Buzzkill

Generally speaking it is a good idea to check with manufacturers regarding the uses of their products. I don't want to discourage that. However, as someone who personally tried to use one of the many refractory mortars/cements out there for my first propane forge, I can confirm that at least the brand I used did not hold up. Kastolite 30 is a good choice for a water setting high alumina insulating refractory material. It's rated up to 3000 degrees F and can be used as a flame face in addition to sealing in the ceramic wool fibers. It benefits from nearly 100% humidity during the curing phase. I usually enclose the casting in a plastic bag with a wet towel draped over the Kastolite material for a day or so to ensure that it stays as damp as needed for curing. Ambient humidity should not be considered good enough. Since you said you know close to diddly, it should be stressed that handling molten metal can be extremely dangerous - far more so than forging. It requires a fair amount of PPE to minimize the chance of serious injury if when something goes wrong. I have a limited amount of casting experience myself, but I would highly recommend trying to find a local college with a class or a local casting club/group that can assist you with all the particulars while you are getting started. All this metal working stuff can be really cool and rewarding, but it's not worth being maimed or worse due to lack of knowledge or protective equipment.

A few things: Are you truly making a smelting furnace? In other words are you taking raw ore and ending up with a consolidated metal ingot? Or are you melting pieces of metal that are already mostly purified? This is an important distinction. First, it helps us understand what you are trying to do, and secondly different temperatures are usually required for smelting than melting. Next we need to know the metal that you are either melting or smelting. 2500 degrees F sounds really hot - and it is - but if you were smelting iron ore (or even melting iron for a pour) you would most likely exceed that temperature. For copper or aluminum it might be a different story. Next, regardless of what the manufacturer tells you, most of the refractory cements simply do not hold up for long under direct flame impingement circumstances. They are designed to stick pieces together rather than to take the brunt of hot, chemically active flames. I wouldn't be comfortable using something rated for 2500 degrees in my forge, let alone something that would require higher temperatures. The refractory I use is rated for 3000 degrees, and it's not uncommon to see people using something rated for 3200 degrees. Again, that's for forging/forge welding, which can be accomplished at several hundred degrees cooler than melting or smelting iron or steel. Depending on the type of refractory it is, removing the water more quickly doesn't necessarily give you the results you want. A lot of us use a water setting refractory that cures best (most strength and minimal cracking) in a high humidity environment. After a day or so of curing we do have to remove the excess water slowly by gradually raising the temperature. If done too quickly it can create steam pockets which can reduce the effectiveness of the refractory and/or actually explode in extreme cases. O/A flames tend to be very hot and somewhat focused even if you are holding the torch back 6 to 8 inches. It's really not the right tool for the job. I don't know if you are seeing the results of rapid surface heating creating steam pockets or something else, but in my opinion you do not have the appropriate material for the job either.

Same thing in my area. There are 5 hospitals total in 3 cities within 30 miles of me, but all of them belong to one of two major health care provider conglomerates. Nearly all the urgent care, specialized care, clinics, etc. are also associated with one or the other. My PCP was in an independent practice with a couple other physicians when I started with him, but now he's also under the umbrella of one of the 2 major providers in my area. I think it's the health care industry version of the national chains squeezing out the "mom and pop" grocery stores and gas stations.

The center part of brake chambers are also a good source of casting aluminum, but you may have to find a way to safely deal with the 1/2" diameter spring coiled up on one end. There's not nearly as much aluminum in one of those as a rim, but it's a much more manageable size. I'll be watching this with interest. At one point I was considering this route, but recently I was able to pick up a Montgomery Wards metal lathe (which was made by Logan and is essentially their model 200) for a hundred bucks. I'm just waiting for warmer weather so I can reassemble it and assess the condition. It won't surprise me if I find the need to cast or machine some new parts for it.

Sorry guys, I'm with acein on this one. He's been asking about hardening of 4340 and how to maximize the hardness of it. He then asked if a specific sequence of techniques/processes would result in the maximum hardness, and instead of anyone actually answering the question he was asked how that would work. That is not helpful at all. He never stated it was a FACT that a process would result in a certain hardness. He ASKED if the hardness was achievable with that technique. Glenn specifically asked us to be respectful of newcomers. I can't fault them for becoming defensive and sarcastic when their questions are met with responses that could certainly be interpreted as obnoxious even if they weren't intended that way. There seems to be a return to excessive curmudgeonly responses lately. For the record, the pinned heat treatment thread does NOT cover flame hardening (at least I didn't see it), so implying that his answer is contained in that location is disingenuous at best. Why is it so hard to just answer the question if you know it, or link to a previous post that has the answer? If you don't know the answer then why bother responding in an antagonistic manner?

It shouldn't be a problem. You will most likely not be reaching temperatures greater than 500 F in the cooking chamber. I don't think that will cause problems with either premature ignition or excessive degradation of the burner surface. In a forge we are sometimes reaching temperatures in excess of 2300 F, so the burners have to be able to withstand that heat for hours at a time without failing.

Frosty's burner was designed to be used in a forge. Those burners in the first pic do not appear to me to be built exactly as Frosty specified. Using a reducer fitting for flame retention is usually better than nothing, but it is not ideal. A lot of naturally aspirated burners will blow the flame off the end of the mixing tube at moderate to high pressure even inside a forge or furnace until the chamber is heated to the point where it glows. Usually you can turn them up as high as you care to at that point.

Glad it helped. Any time you use vinegar on metal you should make sure you neutralize it afterwards with something like baking soda. If you don't then metals prone to corrosion will experience it in short order most of the time.

I come from the school of thought that says, "Check the easy things first." To me the easy thing is to use it again until your problem starts to recur. At that point look at the pressure showing on the gauge. If it's lower than you set it and/or dropping, then you are nearly out of fuel or you're using gas fast enough to chill the tank. You can always take the burner and supply lines apart later and clean them if you need to, but if it's a simple matter of making a water bath for your propane tank .... well, you decide which is easier.

Since the burner is top mounted, once you shut the burner down the mixing tube will heat up if the forge is hot. A hot mixing tube will promote early ignition and flames burning inside the mixing tube. However, you were showing 30 psi at your regulator. Even with a hot mixing tube I would expect it to behave differently than what I saw and heard in the video. In general burners don't just "go bad" where the performance deteriorates slowly and then they don't function. Things can get plugged up and nozzles oxidize to the point where they have to be replaced, but there are no moving parts to wear out. Even if they did, the orifice would become larger from wear and allow too much gas through. That is not your problem here. If your other burner is also experiencing a decrease in performance that suggests to me that your regulator is failing (that could happen in a more gradual way) or you got a propane canister with some material in it that is plugging up your burners. There is one other option that is possible, or even likely. Since you are using a small (BBQ size) propane tank, it may cool off fast enough to be a problem. If you use the gas quickly enough, the temperature in the tank will drop to the point where it affects the pressure. You can even freeze up the regulator in some cases. However, you were still showing 30 psi on your gauge, which is on the output side of the regulator. That makes it unlikely for the regulator or tank freezing to be the issue *unless* the pressure drops rapidly when you turn the gas on at that point. If it does, then that is most likely the source of your problems. Try placing the propane tank in a shallow pan of water and see if that changes things. Alternatively you can link 2 or more propane tanks together to slow the cooling process.

From what I saw it doesn't appear that the pressure on the gauge is going through your burner. The whistling/chirping sound is consistent with flames burning inside the burner tube. That happens when there isn't enough pressure in the fuel stream to keep the flames at the end of the burner. Usually at 30 psi you'd have a very hard time keeping the flame from blowing off the end of the burner unless you choked off most of the air. So, if I'm right you have one of a few possible issues: 1) You have a faulty regulator that isn't allowing the pressure shown on the gauge to go into the fuel supply line, 2) Your fuel line is partially plugged, 3) The orifice on your burner is way too small or is partially obstructed, or 4) the jet is aimed so far off center in your burner that it can't function correctly. The last one is the least likely to me since 30 psi of fuel with the right orifice size should still produce a lot of flame even if it wasn't suitable for forging.

As I understand it, the only reason you can etch forge welded cable to get a pattern is due to the decarb layer that forms on each strand as you consolidate the material into a billet. Generally speaking, multiple (successfully) forge welded layers of the same alloy steel will only show up as a single layer when etched. So, with cable we end up with a thin layer of something approaching mild steel around a core of high carbon steel for each individual strand. The contrast between mild (or mid-carbon) steel and high carbon steel is not nearly as stark as the contrast between a nickel bearing steel and a high carbon steel without nickel. It's shades of gray for the cable or maybe gray to black. Regardless, it's more subtle than high contrast combinations like 15N20 and 1095. Unfortunately I have next to no experience producing a good etch on cable steel, so I can't give you a "best" way to bring out the pattern.

I second that emotion, Frosty. When we were traipsing around the Yukon on snowshoes in temps between minus 20 and minus 50 it was definitely cold, but in some ways not as bad as when it's right around freezing. Snow just falls off your clothes like dust or sand when it's really cold. When it's around freezing water seeps into your clothing and freezes in the fabric. We always slept in underwear and T shirts even at 40 below (in our sleeping bags of course) due to the risk of sweat freezing inside heavier clothing. Watching people (or oneself) attempt to get dressed at -40 first thing after waking up can be amusing though. If we had to thread a needle to save our lives I think we would have all died. Parkinson's patients would have berated us for shaking so much. Gore-Tex gear does help a little with the wicking issue, but there are limits for everything.

You have it right. There didn't seem to be much difference between a T burner "top end" and an AFB inspired vortex inducer on the NARB burner block I used. There is a noticeable difference as a single port burner though. For several sessions I got absolutely no burn back into the plenum and no "poof" when shutting off the fuel when using the block that has over 180 ports which are about 3 inches long - even after being at 1280 C. However, since then I have had a little "poof" when I turn off the gas. I still can turn the pressure down to the point where it doesn't register on the gauge after being at forge welding temp without it backfiring or burning back into the plenum though. The down side is it is a large, heavy burner head, and all those small diameter holes make it a challenge to cast and clean. I made a disposable 3d printed mold form for the burner head. Once I vibrated in the refractory and placed the plenum I put the whole thing in a plastic bag for a day or so. My next step was to put the whole thing on the 3d printer bed and heat it to 100 C for about a day before removing the plastic bag and letting it set another day or so (with heat). After that I cut off all the exterior plastic, built a small fire, and moved the burner block and plenum gradually closer to the fire and then eventually in it. It was a several hour process, but ultimately the burner was in the middle of the fire with coals under it, and the plastic all burned out fairly well. It was still worthwhile to run a rod through all the holes I think. That's not exactly the prescribed method given by the manufacturer, but it seems to have resulted in a solid burner head with no cracks (yet).

I think I could make out that it's rated at 115v, Type S, and the manufacturer was Packard Electric Division then I could make out the word "Motors" and of course Ohio. Applying a little Google-fu, I came to the conclusion that the motor was made by General Motors in the Packard Electric Division, which is based in Warren, OH. I can't tell if it's S 7033, S 7035, or S 7036 stamped in at the top. I did find a 7035 OEM replacement motor on Grainger's site that is 1/2 hp, 1725 RPM, 115v and used in HVAC applications. I don't know if it's a match or not though.

I'm not sure how that would help, Steve. He mentioned that the motors he has have no markings of any kind on them any more. My understanding of electric motors is limited though. How could that be used to identify the hp of the motor? What are the pertinent features to look at or measure? I've got a few old motors myself that I'd like to check out.

I don't know how to DIY test an old motor for hp, but if you had the RPM rating, the voltage, and the amperage draw, I *think* you could calculate it reasonably accurately. One other thing to keep in mind on the motor: You really want a Totally Enclosed Fan Cooled (TEFC) motor for this application. If you use a motor with internal components open to the air, the abrasive and metal dust will most likely ruin your motor in short order.

If you go down to 1hp or lower with a 2 x 72 belt grinder you are going to have to sacrifice speed or you'll bog it down easily. My original configuration was with a 1hp single phase motor and step pulleys opposite each other like you might see on a drill press for changing speeds. On the fastest belt speed configuration I could easily stall the motor with only moderate pressure on the belt. I don't want to discourage you. My belt grinder went through several upgrades to what it is now. I used skateboard (longboard actually) wheels for the top and bottom of my flat platen and I made a drive wheel from 2x4's and Gorilla Glue on the first iteration. That drive wheel is now used on my DIY power hammer along with the same 1 hp motor originally used on my belt grinder. It was definitely better than not having a belt grinder, but it didn't take long for me to want more.

Just so you know where I was coming from there -- When I bought my 2hp motor, the 3 phase versions were less than half the cost of single phase. A VFD/3 phase motor setup also will "soft start" (at least mine does) rather than try to instantly be at max RPM. I don't know enough about the different motors and VFD's to know if you can effectively do variable speed with single phase without sacrificing horsepower. I do know that I like my grinder much better now with 3 phase 2hp and variable speed than I did at single phase 1 hp and step pulleys.

If you are able to use a 2 hp motor at its full potential you should be able to use either a 4" or 5" drive wheel without any problems. A lot of electric motors in the US have stated RPM ratings around either 1800 or 3600. If you have a lower RPM motor you'll probably want to go with the larger drive wheel. If you can fully utilize a 2hp motor, I believe that indicates you either have high amperage 110v circuits available to you or you will be using 220v. If it's the latter and you can afford it, I highly recommend getting a VFD (variable frequency drive) which will allow you to use a 3 phase motor and adjust the speed of the motor to your liking for a given task.

Well, it can be a bit coarse at times.

To play off Frosty's suggestion, the highland cousin of his Bavarian counterpart might be Ruff McGritty.

Looking forward to the pics and the story. As Jer says though, if you can't make it perfect, at least make it adjustable. I'm curious what you will name the grinder. You have the Wonder Hut and Burnie the charcoal retort. I don't want you to get bitten by a grinder that feels left out.

I agree in the sense that I think the size, number, and length of the outlets (ports) affect the amount of friction and therefore the back pressure that is created. However, I've not made a NARB yet, regardless of the number, size, or length of holes, where the flames on the ribbon burner were tuned the same as when I used the same T and mixing tube for a single port burner. The NARBs always seem to run a bit richer for me. It's entirely possible I'm doing something different/wrong compared to other people, but I've always had to find a way to reduce the fuel or increase the air to get my NARBs running the flames I want. This burner head is already huge - about 3 by 7 inches with more than 180 holes, and frankly I don't think I have the necessary motivation to go through the entire process of casting it again. I really like the small diameter ports for a couple reasons: 1) The burner is super quiet. The fuel coming out of the jet orifice makes more noise than the flames inside the forge, and 2) I can turn the burner down to the point where nothing registers on the pressure gauge after being at forge welding temperatures without it backfiring or burning back into the plenum. Since I can reach forge welding temps with it, I can check off all the most important features (to me) in a burner. Part of me really wants to experiment more, but another part wants to heat and beat some steel.

Although there seems to be less than cyclonic enthusiasm for this topic, I did a few more experiments, so I'll post a more summarized version. I attempted to use the vortex inducer on a single port 3/4" burner with a small flare on the end using a .8 mm 3d printer nozzle. I couldn't keep it lit unless I covered about 80% of the air intake, so I abandoned that test and installed a 1 mm 3d printer nozzle. This performed much better. I went through similar pressures for about the same amount of time shown in my previous post above. I was able to reach 1275 degrees C after working up to 20 psi in 5 minute increments and there was a moderate orange dragon's breath (about 6 to 8 inches past the front of the opening). Surprisingly, I was also able to turn this setup down to 1 psi after being at forge welding temperature without it burning back into the mixing tube. Next I tried the 1 mm 3d printer nozzle on the 3/4" mixing tube with the vortex inducer and the burner block using 180+ 1/8" diameter ports that are about 3" long. I abandoned this fairly quickly. The dragon's breath was significant and mostly blue even at 20 psi. Next I moved to a Frosty T setup, but still with the 1 mm 3d printer nozzle. This was not fine tuned and the end of the nozzle was only about 1/3 into the opening when viewed from the side. I stayed with the 1/8" diameter port burner block. This still produced a lot of blue dragon's breath so it was abandoned quickly as well. After that I replaced the 1 mm with a .8 mm 3d printer nozzle, but kept the Frosty T 3/4" setup. I ran this at 20 psi immediately without stepping up in 5 psi increments. Dragon's breath was slight and orange. After 20 minutes the forge had gone from 681 C to 1247 C. Finally I switched back to the vortex inducer, but still with the .8 mm 3d printer nozzle and 3/4" mixing tube on the same NARB burner block. In about 15 minutes at 20 psi the forge went from 970 C to 1240 C with a little more dragon's breath than the Frosty T. I was running out of propane at this point so the experiments ended. So here's my conclusions: 1) I need to refurbish my forge, and it's more of a heat sink than I originally thought. 2) It appears that my NARBs cause a reduction in induced air compared to a single port burner whether using a vortex inducer or a Frosty T. 3) The enhanced performance of a vortex inducer is significantly diminished or eliminated on a NARB with lots of ports. 4) I could reach about the same temps with a NARB as I did with a single port burner, but the single port got there more quickly (but also with a larger jet orifice). 5) Although I really like the performance of a vortex inducer, I like the quiet ribbon burner more.