Operation: Dragon’s Breath

After my new forge lining has dried, I have coated the inside with about 5 mm of fireclay, nothing special about that. Then I have tested it and I was gravely disappointed – my puny little burner was not up to snuff and was unable to reach the 1050°C that I need. Funny, that, the inside volume should be about the same as in the previous model, where it did reach the temperature, albeit after a long time and with difficulty.

So I have decided to build a new burner and I am going to describe how. But this time first a disclaimer: This article is meant for entertainment purposes only. It is not meant to be a set of how-to instructions and I do not encourage anyone to do what I have done here. Propane gas can be dangerous if not handled properly and if you decide to reproduce or imitate anything shown here, you do so at your own risk.

Nevermind that, there is a lot of articles and videos on the interweb how to build a forge burner, but it became pretty quickly clear to me that none of it is what I actually want. So I proceeded to build a prototype to test what works and what does not.

I wanted to retain the handle from my store-bought soldering burner, so I took the burner part off and I cobbled together some stuff instead of it from various plumbing parts. Luckily the burner is attached to the handle with standard 3/8″ thread (yes, piping in EU is the one exception where imperial units still prevail).

The prototype was working reasonably well, it reached a temperature of 1050°C that I need for hardening N690 easily and it heated up the whole inside volume of the forge fairly regularly. It is actually this burner that I have used to harden the Badgermascus this weekend. But due to its cobbled-together nature, figuring things out as I went along, the air-regulation did not work so well, I could not cut it off completely. So I have decided to take the information learned and build a completely new one. I went to the store once more and I bought new stuff, this time knowing what I am aiming for.

From left top to right down:

Propane-grade PTFE sealing tape, 1x 3/4″ x 9″ nipple, the handle from my soldering burner, 2x 1″x2,5″ nipple, 2x 1″ to 3/4″ female/female reduction, 1x 3/8″ ball valve, 1x 1″ to 5/4″ female/male reduction, 1x 1″ brass plug (drilled already – was used in the prototype), 1x 3/8″ brass plug, 1x 3/8″ brass nipple, 2x 3/8″ brass nut, 1x 3/8″ brass ellbow, 1x 3/8″ 2″ brass extension and various sizes of MIG-tips – 0.6, 0.8, 0.9 and 1.0 mm.

Unfortunately, all the steel piping was galvanized because that is the only type the local store was selling. That should not be a problem, because as you can be seen on the prototype, only the very end of the burner gets hot, the rest is pretty efficiently cooled by the flowing propane and air mixture. And I always work outside or near an open door. But I did not want to take any risks and I have decided to burn and brush off as much of the zinc as I could.

After that, I proceeded with the build. I started with the easy part – the brass fittings.

As you can see, I have drilled holes into both brass plugs – in the 1″ a hole big enough for the brass nipple thread to come through, and in the smaller one an M6 hole for the MIG tip to screw into. All connections are sealed with the PTFE tape and I have tested them in water for any leaks (I had to redo two of them). The rest of the burner need not be sealed, but everything before the nozzle must be completely tight. The ball valve is there as emergency shut-off, the handle has a needle-valve for fine regulation and the brass nuts serve as counters to lock the elbow joint and the ball valve in place so they cannot change position.

The air-regulation was the most labor-intensive part. I have taken the male/female reduction and I have ground out almost all of the inner thread so that I can screw it backward over the short 1″ nipple. I have only left 2 turns of the thread left but I filed even that down a bit so it turns very easily. Then I have screwed the reduction on the nipple as far as it would go and I drilled four 4 mm pilot holes through both. Then I unscrewed them and I widened all the holes to 12 mm.

Here you can see the air regulation assembled in open position. I have added an M6 wing screw to be able to lock the reduction in place.

I did not take picture of the next step, but that consisted merely from screwing the two 1″ to 3/4″ reductions on both ends of the long 3/4″ nipple and onto the air-regulator and the air-regulator onto the big brass plug.

To get better mixing of gasses and to slow the flow a bit I have crafted a small diffuser. That is just a piece of mild-steel with a mesh of holes drilled in it as depicted here. I have locked the diffuser in place at the flame end of the burner with a piece of cut-off thread.

With this, the burner is de-facto functional, but it cannot be connected to the forge and it has a tendency for backfire, especially when the supply is quickly cut-off or reduced. To solve both of these problems I have intended to use the second 1″ nipple, but it has proven to be too short. So I took the 1″ pipe from the prototype, I cut it to the proper length and on the outer end, I have fixed inside fine steel mesh between two tightly-fitting pieces of pipe. Nothing fancy just pressed together.

After that, I could assemble the whole thing and test it. In free air, the burner tended to blow the flame away at full setting still, but that could be eventually solved if I needed to (with another diffuser closer to the mesh).

However, I do not need to, because when inserted into the inlet of the forge, this is not a problem anymore. The flame creates a nice vortex, and unless I run really full monty, most of the fuel burns inside the forge.

When fitted with 0.6 mm MIG-tip I can reach 1050°C easily, with the 1.0 mm tip I have reached 1100°C but not more. To get above that I guess I would need a forge with bigger inner volume to get better fuel combustion. 1100°C is still not quite enough for forging damascus, although it is ample for my current needs.

So let us end with a picture of the dragon’s breath I got with 1.0 mm nozzle at full gas.

Project Badgermascus – Part 1- Three Pieces of Steel, Two Kinds of Failure

Well, the title gives away that this article won’t end well. I am glad I did not start to write about this project right from the start as a series, I dislike having expectations build up only to be disappointed so I do not wish to do that to readers. And this is why I was also putting off work on this for so long – it was always a project with the potential of high reward – and high risk of failure.

You may remember that Marcus was so very kind and has sent me some damascus to play with, three pieces to be precise – one san-mai of 1095 and cable and two pieces of just cable.

Here you can see the san-mai piece on the right already partially cleaned and ground, then in the middle is the smaller piece of cable with the scale cleaned off already with vinegar bath and on the left the big piece of cable damascus as it came. On that one, I had to grind the scale off with an angle grinder and after that, I have ground all the pieces to flat-ish until I could not spot any imperfections on the surface that might signify poor weld. This must be done since each inclusion or poor weld increase the probability of failure. It took me the whole last Friday to do this.

With all the pieces flat, I could decide what kind of blade I would want to make out of them.

The san-mai damascus had one end of the bar rather ugly and it had an unseemly weld right in the middle, so making it into a long blade with hidden tang was not feasible. So I have decided to make it into a small drop-point boot hunting knife.

The smaller piece of cable damascus would look great as a dagger, but for that, it was too thin, so I have decided to make it into a pairing knife.

The big piece was just about the right size for either a big chef-knife or a chopper. I have decided to go for a chopper.

I cut the excess with angle-grinder and then ground the outlines and bevels with 40 grit belt (which was a matter of mere minutes with my new magnetic jig, it works really well and I am happy with it). A draw-filing took care of all the perpendicular scratches and flattened the surfaces a bit and my new file-guide has proven itself very useful for making the shoulders flat and straight. It really does speed up the work when you have proper tools at hand. And in case you are wondering why the clothespins – they reduce vibrations and therefore the noise the blade and the tang make when filing the shoulders.

Drilling the holes was a nightmare, I have destroyed three 3 mm drill bits, which is something I did not expect. But I have managed to drill al I need and with this, I was done on Saturday.

Today I have decided to normalize the steel before quenching, so I have covered all three pieces with a thin layer of clay to protect them from decarburization, I have heated them above austenitic temperature and then put them into a bucket of pearlite to cool off. That is a bit slower than how normalizing is usually done (which is air-cooling for about an hour) but faster than how annealing is done (which is very slow cooling in the furnace for multiple hours). I have done this two times for the cable damascus (with straightening after the first cycle – the pieces warped, showing that it was a good call to normalize them) and after that, I have performed one more air-cooling cycle for the san-mai, because it is much thicker than the other two and has required more straightening.

I wanted to try differential hardening on the cable damascus so I have prepared a mixture of clay, perlite, and a tiny bit of water-glass as a binder and adhesive. I did not want to wait overnight for it to dry, so I have used first a heat gun and then the forge with low-fuel reducing flame to dry it quickly, thus the dark greyish color of the clay. No clay fell off, it did not crack either, so far it seemed all to work well.

Well, quench is when it all went wahoonie-shaped.

First I have quenched the small blade, in water. Unfortunately, it was so small that I have overheated it, and thus instead of the differentially hardened blade, I got a full hardened one. I have decided to not try again and I will finish it as it is, it can still be a good blade, just not with a hamon.

As second went the san-mai. I have quenched that first in sunflower oil, pre-heated to 100 °C, and then in water. It has definitively hardened and it seemed to be OK afterward.

Last I have hardened the big chopper. I have learned my lesson from the small blade so I have paid more attention to color, adjusted the flame, and took care to heat the blade to only just above the austenitic transition on the cutting edge and just below that on the covered spine. Then I plunged it into water, agitated, pulled it out, plunged it in again, and agitated it some more to cool it off below the martensite start temperature quickly enough for it to harden.

And during that second plunge, I heard a quite tell-tale “ping” sound. That was the moment I knew this blade has failed. I have scraped the scale and clay off with an old angle-grinder disk and took it in daylight to search for a crack. And I found it, right in the middle of the blade.

I will polish the blade a little bit in order to see whether I have succedes at the differential hardening at least (preliminary scratch-test would suggest yes). However the size and position of the crack make it unlikely that the piece will be salvageable for a smaller/thinner blade, it is smack in the middle and it seems to go all the way through the hardened part right up to the soft material on the spine.

Today was not a good day, however from what I have read, this happens even to very experienced smiths. Even so, it sucks. I hope that at least the remaining two blades have no nasty surprises hidden for me.

I will have to buy some high-carbon tool steel to practice differential hardening some more.

Bonsai Tree – Growing Fast

Previous post.

This is just to let you know that the little persimmon tree is growing like mad. It is about 30 cm in height now and still growing, it might reach over half a meter before fall. Which would be awesome. The leaves are a bit big, not too big, but definitively on the upper limit of what I find permissible for a bonsai. There are techniques to make the leaves temporarily smaller, but it remains to be seen if persimmon is able to handle them. Preliminarily I would hazard a guess and say yes. Still, a deciduous tree with very big leaves can still make smashing bonsai in winter and early spring and I am excited that this tree is healthy and prospering, unlike many others in last years.

Making Kitchen Knives – Part 22 – Second Evaluation

The results are in, and there is not too much to say. First, a picture that is worth a thousand words:

As you can see, I have indeed reduced the time needed to manufacture a knife by working in bulk, but only partially. The biggest time-saving was in the polishing of the blade, and that was mostly achieved by changing the method from manual polishing to mirror-polish, to satin-finish with the tumbler.

Where I have saved time by working in bulk, was in the basic grind of the blade – here has also significantly helped the magnetic jig that I have later improved again – and later on in heat treatment – here I did save a lot since I did not have to wait for the forge to heat-up and I only had to prepare everything once.

The small savings in other steps are “nice to have” but they are mostly insignificant. What I have to concentrate on now is the 20 minutes time per piece that I have spent correcting various mistakes, like re-grinding curly blades etc, and the nearly an hour that my workload grew for finishing the handles. But I think there I can only significantly save time by working with resin stabilized wood, which is not possible for all the woods involved (oak, jatoba, black locust), but could significantly help with the semi-decomposed wood that turned out some really beautiful pieces.

The overall time reduction of nearly three hours is nothing to sneeze at. Plus, it would probably be even better had I really worked on this consistently from start to finish and not with various interruptions over the span of over a year.

From this point onward I won’t write about this project in detail, but I will continue to take time measurements and trying to optimize my manufacturing process some more.

Bobbin Lace – a Doily

This time I have decided not to make my own design, I took one from my mother’s stash.

Women Artisans on Youtube – Fabricator

Today a show that a woman who puts her mind to it can indeed weld better than many a man, certainly better than me.

Making Kitchen Knives – Part 21 – The Last Six Knives

There is not much to say about these, they are all made from one partially rotten palette. Therefore I do not know precisely what kind of wood it is. I suspect it is birch because one of the boards had still a bit of bark on it, but the palette was obviously made from scraps, so there could be several species involves. So other realistic possibilities are poplar and beech.

Since it was from planks, I had no control over grain direction, but I have at least paired the slabs to the best of my ability so they are of the same species – they varied wildly in coloration – and in three cases, I ended up with pairs where one slab had more interesting grain. And, in those cases, I have given this slab on the right side of the knife, where the signature is.

These three are those with more plain-looking handles, besides rich brown color from the ammonia fuming there is not much to see here. I have no idea why the logo etched so strangely on the second one, it just did. Maybe the metal was a bit dirty so it etched only on the edges, where there is stronger current? I did wipe all blades with acetone, but maybe not enough.

This one has a nice dark stripe of ever so slightly more decomposed, but still hard, wood running down the middle. The placement of the pins is purely coincidental, at least I do not remember consciously putting the holes exactly into the stripe.

This one has a knot in the wood. Unfortunately, it is so dark, that I currently cannot make a good photo of it without overexposing everything else. The blade on this one is one of those that curled on the edges, so I had to re-grind it into narrower shape.

And lastly a piece with extremely beautiful grain, almost like a burl. This one piece really shows that half-rotten wood is not necessarily only fit for burning.

Making Kitchen Knives – Part 20 – Three Finished Knives

Works on this project are finished, so today I will share three more of the resulting products with a bit of commentary about the lessons learned with each.

First a knife with handle from larch.

This single piece is one of the biggest reasons why I have lost a lot of time with the finishing of handles. Larch wood, as it turns out, is pretty, but it is really shitty for knife handles. It is softwood, but that would not necessarily be a problem in itself. The problems are two: 1) It is stringy, so it has a tendency to tear-out, burning, and gumming up belts. 2) The late-summer-growth is significantly harder than the spring growth and that causes all kinds of problems when trying to shape it to anything other than a plank.

Further, the ammonia fuming did nearly nothing to it, except perhaps making it a bit darker.

I suspected that it is probably not a very good wood for this purpose, and my suspicion was confirmed. I won’t use this wood anymore unless perhaps stabilized with resin. I only used this one piece because it was a gift by a former colleague, who is in turn the intended recipient of this knife. The result is not ugly, but it is much more work than it is worth.

Next is jatoba.

This was commissioned, so this is the only blade that will be sold (for a very moderate price). Part of the order was the etched star on the left side. I am a bit anxious about how the knife will be perceived. This customer too was warned that they cannot expect perfection, because I am still learning, but you never know. If they toss it on my head, I will have to deal with it.

I probably will not bother with treating jatoba with ammonia in the future, not in big chunks. It only makes the wood significantly darker and it is prone to develop cracks in due course, nothing else. It is not ugly – otherwise, I would toss it away – but I personally do not think it is worth the hassle. What untreated jatoba looks like you can see here.

And last today cherry.

I am a bit ambiguous about how this turned out. I love the look of untreated cherry wood (see here) and I was hoping perhaps, that the orange color will become richer and deeper. Instead, it has turned into chocolate brown. Not ugly brown, mind you, but brown all the same. Cherry wood is also very prone to develop cracks, but these two pieces almost miraculously were crack-free, I suspect that the strictly perpendicular and straight grain orientation has played a role (they were split from a log, not cut). I will perhaps do the fuming for cherry in the future for thinner pieces with straight grain to use them as a contrast with untreated cherry for intarsia, spacers, inserts, etc. The wood is a joy to work treated as well as untreated, I would use nothing else if I had enough of it.

I have messed up the etch of the number, you can see the straight line where I have accidentally run with the etching graphite rod over the edge of masking tape. But nobody is going to complain about this, because I am keeping this knife for myself.

There will be one more post with the remaining six knives and then we shall look at the time-analysis.

Magnetic Chuck for Grinding Bevels

You may have noticed my previous iterations on building a chuck to help with grinding consistent bevels on kitchen knives. Well, I had a lot of thoughts about it and I thought I can significantly improve it. And luckily I have managed to buy some raw materials before the shops were closed.

I am not going to write full how-to instructions this time, a few words, and the finished thing must be enough for this time around I was still figuring some things on the fly and there were some issues that did not go as planned. However I will probably make another, smaller one, for shorter blades and if I manage to not mess that up, I will make a full tutorial on that one, with clean pictures and components and so forth.

Here you can see the face with four magnet batteries up front and a tiny ledge on the bottom to have a reference point for the top of the blade. I have made magnets using the same method as last time, only this time I have glued pieces of aluminum between the faces of the mild steel slabs. The body is made from a square aluminum pipe. I cut openings for the magnets in it and to fill the hollows, I have used squared beech timber. That allowed me to simply glue everything together with epoxy and added a bit heft to the piece. I have also used square pieces of aluminum to glue in the sides of the pipe to get perfect seal all-around against water.

Setting the angle on the last one was a bit difficult. It was done by means of four screws protruding from the bottom, and if they did not stick out all exactly the same amount, it could wobble during work which is not ideal. And they did catch on the edges of the grinding table. Here you can see the simplest solution to that problem that I could think of. On the back of the chuck are two holes with M6 thread. On these two M6 screws hold a flat aluminum profile through two elongated holes. To adjust the angle I simply loosen the screws, slide the aluminum profile up/down as needed, and tighten them again. Against the last iteration, this has the advantage of full linear contact with the base plate all the time, even on the edges, and also it is much easier to set up.

I am trying to get my ducks in the row again, finishing finally the current batch of kitchen knives and preparing for the next one. I hope the two and a half days that I have spent with making this were well spent. I still have no functioning forge, but I work on that too, and hopefully, I will have something to say about that soon.

Law and Order Are Not Intrinsically Good Things

Trump likes to refer to himself as the president of “Law And Order” these days and his sycophants in the Geezers Only Party repeat those three words as a mantra. And their voters, presumably, lap it up as a chant worth following, as if those words represent something intrinsically good.

They do not.

Laws can be, and quite often are, impractical, counter-productive, or downright immoral and wrong. Lawful behavior is only as good as the laws that it follows, and unlawful behavior is only as bad as the laws it breaks are good. The order that ensues from enforcement of laws is in this regard completely value-neutral. It has no moral property in itself, it only reflects that of the legal system that has brought it into existence.

To anyone who yearns for Law and Order and not paying particular attention to what kind of Law and what kind of Order, I would like to put forth following points for consideration:

In the former USSR and indeed the whole Eastern Bloc order was rigorously enforced and kept by harsh punishments against anyone who disobeyed the law. And if that is too far in the past for you, today’s China has plenty of laws too, and oh boy do the police keep order there. I could also Godwin it here and say Nazi Germany has had many laws about what can and cannot be done by whom and to whom and its orderliness was quite proverbial, with some quite fancy police departments enforcing said laws.
The people who cry for “Law and Order” in USA today are often those who bemoan the dangers of Communism and Socialism and whatnot.

Draw from that any conclusions you want.

Women Artisans on Youtube – Resinator

Don’t blame me for the used neologism, it is courtesy of Eric D Red.

But I like it.

I also like what can be done with epoxy resin. I am in no hurry to jump on this bandwagon, but I do have it somewhere on the back of my mind.

Blackheaded Cardinal Beetle

This little buddy has climbed out of a hollow brick yesterday when I was processing dog-daisies into chemical weapons against wooly aphids infesting my bonsai trees (long story).

It was kind enough to remain in place for quite some time, allowing me to take pictures from all possible angles.

A Lawyer Talks About Lafayette Square Gassing

I have never seen LegalEagle lose his cool on camera, although I did not watch all his videos.

I have also never expected to live through a deadly pandemic and USA coming apart at the seams at the same time.

Life is full of surprises. To all our USA readers – please stay safe. Our hearts are with you, although we cannot do anything to help.

Affinity

Art, Fun, & Nonsense.

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Origami: Coffee

Flower in Her Hair (more weird art)

Social Media and Me

The Saber-toothed Salmon: When Fact Is Goofier Than Fiction

2000 Words to Close the Fundraiser

Operation: Dragon’s Breath

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Project Badgermascus – Part 1- Three Pieces of Steel, Two Kinds of Failure

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Bonsai Tree – Growing Fast

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Making Kitchen Knives – Part 22 – Second Evaluation

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Bobbin Lace – a Doily

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Women Artisans on Youtube – Fabricator

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Making Kitchen Knives – Part 21 – The Last Six Knives

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Making Kitchen Knives – Part 20 – Three Finished Knives

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Magnetic Chuck for Grinding Bevels

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Law and Order Are Not Intrinsically Good Things

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Women Artisans on Youtube – Resinator

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Blackheaded Cardinal Beetle

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