Gustav

Found Superwool (25x610x7320mm) which is rated for 1200C (2192F) continuous, 1300C (2372F) max. Is this enough? It will won't be exposed to direct flames, instead deep inside of the refractory. The size is more than I need but I'll sell what I don't use up.

Alright, the search continues.

Some people just have to spread their misery to others. Regarding the forge, I have found some Superwool online that I'll be able to use. There are some refractories I've found that can handle the temperatures, but I'm not sure about the contents. For instance, we have Höganäs Cast CC 50 (I hope your browser can translate if you want to take a look). It's contents are e.g.: 48% Al2O3, 43% SiO2, 6.2% CaO, 1,3% Fe2O3 Anything of this which is too much or too little? I don't believe this one in particular is the best for forges, but it's one I found at least. They make other types with "high alumina" but I couldn't find them available anywhere. This company lists lots of different types of cement/refractory with their contents. Roughly speaking, what should I aim for in terms of the percentages of Al2O3, SiO2, CaO, Fe2O3, etc? If I know this, I could know if some random bag of refractory is suitable.

@Mikey98118 Alright, I'll give it some more thought! Just a small update on the progress: The propane tank has been emptied, filled with water, and drained (each with 24 h between). I've cut away the bottom "ring" but have yet to slice the main tank up in any way. Next up: paint stripper and cleanup

Mikey: 1. I'll change length of the burner to either 150 mm or 175 mm! 3. I'm not sure I can picture the process of casting without cutting anything. I'll probably end up cutting it in 2-3 pieces. 4. I'll look for high alumnia refractory! I saw one with it as "main binding component", and it was rated for 1300 °C (2372 °F). However, I feel safer with 1400 or 1500 °C (2552 or 2732 F).

Thanks for the answers! I'll definitely reconsider the size of the burner. I might go for 175 mm or 150 mm in length instead. And yes, it is indeed going to be a forced air burner. And regarding the refractory; Kast-o-lite is unfortunately not available in Sweden, but it is good to know some key words to look for (high alumnia, calcite). If any mod/admin sees this, please remove THIS post we are in right now. This post is actually a duplicate of the original post. It appeared when I tried to edit the OG post, so let's continue this conversation over there:

Hi everyone! I've recently started designing a new forge I'm going to build out of a 13.5 kg propane tank. It will only be used for knife forging, so it does not have to be big. I'm writing this basically to get your opinion on what dimensions to change, or if complete aspects of the design need to be changed. I also have tons of questions. Here's where I am at now: These dimensions are a mixture of what I could find online and of what may be suitable for me. For instance, I found some 50x50mm square pipe laying around, so it would be nice to use it for the ribbon burner if it isn't a stupid idea to have so "small". This also means that I can't properly fit a 2" pipe to the burner, but 1.5" should work as well? Here are some questions regarding the dimensions: 1. The inner diameter of the forge (145 mm) feels fine to me, since I will not forge anything that requires a larger volume. However, is it better to change it to improve things like circulation? 2. The thinnest parts of the refractory (15 mm and 20 mm) is something I made up on the go. What is the recommended minimum thickness? 3. I plan on cutting the tank into three pieces and casting them separately, but what about not cutting off the back and casting it as a whole? Anyone who have tried that? 4. I currently plan on having 2 layers of ceramic wool in the middle section. Is this overkill? Only having one lets me have thicker refractory. 5. Some people cast room for firebricks, some don't. Is there really a big need for this, since the forge will be cast in refractory either way? If people use their forges daily, I could understand, but I will definitely not use it that much. For some reason, I wouldn't even mind having a circular inside of the forge instead of flat to enable better circulation (OCD reasons lol). Ribbon burner: 6. I've tried to grasp a general rule on [number of holes] * [hole diameter] with respect to [intake pipe area]. If I go for 1.5" or 2" pipe, what's the recommended amount of holes if they are each 8 mm in diameter? I've seen one youtuber "fill up" the pipe with straws to see how many are needed. Is this a good rule of thumb? 7. The spacing between the holes (15 mm center to center) may be too tight, what's the minimum recommended distance (hole to hole, hole to wall)? Gas piping: 8. Does the gas system have to be designed differently if the burner pipe is either 1.5" or 2" pipe (obviously not talking about the final adapter)? Or will 2" pipe work fine for the entirety of the piping? What about the propane piping, should it be 1/2", 1/4"? 9. Would a 29 mbar regulator from the propane tank suffice? 10. I have a 230V blower that I've used in my coal forge, and I'd like to use it in this forge to avoid buying a new one. There is no "cubic feet per minute" rating of the sort, but I recorded a video trying to show the airflow. Do you think it's powerful enough? 11. The end of the propane piping that "sticks into" the "air pipe"; what should it look like? No MIG-tips as I understand it? As of now, I am struggling to find suitable refractory and ceramic wool. If anyone in Sweden reads this and knows a good supplier, please let me know! I've seen someone use Höganäs Low-Cement but I can't find it anywhere. Also, I have yet to design the front and back "porches" to the openings, a way to fasten the burner, legs to the forge etc. There are more questions that will arise but I'll leave it here for now. Thoughts?

80crv2, and cocobolo and brass.

JHCC, it's the third largest province in Sweden (out of 25) at 29 330 km^2 (~11324 mi^2) but compared to most states in the US it's quite small, yes. Everything is bigger in the US, right? And Frosty, thanks for letting me know!

George N.M. Wow, that's interesting. I also have ancestors that immigrated (also from Småland) around the time your grandfather did. I might have heard about a Månsson sometime, but Småland is very big. It's a big chunk of southern Sweden. Buzzkill Okay, it might be the sharpening angle. I thought "oh this is a chopper so it must have a really high angle" but I might have gone too far. I will keep that in mind!

Buzzkill - Ok, what angle did you aim for?

Buzzkill - It stays sharp, but that's good to know. I chopped a lot of wood when trying to get it in place for the picture and it didn't lose any sharpness. I just couldn't bring it to shaving when I sharpened it in the first place.

Thomas Powers - Forgot about that. 80CrV2 quenched in canola oil and tempered at 200°C 1h x 2

Hey guys! This is my first "weapon", a 35 cm long bowie. It's also the biggest knife I've made so far. The blade has a warp and the "brute de forge" might have been too much. I could probably also have ground and polished the guard and pommel a bit. They were cast in a metal I don't know the name of in English, but it's 85% Cu, 5% Sn, 5% Zn, 5% Pb. It also doesn't really shave, which is a bit lame. I went from 300-600-1200 on diamond stones and finished on a strop with green polishing paste. Go finer? Make sure you have a small angle? What do you think?

Thanks guys! You might have noticed it too, but my main problems are 1. The brass spacers between the ziricote and bocote don't line up on each side of the tang. And 2. The brass could've been finished better Regarding the "stubbyness"; no offence taken!