The line between artist and artisan can be a bit blurry and some people can actually be both. As it is in my opinion this case – there is a great deal of craft involved, as well as creativity.
I must confess though, I find the art and the process a bit creepy. A lot creepy. Despite the fact that my own creative process when I was painting was in some aspects similar – first a sketch of a skeleton, then add muscles, then skin, then clothes.
Wait, you’re leaving without touching me! ©voyager, all rights reserved
Jack is fed up with Covid, and he doesn’t even have to wear a mask. Of course, I don’t wear a mask on trail walks either, but I’m just fine with the social distancing. That’s the part that Jack doesn’t like. He’s so used to people stopping to pet him that his feelings get hurt when they don’t. Today, we encountered an older couple out for a walk, and they stepped off the trail to go around us. We exchanged pleasantries but stayed in our personal bubbles a few metres apart. Jack was making happy noises and giving adorable face, but they weren’t interested in getting any closer to him, and when they walked away, I could see poor Jack trying to work out what went wrong. I explained about germs and transmission of disease, but Jack said he heard on the news that dogs don’t get or carry Covid 19. I told him that it might be too early to know that for sure, especially since I heard that cats can contract it. He mumbled some reply about cats being inferior to dogs and walked away. Poor Bubba is suffering from a lack of human contact, and there isn’t much I can do to make it better. He gets lots of love and attention at home, but what he wants is the adoration of the public sphere. He wants people to Oooh and Aaah and to rub his face while he curls around them. He’s 12, now, and I hope he gets it back in his lifetime.
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.
© Charly, all rights reserved. Click for full size.
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.
© Charly, all rights reserved. Click for full size.
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.
© Charly, all rights reserved. Click for full size.
© Charly, all rights reserved. Click for full size.
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.
© Charly, all rights reserved. Click for full size.
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.
© Charly, all rights reserved. Click for full size.
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.
© Charly, all rights reserved. Click for full size.
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.
© Charly, all rights reserved. Click for full size.
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).
© Charly, all rights reserved. Click for full size.
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.
Nice flame vortex © Charly, all rights reserved. Click for full size.
A chunk of steel at 1100°C © Charly, all rights reserved. Click for full size.
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.
© Charly, all rights reserved. Click for full size.
John Muir. Steep Trails. Boston & New York, Houghton Mifflin Company, 1918.
via: The Internet Archive
Lydia Whitaker. The Prophet of Martinique. New York, J.S. Barcus Company, c1906.
via: The Library of Congress
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.
© Charly, all rights reserved. Click for full size.
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.
© Charly, all rights reserved. Click for full size.
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.
© Charly, all rights reserved. Click for full size.
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.
© Charly, all rights reserved. Click for full size.
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.
© Charly, all rights reserved. Click for full size.
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.
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.
© Charly, all rights reserved. Click for full size.
Andrew Lang. The Orange Fairy Book. Illustrated by H.J. Ford. New York, Longmans, Green, 1906.
This week’s Andrew Lang fairy book comes to us courtesy of the colour orange. As usual, I’ve attached all of the full-page illustrations and they’re a delight. Done by the talented H.J. Ford, each one is filled with wonder and whimsy. Last week I told you that this is the last book of the Andrew Lang coloured series and I was wrong. There’s one final book which I’ll post next Saturday. Until then, Enjoy.
The results are in, and there is not too much to say. First, a picture that is worth a thousand words:
© Charly, all rights reserved. Click for full size.
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.
©Giliell, all rights reserved
Oliver Optic. The Dorcas Club, or Our Girls Afloat. Boston, Lee and Shepard, 1902.
