowool there. They also have kaolin clay and kiln washes so ill talk to them. I would buy from w. Coe, but i dont like shipping stuff if i can buy it in person. I have a reusable 3M respirator with particulate cartridges installed. Is that sufficient for kaowool work? Side note-- is that also sufficient for bench grinder work? I have seen a youtuber wear a full face respirator with a belt mounted cartridge for grinding, is that overkill? Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted January 25, 2018 Share Posted January 25, 2018 Step 4: You don't have to let it air dry. You can heat it to drive the water off and set the rigidizer in the blanket without damaging anything. This will also help create a surface on the blanket that won't absorb as much moisture from your castable refractory, but it's not a bad idea to spritz a little water on the blanket before applying the refractory. Step 5: After applying the refractory allow it to cure "naturally" for a day or two. If you are in a cold and/or humid region you may want to use a light bulb or some other means of low heat to speed the process. You do not want to get above the boiling point of water for this though. The goal is to drive the remaining moisture out without creating steam, which can cause problems with your lining. After that use a few short firing sessions with cooldowns in between to finish drying and curing the refractory. Use successively longer and hotter sessions until you can reach full forge temperature. You want to do this before applying the ITC (or comparable product). Step 7: Allow it to dry and then fire it. You should be good to go then. Let us know how it works out. Quote Link to comment Share on other sites More sharing options...
(M) Posted January 25, 2018 Author Share Posted January 25, 2018 How thick of a layer of castable do i need? What else can i do to prevent kaowool fibres from aerosoling? Quote Link to comment Share on other sites More sharing options...
coops1911 Posted January 25, 2018 Share Posted January 25, 2018 most people seem to go with 1/2 inch of kast o lite. What i did regarding the kaowool was to make sure it is ridgidized first and that there were no exposed fibre ( everything under Kast o lite) and make sure there is no where the work is going to be banging fibers loose. Quote Link to comment Share on other sites More sharing options...
(M) Posted January 25, 2018 Author Share Posted January 25, 2018 Isn't it hard to trowel the refractory onto a flexible blanket? Quote Link to comment Share on other sites More sharing options...
Binesman Posted January 25, 2018 Share Posted January 25, 2018 1. Measure. 2. Cut kaowool, form fit to shell 2 layers of 1" thick 3. Remove kaowool spritz lightly with water. Then spray down with ridgidizer. Let sit for about 4 hours to soak in. 4. Put in first layer of kaowool and fire forge to dry and set the ridgidizer (i usualy bring mine up to 1200 or so temp and hold it there for at least 5 minutes. When you are done the kaowool should be more solid and springy(its still a blanket but you should feel a very definable differance) if not spray down with ridgidizer again (while still in forge) let it soak in and fire again. 5. Repeat step 4 for second layer of kaowool. 6. Trowel in refractory kastolite 300 is the generaly recomended here. 7. Let refractory cure (i usualy give it a solid 24 hours 48 is more than enough) 8. Fire the forge multiple times slowly bringing it to higher temp each time. To drive off any remaining moisture. 9. Coat with kiln wash matrikote is the generaly recomended here. 10. Repeat 7 and 8. Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted January 25, 2018 Share Posted January 25, 2018 11 minutes ago, (M) said: Isn't it hard to trowel the refractory onto a flexible blanket? The blanket is significantly less flexible after being fired with the rigidizer soaked in. Quote Link to comment Share on other sites More sharing options...
(M) Posted January 25, 2018 Author Share Posted January 25, 2018 Is it ok to let it air dry? Im afraid of sending out too many fibres in the firing process Quote Link to comment Share on other sites More sharing options...
Binesman Posted January 25, 2018 Share Posted January 25, 2018 No it has to be fired this is what allows the silica of the ridgidizer to bond to the blanket Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted January 25, 2018 Share Posted January 25, 2018 As long as the blanket is well covered it won't release any fibers when fired. You did add a little food coloring to the ridgidizer to show coverage, didn't you. Quote Link to comment Share on other sites More sharing options...
(M) Posted January 25, 2018 Author Share Posted January 25, 2018 Havent done anything yet Quote Link to comment Share on other sites More sharing options...
coops1911 Posted January 26, 2018 Share Posted January 26, 2018 1 hour ago, (M) said: Is it ok to let it air dry? Im afraid of sending out too many fibres in the firing process just wear a mask while firing the ridgidizer its not a lengthy process. Quote Link to comment Share on other sites More sharing options...
WayneCoeArtistBlacksmith Posted January 26, 2018 Share Posted January 26, 2018 Check out the Build a Gas Forge on my web-site. You can find my url and other contact info on my Profiles page. Let me know how I can help you. Wayne Quote Link to comment Share on other sites More sharing options...
Frosty Posted January 26, 2018 Share Posted January 26, 2018 Wow, drive to Anchorage and the thread goes crazy! If you have a bunch of HSS cutters have at it. I was thinking you were going to buy some, I have a couple coffee cans of dull and broken drill bits from the old heavy duty shop. It was less expensive for them to just toss and replace a bit than the time to sharpen one. I've only tried welding a drill bit billet once and it was an epic fail. Let me know how you do. Don't get too carried away worrying about a brief exposure to ceramic blanket fibers it takes time and exposure to do you harm. Avoid breathing it but don't panic. If you wet the blanket with tap water before cutting and handling it it won't shed broken fibers into the air. Rinse them off the floor maybe wax it to encapsulate fibers and you'll be okay. A typical propane forge doesn't get hot enough long enough to vitrify kaolin clay so it will continue to rub off till it's gone. If you want to make your ow kiln wash Maarten has done some experimenting with Bentonite clay and Zircopax. Bentonite fires fast and strong though I do't know if it vitrifies in the typical gas forge. Zircopax is a brand name of zirconium silicate which is sort of magic stuff in a fire. It's just a tiny bit softer than diamond, has a vitrifying temp around 6,000f and has this marvelous property of absorbing and reradiating IR prodigiously. It's not an IR reflector it's a re radiator, yeah it's actually a difference. The only thing I see in all these posts that's not right is how Kast-O-Lite cures. It doesn't "dry" it sets and cures like Portland cement concrete. It absorb water on a molecular level and gets different. Like concrete you have a working time, then it sets and wants a good day at 70 f - 80 f at 100% humidity to cure to full hardness. Then it wants to be heat cured. Basically keep it warm and damp for a day before firing it for the first time. First firing bring it to a few hundred degrees for a little while, you COULD use a kitchen oven but it's not that critical. Second firing to red heat let it cool and it's ready for action. You don't HAVE TO cure it according to directions, the stuff is darned forgiving and tough as nails at 3,000 f. However, I read the directions. I don't know anything about the refractory you're asking about. How's it compare to Kast-O-Lite 30? The main things you need are: high alumina and a max working temp of 3,000 f. The high alumina won't be eroded by welding fluxes and 3,000 f. is a little hotter than our forges usually get. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
(M) Posted January 26, 2018 Author Share Posted January 26, 2018 Thanks everyone! I now know exactly what i need to do. The refractory i spoke of is only rated to 2200 f. I'll talk to the people at the pottery store, they might have something i can use. They also sell alumina so maybe i could add it? I had a bit of a crazy idea for some hss damascus, if i was to take some hardfacing rods and fill the flutes of the drill bits and i have with the bead till it's a solid cylinder, then heat it up and twist it and then fold it a few times. We'll see! Heat treating would certainly be interesting Quote Link to comment Share on other sites More sharing options...
(M) Posted January 29, 2018 Author Share Posted January 29, 2018 I finally completed and tested my burner for this forge. 3/4" t-burner. I couldnt find a 1"x3/4" Tee so i used a 1" tee with a 3/4" reducer. My flare is a 3/4" coupler. It runs, but there is some turbulence and flame swirls back to the tee where i can see it. Clearly this is a problem. It also has a very motorboat soundingness untill the amount of gas hits a threshold, where it roars like a jet. I know this design should be able to sustain a flame all the way up the psi range so there are clearly some issues. Any help is appreciated. 20180128_180944_001.mp4 Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted January 29, 2018 Share Posted January 29, 2018 The chirping "motorboat" sound you heard is the result of the flame burning inside the tube rather than at the end. This is fairly normal at low pressure. At the end of the video you got the flame pushed out to where it should be. Most of the T burners I built sputter like that until somewhere between 2 and 5 psi, but it's not the same for all of them and your experience may be different. If you have to get over 10 psi or something like that to keep the flame at the flare end of the burner then you probably have some issues that need to be addressed. I know it doesn't seem like much of a change to use a 1 inch tee with a reducer bushing, but fairly small changes in design can cause significant differences in performance What you describe may be ok, but it also may be introducing enough turbulence and/or friction to affect the performance of the burner. Quote Link to comment Share on other sites More sharing options...
(M) Posted January 29, 2018 Author Share Posted January 29, 2018 Ok. Yeah with the flame in the tube it made it so hot i could see the tempering colours on the tube. Thanks. I also have no idea the psi cause im just using a needle valve from a prpane stove, not a regulator. Quote Link to comment Share on other sites More sharing options...
Frosty Posted January 30, 2018 Share Posted January 30, 2018 A 1" T with a reducer doesn't work well if at all, the reducer causes turbulence that reduces induction. Shop for plumbing at a proper plumbing supply NOT a big box store. 1" x 3/4" Ts are in common use but take up too much space for deand for a big box to carry. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
(M) Posted January 30, 2018 Author Share Posted January 30, 2018 Oh bummer. Alright i'll have to head to the plumbing store Quote Link to comment Share on other sites More sharing options...
(M) Posted March 14, 2018 Author Share Posted March 14, 2018 Got the part, testing it in a few hours. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted March 14, 2018 Share Posted March 14, 2018 Where are you located? You may be surprised how many members are near you and can give in person advice. https://www.iforgeiron.com/topic/53873-read-this-first/ Quote Link to comment Share on other sites More sharing options...
(M) Posted March 17, 2018 Author Share Posted March 17, 2018 Tested it, still failed miserably, so i bought a regulator, still failed, but less miserably. Was using a coupler for the flare, tried a 3/4" reducer and rested a 1 1/2 pipe nipple on it and got it to finally hold a flame. It still wants to either burn in the tube or blow itself out. Is this critical? Or can i just use it in the forge and see how it goes? Im planning on trying a 1" gas pipe for a flare next, maybe forge it to make it more flarey Quote Link to comment Share on other sites More sharing options...
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