Latticino

I like 3/4" of refractory because of the ease of casting that thickness, not necessarily for it's structural properties. Since Kastolite 30 is also a fairly good insulator, you don't lose as much insulation value in your forge lining as you might if it were, say, Mizzou. Also, depending on what you are forging, a little thermal mass can be helpful.

Good point. I think it is worth noting that many bladesmiths (myself included) typically forge and grind down bevels quite a bit further than 1/4" thickness before quenching. I haven't done specific experimentation like Dr. Thomas, but strongly suspect that this thinner stock allows even slower oils (like heated canola) to accelerate the quench speed. Possibly not up to Parks 50 (which I now use for steels that need a fast quench), but to the acceptable levels Buzzkill mentions above. I believe I recall testing 1084 blades that were quenched in heated canola with hardness chisels and seen Rc at 60, but it was a while ago and I'm not completely sure. I certainly would feel comfortable using heated canola for 5160 or 6150 or for work where high hardness is not preferred like axes, hammer heads, hawks, chisels...

Seems pretty counter-productive to me. When you are done you will have a hammer with softened faces from cutting and grinding (not to mention removal of a fair portion of the initial potentially relatively shallow original hard face). I can typically pickup a fully usable 8-12 LB sledge at a garage sale for under $10. It won't be a "collectable" Altha hammer, but neither will yours be after you are done. Heat treating a large hammer head of unknown steel will certainly be a learning experience. Watch out for "auto-tempering" and make sure you get that eye soft afterwards. Arc welding on it will likely create HAZ zones that can spall chips even faster unless you are very familiar with proper pre and post heating. You likely should do a full heat treatment afterwards anyway. If you are trying to make something useful out of this, you might consider revising the faces to something like double diagonal or cross/straight peens. That would be a lot of grinding work, but at the end you will have something that you couldn't just buy off the shelf much cheaper. Personally this one would go in the recycle bin if I owned it.

Maybe true, but on the other hand some strict scientific protocols for experimentation and rigorous testing might have been able to both shortcut the hundreds (or thousands) of years of trial and error to find effective steel heat treatment formula as well as some of the more egregious misinformation regarding heat treatment (urine of a red headed boy, pointing the quench tank in line with the earth's magnetic field...).

Yes this is certainly one of the critical parameters. Great references for this regarding knifemaking can be found on Kevin Cashen's site: https://cashenblades.com/bladesmithing-information/ The TTT diagrams he includes pretty clearly indicate the speed needed in the quench to get "past the nose" to maximize the martensitic transformation that leads to proper high carbon steel hardness.

I have heat treated leaf spring steel with heated canola oil very successfully. 5160 is a deep hardening steel that does not need an extremely fast oil, so heated canola works just fine. I believe that the others you have listed do need a faster quench. You could investigate interrupted quenches for those (quick couple of seconds in water then switch to heated canola). I really haven't done much of that though, so hopefully someone else can advise.

Just one person as far as I know. I found Craig with a simple Google search. He is not on IFI as far as I know. Forge inner dimensions work out to approximately 918 cubic inches. That is a very large forge, especially for a beginner. If it were me I'd cut about 1/3 away and switch it to a (2) burner forge (and fix the front door at the same time. 0.06" walls are around 16 gauge. I'd be very surprised if they were "pure iron", and that gauge won't last too long if exposed to forge heat, so watch the skin temperature - especially at the openings. Forge is only rated for 1202 deg. F? That really isn't nearly high enough. My forge regularly exceeds 2300 deg. F and would barely be idling at 1200. Fortunately a additional layer of 2,600 deg. F rated blanket and a 3/4" thick coating of Kastolite 30 will bring it up to snuff if the burners are adequate. DON'T use mesh to support the "ceiling" of the forge. Put in new liner and rigidize with forge oriented vertically if you can. Cast, don't trowel on, the Kastolite 30 using a removable inner form (cast a full rectangular tube, including the floor, remove fire brick. leave openings for the burners. remove the inner form when the refractory starts to set since it will shrink when drying). Burners on this forge appear to be loose copies of Mikey's linear burner. I'll let him comment on how faithful and potential drawbacks.

JHCC: that is an accurate interpretation of my comment. Now that I see a photo of the specific forge you are purchasing, I see a couple of potential issues that might be worth consideration (none necessarily critical, just potential improvements): Threaded pipe section in the gas connection/air inlet appears to be capable of both metering the air (with the air gate that is shown closed off in the photo), and potentially adjusting the gas orifice outlet location. For NA burners, this orifice location is very important for final tuning of the burner. If I am interpreting the photo correctly, it will be very difficult adjusting this location once all burners are manifolded together. I recommend that, if this adjustment is part of the design, you tune the burner (inside the forge) piped individually so you can make the adjustment before manifolding all three burners. The manifold appears to be piped with tubing that is a bit small. Typically I like to have a manifold with a relatively larger size pipe to allow it to be a balancing plenum (in a matter of speaking). This one looks like the flow to earlier burners will potentially affect the final ones in the string. This can make adjusting burners for equal output difficult. The 1/4 turn ball valves are not the best option for use in balancing output between burners. This is a perfect application for gas rated needle valves. Adding a layer of castable refractory will hopefully help keep the insulation ceiling up. Otherwise I predict it will sag over time. The door system, and insulation in that area, are sub-optimal. As I've stated before, door systems are hard to design well, but at least the "front" door should be set to close with a castable against castable seal, be oriented so in the open position the hot face isn't pointed towards the user, and be capable of being "locked" partially open (especially for NA burners that need a minimum vent area to operate). I am a fan of doors that either slide to one side (on some form of track system) or lift vertically (4 bar linkage or counterweight). Have you checked in with Craig Kovach from Island Forge and Fab? His profile lists him as a bladesmith in Belize. He may be able to help you directly...

If you have never melted iron (or steel) it is a very different animal than melting aluminum or brass in a small propane home foundry. Cast iron melts at around 1,000 deg. F higher temperature than aluminum. This higher temperature range will task your furnace, crucible, handling tongs, PPE, and (most critically) process. Strongly recommend you take a class in casting iron from an experienced caster before you try this.

Mix as much fumed silica in as you can. Eventually it will cease to go into suspension. You will also want to very thoroughly clean out your spray bottle after application, or use a disposable one as I have. No need to oversoak the blanket, you only need to rigidize the top layer. I know that others do coat with rigidizer in both layers, but I have never found it necessary. As I see it, the rigidizer is only there to provide a relatively hard, relatively impervious and incompressable surface for you to place the actual castable refractory insulation against. If you use other methods of forge construction you don't even need it (i.e. versions of the one that Frosty mentioned the other day where you cast or form you liner first, then pack insulation between it and the shell). Add a precast front ring and you have your refractory blanket well encapsulated and ready to go. I have always hardened my rigidizer by first air drying (sometimes assisted by an overnight session with an incandescent lightbulb) then slow firing up to where the surface becomes glassy. A full yellow glow should achieve that handsomely. The real key is the castable liner. These day I like to use a 1/2" - 3/4" thickness of high alumina insulating castable material like Kastolite 30. An inner coating of an IR reflector isn't a bad idea either. A lot depends on what you want to use the forge for, but this is fairly bulletproof. I was not all that familiar with the Vevor forges. Seem OK, with burners that are knockoffs of Ransome or Hammer style. I have a preference for the former, but each to their own. There are certainly worse forges on the market.

MORE POWER!!!! A 7.5 HP grinder must be a beast.

Recommend for your next one that you complete all grinding and heat treatment before you make the handle section. Then you can form the less time-intensive handle to the blade. I would avoid hot fitting the handle directly to the blade. A piece of stock sized as close as possible to the riccasso will work better. You are right that you have a bunch of finish work to get that blade where it needs to be, and folders are particularly tricky regarding flat, parallel and centered riccasso as well as blade profile, pivot point... With both blade and handle being high carbon steel you don't have the luxury that some do to make easy handle adjustments as you would if mild steel or even brass or copper sheet is used for the friction folder handle. In my experience there is a very small difference between too loose and too tight on that pivot. Also, be careful about scale on the inside of the handle. If you get a good fit and then it flakes off during extended use you will be disappointed. Note: I unfortunately have not had a chance to watch either video, so can't comment on the sample designs. Good luck and I'll look forward to seeing the finished product.

I think the intent is to use the 40 HP motor as a phase converter for running 3-phase eqt in the shop. Unfortunately I don't know enough about those systems to judge whether it is an issue to use a larger motor for conversion when running smaller loads (like a 5 HP power hammer for example). If needed I can ask one of the EE in my company for advice. That being said, I'd love to see a functional line shaft facility, but certainly understand the relative insurance issues.

No forced air forges don't have to have a ribbon burner outlet. Plenty of them have been running for years without (including mine). PSI requirements are related to the amount of fuel/air mixture you need to heat your forge, size of pipe, type of gas fuel... I would still recommend sticking with an adjustable 0-30 PSI regulator if you are anticipating the typical propane forge with nominal 1/4" gas supply line. without a jet orifice you will likely need less pressure (also why pressure is a lousy measure of how much gas flowrate you actually have), but you still should use an adjustable regulator with a gauge for repeatable settings. I personally use residential low pressure natural gas in my forge, but I have a 1" line and relatively large terminal orifice. That is one of the advantages of a forced air system, you don't need the high velocity gas stream to entrain the air into the burner mixer. It is that jet creation and terminal orifice that drives the upstream pressure requirement up so high. Blower sizing is also dependent on your system configuration. Too many variables to discuss here. I greatly prefer centrifugal blowers over hairdryers.

Sorry to keep derailing this into a discussion of French Pattern hammers, but a couple of years ago I saw Joe Keeslar do a forging demonstration at a hammer in for one of his signature Brut de Forge blades. At 70+ years he was still swinging a short handled 6 LB French hammer to pretty amazing effect. It was mounted the "normal way", and he mentioned that he brought it home from one of his many excursions in France.

Well, by appropriate I meant to avoid the typical "squirrel cage" style blowers and lean towards a centrifugal style with radial impeller like this (Dayton 2C862):

Couple of comments: Going to be a rather large forge. Are you planning on doing architectural forgings, or have a power hammer or hydraulic press? Make sure you build in some slop in your front door guides. As the door heats up it will expand. Consider extending your castable past the metal door openings of the forge proper and past the framing around the doors themselves. In the current configuration you will get heat transfer to the forge liner and door frame. These will see scaling and warpage. Might want to add a counterweight to the front door system, or some form of toggle ratchet. Otherwise what holds it open when you move to do forging? Make sure you include a gap of some sort for venting when the doors are "closed" With that baffle and 4" thick burner block you will need to be sure to select an appropriate high pressure blower.

Nothing better than going to craft camp for adults. I've been to several of them one or more times so far (Arc and Flame, NESM, Haystack, Penland, Peter's Valley, Touchstone, Dragon's Forge...) and they are certainly my preferred vacation destination. If I had my druthers, when I eventually retire I'd love to just spend a few years going to these, and other, schools monthly. Maybe even get to the point where I am ready to teach a more advanced class. That is my dream. I also like hand cranked blowers, but have to admit that since you have inspired me to finish setting up my coal forge I'm starting with the electric option. Mine will have a foot kill switch and Variac to adjust airflow, so will be pretty similar experience to hand cranking. Would use the hand cranked blower I have, but it needs an oiler and stand rigged up, so that will take longer.

I just can't get past the French crosspeen hammer being mounted upside down. I guess it does work in both orientations, and might even have some utility being mounted inverted, but still...

I'd be a little less worried about the method of attaching the dies and more concerned about the guide design (typically see longer and more robust design - any racking and you will put a lot of stress on those bolts) and the potential lack of penetration on some of the critical welds for the top vertical piece of plate steel set between the two I-beams and associated gussets. It may all be fine, and I don't mean to be alarmist. Just please be very careful.

Ummm, folks, I'm pretty sure these are photos from the beginner class that Jen recently taught at Peter's Valley. The shop certainly has been updated since I was last there. I think she meant in her post that she couldn't wait to teach a similar class in her own school.

Excellent job. Even with a couple of years in I'm sure I would have learned something valuable.

Very respectful response. I appreciate that. In reply to your questions: While the flue does not have to go straight up, it isn't a bad idea to route it that way. If not, use (2) 45 degree elbows to offset the duct, not (2) 90 degree elbows. The super-sucker style hood should be mounted with the opening as close to your forge's fireball as practical (how close depends on the typical size of your solid fuel pile, but I would go no more than a couple of inches at most). Properly used they will suck the fire horizontally right up the flue. Typically this means that your new hood is mounted right onto the end of the forge, a couple of inches from the fire pot. Don't be afraid to rest the bottom of the hood right on your forge. That's how most I've seen have been installed. A 10" diameter duct should be fine for a super sucker. If possible, the section connected to the new hood should be black steel, not galvanized duct. If you have a large coal fire it can get pretty hot. Going up to 12" won't hurt, but I doubt it will be required. The code requirement for a flat roof is a minimum of 36" above the roof surface. The higher you go, the better the draft on your hood. The limit is the stability of your stack in wind, but you can always guy it off to the roof if you want to really go high. Just be careful regarding the roof penetration itself. Typically these need to have a certain clearance to the structure, and depending on how your roof is constructed you may need to include a ventilated thimble. For example, the code clearance for single wall duct penetrating a wood frame roof is 18" between the duct and any combustible material. You can buy special preinsulated duct that is rated for much less clearance, but that gets expensive.

My recommendation is similar. Ditch the overhead hood, or use an insert like Iron Dragon did, and substitute a super-sucker type side draft. These draw surprisingly well if you have adequate rise in your vent stack. Note that code requirements for roof penetrations are not always easy to achieve. Also, allowing an air path to makeup the exhaust you are removing is also critical If you do go with an accessory exhaust fan, you should size it for approximately 100 ft/min velocity at the inlet face of your hood. It is a little hard to understand from your description, but I assume the inlet area is 45 x 34/144= 10.6 SF. Therefore you should select a fan capable of, say, around 1,060 CFM at a nominal 0.75 inches of static pressure (both values required for selection). The motor ideally will be out of the airstream, and the fan rated for high heat, which can get expensive. You might get away with a used upblast, rooftop, commercial kitchen exhaust fan, but then you will have to correctly install a roof curb. A 1/2 HP Greenheck CUE-120A will fit the bill, but will cost around $1,400 just for the fan, and is only good to 400 deg F. With a large hood like you have, you should entrain enough shop air to cool the stack down quite a bit under normal operating conditions.

Can't post a commercial link, but perhaps something like the VOCIC Lightweight Electric Lift Chair mounted on a very wide spread set of legs with casters?