How To Braze – Tips and Tricks with Paul Brodie

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hi i'm paul brody we are in my shop the man 
behind the camera is mitch thank you mitch   today we're doing a bracing lesson we'll call 
it brazing 101 and i'm going to show you a few   things that i used to teach my class at frame 
building 101 out at the university so let's   have a quick look over here at my oxyacetylene 
setup large bottle is the oxygen smaller bottle   is the acetylene and we have a fluxer this is 
an automatic fluxer in here there is there's a   tube this is the line that is connected with the 
acetylene regulator this line it snakes around   comes in there's a tube that goes down almost 
to the bottom and then there's a level of liquid   flux that comes up to about well somewhere here as 
you use it it goes down then you need to add more   and so the acetylene it it bubbles up through the 
flux and the flux gets absorbed in the acetylene   and it all goes to the torch oxygen line 
acetylene line so that's basically how   the automatic flux it works you never ever 
put oil sometimes these are hard to open   you never ever put oil anywhere here that's 
a big no-no they'll call the bomb squad if   you ever do that so don't do that on the end of 
the torch i used this yesterday see this little   fluffy thing that's flux so we need to get that 
off that i'll show you how i'm going to do that   we need a clean nozzle so it's it's not very hard 
at all you can take a i got a little file here   it's a flat file you can very gently see as 
i do that you can see the copper come through   and then i got a a tip cleaner and there's 
there's different sizes in here this is the   one that fits my zero tip and gently 
it's it's got a little file on it but   you don't want to go in there and file it and 
enlarge the nozzle so very gently there you go   that's all it needs it's a victor torch 
a j28 and i made this little holder here   it's made out of aluminum this is years old it's 
held with a hose clamp and then i have a mic stand   you can buy a microphone stand for not too much 
money very handy having a place where you can just   put the torch in there and take it out at 
will very good the red hose is acetylene   the the green hose is oxygen you always light 
the acetylene first you switch off the oxygen   first as well so it's always acetylene first for 
lighting and switching off i'm going to open it   up a little extra and i'll show you what happens 
whoa okay you see there's a gap if you don't close   down the acetylene and get rid of the gap you 
can't open the oxygen it won't work so when you   close down the acetylene now the flame is joined 
up to the up to the torch if i go really low   there's a lot of soot that comes out can you see 
all that soot you don't want that you want to have   a flame that's not too much soot and that's when 
you add the oxygen and you ink you add it slowly there we go and now you now you can see the cone 
there's a cone in there now this is pretty bright   and why why this is so bright is because of the 
flux that's coming through the torch we've got   the inline fluxes like i showed you now there is 
is two types of fluxes that i know of there's the   one like this this looks like an oxygen tank and 
there's also the gas flux from the the gas flux   company in el ryo ohio i like seeing that and it's 
got a reservoir on top and there's lots more knobs   and levers but they both work pretty well the 
ones that i used out at the university i extended   it by four inches because it allows more flux it 
works better that way so we're going to talk about a different flame what the different flames 
are this is the cone from the end to there   that that is the cone the hottest part of 
the flame is right at the end of the cone   if i want to make a larger flame i add 
acetylene can you see there's a shadow now   from the end of the cone out there there's a 
shadow that means that there's extra acetylene in   the flame so this is a carburizing flame if i back 
off the acetylene and just go down to the cone   that's a neutral flame if i turn 
down the acetylene even more   it kind of looks the same 
but the cone gets sharper and that's an oxidizing flame you do not want an 
oxidizing flame it looks like a neutral flame but   it's a lot harder because there's additional 
oxygen in there you want a neutral flame so to   get a neutral flame the easiest way that i know 
of is to add acetylene until you get a shadow and   then you back it down very carefully and that's 
your neutral flame so if i want a larger flame   i'll add acetylene then i'll add oxygen 
can you hear how it's starting to hiss now   sometimes a hiss is a sign of an oxidizing flame 
sometimes it's a sign of just a large flame   sometimes it's a combination of both 
so it's a little hard to tell sometimes   let's see how large a flame i 
can get here out of a zero tip that's a that's a real hiss there it's not often 
you would want to use that size of a flame if   you're brazing on some chain stays in behind 
a bottom bracket and you've already done the   philip brazing on the down tube and the seat tube 
that's when you might need a hot flame like that   because all that mass of bronze is a big heat 
sink if you want to go smaller you close down the   oxygen and that makes a shadow and then you 
close down the acetylene so you can incrementally   keep going down when you're silver soldering on a 
frame like putting on a water bottle boss you need   a very very small flame something like that that's 
about the size of the flame that i would use   so those are the three different kinds of flame 
there's oxidizing neutral flame and a carburizing   flame when you're braising on a frame when i'm 
braising on a flame frame i want a neutral flame switch off the acetylene first and then the oxygen   i've got gloves on i want you to show that 
i am safety conscious i call it safety third   first is going fast second is looking good safety 
third then maybe that's a good way to remember for   the rest of the video i don't think i'm gonna wear 
gloves because i'm gonna be very careful not not   gonna burn myself we're gonna do an exercise we're 
going to build an icicle when i was teaching frame   building 101 and that was the first exercise that 
that my students ever did was to build an icicle   we have a couple examples right here so what 
we do is to is we start on a piece of tube or   whatever and we start adding bronze so we're 
using a 330 seconds bare bronze braising rod   and this is what some of the students have done 
and it's a bit lumpy it's kind of inconsistent but it's all holding together so oh i can feel 
it see right there i can feel a weak spot   it's gonna break there you go so it wasn't really 
held secure it was held a little point right there   when you're brazing let's say you're brazing 
and you stop when you restart you have to melt   that bronze you have to get this is called the 
base metal at that point you have to get that   up to temperature before you add the rod you can 
just put the rod right on top but it's not really   part of it it's not adhered it doesn't become one 
so that's one of the mistakes students often make   one student made a beautiful icicle i don't even 
know who the student was and they left it behind   and this is what i used to show other students 
that say look if you can build an icicle like that   then you can philip braze because what's going 
on here is that you're learning how to melt metal   most people have never melted metal in their life 
lots of the students that i had had never melted   metal so that was the first thing i had to do i 
had to get them up to speed learning how to braise   so when you're melting the metal you are playing 
in that zone of melting not melting it's a it's   not much of a of a temperature difference you're 
playing in that zone it's heating and then cooling   if you take the torch away for even one second 
it allows the metal to cool down and solidify   momentarily and then you put the torch right 
back on and then you're melting more bronze so   let's let's get set up here and i'm going to 
build you an icicle and i'll see what i can do   okay i got a couple different 
fluxes here i want to show you   this is the flux that goes into the automatic 
fluxer it comes in a gallon containers a gallon   cost me about 50 dollars it lasts quite a while 
it's real stinky you do not want to get this on   your hands or to breathe it in you use a funnel 
you use gloves when you pour it into the fluxer   this is the flux it also also comes from the gas 
luxe company this is what i put onto the tube   before i do the brazing it's type b paste flux 
a lot of frame builders like this i'm going to   build an icicle on top of this little tube here so 
i'll start out with a little bit of flux on there   i wanted to talk about how much flux 
to put on because i've been watching   some youtube videos and some of the frame 
builders especially the ones who start out   they are gooping on the flux and it's like it's 
a paste and it's everywhere and i don't think   flux lasts very long when you put that much on 
your container must must run out pretty quick so   from what i see you you just have to cover the 
area you don't have to build it up that's my   experience when i was teaching frame building 
101 and i'm teaching students how to use a   torch there's three things i would tell them and i 
think it's still valid you need to get these three   things right otherwise your chances of success are 
pretty small one is the size of the cone a larger   cone means more heat smaller cone needs means 
less heat if you don't have the right size of cone   then it's either heating up too fast or it's not 
heating up fast enough and you're just waiting so   so don't be afraid to make the cone a little 
smaller or a little larger and experiment   i've been doing this for enough time that i 
basically know how long the cone should be for   this operation that operation whatever so that's 
the first thing size of the cone the second thing   is the angle of the cone so sometimes if 
you want to get a lot of heat onto something   you have the cone aiming right at the 
metal if you have a delicate operation   and it doesn't take much heat you might 
want it at an angle because now the heat is   it's still making that tube hotter but 
it's not going into it as fast and this the   third thing is the distance of the cone let's say 
this rod is the cone that's the end of the cone   if you have the cone like that you are 
putting a lot of heat right into the metal   if you pull it back it's not so hot but the heat 
is spread now so if you want to if you want to do   attack for example you wouldn't hold the heat way 
back here you would hold the cone very very close   maybe a millimeter away it shouldn't be touching 
but have it back just a little bit that's the way   to get the heat into the metal faster so those are 
the three things you ought to remember for sure   size of the cone angle of the cone and on the 
angle i can hold the torch like this i call this a   pistol grip and then there's a pencil grip if i'm 
braising away and that's where i want the torch   to be my arm's gonna get tired you do this for 
an hour or two you're gonna get a sore shoulder   things like that so that's when you want to hold 
it like a pencil because now you've still got the   torch at the same angle but you can do this for a 
lot longer so please remember those three things   we're going to light the torch now i'm going to 
light the torch and i'm going to get my braising   rod 3 30 seconds gonna build you an icicle this 
is where we actually get to do something now   so i need about i call it about a medium sized 
flame first thing you do is to heat up the tube   and you notice how i've got the rod 
really close because if i put the rod in   to the flame a little bit it it preheats the rod so i've melted my flame's a little hot so that was 
a little larger than what i wanted but that's okay   so i'm going to switch my flame make my flame 
just a touch smaller that'll give me a little   bit more control so i need to bring this up to 
temperature again because i've i've taken the   torch away and then when i add the rod i'm going 
to have the torch at an angle i'm not going to   have the torch straight down so i start with it 
getting heat in there there i can see it melting   so now i'm going to build an icicle so 
i'm i'm bringing the cone down to the rod and the cone oops the cone is focused right on 
the end of the rod because that's the easiest   way to melt the rod the fastest it's like a 
rhythm you get into and you try and melt the   same amount of bronze each time that's 
partly where the consistency comes from   so like i said earlier it's playing 
in that zone of melting not melting   when i take the torch away for a moment it allows that metal that bronze 
to cool very very slightly   because if i heat it up too much it'll sag 
it'll become a blob fall off to the side   if you're just starting to learn how to 
fill it braids this is an excellent exercise   so what's happening is i'm heating and then when i 
take when i add the rod it cools it very slightly and then when i take the torch away that's 
also allowing it to cool momentarily   i might make it look easy but if you 
haven't done this before it's a bit tricky so i'm going to take a little break for a moment 
and have a look and that's it's pretty consistent   and it's strong if i start up again now i have 
to make sure that i get this this is the base   metal i call it i have to get this up to heat i 
can't just melt the rod and put it on top because   it won't be strong have to get this back up to 
heat so let's continue a little bit here and if   you if i hold the torch on there hold the cone on 
there you can see it when it just starts to melt there we go so i have the cone really close when i 
would show students how to do this i'd say   watch me and just copy what i do that's the 
easiest way to learn and then go to their braising   station and then do something completely different 
they would be melting the rod about an inch above   the base metal and then bring it down and then by 
that time the base metal is cool and they weren't   having success but if you keep everything close 
together like this so the base metal never really   cools off but comes up to heat very quickly 
that's the easiest way to build an icicle   some people have asked me do i 
really need an automatic fluxer   and i say well it sure helps me a lot 
so we're going to do an experiment when   i finish off this rod here i'm going to unhook 
the fluxer and we're going to see what happens okay my fingers are getting hot so it's not perfect they got there's something 
going on there something something happened there   it's a little inconsistent but you get the idea 
of what i'm doing see these little marks here   can you see those see these little marks there 
that's an indication that it's left hand thread   oxygen is right hand thread 
so you can't mix them up   so it looks like i'm making it tighter but 
actually i'm loosening it left hand thread i bought this fluxer in 1985 and it cost 
me 800.

I don't know how much they are now   and the other fluxes that i mentioned it's 
from the it's from the gas flux company   those were 500 us this 800 is 
canadian dollars i'm talking so there we go we've hooked it up directly i 
probably got some flux in the line so i'm just   bleeding a little bit so you're 
going to see a different flame now it's not going to be as green it'll be   more of a blue color because there's 
no flux here we go with with no flux so i can slow this down yeah i've slowed it down quite a 
bit and then i can also speed it up i see this one wants to 
lean more than the other one   and i don't feel like i have quite as much control but it seems to be working so maybe that answers your question if you 
really need a flux or not so what do we see here it's a slightly different well this is still hot   but yes you can melt it you don't have to have a 
fluxel although it's not spreading on some steel   and i don't know if you notice 
what i was doing with my hand   i can advance the rod that's good that's good 
practice using your thumb and forefingers   because when the rod gets really low really short 
here i don't want to stop and put the torch down   that's hot you want to just be able to advance it 
on your own it's good practice our second brazing   exercise and this was the second exercise 
in frame building 101 as well is to use   a nickel silver rod a nickel silver rod it's a 
it's a 16 of an inch thick it flows really nicely   it's good for putting on on brake bosses things 
like that you wouldn't use it for a water bottle   boss you'd use silver solder but nickel silver 
is good i have a tube here it's an inch od and   i think the wall thickness is 0.65 and i have a 
little piece of sheet metal plate and that's all   four nine thickness we're going to nickel silver 
the tube onto the plate and flow it all around   a good application for this is the bridge 
tube in between a couple chain stays on a bike   you want to get that to flow really nicely you 
don't want to do any filing this is really hard   to file because even if you have a sharp file it 
tends to skate over top it doesn't want to grab   in like on steel or or bronze somewhat so the 
first thing we want to do is to put a little   bit of flux on there and once again i'm thinking 
about all those some of those youtube videos and   facebook posts i see where the flux is just 
piled on there you don't need to do that   see how much flux i put on there this is 
this is all i need for this application i think some of those other frame builders they 
must have shares in a flux company or something   like that i used to say to my students i said 
which is going to take more heat is it going   to be is it going to be the plate or the tube and 
they would think about it and some would say the   plate some would say the tube but if you think 
about it this plate goes all the way through   so it's underneath the tube whereas the tube when 
we're heating up the tube it's an edge so i would   say that that the plate will take slightly 
more heat so if this is the cone of the torch   what i'm going to do is i'm going circle 
around and i'm gonna heat up the plate   and then i might even put the cone inside 
a little bit get some heat in there   and then i'm i'm gonna tack it and i'm gonna 
i'll put one tack on one side then i'll flip   it round 180 and then i'll tack the other side if 
i just tack one side and start nickel silvering   as the nickel silver cools down it pulls and the 
tube could lift up a little bit so that's why i   put attack on one side and attack on the other 
side if this is the cone of the flame i'm   gonna hold the cone pretty close and i i'm not 
gonna aim it right into the corner i'm going to   back up a little bit so that it puts a little bit 
more heat onto the plate as opposed to the tube   so can you see that's aiming right into the 
corner and you notice how close the cone is   i'm going to back it up a little bit 
and that's how i'm going to tack it   okay here comes the preheat and also what's going 
to happen is it's resting on a on a heat brick   and the heat brick it's not warmed up at all so 
it's going to absorb a bit of the heat as well so i've got a little bit of heat 
into the plate i'll go inside and now we'll do attack and the trick is to get 
each of them up to temperature at the same time there we go that worked out pretty good can 
you see how i've got a little tiny tack there   so i'm going to go through i'm going to flip this 
round 180 see if we do the same thing here again   so holding the flame pretty close but slightly 
towards the plate and when the flux goes glossy or   opaque that tells me that it's up to temperature 
so there again we got a tiny little tack now when i'm nickel silvering around 
i'm not going to hold the torch as close   i'm going to hold the torch back 
i'm going to have the cone maybe 5 8 7 inch back 16 millimeters for metric 
and i'm going to heat up an area back and   forth so i'm going to i'm going to heat from 
here to here it's going to be a segment and i   can do three segments on this side and three 
on the other side for a total of six segments   i'll heat it up and when i see this nickel 
silver start to melt that's when i add the rod   so i'm trying to get this as smooth as 
possible so i don't have the cone close   anymore but i'm still at a 45 and i've got 
about a medium cone not too big not too small   and i'm watching to see when that melts there 
we go see it melt and bring the rod around a   little bit maybe a little harder maybe go back 
over it just once or twice just to make it flow   and then the same thing here i'm going back and 
forth but i'm watching when that's going to melt when it starts to melt yeah see it melt 
and then that's when i put the rod in   and at first the rod melts pretty quick and it 
slows down and i go back over it so right here   right about there i'm going over what i just 
melted the flames at about a 45 so it's not really   harsh and i smooth it out because 
i don't want to do any filing   see it melting there we go put the 
rod in there at first it melts quicker go back and melt it around yeah see it melt pulls around smooth and 
this is the final this is the final segment if you do this right you can't tell where you 
started or stopped it's just all continuous that's   that's what you want can you see on the flux here 
see how it's a little bit of a tan color in there   that shows that the metal got a little harder 
it's not a danger sign if the flux goes black   that means you've overcooked it but so there's 
a little bit of a warning sign that says that   um it's getting a little bit harder see over here 
it's not there that's just flux as it should be   these little bits here see these little black 
things those of that's just balls of flux there   it's kind of sticky still those are 
just balls of flux so it's hard to tell   how the nickel silver is under that until 
you soak it off so i did one yesterday   and this is what it looks like when 
when when the flux is soaked off   and it's smooth i don't think you can 
tell where i started and i stopped   so that's what you want and if you look inside you 
can see where the nickel silver has pulled through   and that's capillary action that's because 
the heat is pulling the nickel silver or the   bronze or the braze inside of it and that's a 
good sign that's how lug frames work because   the heat pulls the it pulls the filler metal into 
the lug that's what helps to make the lug strong   so that's basically nickel silver that's how 
it works so if you have any questions you can   ask them in the comments we'd like to hear from 
you and thanks for watching our video you can   like you can subscribe there's some 
links underneath if you're on a phone   there's a little downward arrow you you 
can you can click on or if you're on your   computer there's two words show more and you'll 
find t-shirts hoodies mugs and you can buy us   coffee mitch and i both like really good coffee 
thanks for watching see you next week stay safe

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