hmm
hey paulie where you been hiding lately oh man you haven't seen me in a while have you
it's been a while well i auditioned for a movie so i had to grow this beard it's about
it's about rip van winkle who is an old blacksmith and he wakes up and has a new welding machine he
can't believe all the high technology so what's going on in the shop today oh we got a customer
who needs a repair on an old rusty thing antique thing i don't think artweld's gonna get it
have you ever tried uh oxy-fuel brazing i've done much of that never had a need for it
huh well man that's great stuff especially on materials you don't know what they are
materials that are odd like zinc stainless to copper regular steel brass and it's and
it's a really strong process too i saw a demo one time where they took some chromoly steel
and braised it together with low fuming bronze rod and then they put it on tinsel tester where
they pull the parts apart and the chrome moly had a tensile strength of 80 000 psi tensile
strength and the metal broke before the weld did a pretty strong wheel didn't it oh it's very strong
so a lot of people think oh that's just a braze weld they are extremely strong they're usually
stronger than the base material so it's good information yeah i mean the big difference is
you're not melting the base material which is why it's so good for fixing antiques and stuff
like that you're actually just heating the base up and then putting this bronze on it low fuming
bronze and it actually sticks to it like a super duper glue it's a bronze glue and that makes it
a lot easier to use and it does less damage to the part and instead of melting the thing and possibly
destroying it you're just basically putting this glue on there and you can always melt the
bronze off if it if you don't like what it looks like or if you miss put it in the wrong position
so i think that's really what you need to use today so good so what do we need to do this
brazing thing with well you got a cutting torch on you and some regulators and oxy acetylene
that's all you need you need a welding tip though that you can use for either the bronze braising
or you can actually weld with that tip and i see you got one of those so uh we're ready to go let's
get started here i thought i'd have to bring in my mom's old torch today this old harris from 1942
she worked out in the aircraft business building airplanes in long beach look at that thing that
thing is old nice antique torch oh look what do you got over there oh this is the new harris you
know this is the new and improved well we'll use that one today yeah we'll do something with it
okay we got our oxygen we want to clear any dust that might have gotten in here
because the cap has a hole so you just kind of crack it and blow anything out that's in there
our acetylene since it's a flammable gas we don't really want to open it up like that we just want
to take a clean rag kind of wipe around in there look at all that dirt coming out of there you
don't want any dirt getting in your regulators so first things first we're going to set our oxygen
regulator on these threads are right hand threads unlike the acetylene which is a left-hand thread
so always remember that in case you can't unscrew one that it's not righty-tighty lefty-loosey
also the fittings are completely different so it's impossible to put them on wrong you never want to
put any oil on your regulators on the gauges on the threads nothing any oil or lubricants with
high pressure oxygen can cause a major explosion they don't have to be vertical they can be tilted
and a lot of times i'll tilt mine so they're easier for me to see if they're down real low
okay a lot of times you'll see a wrench like this it's a handy dandy all-purpose
the problem with this wrench is it's so thin it'll tear up these brass fittings so you want
to keep from using one of these except in an emergency no vice grips no pliers
if you have a dedicated wrench the right size is one and eight but the problem is with that you may
need to do this which is a 5 8 so i'm using this both the right hand and left hand adjustable it's
also metric and imperial threads just snug it down you don't have to twist it off because it is a
brass fitting and you don't want to tear it up now here's one of the most important things when you
go to open your oxygen you don't want to slam it open because the heat of the high pressure oxygen
coming out can literally blow this regulator apart you never want to stand in front of it you
never want to stand in back of it you just want to slowly crack it and then open it completely
because there's two valves in here there's a shutoff valve and then there's a completely
open valve and if you don't go all the way to the top you're going to be leaking oxygen out
on the settling we want to crack it too but we only want to turn it about a half that way if
something happens and we got to turn the fuel off as what is what's going to be burning we can shut
it off really quick just like that now you might have noticed that these gauges are showing the
pressure that's in the cylinder this is the high pressure side this side is the working
pressure it has nothing on it it's controlled by this diaphragm this diaphragm always needs to be
backed off when you're not using the regulator a lot of people say oh don't mess with that because
you messed up my settings well if you have a certain setting you like just get a grease pencil
and write it right on here so you'll know what to go back to but by leaving that in
you're going to ruin the spring in there and the diaphragm so i'm going to turn this up to
five because that's what the manufacturer says on their information for the size tip we have
okay so that's at five psi right there same thing with the acetylene it's showing the
pressure in the cylinder and we're set on five right there we're ready to go
when you're done you want to shut these off i'm going to show you real quick the proper way of
turning them off shut them all the way down leave the diaphragm in purge your hose see that go down
see that go down so we're purging it okay nothing left in there now we back this off completely
and you're good to go when you go to lunch do this when you at the end of the day do this if
you're going to walk away from the torches for 15 minutes shut it down yeah you waste a little
gas but you also make the system safe we're going to use this striker to line our torch
don't use matches a lighter cigarette lighter you'll burn your hands ask me how i know
put a little bit of acetylene in light it notices smoke coming off of here you want to
add more acetylene until that smoke goes away like that and then you can turn in
the oxygen now this is a what's called a reducing or carburizing flame that's not what we want it's
got an excess of acetylene in it we want to add more oxygen until it looks like this
if we add too much oxygen we get an oxidizing flame which looks like
that and that tends to burn the metal it's very similar to what a cutting torch does
when you get ready to turn it off you want to turn the acetylene off all the flames go away
and then shut the oxygen off okay we've got our mill scale cleaned off of our metal that's super
important got some round bar that we've cleaned up if you don't take the mill scale off the bronze
won't stick to the metal it'll just float on top of it and you can tap it off with a hammer
what we're going to use is low fuming bronze this particular rod has a coating on it they make
bare coated rods and sometimes if you have old rods like this the coating may disappear so what
do you do you get some of this flux right here which is basically borax it's kind of hard to get
though because people don't use it as much as they used to and everybody likes these pre-coated ones
but if you're getting a jam and can't find this at your local welding supply place
just go get some 20 ml team borax at the grocery store and that works fine
well back to the rod what is low fuming bronze it's 58 copper 40 percent zinc 1 10 and the last 1
is manganese iron and silicon the silicon acts as a deoxidizer so enough of that science
stuff let's talk about safety obviously we're dealing with heat we need to protect our hands
we also need to protect our eyes there's a couple different ways of doing it there's special glasses
that are made for this these are shade three they also make a shade five i have a shade five in this
big hood which is great because i wear glasses and i can't really use these with the glasses
without it being difficult you can also use your auto darkening hood and put it on the grind mode
that's a shade three you'll be able to see well with that and you've got another type of auto
darkening like this which you can flip up and see everything bright i think i'm gonna start
out with just the shade five see how well i can see on that i do have these groovy goggles here
and they fit over my glasses so i'll use those too let's start out with the goggles what the heck
you want to bring the base metal up to a red hot bright red you don't want it to be yellow
and you don't want it to be white those are way too hot and if you get that hot pull the
torch away and let it cool down slightly once it's red hot you're ready to start brazing
on the other hand if it's a dull red or less than that it's not hot enough to accept the bronze
so you need to get it to that bright red to properly braise
after you've gotten your base metal to red hot then you can start adding filler
what will happen first is the flux will start melting and go to the base and then the filler
starts melting now what you can do is just put it in the flame and it'll wet right out
onto where you have your flux and just move along you can raise the torch up and down to vary your
heat you can do little circles with a torch it's all up to you and what you're comfortable with
okay you'll notice that the bronze is really a thin little layer here and what happens is due
to capillary action that's where the molten metal actually gets drawn into the joint
without any outside force like gravity or anything and because of that it has a lot
larger area of contact and that's really important on one of these adhesive welds
so we're going to test this thing and break it and just see just how strong it is
you can see the wicking action in here where it's gone all the way through and held it this
area here did not have the mill scale taken off so it's probably why it didn't go real far
and also there was no flux on there if i had to put some molten flux down or that powdered flux
it would have definitely come closer but i had a heck of a time
pulling that up yes it broke but it would have broken if it was steel too
it doesn't take much rod at all to do this
one of the nice things about brazing
is even though it's maybe different than the steel and have a gold color it can
be decorative too so if you feel like doing some arty stuff if you're trying to do a repair though
and not have a scene well that's a different animal well that looks pretty darn nice okay well
this is our piece that we we bent and it broke but if you look at how chewed up that metal is
for us to get it to bend and break now i've run a wire brush across here and it's nice and clean
if you look at this little piece right here you can see some scaling or basically it's the
flux that's left on there it's kind of a glass like stuff that'll come off with a wire brush
and a little water you want to get that off if you're putting a clear coat or paint on
because after a few days because there's just glass laying up there it'll actually pop off
let me run the wire brush on a little bit
and you can see how small that is you know the where the bronze has gone inside there
but if you look on the back you can see how it's penetrated through
with that capillary or wicking action so it's got a lot of area this it's touched there now it
didn't make it all the way through here because we were moving a little faster up on that end
so i hope that shows just what brazing can do i'm not even going to try to break this one because i
doubt if i can and uh i'd need a really big hammer to do it so polly i said looks like you like this
brazing thing and looks like it's going to work on the repair that i'm going to have to make
you know i've repaired a lot of stuff that you know no one else could repair and it's
a simple process so you know you got the hang of it now you know what to do that's great hope you
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