MattBower

I'm just surprised they'd use the "good stuff" for A36! ("Good" only in the sense that you know roughly what's in it, unlike the usual case with A36.)

That's weird: the cert. says it's 1018.

[Edited. Do not use correction fluid unless you have excellent ventilation. It turns out that even the water based stuff produces nasty fumes when burned. My apologies.] As far as I know, these things work by preventing the solder from wetting the underlying metal. Cleanliness is the key to good soldering; these are just reliable ways to make parts of the base metal dirty.

I was rereading the soldering/brazing section of an Oppi Untracht book (Metal Techniques for Craftsmen) the other day, and I came across his discussion of blowpipe torches. Of course these are little different in principle than compressed air torches. But what advantage do these sorts of torches give? The air you're adding to the flame doesn't contain any extra oxygen, so it would seem that at best what you're doing is improving the fuel/air mix and perhaps getting it to complete the burn in a smaller area. But don't swirly plumbers' torches do the same thing? What's the big advantage to doing it with an air compressor or your lungs? I'm wondering about this in part because I have a small Smith acetylene torch, and I recently ran out of oxygen. I'm wondering if there's any particular reason not to just forget about buying O2 and switch to a compressed air/lung powered blowpipe to oxygenate the acetylene flame.

The link is in my first post in this thread.

Here's one manufacturer's description of its commercial quality steel:

Yeah: A36 basically has to meet certain mechanical specs. Chemically, it can vary widely. Sometimes it's hardenable. Sometimes it's hard to weld.

If you read the link I posted, yeah: it's basically random, mild steel crud.

"Commercial quality" steel: Wilkinson Steel and Metals: Carbon / Mild Steel - Hot Rolled

True, but a lot of folks prefer blown burners -- and they have some real advantages. Not least being that they're dead simple to build. And it appears he already has a blower, albeit a fairly small one.

The full info is: Make Your Own Woodworking Tools: Metalwork Techniques to Create, Customize, and Sharpen in the Home Workshop, by Mike Burton. ISBN-10: 1565233069 ISBN-13: 978-1565233065 I can't actually review this book, since I haven't read it. But I picked it up and flipped through it at the bookstore the other day, and it looks excellent. (The reviewers on Amazon.com seem to agree.) It seems very reminiscent of The Complete Modern Blacksmith. It's not a general smithing book, but his techniques certainly involve lots of smithing.

Why is that, Grant? CI has a nice low melting point (relative to steel) and it might just maybe help a tad with decarb at the weld. I'm not being a smart-aleck here; I'm genuinely curious. I don't entirely understand what purpose filings serve in flux, so I don't understand why iron or steel might be preferable to cast iron.

You must not have read very carefully. There were several suggestions in the thread before your post: borax (pretty much the standard), boric acid, and clean silica sand. Some other possibilities not yet mentioned include fluorspar (pretty nasty stuff when it burns, though), various forms of ash, crushed green glass (and other colors might work), and ammonium chloride. But I suggest starting with plain old 20 Mule Team borax. It's pretty readily available, inexpensive, effective, and relatively safe compared to some of the others.

27 c.f.m. isn't a lot, but at least it's rated for some back pressure. You could probably run a decent little gas forge on that.

OK, I apologize: I should be more careful about joking with new guys. Cast steel of any sort, mild or otherwise, is not a realistic option here.

0.6mm is about 0.023". Give it a shot. You can always drill it out later if you turn out to need more gas.

Good catch, Thomas. And this is assuming you're running on high pressure bottled gas, not a low pressure residential NG system. (At least in this country they're low pressure.)

Have you thought about using MIG tips instead of drilling your own orifice? They're cheap and interchangeable, and that way the tiny holes are already drilled for you. For a 1" burner, a 0.035" tip is probably about right. (Some folks would say it's too small, but the atmospheric burners I've made and played with always seem to have a tendency to run rich, so I often end up using a smaller orifice than many sources recommend.) If you must drill your own, roughly a #57 or #58 drill is in the ballpark. If you need metric conversions I'm afraid you'll have to look them up yourself. :)

I do all my coal forging in a forge with a proper chimney, which does a good job of whisking most of the nasties away. I'm not sure what I'd do in a brake drum forge without a chimney. I guess I'd probably use charcoal or maybe anthracite.

The black liquid that comes from the decaying husks isn't walnut oil; it's a water-soluble solution of tannins and I dunno what else. I predict you'd crack a lot of blades trying to quench in it. Walnut oil comes from the meat of the walnut, and it's oily and only a little darker colored than typical vegetable oil. (It's also expensive to buy and a real chore to make, and I'd guess it would make a very poor quenchant in a number of ways -- two being that it oxidizes readily and it's especially sensitive to heat.) You can color steel (or maybe just rusty steel?) by boiling it in a strong tannin solution like a soup made from walnut husks. That's an old trapper's trick for dyeing steel traps. You might want to experiment with that. But I'd do it as a separate step after quenching.

Unless you have the capacity to do lost-wax casting in steel, I don't think your casting is going to end up hard enough to use as a stamp, or even as a die for forming a stamp. You can carve simple designs directly on the end of a stamp blank (e.g., annealed spring steel or the like) with files, a rotary tool, etc. You could also look into electro-etching. It has a lot of advantages, though it's probably more suitable for finely finished pieces like blades than for general blacksmithing.

I've used fine, clean play sand (nearly white) as a sort of extender for Dr. Hrisoulas's "steel glue." I cut the flux almost 50/50 with sand, and it doesn't seem to have hurt anything. I haven't tried sand alone, though.

Excellent. I buy it!

For the record, wah-la is not spelled "viola" -- that's a stringed instrument that looks like a violin. It's "voila." (The French add a diacritical mark, but this is Uhmurrica, dang it.) If you're going to correct others' spelling, be sure you're right. This is why I rarely mess with trying to correct others' spelling and grammar on the Internet. The best-case outcome isn't that great, and the much more likely worst-case is that you end up looking like a tool. No offense. ;)

Not to get too far off-topic, but dickb, water isn't an appropriate quenchant for all steels. In fact it's pretty darned risky for some. When you say "the quenchant would be water," is that because you've done some research or testing that indicates it's an appropriate quenchant for your steel? If you're going to use a magnet, you generally don't want to quench from just non-magnetic. A hundred or so degrees hotter than non-magnetic is more like it for most medium or high carbon, simple steels.