so about that black flux...

don't believe everything you hear about it. it's way better than white (for me to learn with at least), but it's not a complete cure-all. witness the following bits.

the BB shell is the Long Shen i filed but couldn't use due to chainstay fit problems discussed in earlier posts. the head lug is a $2 Rivendell reject. i did the shell Sunday and the lug earlier today. on the lug i tried all the silver i have now: Sif 55%, Wolverine 45%, and Harris 56%. the higher-Ag pair felt about the same...maybe the Harris was a little faster to flow, hard to say.

first, BB shells are frickin'hard. there's pins in the way, there's a lot of surface to cover, and the thing is thick. i thought a bigger tip would help with the extra bulk. i tried a #15 in my PurOx/OxWeld rig, compared to the #6 i used for the previous sleeve joint. (the only intermediary step is a #9.) this was so big that i couldn't direct heat where i wanted it when doing more focused heating of the area to be brazed. broad convex surfaces worked fine, though.
also, i find my brazing improves dramatically over the course of a joint. when i start, i tend to overheat things badly, but after a few minutes it's like muscle memory kicks in a little and i'm better. so there's a few spots that are nicely done, and those are the last spots i did. i think before i do any "real" frame brazing, i'll warm up on mild steel.
the damn curly things on the Riv lugs are really tough, they're so small and right at the edge. i burned the hell out of one.
for the head lug i had the shop to myself so i and set up 2 torch rigs. i set a #9 for preheating and a #6 for brazing. i had tried to change tips mid-braze before, but that took so long that it almost wasn't worth preheating with a larger tip. the 2-torch way worked well enough that i'll likely use it again, maybe with a #9 and #4 instead.


it's pretty much a perfect Z shape.








here i it got way too hot and i could tell i'd done it.





this i like. i broke off the pin and filed fluch to try that part out.


no silver penetration around the DT at the BB shell á la Little Fish's first Audax. i'm glad i tried a BB beforehand.

worship at the temple of the black flux

tried it today and loved it. gave me lots more flexibility with heating. i did overheat one part trying to bring the filler down with the flame, but i felt the difference between "filler filling" and "cooked like a biscuit" was far greater. even the part that i cooked had decent penetration.
i had expected more trouble getting the flux off afterwards than with white flux, but it wasn't noticeably harder.
this was another split-tube practice joint, which isn't really the best way to practice i think; sometimes the gap isn't very even so the silver won't flow evenly. i'm gonna try a bottom bracket shell this weekend.


i took these right after i turned off the torch. the metal was still hot enough to need holding with pliers.



here you can see the part i mentioned that i had cooked. after clean-up with hot water, this black spot was still mostly there. other than that blotch, the joint cleaned up to about what it looked like pre-braze.

i'm awful proud of that line of silver all the way round the edges.

update

black flux, more silver, cotton gloves, one temp. crayon shipping tomorrow from Airgas Reading. the black flux is what i'm really waiting on.

i tried another couple brazes today with a technique recommended by Chris at Circle A Cycles in Providence. i found out about them from a messenger buddy at work; i'm planning to visit when i go up to tour RISD.
he told me to split a tube lengthwise and wrap it around a length of same-size tube, and braze it like a split lug. this worked pretty well, except that there was a part where i think the gap got too big and silver didn't flow. my furniture teacher (who's one of a couple good brazers at school, both otherwise wood people) helped, directing a propane-air torch up through the tube, giving some nice even heat while i provided more focused heating with a pretty big, wide oxy-acetylene tip. i had the fan blowing from the same direction as the propane torch for ventilation, which made the tube into a little blast-furnace typea thing.
i tried to do the same furnace thing later on, but i had the lights on and the torch adjusted poorly so it overheated quickly and the flux burned off quickly.

bending the other day was not successful. the plywood split along the plys with the 90° v-groove cut into it, so i reinforced with 1/4-20 bolts just under the groove. that took a while, and even then i wasn't able to get the bends i wanted. i got one blade curved nicely, but in doing so i kinked it with the solid round cheater bar. that one i bent first on the 8" radius bender, then on the 6"; i tried to start the second blade on the 6", but then it kept popping out of the hold-down bit when i tried to switch to the 8". the second time that happened i called it a day, figuring things were getting a little unsafe.
i'm working on getting new blades and outsourcing their bending. Bringheli's Deda ZeroTres will likely be the winners, but they may be a bit short for the brake reach of the Dia-Compe centerpulls (70 mm). so maybe the pads will sit in the top of the slots, or i'll dig up some shorter centerpulls.

more on the school front as well: i'm planning to take a tour next week of the shop at CVCC, a comm. college in SW Virginia offering an Associate's in Machine Technology. i found out about it through this list of schools offering CNC instruction. i'd been looking for a list like that for a while--it's given me some hope that there are schools out there (actually, nearby) that have programs i'm interested in.

bending, finally

later today i'll (hopefully) bend my fork blades. i've got an 8" and a 6" plywood bender ready to groove with the v-groove router bit i just got. the hold-down/bit assembly worked well on a test bend with brake line. the plan is to first put an 8" bend in both blades, then switch to the 6" if need be to add a tighter curve to the dropout ends.
the only missing piece is a cheater bar. last time i used a partially ovalized piece of black pipe, a la the Henry James instructions, with poor results--the blade de-ovalized somewhat. this time i'll scrounge around for some solid bar that will fit inside the blade. i might even forge a blade-specific cheater bar if i can't find something suitable.
i had really wanted to use sand to help prevent kinks while bending. the problem is, i can't think of a way to plug the blade at the dropout end while still allowing the hold-down bit to fit in. maybe melted wax dripped in from the crown end? i'd need some kind of stop to prevent it from dripping out the dropout end.

blaze-n-braze

i tried a brass joint yesterday with (i think) pretty good results. the joint definitely helped me relax and take my time with heating. also i turned out all the lights for the first time, which helped as well. there was still some ambient light coming from other parts of the shop, and plenty from the torch. i'm _starting_ to get the hang of this.
this was the first test of the aforepictured tube holder, and it worked well. there's a fair amount of slop between the pipe attached to the pliers and the vise, which was only bad when i wanted to precisely position a tube.
the reason i wanted to do that was kinda silly. i'm running low on lugs, only 3 Rivendells left, so i tried brazing two tubes together without a lug, just letting one rest on top of the other. i tried to pin it, by drilling down through the top of the mitered tube, but the nail wouldn't go in right and the flux was drying so i just let one tube rest on the other. this required positioning the bottom tube horizontally, as i discovered when the top tube slid off when the flux heated up. i re-positioned and tried again, and the brass seemed to flow pretty well, except in one spot where i think the miter was off and the tubes were too close.
today i cleaned the flux off a bit and tried some destructive tesing. i held the unmitered tube in the vise and stuck a bar of solid stock into the mitered tube. it pried off without a whole lot of effort. i guess that's the reason for a fillet.


things seem good here.


that big black blotch there isn't so nice. i could tell when i was heating that i overdid it in one spot; i think that was it.


note the hole in the upper tube where i had tried to pin.


you can see a little line of brass around the inside there.



the weird red coloration appeared after soaking in diluted toilet bowl cleaner for a few minutes. today i tried soaking in pure T.B.C. for about an hour with better results. the flux came off quickly with some convincing from a file, although i had to emery off a lot of rust.

"you destroyed a perfectly good pair of vise-grips!"

....the lab tech said while i was modifying some pliers to make a tube clamp for brazing. previously i had been using the tube jaws of a vise to hold a tube while i brazed:

this didn't permit good positioning of the joint--the vise being a bit too low and the tubes being quite short for these practice joints; loads of flux dripped all over the vise, which was a pain to clean up; and the lab tech, Bob, suggested that the vise may have been absorbing a lot of heat, which would be bad for the vise and would make brazing more difficult.
i got the idea for a solution from a buddy at school who directed me to instructables.com, where i found this set of instructions for a work stand. what interested me was this part on making the clamp. i made mine along the same lines, although i used regular "straight-jaw" vise-grips--not the brightest idea. what i made will probably work fine, but i imagine it would have taken a while less to make if i had used the type of vise-grips pictured in the instructable.

first i ground off the zinc plating/coating (to avoid nasty fumes) around where i welded the arm extension. i bench-ground a piece of square stock so one side was slighty concave to match the curve of the handle. i clamped the square stock to the handle, tacked, and welded in a couple places--just short welds so the pliers wouldn't get very hot. then i ground bevels into the square stock, and into a longer length of angle, tacked, and welded the angle on top of the square. next came a ~2' section of plack pipe, about 1/8" thick, which i welded into the angle. this pipe will get vised into the pipe jaws when i wanna braze; i left it long to give me lots of flexibility when positioning things.
last came modifying the jaw faces; this was damn tricky and took several hours. first i removed the hard jaw face from the top of the grips, the part that stays stationary when the jaws are closed. the face itself is too hard to cut with a bandsaw or hacksaw. i had to cut around it, into the softer steel that makes up the body of the pliers. to do the bottom, i attacked the jaw face with an angle grinder, and it was slow going to make the notch i wanted. the notch is to allow pieces of angle to be welded on as replacement faces.
the angle i used was some small scrap, 1/2" on a side, about a 2" length for each face. i spread the angle a bit by cold-forging: i sat the angle on an anvil with the apex up and hit the apex with a hammer. my metal teacher explained that hammering when forging is a lot different than other hammering; you hold the hammer up near the head and strike the work many times quickly, letting the hammer bounce up so you can recycle the energy you put into bringing it down. the angle deformed enough after a few minutes of hammering, although the apex was flattened, so i filed the outsides down to make it sharp again. i also rounded off the corners and made the inside faces a little convex--to hopefully prevent any damage to the tubes.
with the new faces done, i test-fitted them into the modified pliers around a 1.25" tube. the angles were a little off, so i did some more grinding and filing until everything clamped in right. i ground off the zinc coating before welding, but i didn't get it all so i wore a P100 respirator. i'm anal like that, plus the ventilation near the MIG isn't that good. to do the welds, i left the whole thing clamped together around the tube so 'twas all lined up. initial tests indicate the clamp will work down to 1" tubing. i think i'll plasti-dip the jaws once i'm done with practice brazing...until then i'll be putting some serious heat near the thing.
elapsed time: 4+ hours today, plus maybe 30 mins last week.


this is the "top," the stationary part, where i completely cut off the original face. note the cold-forged angle stock cradling (?) the tube. this will ultimately get coated with Plasti-Dip.

now the other side. i was worried about MIGing the hardened steel face, but it wasn't a problem. i would've cut it off, but i didn't think i'd be able to get the angle in there right without it.


the square stock between the pliers and the dyed angle is to offset the pliers so the adjusting bolt is still usable. also it was easier to put a concave radius on square than angle, and it was scrap.

the other side, showing the black pipe welded into the angle welded onto the square welded onto the pliers.
the school's tools are all marked with pink spray paint, so i've taken to marking mine with blue layout fluid to avoid confusion. goes on looking and smelling like nail polish.


end view showing the whole assembly.


the whole thing in the vise holding a piece of 1.25" 4130. previously i could've only held that tube about 2 feet lower than it's pictured. i'm hoping that 2 feet makes a difference.

i'll put it to use tomorrow afternoon. perhaps i'll blaze a joint and then braze a joint.



laminated maple blocks, ~3" square x ~5" long, waiting to become tubing blocks.

Kogswell P/R

the Koswell Porteur-Randonneur is a bitchin' low-trail 650b-tired utility bike/touring machine/grocery getter all in one. Matthew, who runs the joint, is a BOB contributor and linked to this CAD drawing the other day...very helpful and nicely done.

DKG: custom machining

i saw a reference to this place on the i-Bob list, and i feel compelled to mention it here.
their website isn't fully functional, but even so, i keep thinking while i read through it, "this is the kind of place i want to run one day." they don't really specialize in one area, likes bikes or mechanical parts or musical instruments. they've worked with all kinds of things, so they know a lot about a lot of stuff, so whatever you need made they can figure out a way to do it. this is the way i work...i don't know everything about one thing, i know some about lots of things.
the words remind me of Zen: "...we are passionate about quality design...[emphasis mine]"--that's everything that needs to be said about that, right? beyond that, it's a matter of seeing their work, which i can hardly wait to do.
i don't even remember the topic of the post...maybe it was brakes?

things are changing

several things going on that i want to ramble about, some well outside the subject of this blog. you probably don't care, but i write this anyways.
i'm getting more serious about applying to colleges for next fall for industrial design. the finalists at the moment are RISD in Providence, RI, and Parsons in New York City. i'm scheduling visits, interviews, and shop tours for the week after Thanksgiving.
tonight in Metal Sculpture my teacher, a great, smart guy, recommended i put the bike on the back burner and concentrate on work to submit to these schools.
he said:
focus on 3 pieces, probably furniture-ish, that i can make with the skills he can teach me and that i can do in our shop: MIG welding, forging/smithing, grinding, drilling, cutting torch, hot and cold bending.
"you're into bikes, so incorporate that into what you make."
models (scale or otherwise) OK, especially because i'm making a couple full-size pieces in my wood class.

here's the thing. he's an artist. not that there's something wrong with working under that title, but i couldn't help but think while he was talking: "yea, but what's the need for any of this stuff?" the things i've made that i've really gotten into are things that i needed, that solved a problem, that filled a gap in my life.
my podiatrist said to me, "use a stool when you're working, to elevate one foot about 8 inches." so i designed a stool around that dimension and other constraints--e.g. i wanted it to fold or come apart easily for storage. that's one thing i'm making in wood/furniture class.
the other thing is a big, heavy cutting board made of laminated end-grain hard maple. i love to cook, so i spend a lot of time chopping. i had used a really nice Calphalon circular block at a previous apartment, so i thought about ways to improve it.
i like the idea of building stuff i plan to use every day. i'll think about and appreciate the making of them every time i use them.
this is the same reason i undertook to build a bike; i want to start doing an occaisonal tour, plus i want a geared long-haul commute bike in my stable to compliment the single-speed i've got.
so what do i need that's made of metal and that i can make in our shop?
a front rack comes to mind...á la CETMA and maybe Wald...
i've started working for DC Snacks, a late-night delivery company mostly serving the GW campus area of DC. i deliver food by bike for 8 hours at a time. they provide big Chrome bags to carry the food in, but this struck me as a terrible way to do it on my first night--a front rack would make for quicker deliveries, easier access to the orders and destination info, less back strain/pain, and maybe better handling. all at a minimal weight penalty.

next questions...is he right? should i focus on producing some small and concrete pieces for the February deadlines, and leave the bike for later?
or perhaps a medium will work...

the tricky thing about reviewing my progress is that this is the slowest, most aggravating part--learning to braze and making tools. once i can braze decently and have the right tools at my disposal, the frame isn't going to take long, i figure. otoh, i usually think that

am i getting better at brazing? hard to say. i tried heating in the forge today with no real success. this was two mated pieces of black pipe that i MIG-tacked together and tried to join with brass. i later ground off the oxides and flux and re-tried with the rosebud tip to heat and then a cutting tip for the actual brazing. i got a bit to flow and then the teacher, who had been watching while i heated, said i had probably cooked the flux. he's not a good brazer, by his own admission; he said i was running into the same problem he had always run into.
that problem seems to be heat control. i can tell that i'm generally too heavy with the heat at times when i should be lighter. it seems there's a sharp divide between preheating, when the goal is to get the metal hot pretty quickly, and brazing, when more gentle heat is critical.

another thing i'm investigating: using temperature indicator crayons to help me see how hot things are getting. Airgas has a bunch and i've gotta order from them soon anyways. The number at their Reading, PA warehouse is 610-374-2137; tomorrow i'll call to have them send the stuff i need to my local store in Alexandria.

to order:
TEMTS1100 56% Ag almost melting
TEMTS1150 56% Ag melts
TEMTS1500 white flux almost cooked
TEMTS1600 white flux stops working; C-04 melts
TEMTS1700 black flux almost cooked
TEMTS1800 black flux stops working

HA SSBF1 Harris black flux 1 lb.
(or ALL69080222 All-State black flux 1 lb.)

HA 5635 Harris 56% Ag 5 oz.
(or RAD64001748 1/16" X 18" Radnor® by Harris® Safety-Silv® 56 Brazing Rod Job Pak
or HA 5631 Harris 56% Ag 1 oz.)

thin leather gloves?

tubing blocks

over the past couple days i've been working on tubing blocks. i had planned to make them from 2x4s, but the shop i'm working in has these maple blocks, sort of like flooring pieces, available for $0.50 apiece.
i'll post pics later on, but the basic procedure is: plane the blocks flat (the shop flooded a while back so there was some water damage), then laminate 4 of them together, then clean up the edges with the jointer and planer, cut to vise width with the chop saw, drill the appropriate holes, then split them lengthwise on the table saw. total cost should be under $10 for the whole set of blocks (1.125", 1.25", plus a set for chainstays, seatstays, and fork blades), including a couple spade bits. the problem i ran into right before having to close up today was drilling the holes. they have to be quite deep, maybe 4" or 4.5", as well as pretty accurate in diameter so they'll hold the tube well. the maple's pretty hard, so the bit kept getting real hot and smoking. the bit's brand-new, too. i sharpened it with needle files and tried going a little at a time, with a break in between cuts to allow cooling, but the progress was slow. i got maybe halfway through the 1.125" block before i had to go to class.

filler and flux specs

as listed here:
SIF SILVER SOLDER No.43 (Cd free)
BS: 1845 AG14

CADMIUM FREE 55% Silver Solder, which is free flowing and ideal for close fitting capillary joints and for colour match on stainless.
1.5 mm diameter; melting range 630-660°C (1166-1220°F); typical composition 55% Ag, 21% Cu, 22% Zn, 2% Sn

their Cadmium-bearing No. 42 solder (42% Ag, 25% Cd) melts at a temperature about 30° F cooler and has slightly higher tensile strength.

as listed here:
Gasflux Type U white paste flux is effective from 565-870° C (1050-1600° F).

as listed here:
Wolverine Silvaloy A45 (45% Ag, 30% Cu, 25% Zn) melts between 1225° F and 1370° F.

i'm planning a trip down to the Airgas store near me for from Harris black flux (sorta cheating, this is getting frustrating), maybe some Harris 56% filler, and thin leather gloves (filler is tought to pick up with welding gloves, and i'm not yet very experienced with the torch).

as listed here, Harris Safety-Silv 56 has a different makeup than the similar Sif product: 1 percentage point more Ag, 1 pp more Cu, 5 pp less Zn, 3 pp more Sn. i could see that making a bit of difference, especially the extra tin. and i only have a couple troy oz. of Sif left because i've been globbing it on so much, so i need more anyways.
oh, the Harris spec sheet pdf lists a melting range of 1145-1205°F for Safety-Silv 56, about 20° F lower than Sif 43. will that be noticeable? i'll report soon.

big jig and hold-down pics

as promised...

the main triangle jig, complete so far as i know. the angle stock is 1/8", mostly 1.5" on a side, but somebody stole my DT piece so that's 2" on a side. i ground the corners down because i kept hitting them. the bolts are all 1/4-20.
the procedure for getting all this aligned and locked down tight: position the angle stock, with two 1/4" holes pre-drilled per piece, along the proper line on the drawing, using the actual tube as a guide. clamp down the ends, checking while you tighten that everything's still aligned. drill through the holes, through the plywood backboard, with a cordless drill and a 1/4" twist bit. with the clamps still tight, set up the bolts, nuts, and washers. tighten down, again checking alignment with the actual tube. remove clamps.




the hold-down bit. material is 1/2" 4130 hex stock cut from a 6" sample piece from McMaster-Carr. turned down to fit inside the fork blade by chucking into a massive drill and taking it to the bench grinder. finished up by chucking into the drill press and filing. really wish i had a lathe.
the bit essentially replaces e-RITCHIE's sacrificial front dropout. the 4130 was cheap and easier to get and hopefully will work at least as well.


the complete hold-down setup. material for the hold-down is 3/16" x 1.5" (?) flat mild steel stock. MIG welded--i'm still learning so they're kinda sloppy. it's not especially precise, as you can see, but it seems like it'll do. the next step is to drill through the hold-down sides and run bolts through to secure it to the bender.
the nut and bolt were in a box of random hardware. i had to grind off the galvanized surface of the nut. they're 1/2"-13 tpi. i pre-drilled a 1/2" hole in the top horizontal piece and reamed it out a little, but the nut ended up a little off-center so i ran a tap through to put some threads in the mild steel piece.




pictured is my 3rd bender, 8" radius. i plan to re-cut the groove using a V-shaped router bit from Grizzly. if i can, i'll sand flat the part that contacts the hold-down bit so it has a nice stable surface to sit on.
i'm also planning to make a 6" radius bender. the idea is to use the 6" bender to start for a tight bend near the tip, then switch to the 8" for the upper part. i'll try some test bends on the 8" and see how it looks first.

1st brazing pics

after brazing and soaking i cut up the joint with a hacksaw (32t Starrett RedStripe), then cut each half into thirds and cleaned up the edges with a stationary belt snader. this allowed for good inspection of the filler penetration. it's hard to see and especially to photograph. it appears as a thin line of gold between the silver steel. generally it's better than i had expected, although i overdid it in several places. the camera died before i could get a photo of an area with poor penetration. those areas were usually at the edges, where it seemed clearances might have been too large, or perhaps i just didn't use enough in that spot. generally i think i'm still using more heat than necessary, but heat control is real tricky.

previously i had tried with a #4 tip (we have either PurOx or OxWeld torches--working on translating that based on this). today i used a #6 with a more carburizing flame than before. the steel still kept getting too hot--bright orange, asopposed to the dull red i think i want. and i'm still unsure what part of the flame to use to heat.

also the miter wasn't especially good on this one. i re-used the length of 1" dia. tube that i had failed to join last time, and it didn't match especially well.
even despite that, don't go thinking these shards are fragile. even with a thin lug and all cut up like this, they're sturdy enough that i can't bend and part by hand or with leverage from a table.

i'm intentionally showing these with minimal clean-up, both because i can't recall seeing photos like this anywhere before and because it should help a more experience eye tell how well i'm doing.

1st good braze

spent most of today down in the metals cave.
brazing takes loads of preparation. i made the mistake the other day of not setting up the torch until after i had cleaned and fluxed the parts, so the flux dried as i set pressures and hunted for a decent tip. here's a review of my procedures today, which i'll practice and tweak in the coming months:

set up to clean and flux the parts. run a compressed air hose and nozzle near the sink where you'll be cleaning (bleed the compressor of water beforehand so the air is dry). have near the sink: a respirator with Organic Vapor and Acid Gas cartridges, safety glasses, rubber gloves (i previously tried non-latex, medical-type gloves that i had used with photo chemicals--HCl dissolved them quickly), a solvent (i'm using mineral spirits; denatured alcohol would probably do; acetone is stronger); toilet bowl cleaner (i'm using Lysol Power; see previous posts); something to scrub with (Scotch-Brite pads work well); paper towels or rags for applying solvent; flux; flux brush; and a suitable place to put the dry parts while waiting for flux. for dissolving flux later on, the sink should have hot running water, the hotter the better, and a bucket large enough to hold the work.

set up your brazing area. have handy: torch and related accessories (striker, tip, etc.); gloves; shade 3 brazing glasses; respirator (i use a combo OV/AG cartridge plus a P100 filter, probably overkill); and brazing filler.
set the line pressures. this is an area where there are as many opinions as there are brazers. Paterek says 5 psi both. i brazed with some success today at 7 psi acetylene and ~10 psi oxygen.

prepping parts:

first wipe all the parts down with your solvent of choice. gloves, respirator (OV cartridge), and glasses are necessary. be sure to take care of the insides of the tubes by stuffing them with a solvent-soaked rag and a dowel. this can be done well in advance to remove packing grease and grime, although said grease also prevents rust, so re-grease with WD-40 or somesuch as needed, and re-de-grease before continuing with brazing prep.

now go at the parts with some abrasives. steel stock is usually covered in mill scale from being rolled between the dies that made it. it's sorta gray-black, sometimes with lettering indicating what type of metal it is. this has to come off completely for brazing to work. a shoe-shine motion with production cloth works well. 3/4" and 1" diameter grinding bits work well in an air-powered die grinder for interiors where necessary. the Deda tubes i bought only have a light layer of scale, but Aircraft Spruce's 4130 is covered in it. with enough ventilation, a respirator (particulate filter, N95 or better) isn't essential for grinding, but glasses are. and wash up before returning to the civilized world.

now wash off all the abrasive dust you just covered everything with. don gloves, respirator, and glasses. squirt the toilet bowl cleaner on the parts and scrub. HCl is pretty good at removing scale and rust, but only with plenty of elbow grease. wash the acid off with cold water, blow dry with compressed air, then set aside in a dry place.

now for the flux. leave the safety get-up on. apply flux to all mating surfaces liberally--i.e. the inside of the lug, the outside of the tube that goes in it, even the inside if it seems necessary. now the clock is ticking a little: the flux starts to dry up as soon as it goes on. it can be reconstituted by adding water, but i haven't any experience doing so.

the last stage of pinning, as i understand, happens here. i haven't yet practiced this part, as i seem to have misplaced my Fred Parr pinning kit.

now secure the parts--no safety gear necessary, except for rubber gloves when touching fluxed areas. this can be tricky on unpinned practice joints: they'll want to slide around as they heat up and the flux starts to get runny, so they can't be held so that any piece will fall. also, the part you're currently trying to fill with silver needs to be below the point where you're adding silver or it won't want to run in there--capillary action alone isn't enough.

the brazing itself is harder than i had imagined. you have to heat the whole assembly up, then focus the heating in a specific spot and add silver. all while keeping the torch moving.

this was my first real decent attempt, and it went OK. i got good penetration, not perfect, and very sloppy. i think i used about triple the silver i should have. and 56% is definitely the stuff for this type of joint...i switched to 45% for a bit and found it really gummy, not smooth enough to really shoot in. i could see it working well for drops though.

in review, i can see that brazing is easy to learn with enough practice, but hard to do really well.