Welcome to Weld.com.
last time we did some brazing, never.
Let's do some brazing today.
You wanna?
I've got a product over here, it's by a local company, local vendor.
It's called, LF BFC and it is a low fuming bronze type application here.
It's got the flux on the outside.
I like using this stuff for general repair, but
I wanna demonstrate just some technique.
When I tack these up I wanna use quite a bit of gap.
And the reason I wanna do that is because I wanna show you some heat sensitive.
If I just poured the heat in here and stuck this rod,
then I expect this to just fall through the backside, we don't wanna do that.
So I wanna do this exercise of actually controlling our heat.
I do want the penetration, I want this to show on the backside and
I also wanna fill this on the front.
It's an outside corner joint but it's gonna have gap in it, so
I wanna fill this up enough that it's nice and round up on top or
at least fused along the edges here.
So let me get some gear on and we'll, we'll put some space in this.
When I tack these, I'll probably light the torch and put a big old dot out here and
bring it out a little bit and then I'll get a magnet, and
I'll have this held up here where it's got some gaps.
I'll fuse these parts together, but
I do wanna show probably about an eighth of an inch of gap.
I know that sounds big for 316 plate but
again I'm trying to show a couple of exercises here of control, and
how this stuff flows and everything, and how to manipulate the torch.
So old school stuff.
I like doing brazen.
I do a lot of repairs on various equipment and
one of the first things that I consider is brazing.
I always do for some reason probably because I just like it so much.
So, let me get my stuff on, I'll be right back.
Welcome back.
I have these tacked, I have 316 plate and I went ahead and
put 332 gap, maybe a little open there.
I don't think that's an eighth of an inch, I'm gonna call that 332 and
it's pretty good size gap if you can see that on camera.
So the attempt here is, I've already have some glass showing here,
and this glass is an end product of the flux.
Could we use a bare wire and powder flux?
Sure.
Maybe we can demonstrate that in another video.
This one, I wanna use this product here, which is the low fuming bronze product,
has the flux already on the wire, it's just real convenient.
So I'm gonna start out and I'm gonna start heating this up.
So what's the, there's brazing and there's welding.
So what's going on here?
How do we make a bond with brazing?
Brazing is generally 840 degrees and
above but not melting the parent metal, Okay?
So the filler wire is gonna melt at around 840 and
it's gonna bond by what we call a capillary action.
I have cleaned these plates, they're rusty down here, but
they're clean down to pure white metal.
The flux will pre-clean the surface and
by this capillary action it will make a bond into the parent metal.
It wets into the parent metal and it sticks and bonds to it.
Soldering is 840 degrees and below, so
we start talking about these concepts of brazing and soldering.
What can you do with them and the alloys?
It gets kind of interesting when you actually look, see what's in them and
how they melt, and how they bond, and what you can actually do with them.
And then again how strong they are.
That's what's amazing to me is how strong this stuff actually is.
So let me light a torch here and I'll be right back.
I may put my dark shield on because some of you ding me pretty hard on not wearing
a dark shield.
When I did the brass tree showing how to manipulate this stuff, so
I may wear my dark shield here.
Be right back.
I'm using an OTT tip, and
my oxygen pressure is set about 4 pounds,
my acetylene pressure is set about 3 pounds 3 PSI.
My torch angle is about 2030 degrees point or
20 degrees pointed forward.
And you'll notice that I'm taking it out of the pool here.
This is liquid solid.
So and the reason I'm doing that is because again,
as I said when we did the intro, if I just left this in there,
it would probably fall through to the backside and kinda make a mess.
It'd be too much on the backside,
I'm trying to get this to
round, up slightly.
So I wanna fill it in, but I don't want it to drip through.
I want it to show
on the back side
just like amperage
and voltage.
When you're wire feed welding, you can turn things up.
How about stick welding?
Could I use a bigger size wire?
And a bigger tip and more pressure?
Sure.
I would probably do these manipulations
a little quicker, and this is a little slow.
But again, I'm trying to show this technique.
I remember when I first started welding,
very first thing we did was oxy acetylene welding.
Learn how to manipulate the pool and the filler wire.
I have laid the filler
wire a little lower.
Now every time I introduce the torch,
it may look like I'm melting the wire with the flame, and I'm not.
I'm creating a weld pool first.
I'm leaving it right on the leading edge.
I teach this class in my program.
I teach oxyacetylene welding, brazing silver soldering.
Right alongside the introduction to tig welding.
If you think about it, it's the exact same hand
eye coordination, filler wire, heat source.
I think I wanna leave
this open at the end
just to show you what
the original gap was.
I'm gonna do a little remelt here.
Saw a couple of bug holes right on the surface that I didn't like,
so I went ahead and just remelted them slightly.
Could I remelt this whole thing and reshape it?
Sure, but then I take a chance of all of it dripping through again.
I'm gonna go quench this off and I'll probably leave it before I buff
it off with the wire wheel or whatever we do to clean it up.
So let me go quench this off because it's saturated with heat.
Be right back.
Welcome back.
I finished this part.
I went over and quenched it and I very lightly touched it with a wire wheel
just to get this excess of flux and glass off, and I did the same on the back.
We could have gone a little bit hotter.
We're showing that we melted some on the backside.
We didn't get through as much as I would have liked for a demonstration,
but I'm pretty sure you can see this.
We've gone just a little bit more in heat and let it fall through a little bit,
it would have bonded on the backside.
What came through on the back was it really looks like a glass.
And so, I mean, when it solidifies, you can knock it off,
you can chip it off, I hit it with a wire wheel.
Again, we could have gone a little hotter, maybe a little more aggressive.
I just wanted to show this technique of filling this thing up.
You can see some dark discoloration spots in here.
I didn't hit this with the wire wheel because this is soft enough that it will
re-arrange the patterns in here.
I've left these ripple patterns down here at the bottom of this part.
I went ahead and hit it with a flapper wheel with a 40 grit.
I believe it was just to blend this and sand this over.
I mean, this thing looks pretty nice, very slight bug holes in it,
which is kind of normal.
You can go back and melt those out.
You could sand this and polish this off, and it just look, it looks like gold,
It's cool.
So we've done some projects where we're putting some stuff together and
we get that color differential.
You can play around with this and weld some,
some other types of material other than carbon steel.
I have my students memorize chemical symbols,
all kinds of other technical data.
They think they come in here and they just get to strike an ARC, and that's not.
So we need to know some things, and we need to know about
35 elements of the periodic table for chemical symbols.
And right here they are technical data.
We've got a melt point of about 1620 Fahrenheit, 882 Celsius.
Again, I said brazing is 840 and above, but
not to the melting point of carbon steel that we were welding on.
So this says that the nominal, let me back up.
It says to pre-clean the joint, bevel heavy sections, preheat broadly,
then concentrate oxy fuel neutral flame into the joint area,
melt some flux off the end of the rod so it'll be activated and
it gets down in around the parent metal.
And then you can start dipping the alloy and
melting the alloy like we demonstrated here.
The technical data.
The nominal analysis says Cu 58%.
So what's Cu?
It's a chemical symbol for copper.
And Sn is 10.1%.
Mn is manganese, 0.040%.
Fe is ferrous iron, 0.75%.
Si is silicone, 0.1% with a Zn balance.
Zn is zinc.
So now you know what chemically you're working with here, and
that is typical of all filler metals.
I don't care if you're looking up a stainless electrode,
you're gonna be given the chrome, the moly the nickel, the carbon content,
anything, it's all gonna come to you in chemical symbols I have not read.
I can't remember looking up a technical spec of something that hasn't,
whether it's a base metal or a filler wire.
I can't remember looking it up, having it spell out chromium,
or carbon, or nickel, or molybdenum, or whatever.
Every one that I've ever read has been given to me in a chemical symbol fashion.
So anyway, I hope this was fun.
We'll do some more brazing demonstrations and we might do.
Hopefully, we can dream up a project where we can braise it together.
I know in the past that we did a brass tree and it was an exercise of
manipulating this wire, and building this tree, and starting out and
going all over the place, which is a really good exercise for
learning how to manipulate the torch and the heat.
So I hope this helps.
Thanks for watching our videos.
Bob Moffett with Weld.com, make sure you subscribe to the videos.
New videos come out every Monday.
Thank you.