twigg

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About twigg

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    Boulder County, Colorado

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  1. Thanks all! There's a bunch of replies I just caught up on. Since my last post, I spoke to a mechanic on my commute to work. They pointed out their scrap pile and said I could take what I like. Apparently, there's no centers in the county that buy steel. On another note, I've just run totally out of storage space with my last few acquisitions. Gotta take a hard look at my shop plans and inventory, and I gotta get rid of the stuff I don't need.
  2. Haven't done any forging recently. My brain's been preoccupied with a 42000 RPM vacuum pump at the lab where I work that's been making a concerning amount of noise. Time to start bringing my face shield to work... I did manage to braze flexible accelerators for my 1/2" burners (design from Michael Porter's book), and hang a 15 oz cross pein. Used a section of ash I got from a dirt tamper my folks were getting rid of to make the hammer handle. I ended up needing a steel wedge and cracking my handle. I gave it 50 or so whacks on my already-swiss-cheese railroad anvil, and I didn't see the crack grow. So I just filled it with epoxy and wrapped some thick thread over the cracked part to hide my shortcomings. The coverup is mostly so I don't have to look at it all the time.
  3. Thanks all for the input. I hear you about getting known steel for razors. I've already started stockpiling 1095 and 52100 stock from ebay auctions for when I know what I'm doing. I've been practicing my forging technique on RR spikes in the meantime. I was thinking of scrap steel mostly for kitchen knives. I can probably get 6ish razors or 1 chef's knife or 2 paring knives from a single knifemaking billet like I'd buy online, so it's way more economical for me to buy known steel for razors than for kitchen knives. And I don't know if I'll really enjoy making kitchen knives until I get started. That's why I'm hoping to find some spring steel. Also, I'm just curious what the best quality I can get from scrap materials is (again, not for razors, I know from experience the feeling of shaving with a razor that doesn't hold an edge and all I can say is ow) Also, I have no idea where my interests will lead me in the future. Razors are a nominal goal for me, just something tangible I can aim at while learning. I'm totally willing to be seduced by other crafts. It just turned out that razors were an interest of mine that lead me to blacksmithing in the first place. I started by restoring antique razors by hand, and it got out of hand from there. I'm a serial dabbler with no shame I'll keep an eye out for plow discs.
  4. Thanks all! Really appreciate the heads up, both. Definitely out of my comfort zone. I'm hoping to make straight razors and kitchen cutlery, so that would mean scrap tool steel (O1, A2, W1, etc) or 1095 for the razors and I probably want to experiment with a variety of mid to high carbon content steels for the kitchen knives. I have a feeling 5160 will probably be the most available knife steel, if I manage to get some scrap springs. I'm also trying to learn to weld, and have plenty of small fab tasks, so I'm always on the lookout for A36. Putting together all the advice thus far, it sounds like my best options are to ask for the foreman at the university construction site, and to try the nearby mechanic. I have a hunch that the price of scrap must be relatively high around here, but it's still worth a shot. I'll definitely take your advice and show up armed with pastries. I'll start asking around and letting people know I'm looking.
  5. To be honest, I'm pretty embarrassed to have to ask this. How do you find a scrap yard where you can buy material? I've looked up some scrap businesses in my area, but if they do sell scrap to the general public, they don't advertise it. All the websites advertise that the yards buy scrap, but don't really mention selling any. Plus, I have yet to find a single business in my area that advertises itself as a "scrap yard" or "salvage yard". Instead, I find salvaged auto parts sellers and recycling centers, and I'm not sure which businesses would sell and which would tell me to get lost. What do you all look for? I'm in Boulder, CO if that helps. I have a car. I have an angle grinder and hand tools, but I do not have jacks. So I'm not able to take leaf springs or axles from auto scrap yards unless they're already removed for me. (I would just buy jacks, I know they're cheap, but I am completely out of room to store more tools for the time being. On top of that, I've never used jacks before and I've got some anxiety about going under a raised car for the first time with a grinder and no one watching out for me.) Of course, I do keep my eyes open for other sources of scrap. Last weekend I snagged a cheap metal desk off the curb and broke it down for rectangular pipe and sheet metal. I always keep an eye out for bed frames and such. The only construction sites I know of in town are on the university campus, and I haven't bothered asking for drops there because they're large outfits and the foreman probably wouldn't take the time. Other than that, I am networking with local fab/welding businesses, but, well, I'm a painfully shy individual and I'm taking my sweet time before I feel comfortable enough asking for anything. I prowl craigslist regularly, but I'm too slow on the draw. The big reason I'm interested in scrap yards is because it would be great to be able to shop a larger variety. Not likely I'm ever going to find A2 on the curb (not in my neighborhood anyhow ) P.S. I do realize I could solve several of these mysteries by picking up a phone. It'll be less of a strain on my nerves if I have a better idea what to expect going in. I couldn't tell you why but my millennial instincts would rather get a broken arm than call up another human being
  6. twigg

    My first forge!

    Thanks! I really appreciate all the time and energy you put into this thread. I'll be back when I have made progress on the 3/8" burner.
  7. Total beginner here. I forged my very first piece yesterday from about 1-1/2 inches of railroad spike. It's more letter opener than actual straight razor. Plenty of issues (cracks in the tang on the other side, grinds are nowhere near slim enough, completely zoned out and misplaced the pin hole, left the tang too skinny, etc etc). Purpose of the project was to have fun and get me excited enough to keep trying. Managed to do that. Learned a bunch along the way. Also, I'm glad to be making these mistakes on bits of railroad spike instead of 1095. Also, to be fair, I did a bunch of grinding to get that shape. More or less, all I forged was beating the RR spike to length, forming the tang, and bending the tang. Going to add on forging the bevel next time around. I didn't bother trying to get the proper edge geometry because right now all I've got is a bench grinder. I plan on getting a 2x72 belt grinder in the future, so I'll start the fine grinding then. Plenty to practice in the meantime.
  8. twigg

    My first forge!

    Thanks! This is really helpful! I did a little more forging in the forge, in the same status as my original post, just to get a feel for things. (I already layed some ITC-100 down, so I figured I might as well play until the lining breaks down.) I decided I would like even less forge volume (got tired of reaching deep into the forge to position a tiny straight razor blank near the hot spots). I don't ever see myself working anything more than 2" wide, and I don't see why I'd ever need length (actually length seems to be a real pain). Also, my burner angle is not what I hoped. With all this in mind, I came up with a redesign plan. My thoughts are: I can cut the length by ~3" by removing the front and back domes and replacing them with flat sheet metal. While I still have the interior open, I can add another 1/2" of ceramic blanket and bury it in a 1/2" protective layer of refractory, followed by ITC-100. That would make my total lining as follows: 2" ceramic fiber blanket, followed by 1/8" satanite + ITC-100HT (oops!), followed by 1/2" of ceramic fiber blanket, followed by the 1/2" sealing layer of refractory. That should bring me down to an inside diameter of 2.75". According to the gas forges / burners book I mentioned, a 1/2" burner needs 5" of clearance before hitting the work piece. So, if that clearance scales with burner cross sectional area, a 3/8" burner would need 2-13/16" clearance before the workpiece. That I could easily achieve by slightly recessing the burner more than 1/16" from the lining. Because I will be replacing the front and back, I can rotate the forge to have any burner angle I want. With such a small diameter forge, I don't think a swirl would be helpful, so I'll just go roughly 15 degrees off TDC. Biggest remaining issue is that the burner collar will be huge relative to the burner. Oh well. I shrink the opening a bit with refractory. With all those changes, that should bring my final forge volume to 90 cu in. This might be a bit off the deep end, but here goes. I was wondering, would it be worthwhile to try and internally flare the entrance of the capillary tube with a 00 size center drill? My thought was tapering from the 1/16" tube OD to 0.025" (drill diameter for size 00) would preserve more momentum in the transition from the MIG tip to the capillary tube? I guess that would also reduce the pressure a bit. Again, I could be making a fool of myself. I just find these design challenges fascinating
  9. twigg

    My first forge!

    Ain't that the truth and thanks a bunch, Mikey! So I did a little more playing around with the forge. Even forged myself a (fake) straight razor for practice/experiment. Saw a couple of issues: First off, turns out my burner collar isn't the issue, it's the opening in the lining that sets the orientation of the flame. If I try and tilt the burner up, the tunnel through the lining steers it right back down. So I'm going to have to mess up the lining one way or another. Might as well fix the whole darn thing and bulk up that refractory layer! To avoid having this same issue again, I'm going to try and make a funnel shape in the opening where the flames enter the forge. That way I should be able to adjust the pointing of the flame without smacking into the lining. Another line of thought I'm having. With another 1/2" of refractory, my forge inside diameter goes down to 4" and my forge volume goes down to 113 cu in. I'm worrying I will absolutely roast this forge with a 1/2" burner. Also, after I did about an hour and a half of forging, I set off my CO alarm, an hour after I turned off the forge. I take that to mean I've got a bunch of chimney effect, and I'm pretty sure I know the reason. Mikey, I believe it's your design I followed for my 1/2" burner. It's from the book Gas Forges for Forges, Furnaces and Kilns. The reason I think I was chimney-ing was because I had an unexpected twist where my bell reducer would not thread on the burner tube far enough to meet the choke collar (it did just fine before I drilled out those slots! must've banged up the threads somewhere along the line), so there's about 1/16" of gap when the choke is fully closed. I was sick of filing at that point and left it as is. It would be an easy fix, but with the volume constraints, I'm thinking of scaling down to 3/8. This time, I'd take my burner tube and choke collar to the machine shop where I work. They got a couple of Bridgeport mills. I was just feeling too shy last time. Now I'm too sick of hand filing to care The other option, as I understand, is to use less regulator pressure on my 1/2" and position it further outside the forge. Makes me uneasy having the burner in such a mechanically unstable way. Set screws / position screws love to back themselves out during heat cycling, and I've never arc welded before, and I suck at silver brazing (as you saw!), so I'm not gonna risk that setup. Also, will a 0.023 mig tip still be the proper size for a 3/8" burner, or should I go smaller? I'd love to understand the math behind the accelerator dimensions if it's not too much to ask. Thanks!
  10. twigg

    My first forge!

    Thanks for clarifying. I put about 1/8" thick layer of refractory the whole way around (main reason being to totally seal the ceramic fibers. I already got lung problems and don't need more). Just to make sure I understand, you mean having the burner near vertical would be worthwhile, because it increases the distance between the flame and the work, right? Just curious, doesn't having a more horizontal angle, with the flame swirling down the wall, give an even longer distance to the work than a vertical burner? Since I have a cast refractory lining already, do you think it's worth it?
  11. twigg

    My first forge!

    not sure I understand. Do you mean to have the burner pointing slightly less than 90 degrees off the vertical, or do you mean to have the burner only slightly angled off TDC? Also, I just realized that the pictures I put in my original post make the burner look lower than it actually is, at least to my eyes. Not sure if this threw anyone off, but just in case here's a better shot. Ignore the forge cart for now. It's not finished and there's a bunch I want to improve about it. This is just the setup I had for my test run. Also, to clarify, what I saw during my test run that had me concerned was I saw the flame off the burner hitting the far wall of the lining at a 90 degree angle (see first sketch). I was hoping to get glancing incidence to encourage a nice swirl, but I got a hard sudden stop instead. Before I read Mikey's comment, I was going to make a new burner collar with a miter so the flame would skim horizontally off the top of the forge lining and get a swirl from the top down (see second sketch). Now I'm starting to think I have the wrong idea. Can someone point me in the right direction? Just want to know which design principles I've misunderstood First sketch: what I saw happening during the test run Second sketch: what I thought would be better
  12. twigg

    My first forge!

    I lit the forge for the first time to see what needed improvement. Yeah, I saw exactly what you meant during the test run. Great idea, thanks! Still need to make a few tweaks to the cart. Will post when ready.
  13. twigg

    My first forge!

    For those who haven't read my intro, I'm green as can be. I have been dreaming up plans for the past five or so months. I mostly plan to work on straight razors and kitchen cutlery, so I planned on a small propane forge. I didn't feel confident with the idea of cutting into a propane tank, so I went with a helium tank like they make for party balloons. The main difference (besides safety) is volume. These helium tanks are about 9.5" diameter and ~13" tall. I recall 20lb propane tanks are closer to 12" diameter, and a few inches taller. Since I'm only interested in smaller pieces, it works for me. The main downside was that the ceramic blanket was a tight fit. If anyone else is thinking of trying this, use four layers of 1/2" blanket instead of the usual two layers of 1" blanket recommended for propane tank forges. Lining: 2" of kaowool 8# density (two layers of 1" blanket), rigidized, followed by about 1/8" of satanite (2 coats, each approximately 1/16"), followed by one coat of ITC-100 HT roughly 1/16" thick. Floor: none yet. I couldn't fit a firebrick inside, so now I'm debating doing a refractory floor. On the other hand, on the front of the forge there is only a 1/2" lip between the bottom of the opening and the interior lining, so part of me thinks I could get away with not having a floor. (On the back opening, the lip is about 1" because I didn't take the time to do proper layout). Your input would be appreciated! Burner: I've made two kinds to experiment with. I made one 3/4" burner following David Hammer's video (shown below), and I made two 1/2" burners following Michael Porter's book designs (not shown). The forge volume, as is (without a floor), is 214 cu in, which is closer to 1/2" burner capacity. I only put the 3/4" burner in there because the 1/2" burner was still hot from the tacking. I'm gonna put the 3/4" aside for the future. Ok, I know the tacking holding that shell together is really bad. Go ahead and roast me, I deserve it. In my defense, it was my first time brazing (no welding experience either), and I was armed only with my 1/2" propane burner (not shown). Also, for the record, I do not plan on mounting the forge on that wood table. I decided to save some money on a forge cart, and just bought one of those steel racks with casters that amazon sells. I'm very short on materials, and I have yet to find a lot of scrap or drops in my neighborhood. I'm going to cut a rectangular slot in one of those shelves for the forge to sit in, and secure it with a chain and ratchet strap. Going to fabricate some kind of support for the burner just in case the positioning screws back themselves out with heat cycling. Also going to add some bolts to the joints holding the shelves up, because the last thing I want is a shelf with a forge on it crashing down. I'll show you what I come up with. Bonus photo: My crudtastic silver brazing abilities (burner collar) Yuck. As always, feedback and advice appreciated!
  14. I'm a graduate student in the Boulder area. I play with lasers for a living. I've been interested in blacksmithing for a while, doing my research and dreaming up plans. I hadn't worked up the guts to invest in equipment until last month. As of now, I've got: a 12" long 55lb hunk of "railroad" track, hardened, with no features yet, mounted up on a hunk of tree trunk and some 6x6's (see photos) a single David Hammer style burner, without a flare (can't forge a tapered flare until I have a forge) that I just finished making, and is ready for testing and adjustment parts for a second burner of the same design a 12.5" diameter x 18" long helium balloon tank that I'll use either for a forge shell or a quench tank (if I made a forge out of it, after insulation, I'm estimating 400-500 cubic inches) parts for a Jeremy Schmidt style 2x72 belt grinder, in the works access to a woodshop and some access to a machine shop Bonus photo: me using a high-tech "turning tool" on a 1/4" pipe coupler, following David Hammer's burner making instructions (without a belt grinder). P.S. that divot in the railroad track was a failed attempt at drilling a hardy hole, because I forgot that I bought the railroad track already hardened. I broke three cobalt drill bits and emptied two small bottles of cutting fluid before I remembered.