Solder for Habaki

[Burchtree]

I plan on making some nickle silver and copper habakis, but when it comes to soldering I'm pretty clueless. I tried searching, but didn't find any specifics. Any thoughts?

 

 

Thanks!

[Jesus Hernandez]

Stay-Brite solder becames fluid at 400-500 degrees and works well for me for most applications.

 

I also use bracing rods. It requires a higher temp and may cause some distorsion in the joint but it probably results in a stronger joint too.

[Burchtree]

Thank you very much -- great tutorial too.

[Brian Vanspeybroeck]

I have used soft solders like lead free plumbers solder and silver bearing solder and rare earth solders (indium) for special applications like soldering plates together for sword furniture stuff. The lower temp. softer solders are easy to use and good for a beginner but not as strong as the higher temp. stuff.

 

Technically, for habaki, the higher temp. silver "hard solders" or brazing rod works better for a lot of guys that soft solders. Stuff like this: http://www.brownells.com/aspx/NS/store/Pro...LVER+SOLDER#sku

 

But you need to use the right flux and the right technique...practice on scrap to get good at flowing the solder and become proficient.

 

Personally I use phosphorous copper brazing rod and it is *very* strong and very hard. Quite a bit harder than copper bar stock but it matches the color very closely and is self fluxing on copper habaki. You can file or sand phosphorous copper but dimensionally you need to have very close tolerances 'cause this stuff is a bear to work after you have brazed the joint closed. You can do final fitting but it is too hard and strong to make major adjustments to the habaki if you use this stuff.

 

http://www.bernzomatic.com/bernzomatic/con...ernzoProd100062

 

 

It does a great job of hard facing the notch areas on a habaki so they don't get cut or deformed by the shoulders on a sword blade (which is why I use it) and I highly recommend it if you have a high skill level...otherwise, stick to the silver bearing solders as they are more maleable and softer/easier to work with.

 

Brian

[dan pfanenstiel]

Gotta agree with Brian here mostly. Its my understanding that the soft solder in such a high stress fitting is not a good idea and that something like silver braze is far more desireable.

 

Nothing dangerous about having a habaki fail in pratice use, but to your reputation. The goal is a nice tight fit up to the blade and a strong joint. Then there's the geometry outside the habaki.....gnaa!

 

I've found that the skill level to using braze as opposed to solder isn't that far off. The real important thing is proper flux for the braze and proper heat source. Things gotta get hotter for it to work. I've tried just using the 'ol MAPP torch and just made a mess. Went with oxy/acetelene torch and worked fine. Temp control is important too. Oh, and a little braze goes a long way in such a thing, if joints are tight and all. You can quickly make a big mess inside the habaki that has to be cleaned out with too much braze.

 

Jeez, a guy could write a book about the habaki building thing, if you get down to it.

 

Dan

 

Edit: Just went back and read Brian's part about the phosphorous copper braze rod. Worth trying.

Edited February 21, 2007 by dan pfanenstiel

[Christopher Makin]

I would use soft jewelers silver solder paste.It comes in a syringe and is already mixed with flux and is available at most jewelers supply stores.Good clean tight joints are a must but with this you can lay a bead in the right spot and heat from the outside till it flows into the joint.Tis will give you a very strong join that will be as strong as the copper itself.

[Brian Vanspeybroeck]

There's a lot of stuff and ways that will all work very well. You have to experiment. I soldered a lot of habaki together with plain old lead free plumbers solder and they worked just fine...or have for like 10 years or so. The habaki on my training sword is a multilayer done with soft solder and it has been beat and abused far beyond what I would expect to be "normal" use and has no problems at all.

 

For the first timer I'd get a few small pieces of copper plate and practice and then whack 'em and file 'em and see what you like and get the best combination of holding strength and hardness and best working characteristics. For me the soldering/brazing (like Dan says...) is the easy part. It's all the shaping and final fitting that takes a whole day and then you ruin it and start over! I'd not suggest the phosphorus-copper braze rod for a beginner *but* I sucessfully talked a beginner thru using it and he loves it. The hard silver solder or the little syringe stuff Christopher suggested or the Stay-Brite stuff is *real* easy and intuitive I think. The harder/high temp stuff is better and more recommended but a beginner should use what he's comfy with until he gets good with it. A lot of what works "best" depends on your exact method of making the habaki. I tend to get them very closely fit and very close to final inside dimensions so very little hammering (other than work hardening) is done when mine are sealed shut. If you really need to do some serious hammering or reshaping after brazing then the silver or even soft solder is better as harder solders tend to be more brittle in general but stronger and more grippy. If you use a very hard/high temp. braze and need to really move metal after the habaki is sealed you will tend to crack the hard/high temp. stuff more often that the softer stuff...the softer/low temp. stuff is more maleable.

 

Making the machigane (the little triangular/wedge shaped piece that butts up against the notch at the edge...the "Wedgie from Hell"!!) requires that we have a support (Errr...therapy?) group as it is a lot more frustrating than soldering.

 

IMO!

 

Brian

Edited February 21, 2007 by Brian Vanspeybroeck

[dan pfanenstiel]

I would use soft jewelers silver solder paste. Tis will give you a very strong join that will be as strong as the copper itself.

 

You would use it, or do use it Chris? I know people who've made hundreds of habaki and laugh at the idea of using soft solder in this situation. And not a funny laugh.

 

Soft solder in this type of joint is prone to tear out. There is examples of this on the net. Don't remember where. Might seem fine in most habaki, but then there's that once or twice that it isn't.

 

Kinda like the steel welding thing. The MIG process would seem like an all purpose deal, but in reality it is prone to tear out because of penetration problems inherant in the process. In cases where really good strength is required, a properly sized stick welder'll do better. People don't like this because they have their handy little 110v MIG in the garage, but the reality is.......

 

Dan

[Brian Vanspeybroeck]

Yeah...not to get a flame war going or anything but I'd have to dispute the statement that a soft soldered joint is a strong as the copper.

 

I have not found that to be the case at all. I think you *can* (and I have...) make a habaki or any other fitting using soft solder *but* there is no doubt that a higher temp. silver bearing hard solder (or brazing rod) with a melting point at or over about 1100f is a lot better. And, as Dan pointed out, if you survey a number of guys who have made bunches of them and who do a lot of this kind of work you'll find an awful lot of them (most of them..) that aren't very impressed with soft soldering anything.

 

You can use almost anything as a beginner but it will behoove you to get to the good stuff as soon as you get the learning curve under control and feel comfy with the high temp. stuff/hard solders. If it's for "show" and not "go" you might get away with soft solder but on anything designed to be used soft soldered habaki joints will tear out under stress of cutting or even swinging.

 

 

 

These pictures are shamelessly borrowed from Fred Lohmans site but they show habaki joints that have failed. I have seen a number of habaki like this (old ones....antique ones) and some of them are indeed soft soldered habaki. Soft soldered units will do this kind of thing but I have not seen these kinds of failures in modern, hard soldered varieties.

 

I'll defend my occasional use of soft solder by adding that it is now only used in my multilayer habaki where the solder is used to stick compressed plates together and there is no force against a joint in use. And I now use Indium solder (rare earth stuff. An alloy...melts around 600f and sticks like you can't believe!) that runs about $500 a pound. Well, it did when I bought it.

 

Nutshell? Use the hard/high temp. silver solder that the worlds best habaki makers use.

 

IMHO/YMMV

 

Brian

[Sam Salvati]

Make a solid one.

[Jesus Hernandez]

This is turning into an interesting thread and I hope we can all learn from it.

 

I understood that the success of a soldered joint will depend on the tensile strength (TS) and shear resistance (SR) both of which may be measured in psi. Joint strength being based on the base metal used (copper to copper for this particular application), joint clearance (they always talk about tight fit which usually means 0.001-0.005 inches and clean surfaces) and filler metal characteristics. For copper to copper I think one of the best choices is silver-based alloy hard solder (flowing temp over 900 degrees F). If it is self-fluxing like silver Phos (phosphorus being the flux) it may make the job even easier. The respective TS and SR for tin-based solder joints being less than copper-solder or silver solder-based alloys by a magnitude of 6x (give and take a few). But the psi for even the "weakest" solder will be around 5,000-10,000 (I don't have any books in front of me right now but I will check it later). So the question is whether that level of TS and SR is sufficient for the purpose of what we are trying to achive when making a habaki. Has anyone here done any destruction testing of their own to see what happens? How much psi do we actually need for our particular application?

[Jesus Hernandez]

Make a solid one.

 

 

A properly brazed joint could be stronger than the base metal.

[dan pfanenstiel]

Also would have to do with amount of surface area contacted, I suppose. We're dealing with a very small surface area here. A rating of 5 to 10,000 psi is probably under ideal conditions.

 

In habaki we'd have pressures hard to measure. There's twisting force perhaps, compressive force, the force from the blade pushing outwards because it is a wedge, etc....

 

I agree testing would be appropriate.

 

I vote we eliminate habaki as a physical entity as well as those pesky little machi-gane. WHO'S WITH ME!

 

 

Dan

[Beau Erwin]

I like Jesus's tutorial, but I've never really soldered anything. Do any of you know of an exceptionally good tutorial for doing so?

 

How to apply flux correctly, and things of that sort.

[Sam Salvati]

A properly brazed joint could be stronger than the base metal.

 

WOW really? COOL, that is very good to know, I need to learn brazing......................

[DanM]

Edgar, take a look at this tutorial.it's not a habaki,but hard soldering is about the same for most non ferrous materials.

 

Silver Soldering

[Beau Erwin]

Very cool tutorial Dan. Be a neat one to practice soldering on as well, although I don't think it'd be getting an engraving like that at the end.

 

So you just rub the flux on all of the surfaces you want the solder to adhere to?

 

So for example soldering a guard to a blade, you would flux both the part of the tang where the guard would contact, as well as the inside surfaces of the slot and maybe the edges of the slot on the handle side?

 

Had read where lots tend to solder a guard on, but have no experience doing so.

 

It's not nonferrous for both materials, and depending on the guard material it might be that neither are nonferrous.

 

Thanks for info guys.

[Burchtree]

Great information -- I have some hard-solder coming from another knifemaker and will be trying it out.

[dan pfanenstiel]

Here's another spot where things get confusing, soldering and brazing.

 

A long time ago, I separated the definitions by choosing different words (along with some other knife folk at the time. Anyone still on the Knife-list?)

Instead of soldering (420deg flow temps) and hard soldering, where people can easily mix the two, I went to soldering and brazing. Brazing being the high temp stuff. Too easy, for me, to simply say "soldering" and mean either process.

 

Both processes are considered compatable with combining two dissimilar kinds of metals. As in the guard to blade useage.

 

Not telling others what to do, just how I kept it straight in my head.

 

Dan

[Christopher Makin]

The soft solder paste I'm talking about is actually the soft side of hard solder(called easy solder) melts at 1200F or so it is mostly silver and yes I use it often.

Edited February 22, 2007 by Christopher Makin

[Brian Vanspeybroeck]

Back in "The Day" like about 12-15 years ago I started remounting and refurbishing/maintaining swords to be used for test cutting by students and instructors at a couple different dojos. There were initially lots of WWII Gunto and a few decent antique blades as well in older mounts and primarily I cut my teeth in the sword crafts by learning to make new wooden cores, rewrap handles, and remount/modify swords to incorporate new hardware including habaki. I learned to make habaki by reverse engineering broken antiques and by making my own and destruction testing.

 

There was no one to teach me or help. No books in english (we are back to 1991 here...) and no traditional craftsmen to show me time honored and "proper" techniques or materials. I have probably made about 35 or 40 habaki in the last 15 years and maybe a dozen of those were deliberately destroyed to see how and where they came apart, under what kinds/levels of stress, and with what kinds of materials and braze/solder joints.

 

All of the testing was "real world" as I used to teach Japanese swordsmanship and I also make blades and mount swords. I don't have any specific data like tensile strengths or specific details...all of that is boring and (trust me...) quite a bit over stated and misunderstood. Without turning this into a diatribe I'll relate some information if you are interested.

 

Even is severe tests where sword blades were bashed against 4X4s and concrete blocks and flexed and shocked the habaki (even crappy, soft soldered habaki of unhardened copper) seldom (never) gave up the ghost and just fell apart. The most common area of the habaki that is the first to get damaged is the machigane area where it contacts the hard edge (hamachi) of the sword. The most critical factor in strength and longevity under severe cutting stress is that the habaki is fitted to the blade to eliminate all play in any axis and plane. Loose habaki start to move under impact and they simply get hammered, looser, and begin the allow the hardware (tsuba and handle) to move and then the whole assembly destructs in short order. Proper, tight fitting is the single most important factor.

 

The hamachi area is subject to rapid degradation because the forces of cutting force the hard cutting edge into the soft copper machigane. The braze/solder joint that seals the habaki and secures the machigane is vulnerable as the hard edge is driven into it like a wedge and it will try and split. It doesn't matter if it is soft or hard solder it's gonna get cut and damaged. *But* if you stop cutting as soon as the sword begins to rattle and shim the handle to take up the slack, the level of damage ceases and you can salvage the mount. The key is to take up the slack. All of this happens when a sword is subjected to forces way above anything that would be considered "normal". I have soft soldered habaki out there that are just fine after having been used hard for many years.

 

I have seen many antique habaki split at the joint. Many of these split because of two primary reasons. One is that they were soft soldered and soft solder (probably had lead...most certainly contained lead) has a much different shrink and expansion characteristic than the copper or silver that the habaki were made of. The body of the habaki expands and contracts at a different rate than the solder joint and after 40 - 200 years of shrinking and expanding due to temperature changes the joint just plain pops apart. The second reason is that soft solder seems to evaporate or shrink away after a period of time...I don't know why. I have seen this in old TV sets that were soldered with lead and tin solder. The solder joints just disappear and shrink off of the connections till there is no more solder around the joint.

 

There is no doubt in my mind that hard solder/braze is better, stronger, more desirable than soft solder in this application but my opinion is that it is very much mental masturbation to select hard solder because of it's greater tensile strength or whatever. The habaki isn't going to care. A soft soldered habaki is not "defective" if it has been well fitted, work hardened and has a well made and properly inserted machigane yet soldered shut with a soft, low temp solder. Not in my experiences with real world destruction testing. A soft soldered joint will offend tradtional craftsmen very much because it does not satisfy the conventionional collector/sword aficionado. You can't argue with them...the best habaki made in modern or antique times are done with a machigane and joint brazed with hard/hi temp. solder and they are made to rigid and well established guidlines that may (and often do not) have their roots in what collectors and Mukansa level craftsmen have established as "proper and correct".

 

Resistance to this mindset is futile and will just make folks mad.

 

For new and aspiring craftsmen I urge you to study the traditional ways and then verify that what they have always done works the best for you. Use hard solder, use soft solder, make habaki with slightly different features and above all be empirical, subjective, and brutal in your testing. Find what works for you using your methods and build on that. You don't have to reinvent the wheel but you should verify everything and every concept and technique you read and learn thru rigorous testing.

 

Unless you simply want to be a traditional Habakishi and want to make faithful, accurate and proper habaki and in that case I urge you to study from a recognized expert and adopt the time tested ways and materials and never vary from that recipe.

 

Habaki are generally not delicate fittings if they are properly mounted and fitted. Use the solder that works for you and bust a bunch of them and you'll see what I mean. And I agree with Dan...let's ban the machigane and form a support group for guys who have been ruined by trying to make them.

 

The more forged habaki I make, the better I like my multilayer ones. They take more time but they look cool and I haven't had one fall apart yet and I ruin a lot less of them.

 

Brian

[Jesus Hernandez]

Sounds good. Where do I sign up for the machigane club?

[R.H.Graham]

How bout a habaki Boycott group....

 

 

(stupid habaki....)

[Brian Vanspeybroeck]

Sounds good. Where do I sign up for the machigane club?

 

Dude, at my house a machigane *IS* a club....and I got the lumps on my head to prove it!

 

Stupid habaki.....

 

Brian

[Christopher Makin]

I wonder if anyone has ever tried to cast one using the lost wax method?You could build a dam around the area and fill it with hard casting wax(melted ) let it cool and file away whats not wanted.The slight shrinkage you get from casting might give you a tight enough fit.