Latticino

That is what torches are for... I have both an oxy-acetylene setup and a high end propane hand torch that puts out some serous heat (looks like a really good quality weedburner, but can't remember the manufacturer offhand)

One of the key drawbacks of a gas forge. In addition to Buzzkill's excellent suggestions also consider door configurations like this one from Majestic:

I just meant that the 450 BTUH/ cubic inch is a rule of thumb and that there are a lot of factors in addition to the interior volume that need to be considered. Good place to start though. The interior volume and exterior surface area are linked, but not directly, as the forge configuration and even more the overall thickness of the insulation also play a factor. I agree it is not a huge issue, probably just being overly pedantic. As far as flame directly impinging on the stock, I'm of two minds. There are times when it is a good idea to have a "hot spot" on your stock, but in my experience I have found it more useful to have general radiant heat inside the forge rather than spot heating. Again, a lot depends on how you actually use your forge. I tend to put my stock inside and walk away, knowing that I'm looking for a nice full soaking heat that heats not just the surface across from the burner, but all the way through to the interior of the stock so it moves easily under the hammer. I believe that keeping the stock directly under the flame risks accelerated scaling at that point as well as well as decarb, but I could be wrong. I will admit that when I needed to reweld a wrought iron/5160 2 bar billet that had experienced too aggressive cross peening and split, that I did make an effort to put that section directly across from my burner outlet, and I think that may have helped, so go figure. The Ward system looks lake a good one, and I have used similar ones in the past for glass equipment. I currently use a SS flame retention nozzle like the Ward, but plan on upgrading to a ribbon burner when I get a free moment. Based on the scale of the piping for the gas line it looks to me like this one is for natural gas, if you order from them make sure that you specify the fuel choice. As far as feeding a ribbon burner, it is all based on whether there is enough external static pressure available from the blower supplied. No reason to make a 18" diameter x 3' long forge, unless you are doing very large industrial forging. Your forge design is way too large. What are you planning on making and how many tons is your press or power hammer?

Was not familiar with thermal barrier coatings, so did some research on Wikipedia here: https://en.wikipedia.org/wiki/Thermal_barrier_coating . Interesting stuff, thanks for bringing it to my attention. As far as I know, correctly used, most of solid fuel forge body should not get up to the temperatures that would require such a coating. The only place I could see getting that hot is the firepot, where I believe the typical failure mode is cracking from thermal cycling (for cast iron) or accelerated scaling for mild steel. In the latter case the TBC coating might be appropriate. Why not try it and get back to us with your results? As far as gas forges (though you have this in the solid forge section) from the article it appears that there are several types of TBC, some of which prone to thermal shock and spalling at the temperatures that could be anticipated inside gas forges (particularly in the flame contact zone). On the other hand, a top coating of a high alumina or a zirconate over the conventional refractory blanket/castable refractory lining might be just the ticket for both IR reflectivity and flux resistance in a gas forge.

A precision nozzle is not really required for a blown burner, but correct orifice sizing will make it a bit easier to modulate the gas output. I'd have to check my notes at home, but I believe that the propane orifice size (at 1/4" for each of two burners) is a bit large. You likely only need 1/8" at the outlet, but will want a larger tube leading up to that orifice, of course. The method I've seen/used for forced air/propane burner construction is to weld or braze a piece of 3/8 or 1/4" pipe into a hole cut centered on a pipe plug. Then either directly cap the pipe with a fitting that has a 1/8" hole drilled in it or add a fitting or bend to point the gas outlet towards the blower (for mixing) once the plug is put into the mixer Tee fitting and cap that with a similarly drilled orifice. For gas metering I would use the assembly that Michael is suggesting. It is an economical and proven design. My larger Natural Gas/forced air forge was made from an 11 gallon air tank (Harbor Freight floor special: $10 as it was missing the air pressure gage that I didn't need anyway). I cut it down about 8" in length, and wish that I had made it even shorter. In my opinion, short and wide is a good choice for forge geometry, but I guess it matters what you plan on forging. I have only one burner in it currently and it reaches welding temperatures for high carbon steel just fine, but it is a 1 1/2" mixing tube outlet I believe. Things are a bit different for natural gas though, as you need more volume of air gas mixture to get the same BTU output.

Thanks Michael. Forgot to mention that the multiport (ribbon) burner will also be a lot quieter. Subjectively this makes a big difference, and for that alone might be worth the hassle of making or purchasing one.

I've played with it before, but it was a long time ago. All I can recall offhand is that it is quite fragile and typically found in sheets that are made up of many thin layers of the naturally occurring material. I think I just cut it with a heavy shears or tin snips, or even utility knife and straight edge. Strongly recommend mounting it in a frame that holds the entire perimeter of the material. IMHO it makes a extremely beautiful shade for a lighting fixture.

Dudley Giberson's book is still very helpful, and glassblowing temperatures definitely get up to the 2400 deg F range (needed for melting glass from batch). Another good source of info is a somewhat more exhaustive book on glass equipment design and DIY style construction by Henry Halem. Both of these have great info on forge burner design, and I believe that Dudley still sells his multiport burner, and has even developed one for a small gas forge. Here is a link to his site, which is crammed with useful info: http://www.joppaglass.com/ Calculations are certainly helpful, but far from straightforward. As I see it the internal volume isn't as big a factor as the forge surface area (which is, of course, related to the volume, and why the typical rules of thumb are useful). That surface area is what directly influences both the conductive loss (that you insulate against) as well as the convective loss (as the forge heat gets released to the environment). Also as you correctly state the ports that are used for combustion product exhaust/product doors have a significant effect. These not only in the loss of heat due to the hot exhaust gasses (which is why Michael and Frosty often mention that a slower flame speed is more desirable, all other things being equal), but also due to radiation losses. Another part of the equation is that all things being ideal, the time it takes to heat your stock can have a great effect on the usability of a forge. That time is not just proportional to the temperature inside the chamber, but also to the thermal mass of that same chamber (which is one of the reasons that many industrial forges have a thick, heavy refractory layer instead of the light insulation a hobbiest may favor). A production shop can afford to trade the slower initial forge warm up time against improved product throughput. Try heating up a 2" piece of bar stock for a hammer head and you can see it suck the heat right out of a thin shelled gas forge. The only downside to having too much burner for your forge is the potential for not having enough turn-down capability to run the burner at the correct settings for the chamber (unless it is just so large in comparison that the flame can't develop at all inside the chamber). As I see it, if the burner can't turn down far enough the flame speed will be so great that the forge won't operate efficiently.

Not at all bad for a third forged blade, but... What grit did you grind your bevels to before quenching? As Thomas said you have a ton of surface issues, most likely due to scale to clean up, and now after being hardened it will be much more difficult. You may have similar issues with your tang. Depending on how you plan on attaching a handle the curve to the tang, lack of hole for a pin, and the geometry of the tang/blade connection may prove a bit of a challenge also. What is the blade size? If in proportion to the plug in the first picture it looks pretty small for a tanto. You may want to peruse this site which goes into some detail on classic tanto geometry: http://islandblacksmith.ca/2014/06/classical-tanto-geometry-blade-kissaki-tip/

Nice paring knife, especially for a first effort. Great to hear that someone is actually doing their research and using the stickys to achieve success. Hopefully you also tempered the knife after quenching. I assume you mean the tang is 1" wide, not thick. For a paring knife of that size you probably don't need such a substantial tang, 1/4" x 1/2" in crossection should be more than enough, but it never hurts to go big. For your next effort, consider adding a mechanical pin to the tang/handle construction to avoid using epoxy as the only means of keeping the handle on. While epoxy is certainly strong enough, it may get challenged by long years of use/abuse and regular washing a paring knife can experience.

As regards your theoretical question: I would quench in oil. My logic: I have hardened W2 and O1 in an oil quench before (in separate instances, not together), and wouldn't anticipate that A2 would suffer from a more accelerated quench rate (nor would it be particularly better for the knife edge anyway, so who cares how well it hardens...). Of course, I can't see a reason to use A2 as part of a knife billet anyway, so it really isn't all that interesting a question.

A couple more minor issues regarding safety: NEVER light a blown burner without the air source operating. This can result in having the gas both at the burner outlet and at the blower (especially if you have a flow restriction at the outlet, like a pipe reducer or multi-port/ribbon burner block). If you have a blower motor that is not "sparkproof" or even worse has heating elements, you can get combustion in the blower when you finally turn it on. Disable the heating elements in your hair drier for this application and develop some way of modulating its output more than High/Low (waste gate/inlet shroud...) Don't use plumbing putty to seal up the connection between the gas inlet and mixing tube. If you don't have the ability to weld or braze that connection, find a way to do it with gas rated swaged fittings. Leaks at that location are bad. Another method for getting the turbulence that Frosty and Thomas mentioned is to have your gas port pointed back towards the blower (which will always be on when the burner is operating, right?) You may want to rethink your choice of materials, depending on how you eventually use the burner in the forge. Currently they are fine, if you keep the blower on all the time the burner is in use and afterwards until the entire assembly (burner and forge) cools down. Otherwise there is a chance that the radiant heat from the forge will backfeed into the burner after it is shut down.

In my experience hitting a billet on edge will stress a new forge weld considerably. Even if you are sure it is welded sufficiently you should endeavor to keep it up to close to welding temperatures when forming it by hitting on edge.

If left as pure iron would be extremely soft. If processed into steel it would most likely lose the bulk of the interesting/magical/spiritual/whatever characteristics you are looking for. You might want to clarify a couple of things: who is supplying the iron, what size/type/quality sword are you looking for, functional or a wall hanger, what kind of price range are you considering... I have heard of bladesmiths that incorporated a small amount of meteoric iron into their knife forging, but not exclusively. Hope you have very deep pockets if you really want something like this.

There is a straight line just begging for a pun...

Will be interested to hear the feedback from the manufacturer. From my limited experience with high alumina castings I think you may end up having a problem with the relatively rapid thermal cycling potentially cracking the high alumina tile, depending on your installation details, use and forge design. The high alumina castings I've used didn't like any kind of quick temperature changes. A crack is not as big a deal for a forge floor as it might be for the walls or ceiling, if either are used for the forge structure support. If you do try to line your forge interior with the shelves I'd love to hear how it works, but I'd suggest you make a kind of ceramic fiber blanket "gasket" to allow differential movement of the shelf at any ends that rest against other hard substances (other shelves, forge frame...)

I remember those old Johnson Natural Gas forges. They still have one in use over in the Metal Sculpture shop over at Rochester Institute of Technology (where Bill Moran taught a class back in the '80s that I unfortunately missed). As Frosty says, horribly inefficient, huge thermal mass, with a ribbon style burner with a metal slide to change the outlet length (if I recall correctly). The best that can be said about those forges is that they are pretty much bulletproof, which is why they ended up in so many educational institutions (back when they were actually teaching tradecraft that is). There is a young man over there currently who is turning out some nice pattern welded billets and making knives from them. I'm not certain if he is using the gas forge, but I don't recall seeing any other forges in the shop.

Yes, Buffalo has an active chapter of the NYSDB (Niagara region). There are quite a few talented smiths in that group with plenty to teach. Unfortunately Theo, in Brooklyn if I recall correctly, is a good 7 hr drive away. New York may not be as large as Alaska Frosty, but it is no Rhode Island either...

Suggest you look at Ken's Custom Iron, who make their "Quick Tongs" in a similar method. Not sure if, including the cost of materials, labor and utilities you would be able to beat their pricing: https://kensironstore.com/collections/quick-tongs/products/best-selling-quick-tongs-bundle-set

I have also tried to contact Euclids to get more information. One thing that concerns me is the composition of what they are calling a high alumina kiln shelf. Their site says it is Cordierite - Mullite. According to other research on refractories I've done this material combination may only be rated for 2,150 deg. F, which may be an issue in some forges, and certainly for flame impingement. Of course, what the material is rated for doesn't necessarily mean we can't use it for a forge floor at higher temperatures, just that it may not be able to be used as a wall or ceiling element at elevated temperatures. This is the site I used for additional info: http://www.usrefractories.com/products/prod04.htm

Welcome to the site. Fantastic job for a first try at tongs, wish mine had looked that good. I suggest for the first couple of tongs you drill the rivet holes rather than trying to punch and drift. Timing gets tricky for that operation, if you don't have a more experienced smith nearby to guide you through it the first time. I recommend that you practice punching and drifting on bar stock first (say 1/4" thick) to get a feel for how it is done. Typically I do my "front" punch at almost an orange heat and hit the punch no more than three times before cooling the tip of the punch in water (to keep the tool from overheating and deforming). Rinse and repeat until the punch feels like it "bottoms out" against the anvil. Steel should then be dull red at best, possibly showing no color. Flip billet and look for the cold black mark from your front punch. A quick punch on that side should knock out the plug. This needs to be done at a black heat or the plug will just deform to the other side. Needless to say it is easier with thinner stock. From what you are showing I can only expect that you were working the steel too cold. Remember as the crossection gets thinner it heats and cools more rapidly. I don't see any sign of your punching the bolster in the photo. Also check the steel to see if truly mild steel. Using mystery steel from the scrap yard is always a bit of a challenge. Test it with a "snap test" to be sure before putting too much more work into it.

Just to clarify, though I don't disagree with any of Thomas's points, the site the OP has referred to is not a forum, per se, but an informative site setup by a fellow who is extremely generous with his time in posting about blacksmithing and associated tools. His site is chock full of great information, in particular on old post drills, and was extremely helpful in assisting me to get mine arraigned to function well. My guess is that he got a bit upset with the, likely manly insistent newbie questions from folks assuming that because he was kind enough to post some great background information that he would be available to walk them through any equipment repairs. Here is the site: Link removed as the post was a long time ago (1999), and does reflect well on the site.

Suggest you seal the frax with before coating with Plistix to avoid wasting the expensive IR reflective topcoat product.

Haven't built a solid fuel forge myself (as yet), but just curious why folks don't just use commercially available cast iron floor drain covers for their grates. You can get them either perforated or slotted in different sizes: https://www.hardtofinditems.com/floor-drain-covers/ Pricing seems pretty reasonable to me.

Check out this video of Jason Knight forging a point on rectangular stock: https://www.youtube.com/watch?v=fqCieOsxlrc. Note that he hangs the stock a little past the edge of the anvil and then forges the point down later in the process. This works pretty well for limiting fish mouth, but I'm not sure how it would influence a precise pattern welded billet.