so Adam booth a bomb 79 has been working on a weld
test fixture for me a back purged will test fixture like you would use an
aerospace testing and he did a video series on that and he sent it to me and
I've got it now so today I want to do the first two welds on it one stainless
one aluminum let's do it so in this video I'm going to first show a few
clips of Adam and making the fixture and then I'm going to make the very first
weld on it which is going to be just a stainless plate Oh 63 thickness nothing
special just a 304 l stainless but then also an aluminum joint 6061 and along
the way I'll try to provide some tips things that I have learned and given a
whole bunch of these tests a big thanks to Adam for working on this project with
me and another friend of mine I'd like to say thank you to my friend Mike best
for making the drawings I will make them available for download on my website you
can you'll see a link in the description of this video this this big chunk the
base of it is three inches thick by six inches by 12 inches didn't really need
to be that big but smaller ones I have used in the past got hot after 10 or 20
plates so these hold down bars are made of steel and the insert is copper so the
copper insert has been milled it also gets holes drilled in it about every
quarter inch 1/16 holes about every quarter inch that's give or take this
brass tube runs the whole length of the fixture pretty much in the Argonne
cavity that was milled in there and this is silver brazing a little plug on the
end of that tube and then the fitting on the other end where this will just screw
in after that's cleaned up it's pretty much ready to go after a blackening of
those hold down bars almost too pretty to weld on and scratch up but just
almost I'm definitely gonna weld on it but this thing is just beautiful and the
final touch was this tag that Adam had made with our combined logos on there so
serial number zero zero one that's pretty cool alright let's get into this
process now one of the most important things is filing an edge on a joint like
this it's best to use a clean new file followed by our acetone wipe some
times you you might use a fine abrasive to knock down an oxide layer depends on
the alloy this is just 304 L stainless doesn't really require anything other
than a filing and a wiping it would be rare to weld this alloy for a test
mostly it would be something like 321 17-7 I've got a whole article on the
page on my website that explains a lot of the process for testing ten cfh on
the fixture and I will use some small pieces of tape to tape off the unused
portion of the of the Argonne trough this is a nice weld tech SW 320 amp
water-cooled torch I'll be using and on that number 12 Cup I'll be using about
25 CF H this stands quite a ways up off the table because it's pretty thick so
I'm using this little block that I made a while back to to get comfortable with
that's what I'll do for this stainless joint filler wire even though it looks
clean it's usually not there's usually some residue from wire drawing
lubricants and things like that now that I've cleaned the wire I'm ready to
attack the ends I'm adding a little extra wire on each tack a couple of
extra dabs I like heavy tax when I tack on the very end like that it gives me
some like a launching pad to prevent from melting away when I travel from and
it also gives me a little extra second when I get to a heavy tack on the very
end when things are kind of heated up so you don't even have to tack a joint like
this the fixture will hold it down pretty well so if you really lock it
down the reason I gaped at two reasons number one it helps it distort less and
even though I gapped it about say Oh 40 or so it pulled shut to where it's less
than Oh 30 now and it just really helps me see the line it's not at all
necessary to have a gap to get full penetration on something this thin but
sometimes it just depends on the alloy sometimes a gap helps sometimes it it
hurts
51 amps it takes two to penetrate this stuff that was what I settled in at will
probably take a little bit less than that if it wasn't such a chill a chill
block anytime you put something in a fixture that's a heat sink or a chill
block like this it's going to take a few more amp
to weld then it would be out in its free State you have to have something to hold
it down and keep it straight and a fixture like this is very common in the
industry let's take another quick look at that tapering off there again this is
why I put a little bit heavier tack on the ends and I'll show the other end in
a minute but once I get about right here I start letting off the foot pedal a
little bit then I keep a really close eye on the leading edge of that puddle
and when I watch it run about halfway into that tack then I really get off on
the foot pedal and then back up the arc a little bit as I taper off slowly and
that works really well for not only a test like this but it works for actual
aircraft parts when you're welding a crack out to the edge of something like
that and then you have to maybe blend it off flush afterwards it's just really a
good technique now something I didn't mention there's a reason why I'm welding
this in halves and it's called backstep welding when I weld to a previous weld
and that basically is because this is what I required when I had to administer
these tests I thought it was a pretty bad idea not to have any stops and
starts so this at least demonstrates the ability to taper off and not leave a
crater crack or a crater I on some of these crack sensitive alloys so you can
see they're in slow motion it works just as well coming from attack as it does
tying in to attack and then when I tie into the previous weld here I just keep
the torch moving add less and less filler and kind of comet trail on out
and that that wound up being about the best technique I could find for crack
sensitive alloys like inconel 718 4130 chromoly or 15-7 pH stainless let's look
at it backside now and see if the fixture did its job see what the purge
looks like it looks pretty good it looks like we can tweak it a little bit with
the flow rate and maybe the amount of tape I put on there and maybe some other
things and get it even better on the back side usually you have to make some
adjustments on them to get them just perfect to wear that back side is
completely silver in to end but I'll get there in practicing
on some more of the stainless and some titanium and some other alloys for
future videos well I captured this additional arc shot here of welding to
attack and I was a little hotter and let it run up in there a little bit farther
than on the previous one but just it's just a good example of how it gives you
that extra I don't know half a second or maybe even less to let off the pedal and
having that little bit of a heavy tack there sometimes makes all the difference
even though the code allows you to pretty much melt that into a on a test
piece that's not something you want to do on an actual aircraft part so it's
just a good technique for the test as well as actual parts alright well let's
take a look at an old fixture this is the first fixture I made for giving
tests like this it was just one of those situations where a bulletin came down
and I had to start testing welders right away and couldn't wait on a tooling
request so I made this in about a day cobbled it out of a piece of steel and a
plasma cutter and up inside here some diffuser material with a tube running
the full distance and just a bunch of stuff tacked together so that I could
get going quickly and it worked pretty well it worked well enough anyway while
I well I had a tooling request submitted and while better ones were being built
in this case I use a slightly larger filler metal I think I used a 1/16
filler here that's another tip I used an O 4-5 filler in the previous plate on
the better fixture but you can see the the very distinct and kind of choppy
looking ripples there that's from using a larger filler wire so usually on
stainless one size smaller because a good rule of thumb than whatever you
would use on chromoly or carbon steel so you see that fixture didn't didn't quite
purge as well it could just be I had the flow rate a little bit low but I just
thought I would show that and this is a ceramic 12 Furyk cup welding just on an
outside corner joint with with no fixture I just thought it was a kind of
a cool clip so I thought I'd throw it in there
alright next is an aluminum joint in the same thickness
Oh 63 for me it works better with no gap and so I'm gonna get tax on each end I'm
using my TIG finger product here not for heat resistance in this case but just
because it it slides so smoothly that bar and I want to make a whole run
I'm not gonna stop halfway on this one I'm gonna weld it end to end so first
thing I'm gonna do is get tax on each end and again I'm going to add a little
bit of extra filler metal a few extra dabs for the same reason because it's
gonna help me prevent blowing that into a when I get there and then I'm going to
weld the whole thing in one run without stopping so I'm using a 1/16 40:43
filler metal here show that again because you can see my electrode is a
little bit bigger than it needs to be this is a 3/32 electrode probably a 1/16
would have prevented that arc wandering but it's workable I'm going to be up in
the close to 80 amp somewhere between 75 and 80 amps at the hottest point of this
joint so it's it's in that range now this is how I'm gonna feed my filler
this is how I usually feed my filler pinch it between my first two fingers
and alternately grasp it between my palm and my thumb there it's just something
that takes practice and to get good at it where it feels second nature the best
way is just sit in your chair if you're ever watching TV or doing something
mindless just practice feeding rod with your filler wire hand and just find a
way that works for you and get good at it I'm using a number eight clear cup
here and you can watch me light up on this tack just like you did on the
stainless and it gives me an extra an extra like I said an extra half a second
or so to prevent from melting that end away and the technique works on pretty
much every metal that I've ever welded definitely not the only way to do it but
it works now for passing a test like this on aluminum I have found that
having my AC balance setting with quite a bit of cleaning helps in passing x-ray
and also I don't typically use the higher frequencies this is set at 77
Hertz which is just slightly higher than than what you can get out of a
transformer type machine but all I'm saying is that's what worked
that's what yielded the best results when we had to stop and test things and
figure out where porosity was coming from so I just kind of leaned into those
settings
almost made it all the way we're coming up on that tack started letting off
right here and leaving the rod in the puddle tapering off here we go
now you can see there is quite a wide white band of cleaning action outside
the toe of the weld and that's fine there's no requirement in the code for
limiting that and thus the engineering authority wants to for some reason so
that's that's the penetration side fully penetrated from one tack to the other
and then welded completely in to end with plenty of cleaning another way to
do this joint instead of tacking each in first it's just gapping it on one end
only and then the shrinkage of the weld metal will just pull it shut if you gap
it right it just takes a little bit of trial and error to figure out the
optimum gap the weld will shrink the gap shut right in front of you and you don't
have to tack it or anything and just weld it from end to end now this one I
probably welded a couple amps colder than the other one but still got through
there well hey I have an online store at weld monger com that is how I pay for
these videos and everything for sale there is stuff that I have used this
dual flow meter is good for when you need a purge and you need an extra flow
meter without an extra cylinder the tick finger is not only good for protecting
your finger against really hot stuff but for just gliding along in cases when you
just want to slide along smoothly and make a long run this is a Furyk number
12 clear cup also available in a ceramic and this is the Furyk number 8 Pro which
not only provides a really good gas shielding but just kind of lights the
way like a light bulb and helps you see where you're going thanks for watching
thanks for your support we'll see you here next time
you