Adventures in TIG Brazing

people are always talking about it you read about it in the papers you see it on YouTube but seeing this joint hold up first person just blowing my mind finally broke down and got some proper silicon bronze brazing wire sometimes called SIB for short okay nobody calls it sip but wouldn't it be a cool name it's mostly bronze which in itself is mostly copper all with a dash of silicon and some other junk not to be confused with silicon bronze which is different pound-for-pound this stuff costs more than a good steak and to me anyway only tastes about half as good i got it in 330 second size already cut the three foot lengths down in half so it feels like i bought more of them but I'm getting ahead of myself TIG brazing is a way of joining metals without technically welding them in theory you never melt the base metal so it's not welding that potentially has two advantages first it doesn't involve as much heat as welding does well that's just dandy old Tony but who cares I'll tell you who cares this crazy thin piece of steel might maybe it wants to be soul mates with this thicker piece you certainly could weld this but it can get tricky the thicker part is gonna want a lot of heat by the time you get to fusion temperature well the thin part may have gotten away from you gotten way too hot and completely burnt through don't usually see it on the fabrication drawings I'm not a hundred percent sure but I think it's sort of implied giant melty holes aren't a good thing and since the melting temperature of the silicon bronze is much lower than the parent material well in theory it should be easier to weld thin to thick I guess that's pretty cool but is that all but that's not all because we're not melting the base metals we're not messing with the chemistry of the joint mean as long as the copper can bond to it you can join materials that normally don't like being in the same room together I mean how many times have we all tried to weld cast iron in the tool steel only to have it crack after cooling with copper as the marriage counselor you can get them to play along stainless steel to steel no problem copper to steel not a problem mahogany to cherry that's a problem but just like marriage counseling there are some compromises if it's going to work silicon bronze is now what's holding the parts together like hot glue the strength of the metal isn't technically as strong not by much but it's not as strong Sid but clocks in at around 50 or 60 ksi steel filler is probably gonna start at 70 ksi and go up from there now notice I said the strength of the metal not the strength of the joint the joint could be as strong or stronger since the filler is of lower strength you'd need a properly designed joint to account for that before we Don our gay apparel let's talk about the setup a minute I get a lot of questions when I just glance over details like that today my welder is wearing a CKD air-cooled torch complimented by a lovely number seven pink cup that really brings out its eyes this torch is the FL 125 the smaller one with the funny kink the neck the flex lock it's called a flex lock torch and just a regular cup no fancy gas lens 3/32 lanthanide tungsten though I doubt that's gonna matter much I won't be using the foot controller I've got the button attached being sure to use only genuine TIG torch rubber bands of course two reasons I'm opting for this setup first I want to get a good feel for what the amperage setting should be and just how sensitive this filler is on small eighth inch plate to small changes in that amp setting where I sporting a foot controller all of those adjustments to some extent would be subconscious as I watch the weld and I don't know probably be constantly making updates with my foot reason number two the machine was already set up with this torch from the last time and I'm not really in the mood to swap it out I'll be braising these small pieces of hot rolled steel this will need a good cleaning of course with a flat disc which I'm now looking forward to helmet is a 3m speed glass sorry about that that looked a little gross I should have cleaned it beforehand no matter what would you use keeping it clean is nice being able to see through it really goes a long way it's got this three piece Bay style window got a light behind it hopefully that makes it easier to see only the middle lens Auto darkens of course the side ones just give a bit more visibility give you some peripheral vision no maybe you can see if your cats on fire when it's not supposed to be not a must-have but certainly airier in there if you're just getting into TIG welding or any welding and don't own an auto darkening helmet I highly recommend one they can get a bit expensive but you certainly don't need to buy the most glamorous one and if it turns out you don't like welding well you can always wear it to the beach and finally or firstly do you hear that that sound you're not hearing is my welder let's have you been asking how it's settling in and to date no complaints it's been great we'll be brazing on DC standard stuff electrode negative pretty low amps probably I think you can do this in AC brazing I mean but this is my first time so I'm gonna try to keep things simple okay I think I'm ready to give this a try I've got the parts super clean well pretty clean okay fine all I did was knock off the skin we want to get things hot enough to be able to melt the bronze filler but not so hot that we're melting the base metal we're using the TIG torch just for the heat and the shielding gas the brazing rod itself has no flux and I'm not gonna be adding any let's start off with I have no idea eighth inch material just enough to get it dull red without forming a puddle let's try twenty horny is way not enough let's try 40 forty still isn't enough and it's a cold weld try 50 still not enough 60 I think that's starting to get there with thinner filler that might actually work but I'm gonna push it to 70 seems like we're starting to get someplace with 70 I'm gonna let this cool down and do the other side or prep two more pieces of steel I added quite a bit of heat by the time I got to the middle so I'm not sure if that's really 70 or not I want to try this again at 75 maybe 80 on some cold steel now I think you can tell that it started off very cold starts to look good maybe in the middle in terms of you know fill leg size of that fill it here it looks nice it was flowing a little consistent but it looks a little too concave two new pieces of steel these are cold room temperature try it at 75 amps seventy-five amps starting off on cold coupons seemed to go pretty good though there's just a touch of weirdness going on it's happening almost automatically but I noticed that I'm washing the bead between the two parts I'm adding filler it's not quite wetting out on its own I use the arc to pull it down a bit shape it sounds a little dramatic but I find myself waiting and working a bit for the one bead to fully develop before I move on I want to try this again at 80 amps there's also some junk on there looks like some kind of copper oxidation I'm going to take just a little more care in cleaning the parts I'm also scotch braiding the silicon bronze filler and given everything I wipe down with some acetone let's see what happens with clean stuff and 80 amps Shh okay that did come out a lot cleaner bare with me just a moment I want to try this again but this time without the camera all up in my stuff it's always tricky to get those shots I'm always worried my helmets gonna hit the lens or my hands gonna obstruct something I just want to try it with my natural range of motion I should have just stopped while I was ahead with the camera excuse okay that's the one I just did and wire-brushed and that was the one from before same settings although things seem to run a lot better at 80 amps I keep hesitating on some of the beads you can see them there there yes they're probably that one too I want to almost go hotter I'm not careful I am starting to melt the base metal when I move ahead I can see it start to puddle before I kind of put that fire out with the silicon bronze I don't think that's a legit move but the way the bronze is behaving I almost want to push it up a few more amps don't want to melt the base metal but I want more heat to melt the filler rod which is completely like bizarro world TIG welding against every rule the rule book against every fiber of my being and my being is at least like 400 thread count I can almost guarantee had I've been doing this with the foot pedal I almost certainly it would have been pulsing this probably given the filler a hotter shot and then dropping back to tie it in with the rest of the bead and now that I say that out loud I wonder if I'm using too large of a filler rod but maybe we try this with the built-in pulsar in the HTP before I do that though I'd like to try to break these break these joints just see how they're doing that and blow off some of this pent-up rage I'm going to try to break this first one towards myself I think that should be the weaker direction I expect to crack that bead through the bronze this one I'm gonna try to bend backwards that was the same settings about the same bead size that's still pretty impressive for kicks let's try this with pulse and do you need pulse to do this certainly not although mine aren't the prettiest welds in the world they do seem sound and since the HTTP has a built in pulsar well maybe I can use that to make up for my lack of practice for the sake of time I've already run two test pieces trying to get the pulse settings in because of the amperage tests we did up until now finding the settings I like hasn't taken very long at all in fact I'd like to make one last tweak and try this once more big picture what I'm trying to do is balance the heat so I get a more consistent looking bead note I didn't say just consistent I said more consistent more of that stacked look I want to mimic what I would do with a foot controller give the filler a shot to melt it it ties in then cools off into a consistent ripple and move on to the next you certainly don't want to hit it so hard and so fast that all you're doing is melting the bronze onto the base metal you don't want to trade off a good-looking bead for no tie in or no mechanical strength anyway let's look at the machine settings that last weld you saw was at a hundred and ten amps I'm going to add just a little more 115 amps pulse frequency is 0.5 maybe a little slow but that's one cycle every two seconds pulse duration is forty percent that means I get those 115 amps for forty percent of that two-second cycle the remainder or the background current is 60% of my amp settings 60 percent of 115 that's almost 60 sit it's called 70 amps so the welder is alternating between 115 and 70 amps the net effect is a weld heat of about seventy five amps give or take which seems about right although it couldn't hurt you don't need a degree in advanced experimental mathematics like I have to setup a pulsar a pulsar on the other hand just fiddle with it try it out think about what you want the heat to do how hot and how long you want it on for then how cold you want it to drop to finally figure out the pulse rate you can keep up without killing yourself or getting a migraine the difference between machine pulsing and manual pulsing with an amp controller like all robot overlords machine will show no mercy once you hit go it's gonna force-feed the torch with an exquisitely timed pulse train and now the onus is on us to keep up so you know no pressure there with a foot control if you need to hang out for another split second you can maybe you advanced too far and need a smidge more heat or you're frantically running out of filler and you need just one more god second to keep up well you can let off a bit with the built-in pulsar you can't do that how well you maintain that balancing act to some extent dictates how your weld looks which should explain what you've been seeing me do so far hold the boat and/or phone I'm about towards the end of this video and I just moved the tripod around when it dawned on me that if I rolled the joint away from me I could film it from across the table I could try to get this arc shot without having the camera in my armpit i tacked some square tubing up at an angle and I think if I have the camera watching from back here we should both be able to see what's going on it's technically a different style joint now but close enough don't you think on your screen this stuff probably looks absolutely gigantic doesn't it but for a reference there's a 3/32 filler up anyway let's see how this camera angle works and how the pull settings turn out not bad I guess but for this outside corner joint that setting seemed a little too hot the ripples are starting to disappear into each other which is fine I think it's still a sound joint just not exactly what I was going for so I just watched the video to see if I actually got the shot and I notice two things right off the bat first I think my torch angle is a little too steep second I might be pulling that bronze out of the shielding gas a little too far so in theory what I want to happen is the background current or the low side of the pulse I want that to heat up the joint at the lower amp setting and then get in there with the filler when the hot pulse comes on to wet it out let me try this again I'm going to drop the welder to a hundred amps the relative pulse setting should be the same since the HTP works on percentages let's see what happens better but it's still a little warm let's knock it down five more amps okay that's it I've run out of stuff to weld this is the one you just saw me do at the reduced pulse amperage so in reverse order is this one this one and then this one I think I'm starting to split hairs here under the hood you can sense the small change in amperage but it's subtle something important though that I have been picking up on the more of these beads I run perhaps this will sound self-evident once I say it out loud but the bronze filler acts a lot different than steel filler almost more like aluminum filler it melts very fast if you look close in the last well shot on this piece at the lower amperage I was almost force-feeding the puddle with the silicon bronze watching the beads bulge up to about the height I thought looked good before moving on I don't know if you can make it out but this one is a little more crowned and these two are a little flatter granted they were a little hotter but I was just dabbing on the hot pulse here I was more again sort of force-feeding it on the hot pulse probably using I don't know not twice as much filler but 50% more per bead as I was making my way across the joint some takeaways first brazing with a TIG torch is nothing like brazing with a gas torch I mean nothing I don't even know why they share the same name gas braze will wet out the entire joint if properly prepared of course a TIG brace from what I'm seeing anyway only wets out where the arc is pointing mechanically a TIG braze joint is very different than a gas braze joint so keep that in mind that may sound like it came out of the blue but I don't know why I had it in my head that the processes would be somewhat similar oh and by the way do not try to take braze using bronze meant for gas brazing looks almost identical I know but the gas brazing stuff has zinc in it the TIG brazing rod does not if you try to TIG with gas rod you'll foul everything the joint the torch your helmet your language everything don't ask me how I know second I'm finding it's a very fine line between flowing the bronze nicely and not melting the base metal so fine in fact I think I nipped the base metal in every single one of these maybe tungsten prep should be different perhaps a wider softer arc I don't know as you can tell just by looking I'll have to spend more time with it finally mind you feedrate with the filler that's more a note to self kind of thing I'm gonna have to try to be more consistent with each dab in terms of material I'm leaving behind as I make my way across a joint no don't try to adjust your TV you're seeing that right a hex braised to around doesn't get any more dissimilar than that [Music]

Channel: This Old Tony

Views: 1,953,265

Rating: 4.9117036 out of 5

Keywords: tig brazing, silicon bronze, flexloc torch, flex lock, tig torch, 3m speedglas, welding helmet, flexlock, ckworldwide, htp221, usaweld, ac dc tig, pulse welding, pulse settings, tig pulser

Id: jM2_LBvzg6c

Length: 18min 11sec (1091 seconds)

Published: Wed Oct 03 2018

Reddit Comments

[u/brentnowlan]

I've never welded in my life but want to try after watching that video.

[u/avebigclive]

Do you guys know were he got the tool that looks like a hammer but cuts his parts true just by tapping them.

[u/AlphaDeltak]

I feel he does such an excellent job on all of his videos. Similar to AvE I have learned a lot from him on several different subjects.

[u/Smug_Jerk]

I don't know nothing about no TIG brazing. When is this preferable over using flux and a torch? It seems like this generates substantially less brazed surface area and would result in a weaker joint.