evfreek

Do you have large enough tanks? Most newbies to OA welding are not familiar with the 1/7th rule. Be sure to pay attention to it. I am not really a big fan of OA welding and I have an oxypropane set, which doesn't weld. I visited my art buddy's workshop and he handed me a torch and told me to get to work on his T-Rex wireframe for a sculpture. It was great, almost like TIG but without the foot pedal or current control. There's no way I could do that with my stick welder. But heavy stuff is different.

For some odd reason, people who ask these sorts of newbie resource-limited questions are often kind of cheap. Not saying that you are, but as soon as you lease that big tank and try out that huge tip, you might be clutching your pockets like a penguin. Been there, done that. But, then again, I have a buddy who does all his big welding with a torch, and his gas budget is huge. Gone thru a bunch of stick welders in tank refills, and he loves the big tips and rosebuds. And, this guy is anything but cheap, being generous to a fault. But, somehow, I smell il pinguino waddling around, so watch your costs!

Rebar can be confusing to beginners. If you find a free piece, you could compare it to a piece of mild steel that you paid for. If you go to a blacksmith conference workshop, you will find that they do not pass out rebar to the students, unless it has been qualified by a master smith. Most of the rebar is inferior to mild steel for making j-hooks, leaves, and the like. Time is precious, especially the most rare and coveted species of time that a person uses to get an education. Why squander this time?

If you really want to use rebar, know what you are getting into, and try to have made at least one leaf on a real anvil with real mild steel. Also, it helps to know how to do a spark test, since some grades are medium carbon, and it is good to know this. When I started out, I had a little railroad track anvil at the wrong height, some pretty hard rebar, and no instructor. It was discouraging beating myself to death, and it's a good thing I didn't quit.

What a major loss for blacksmithing. I met Grant at a conference: lively, animated, opinionated, and helpful. Just a great guy all around. We'll miss him.

We have a nice heavy Vulcan in the shop. An old geezer dropped by and said he remembered that anvil from something like 70 years ago. I don't know when the face was welded on, but someone really went to town on it, especially on the edges. Lots of undercut, poor color match, rough results, and decreased rebound. I've been hammering on it, along with a couple of students and enthusiastic interns for the past 6 years, and it is fine. It has seen some heavy work, with double striking using sledges. A little rough, and it marks up the work, but it is still intact, with no cracks/spalling.

I noticed the comparison between coke and propane BTU on the Phalen Horseshoeing website:

http://www.phalenhorseshoeingsupply.com/

It says that one $35 bag of coke has the same BTU's as 67 Blue Rhino propane tanks. The latter is 67x17 = 1139 lbs of gas.

Does this make sense? Or is it that these amounts do about equal amounts of forging? Or, is it a typo, and it really means 6-7 tanks?

Sounds like it is safer to leave it as a fire extinguisher. I'll try craigslist.

I just had a fire extinguisher training party. Picked out all the fire extinguishers older than 10 years, set a bunch of gasoline fires, and let the boys have at 'em with the extinguishers. It was a great time to be had by all, with many of the classic mistakes including spraying the flames and not the base of the fire, and walking away before the fire was out. We just gave them a little shake and they all performed flawlessly. Some of the people were surprised how little of a fire you could put out with the small 1Abc ones. I pointed out that big fires should be left to the firefighters, and these little extinguishers are only good for trash cans, overheated frying pans, and smoldering electrical appliances. Next time the rotation goes around, we'll just add the CO2 extinguisher to the line-up. When I took them in to be recycled, I was shocked at the $5 recycling fee. These little ones are more expensive to refill than to let them "disappear" and replace with a made in China one. Seems that the local extinguisher place refills and sells them, and it would be a loss for them if it wasn't for the fee. The trash company won't take them, especially if there is a whole bin full of them. ;)

Both are fine. Sometimes, when a motor burns out, it gets continuity between the windings and frame. Also, sometimes a winding goes open, or the capacitor burns out. Does the motor hum and not start, or does it just sit there and draw no current?

It looks like the consensus is "do not modify". As for the comment that "no one will fill it for you", at least one place will fill it for me. The shop that offered to do the conversion. Apparently, they are the only place around here that refills fire extinguishers. If they convert it, they certainly will service it. They get to do hydro's every 5 years, anyway. The CO2 tanks require more frequent testing due to corrosion possibility.

As for bells, I have an OSHA buddy who de-certifies gas cylinders. There is an endless supply of these things, but they are miserable to work on. They are made of a tough steel, they are scary to cut with a torch, and they radiate a lot of heat when they are at forging temperature. It is a lot of work being asked to assist on forging a bust and hips on one of the 5 foot ones.

This was really more of a complaint or rant on the throwaway society that hurts a traditional blacksmith's heart. Most of my buddies have the small grow or keg sized tanks that they picked up cheap from some Chinese importer. Probably safer too. Gotta get with the times :(

Hi. Someone gave me a CO2 fire extinguisher. It is the small 5 pound one, with the valve handle on top and a plastic horn on a swivel hose. I want to convert this into a CO2 tank for my mig welder and for carbonating water. I have a spare regulator for CO2, with a CGA-320 fitting on it. The fitting on the fire extinguisher valve is an odd one. It has about a 1/2" opening and appears to be a 1/4" NPS thread, not the more common NPT thread that is tapered. What would be ideal is an adapter that has one male NPS end and one male CGA end. Unfortunately, these are almost impossible to find. I called a couple of fire extinguisher places, and most don't deal with CO2 extinguishers. Others just send them out to be refilled. Finally I received a referral to one who said they know what I am asking. Although they said that they have the adapter, they said that they it would be better to vent the cylinder to the atmosphere, refit it with a handwheel valve, and hydrotest it. In total, that would run about $90. Looking around Ebay, I noticed cheap new CO2 tanks about the same size selling for between $50 and 100. Some of them were substantially less, but would require high shipping charges. Locally, they are probably more, but there wouldn't be a shipping charge. It looks like it would cost less just to get the cheap made in China new tank than try to retrofit the old one. But, then I would waste the tank.

A lot of people lament that we live in a throwaway society and that we depend too much on Chinese imports. But, it seems like, at least in the short run, it is much more convenient and less costly. The way the fire extinguisher shop was talking, it was unclear whether they really had the adapter. Now, I am beginning to doubt it, and since it is pretty far away, it will cause a lot more carbon dioxide impact to drive there than it will to vent the tank to the atmosphere. Searches on the internet do not show adapters of this type, although there are several hits for paintball tank adapters. One resource did say that it is safe to adapt an NPT thread to NPS if lots of sealant is used. 800 psi of CO2 is enough to cause a lot of damage if it comes loose, but a simple thread shear calculation tells that a silver soldered homemade adapter of this diameter would be safe at these pressures as long as it was made of brass and not cast iron.

If it is desirable to minimize the waste stream, are there any other good ideas for salvaging this tank?

This is almost certain to produce too much carbon monoxide to be safe. Even a small Asian hot pot can make you sick, and this is an order of magnitude smaller than your bucket forge, at least in terms of rate of fuel consumption. It sounds like you are a high school student from your style of writing. You have data on the rate of consumption of charcoal by your forge. Do some chemistry calculations and see how fast you will build up a dangerous concentration of carbon monoxide. Not if, when. Then, do a little surfing for the response time of a home improvement store grade carbon monoxide detector. Note that these detectors are not for measuring in dangerous situations. They are useful to warn you if there is a slow build up due to a furnace malfunction or an internal combustion engine in the vicinity. It is not advisable to use one of these detectors for a lab experiment, at least without knowledge of response time, calibration, reliability. And, if you are wondering, yes, I have had a first hand bad experience.

This book was written by S. Ann Dunham, whose name is mainly recognizable through that of her son, Barak Obama. Despite the title, it is primarily about blacksmithing. It does contain an academic review of the recognized anthropologic historians of Indonesia, including Geertz who wrote "Peddlers and Princes". Although the book contains many references to subjects which may be considered to be politically supercharged today, such as government corruption, class stratification, and perception and racism of other cultures, it is primarily focussed on blacksmithing, and as such provides an intriguing window on Indonesian blacksmithing practice. The primary product of Indonesian blacksmithing is agricultural tools, such as hoes and pick axes. The book is not a how-to book which tells how to make these implements. Rather, it seeks to explain how blacksmithing works in society, economy and culture. It contains rich color and black and white photographs of blacksmith shops, and explains their detailed operation, including such interesting things as the progression of a blacksmith's training and career ending with his succumbing to various work related disabilities. It also contains a helpful translation guide at the end with a list of blacksmithing terms.

The shop functions more like older shops than new in the West. The master smith is called the "empu". He is the top ranking person in the shop, and he rarely strikes the metal. Instead, he is responsible for pulling the metal when the heat is correct, holding the piece on the anvil, directing the strikers, and heat treating the implement when it is done. The empu usually is too old to do the physically demanding striking, and his right hand is often knotted due to repetitive motion wear from tongs (which are held in the right hand). The second rank is held by the "pajak" who are the strikers. Shops which make small implements have one of these, while those making larger tools use 2-3. For example, in regions with heavier soil, the hoes may be 50% larger. The "takang ubub" is the lowest rank, and he operates the bellows, usually double chambered pipes, or Chinese style box bellows. The "takang kikir" does the cold work and finishing, and this is traditionally not a held position, but the others fill in as shop schedule dictates. Note the use of the male gender. Due to cultural taboos, women are not allowed near the fire, and (rarely) do peripheral work.

The author has a keen eye for descriptive details of the blacksmithing industry, and an erudite, though academically dry, presentation. The politics may be enlightening, especially to those who follow the red-blue struggle and deadlock characteristic of these times. All in all, it is a captivating read, full of amazing facts and connections around the facinating story of blacksmithing in Indonesia.

Wayne's World. Check the CBA events page. Coming up at the beginning of next yr.

Really nice rack. Good photo's too; they really show the design details. It is quite an inspiration.

About the torch, it helps to be patient and one might appear for a real deal. I picked up my set in pieces. I needed a plumbing torch for an unpleasant, but necessary, task. So, I got a turbo torch clone on Ebay. I know, this is not an oxy-fuel torch, but it still can be useful, and it has a lot more grunt than a bottle torch. The BBQ tank came from a neighborhood discarded grill tank. Shortly afterwards, I was buying a large hand drill from a pro tool picker and she had part of an oxy-fuel setup. Oxy cylinder, reg, and handpiece with one tip. She said that she would let it go for a hun. I told her that I was just looking for a drill. She said that she saw me eyeballing it, and maybe I would want it for 60. Well, twist my arm! Since I had the fuel reg and tank already, it was turnkey, and it really helped for the collars and wraps, especially for the big stuff that I couldn't muscle down to the ground forge. Recently, I scored a broken MIG welder on a gas welder cart for cheap. Bingo! Done!

I used a handheld propane torch to braze a copper reducing fitting into a sch 40 steel nipple for a forge burner. The trick is to reduce the heat loss, since the propane torch does not have the temperature to spot heat the braze area. You have to get the whole piece to orange before the braze will melt. I did it by putting the assembly into a soup can filled up with ashes. Only the top with the gap was above the surface of the ashes. Naysayers will cry out that the propane torch will blow away the light ashes. Yes, that is correct! Sprinkle a thin layer of sand on the top. It will be enough to keep the ashes from getting blown out, but not conduct enough heat away to cause failure.

Remember that to reach a high temperature, you will need to keep the piece small and/or well insulated. It also helps having two torches, as mentioned above, especially if one of them is a MAPP torch (the one you use for the brazing). Really, it is so much easier with a proper oxy-fuel torch. Also, a propane or charcoal forge works great for forge brazing.

Again, as everyone says: it depends. Tell us what you want to do. I have heard of people brazing cannon balls together with a propane torch. These torches use compressed air, and make a fearsome amount of noise. You will also need some clever insulation.

There are a lot of pesky neighbors in my neighborhood. A lot of them know that I do blacksmithing, and they get super sensitive everytime they smell smoke or hear noise. There was a guy moonlighting with auto shop work in his garage. He ground sheet metal at 10PM, and I got blamed for it. Someone else was jackhammering his concrete patio, ahd I got blamed again. Sometimes the neighbors figure out that it is not me, since they see me looking around for the source of noise, but there are just those dimwits who just stare and ask "where that hammerin' noise is coming from" when it obviously cannot be me. Then, the jackhammer guy's wife gets all upset when I come snooping around, saying the noise is none of the neighbors' business. Then, this guy is dumping his lumber all over the place, and the neighbors go, "oh, it's the blacksmith again." It is very obvious that the noise is coming from boards falling. It is more of a wood kind of noise, not a metal clanging. Besides, I am out there trying to figure out where the noise is coming from, along with all the neighbors, and they still think it is "the blacksmith". Some of them kind of scratch their heads and I am sure they are thinking how could it be him when he's standing right here.

I have had the city inspectors called on me, and the police called, but the interesting thing is that they seem to be pretty sympathetic. I hope that nobody calls the EPA. I have heard that they can be pretty troublesome. In fact, I've never gotten in any trouble. It has gotten to the point that I don't do much work outside, since I don't like the negative attention. The funny thing is that one of my buddies does lots of blacksmithing, fabrication, and welding just up the street. He has a whole bunch of junk cars and he burns a lot of smoky coal and nobody seems to mind. Different neighborhoods, I guess.

Hi Philip. Thank you for the detailed description of the different types of China made anvils. That is very interesting. Perhaps one of these was what southshoresmith was referring to. Since this topic piqued my curiosity, I started looking around the WWW for information. There actually is quite a lot, much of which seems to have been added in just lee last few years. It seems that this "steel-like" cast iron has been around since 200 BC. The Chinese have learned a lot and forgotten a lot. My Chinese colleagues are not much help from the physics, engineering or metallurgy fields. Snappy one line answers and suspicions about why I am snooping about this stuff. Much better luck from the historians.

If the "bread loaf" anvils are fabricated, why do they have to look like bread? Edges are useful, and junk steel can support some decent radii unlike junk cast iron?

Interesting topic. Regarding steel anvils I was under the impression that all steel has the same modulus of elasticity - regardless of grade. Which logically suggests that a mild steel block will have the same 'rebound' properties as an alloy steel block of steel. Assuming that the yield point of the block is not exceeded. ...

That is a huge (and incorrect) assumption when you are bouncing ball bearings off a steel block. A hardened 52100 ball bearing will leave a dimple on a mild steel block when dropped from 1 foot above. Computing the impact force and finding out that it is above the elastic limit is not a trivial problem. There once was a website which told how to do this, but it is now defunct.

I remember reading that the traditional cast iron Chinese anvils were more like cast steel than cast iron.

Interesting. There is a wide range of cast iron strength levels, depending on processing. Do you have more details?

I wonder how dangerous it is to use an ASO as a substitute swage block. Cast iron is weak, but its elastic limit is pretty low, and it seems that it wouldn't store all that much energy. Would flying chunks be much of a hazard, or would they just crack off?

Here is a link in which forum members discuss the danger of using cast iron for press plates. Note the injury picture. Is this likely?

http://www.pirate4x4.com/forum/showthread.php?t=849831

Hi southshoresmith. Both you and Thomas/HWooldridge may be correct. It is pretty close, anyway. The following reference may be helpful:

http://www.esm.vt.edu/%7Erbatra/pdfpapers/confproceeding1994%28533-537%29.pdf

It gives curves for shear stress of 1151 steel at strain rates associated with hammer forging. At 800C, 18850 psi is shown. At 1000C, 7800 psi is shown. Cast iron has a yield strength of about 20000 psi. If you strike a centered piece of hot steel in the middle of the anvil face, you are in the safe zone. Any cooler, and striking over an edge, especially if the target is thin and provides little shielding, may put you in the danger zone. Alloy steels retain significant strength, and extrapolating to a dull red may give values exceeding the cast iron yield strength. There are no curves for 1045 or 5160, but the latter might be stronger. If you look at old cast iron anvils, they can be in pretty bad shape. The traditional Chinese bread loaf shaped anvils would tend to survive better.

All this exploration gives some suggestions. Work hot. Avoid the edges, if any, when drawing high carbon steel. Use the hammer peen instead.

Actually, surfing around for some forging dynamics papers and combining with some physics can go a long way towards solving the problem that Thomas was asked to pose to a grad student. I am afraid, however, that the typical grad student may have some difficulty making much headway on this problem.

Hi.Dave. The article in the CBA magazine is a good start. There will be a few more articles in the series, and the second is coming out in the next issue. If you are interested in more technical details, the full version is available on the website. It is a little bit heavier sledding, though.

My neighbor once drew me aside and asked with a sly look on his face, "Don't tell me that you don't cheat a little when you go to those 'blacksmith conferences', eh buddy?" I told him that it was not possible, because they don't have 220 available for the arc welder in the forging areas. Some people just don't have a clue. :rolleyes:

Using a chisel is pretty hard. My friend torch cut a hole, and I worked it with a chisel. It took a few months of work, on and off. It helps to have sharp chisels. They get dull, and if you have several, they can be ground in a batch. Also, the noise is extremely annoying. This is too much work compared to the weld and build up method One can weld up a hardy hole in an afternoon, not including the bevels. Drifting it hot may also be workable, but that is a big hot heavy dangerous piece of metal to be moving around. A hydraulic press and a broach is another possibility, but this will probably end up costing more than a water jet shop.

What kind of steel did the instructor provide you? I was given sucker rod, which the instructor said was "blacksmith qualified" 4130, and it hardened just fine in warm water. There was an old auto coil spring in our shop which sparked high chromium, and after air cooling, it was too hard to file. A subcritical anneal got it soft enough to file a little, and probably hard enough still to use as a punch. Mild steel doesn't seem to gain much advantage with heat treatment, at least with a water quench. I wouldn't quench M-2 or even S-7 in oil. The S-7 seems to do just fine with an air quench followed by a temper at 900 - 1000F. This is a bit hot for a simple carbon steel. It is supposed to be about 42RC at this point, but my touchmark was a little hard to file. Got it touched up just fine with a carbide mill lubed with kerosene. Really depends on the steel.

Hi Fewood. I had the exact same problem with almost the exact same element that you showed above. The problem is that the little finger has enough mass so that its inertia causes flexing at the root when the main trunk is impacted. There are a bunch of ways to solve this problem. The way I solved it was changing the order of operations and doing any forging after the tendril was developed at a very high heat. Also, it helped to interpose a lossy material at the places where vibrations can cause problem, like a wet sock or piece of rotten wood. The problem is not really vibrations, it is the inertia of the secondary piece. Imagine standing on one of those whirly platforms that are often found in playgrounds. Someone starts it impulsively. You are liable to slip. Now, imagine holding a big heavy box over your head, and the person does the same thing. Give it a try. See???