Andy98

Thanks Mikey - I found that very encouraging. As I mentioned in my post above, I have actually used the forge now - which was great, although I discovered exactly how much of a wuss I am with a hammer. Regarding the flare: There is none. The burner mixer tube is setback approx 3/4" from the interior of the forge, with the forge lining shaped into somewhat of a flare/nozzle. Here is a photo of the burner opening from the top half of the forge when it was removed: ...the burner isn't installed in the photo, but if it was you wouldn't be able to see it - it's set back a little further than the angle would show. I realize the flare/nozzle is not the correct taper - I was worried about losing too much insulation depth. Do I need a flare? Now that I have the forge actually going, and now that I have an anvil, I am in a position to make one - or at least attempt to. The mixer tube does show some temper colours on it, so it must be getting hot. The temper colours extend just a little but further back past where the pipe-threads end. I can take a photo if that's useful. The external part of the tube remains cool to the touch while in operation, but it does get hot after I shut the burner down - I can't say when the temper colours appeared. I can try pulling the mixing tube back some more. I'm paranoid that the gas will choose to go into the forge shell, rather than the forge interior, if I pull it back too far. Advice and comments are appreciated.

I've never used a PID controller for a forge, but I have used a lot of PID controllers and done a lot of other control applications. Disclaimer aside, are you sure you're actually doing PID control? Your description sounds more like on/off control. If it is actually a PID controller, and it has digital control outputs (and not just digital alarm outputs) then it should be able to do PWM (pulse width modulation) to vary the output and achieve something close to "in-between" values - see PWM here. If it's doing PWM and you're not getting good control then maybe you haven't configured it correctly? It could be poorly tuned, or have too long of a duty cycle, etc.. FWIW, in process industries at least, you wouldn't typically have an "electronic regulator" - your controller becomes the regulator, and you wouldn't have it controlling for pressure - you'd have it controlling for temperature. It would naturally adjust for input pressure changes as the tank empties.

...this has confused me for quite some time. I keep reading about ITC-100 etc.. being highly IR reflective, yet when I try go and do some research I find they have very high absorption and emissivity instead. So to put the matter straight in my head: Reflection has nothing to do with this - it's all emission? An "ideal" forge interior coating will get very hot (via IR absorption plus conduction) and will then emit lots of IR. That emitted IR is doing the bulk of the work heating the workpiece. Is that right? Using the term "reflection" might make for easy understanding, but is not actually what we're dealing with....?

I intend to lose no material, but some trial and error might be needed to ensure that. Where i am, metal will not rust due to humidity - it will only really rust where liquid water has been allowed to remain in contact with the metal. So its not so humid or salty that the metal will errode just sitting there, but it is humid enough that if water does land on the metal it might not dry for days unless it is exposed to direct sun. Another way to say it is that my garage has roughly the same temperature & humidity, but no condensation or precipitation. Plain steel does not rust in my garage at all.

..at least 2.5 seasons it'll be outside. I could bring it in for the dead of winter until mid spring. Due to the exact nature of my work area, its impractical for me to move the anvil in & out more often than seasonally. That said, I would prefer to pack it up for winter instead of bringing it inside. During "operational" months I intend to keep the anvil misted with WD40 with an oiled cloth covering the face, and then a waterproof cover over that (likely with some spacers to allow airflow. I'll adjust based on observations (and good advice). During storage months, I thought I'd do the same (WD40 and oil) plus wrap it up more snugly, and throw a descicant pack inside the tarp. I'd also consider slathering something on the anvil like paste wax or vaseline. I havent started to fully figure this part out. Again, suggestions welcome. Regarding the silicon, I'm suprised that doesn't reduce the anvil rebound. I guess it's not a thick enough layer to count as a shock absorber..

Ok - asked and answered. I'll set it up as a striking anvil, and based on need will radius and plus possibly add a hardy (although I'd have to send it to a shop for that...)

Hi, I've read lots of posts about how to keep an anvil body and face rust free, but nothing that talks specifically about the anvil bottom. In my region a standard construction rule is: Don't put wood and steel in contact. Most of the wood anvil mounts seem to do just that. Should I be doing something to protect the anvil bottom? I think a thick coat of paint would seal it, but I know most people do not like the idea of painting an anvil. Other options would be to slather it with grease, or varnish. Any suggestions? My anvil will be unsheltered outside through 4 seasons, so I want to make sure I do whatever else I can do to protect it.

Hi, I'm a total beginner building up my tools. I've just acquired my first anvil: A 100lbs John Brooks, and now it needs a stand to mount it on. The stand is no biggie - I have lots of ideas for that. I also have a 100 lb piece of steel plate (approx 2" thick x 10" x 18") - it's construction steel, probably 44W or 50W. I'm wondering if I should use that plate in my anvil stand. So the plate would sit on top of the anvil stand, and the anvil would sit on top of the plate. I'd metal-strap the anvil down to the stand (pulling it tight against the plate). In my head, I'm 50/50 on whether this would help or not. The anvil does ring less when it's sitting on the plate, compared to sitting on my concrete floor. Part B of this question is: If using the steel plate on the anvil stand is not helpful, might it be useful on it's own for something? Should I build a separate stand for it? It is, at the moment, extremely flat with very sharp edges. At a minimum, I could see myself using it as a surface to hot-cut against. I realize it'll get beaten up - I don't have any other use for it, and I got it specifically to act as an anvil. Thanks in advance!

I'm surprised to be getting the gears on the flare fitting. I'm happy to replace it with 1/8MPT per this post or hunt the province for requisite schd 80 1/8 nipple if what I have is even potentially a problem. I didn't realize I was doing something so controversial but I didn't do it because I am incapable of reading instructions or following plans. I did comment in this post that there seemed to be a lot of variation in the fittings, and the advice I was given was take a drill bit and find something that would work. I've read just about every burner build post I could find and I've seen all manner of fittings go into builds with the builds getting complimented, and nobody saying that the exact fitting used to hold the mig tip will matter much, or that they need to go back and swap it out. I've even read old posts commenting how the fittings parts list shouldn't even publishable because people need to just find something that works. It seems to be difficult waters to navigate.

Unfortunately, you'll have to keep searching - wasn't me

In my case, it was the only fitting I could find with a small enough ID. The plumbing store didn't have sched 80 in 1/8", so I took my drill bit (and tap) and found something that I could tap. I can't say why others are doing it.

...err, that should have read "1/8" flare to 1/4" MPT.

Yes - the 1/8" flare ID was small enough to drill+tap to accept the mig tip, and the 1/4" MPT is for my hose connection. Here is the built burner: From top to bottom that is: 1/2" coupling (they didn't have any metal thread protectors) for an initial test outside-the-forge. 4" long 1/2" black pipe 3/4" run x 1/2" drop black pipe T 0.023 mig tip, cut down in length a bit. 1/8" flare to 1/3" MPT 1/4" ball valve 1/4" pipe nipple (supply house's best suggestion for getting a male fitting to accept my hose) ...then the hose connects on to that, which goes back to the regulator. Are there any issues with my build? I put thread tape only on the connections that are outside the burner (e.g., none on the mig tip) - somehow I couldn't bring myself to skip it. I gave it a first light, and the results were unspectacular. Running at about 6-10 psi, it wouldn't stay lit: I used a propane torch to try and light it and the flame would just never catch. It looked to me like the velocity was just too high...? It seemed like it was "blowing away" the propane torch's flame. If I blocked approx 90% of the air inlet ports, I would get a sustained and very rich flame (the kind of gently rolling burn sort of flame). As I opened the ports, I would get a more intense flame and then it would just blow out. ...my guess from this was that the coupling was insufficient as a flare. So I made a temporary flare, approx 3" long with a 1:12 ratio out of an aluminum tin can (the only thing I had handy) and that did light and burn intensely (for the approx 4 seconds it took for the aluminum to melt). So, I took that as generally positive and that there was nothing more worth doing until I have the burner in the actual forge. Does this all seem reasonable and normal? Or does any of the above point to a problem with my burner thus far?

Hi - fear not, I'm working on it. I just like to understand what's going on - I'm not paralyzed trying to make a decision or anything. I've got a plan, and am working towards it (with unfortunately very limited time to dedicate) For sure you can build a non-functional burner. But the common burner designs are all functional, and all have at least some operational range in which they, you know, work. What I've concluded from all the conversation on the topic is that the real difference between the burner designs is: Ease of tuning (ability to get the flame characteristic you want) Ease of construction How wide the operational range is (expressed by input propane PSI) Stability: Once tuned and running, how likely is it that the burner will continue to deliver the desired flame when confronted with wind, backpressure, etc. I've decided that burner engineering is an efficiency trap: It's easy to get obsessed with making the most "efficient" burner but the actual improvement in performance is small. While I would have fun pursuing the "most efficient" burner, it's not necessary to run an economical forge. I've also concluded that I'll get more efficiency gains by improving the forge itself, than I would by worrying about the burner: Keep the forge interior small, well insulated and IR reflective. Possibly add an idler circuit. Don't have too much dragon's breath. These are my personal conclusions - they may be totally off the mark, but that's how I'm proceeding. To @SomeGuy (the OP): You've mentioned a few times that conserving propane is a big deal for you. If you have access to natural gas, you might consider following this person's lead: http://www.flemingknives.com/ribbonforge.htm - I don't know if he is a user here, but he is a user on bladeforums: http://www.bladeforums.com/forums/showthread.php/934512-Table-Forge-with-Ribbon-Burner/ ...he built a natural gas forge, using a blown ribbon burner, that he runs off his residential NG supply. It runs (and gets welding heat) using 1/4 psi NG (I have no idea what volume of gas it uses - but he says it is so little he can't even notice it on his monthly bill).

...but all the burners can be tuned to get the ratio you want, therefore by that measure they are all equally efficient...? I must be missing something because the "induction ratio" of a burner gets a lot of talk so it must matter. Perhaps none of the (non-commercial) burners actually induct enough air for complete combustion? That would create an inefficiency (require air be drawn into the forge from the openings and create lower-temperature combustion zones?) Fluids + combustion + heat transfer = voodoo.

Question: What determines how much of a secondary envelope is created?

Again, noting that i don't really know, what does "more efficient" mean? Grabs more air per unit of...what? And what is the consequence of that inefficiency? Again, I'm still trying to figure a lot of this out - and the dynamics of a burner seem quite complicated.

It's not a theory - it's the first law of thermodynamics. That's an interesting question that I am completly unqualified to answer. Ultimately you want the right amount of air, not necessarily the most air possible. But then don't listen to me, I've never even built a forge or lit a burner before.

No. A high-volume flow at low pressure can move as much gas as a low-volume flow at high pressure. Think of a slow moving wide&deep river vs a fast moving narrow&shallow river. Ultimately, a burner is simply releasing the energy stored in the propane (by burning the fuel). So if you want 60k BTUs of energy, you will consume 60k BTUs of fuel (plus some extra due to inefficiencies) whether you deliver that quickly through a thin tube, or slowly through a fat tube. I'm thinking (and would love to be further educated on the topic) that basically all the burners are equally efficient (e.g. no burner is producing a lot of unburned or incompletely burned propane). The forge itself might be inefficient (some burning might take place outside the forge, it might be poorly insulated and not retain the heat, etc...)

No fun doing it that way, plus it buys me an extra 45 minutes waiting at the other end for my luggage. Turns out security was fine. They didn't really blink at the regulator, and the two "bricks" of powder (the satanite and bubble alumina) were dutifully removed, tested, and allowed on. The agents were more amused than anything else. The regulator is now here, ready to go. Just waiting on a propane hose. Really interesting - You wanted to minimize/eliminate the secondary flame envelope for efficiency reasons (...because it's burning fuel at a lower temperature?) or am I not getting it?

Hmm - I'm not sure where I got confused on this - I had consulted a data sheet that said both the K23 and K26 bricks had the same temperature rating, but I must have misread since I've now checked several mfg's sheets and they all clearly indicate the K26's are 2600oF vs 2300oF for the K23. Anyway, I'm straight on this now. Understood - in my post I said sched 40 is too thin, and it's ID is too large. Sorry - I know I'm asking a lot of questions - I just like to do a lot of research before I actually go and do something. Unfortunately, I have more time available to plan things than to actually do things. The other factor is that the "real" plumbing or industrial-supply places I'm likely to go to are the order-at-the-counter deals, so I'm trying to walk into the store knowing exactly what I want - or as close as possible - I've never found them to be very friendly when you walk in unprepared. That said - I have my contact-tip-holder: A 1/8" flare x 1/4" MPT. The 1/4MPT will be for my hose connection, and the 1/8" flare is narrow enough I can tap it to 1/4-28 to match my contact tips. Do I need to worry about the contact-tip-holder unthreading from the "T" every time I screw on/off the propane hose? Thanks - I've never heard of greelinehose before, I'll keep them in mind - thanks for the reference! Amusingly, I managed to find a Flare x MPT at Rona, but couldn't find a 3/4 run x 1/2 T. I know I can buy one from Acklands-Grainger (closer to me than Greenline Hose), so I'll probably swing by today to grab it. That T should be the last part I need for the burner. There is also a (seemingly) good pottery place that I can easily get to: http://www.psh.ca/ - they seem to have all the kaowool, high-alumina-shelves, IFB, etc.. so that should do me fine.

Well, I pretty well am a safety nanny. I didn't mean to imply I agree with this person's approach. I was just using it as an example to illustrate that in-use vs storage are different. In rereading, I realize that wasn't clear.

Ok, totally excited about this approach now - thanks everyone for your comments. My thinking is that I'll build the two brick forge first, and then if necessary I can make a slightly larger forge down the road (probably along the coffee can/freon can style). For a two brick forge: Should I use K23 or K26 bricks? I couldn't seem to find that question being asked before...which is somewhat surprising. For the 1/2" T burner: If I swap the 3/4" x 1/2" (run x outlet) with a 1" x 1/2" - is that a problem? I can get the 3/4" T, it's just going to be a little harder than the 1". Also, for mounting the mig tips: I understand that 1/8" sched 40 pipe is too thin (ID of the pipe is too large) to tap 1/4"x28.- but I see plans that have used various fittings: 3/8" flare to 1/2 IPS (mig tip going into the 3/8 flare end) 1/8 mpt to 1/4 flare (mig tip going into the 1/8 mpt end) ...so it looks like fittings must have a more narrow ID than pipe nipple? Is there any way to predict which fittings will have a suitable ID (e.g., any brass 1/8" mpt fitting is likely to work?) or is it really unknown and until you try/measure you can't know? Thanks again!

In case it helps: I can't remember the exact numbers, but I was recently chatting with a guy near that rents his 100# tanks. The monthly charge was silly - like $5-$10 for the tank, and the refill cost was also really low (I recall thinking it was only a little more than I pay to swap my BBQ cylinder - plus they came to him). He has three or four of these tanks in his shop, and he would only refill/swap the tanks maybe every couple months (so he was not a high volume guy). A propane tank attached to something is not being stored - it is being used. Different rules. Same guy as above keeps all of those tanks attached to something at all times (cutting torch, forge, etc...) specifically to circumvent the "storage" requirements. I can't say if an inspector would buy this dodge or not, but a legitimately in use cylinder isn't a problem AFAIK.

Ok - thanks again. After some ruminating, and realizing that (as Frosty said) that I'm almost certainly going to have to keep moving the blade around to evenly heat it, a very small forge is starting to seem really attractive. Being able to box it all up in that toolbox is just as useful to me as making it out of that toolbox (storage is a real factor for me!). I can also worry about making a hammer later (so this forge need not be big enough to accommodate). So... Questions relating to my actual forge: On another thread (this one) - @teenylittlemetalguyposted about his 2BF with a 1/2" T burner, 2-1/8" ID chamber cut the full length of the brick. Is there any reason this shouldn't be my first forge? Or would a paint/coffee can with a backport be better? If I do go with the 2BF should I bother coating the interior at all with my satenite & bubble alumina? General knowledge questions not specifically related to my forge (meaning, don't worry about putting ideas in my head that'll cause me to mess up my actual forge): I'm under the impression that almost all of the heat loss for a forge will be through the doors. Most people describe their forge exterior as being warm, but not hot. Is that accurate? Is it true that in general, a forge with a larger cavity and small doors will be preferable to a forge with a straight tunnel design (assuming you've insulated well enough to make total heat-loss through the shell equal? Thanks again.