welding ti, machine setting and filler rod size

[michäel2]

Hi all,
I am practicing welding ti tubing, i have a bunch of 32 od (0.9) mm tubes mitered in a 45 degree angle and weld them together changing one parameter at the time.

first i do a fusion pass no filler rod i do this at 30 amps all round. my pulse setting dont work on hertz but on peak and down time, i use 0.20 of a second peak amp and 1.0 sec. down time.i realised now i forgot to check my down amp setting but i think i set it 20 amp.

after the first pass is done i use a 0.045" filler rod and change the peak setting to 45 amps and do the second run.about 3 sec pre flow and 7 second post flow monster gas lens, nice shinny straw colours.

first of,I find the filler rod super tricky, its kinda stuck into the pool regardless of where i am in the welding cycle, so i don't dip (or feed) in the puddle so to speak but 'make the rod the pudle' if that makes sense. my only problem is that i seem to run out of rod with that i mean to say that the first maybe ( im guessing haven't actually counted) 10 pulse im still having filler rod under my tungsten but after a while im consuming more rod and so i actually have no rod under the tungsten, heat will still pull material away from the rod but its something i would like to get under control.

when i have build with steel i use thermomold 0.9 rod and feed it but with ti i don't seem to have the ability to feed more material. I have played a little with amp settings hoping that at lower amperage i would be able to combat this issue but it din't make a great deal of difference, only get a more narrow or wider bead.I also thought of the torch angle but it doesn't change all that much( the angle doesn't.

since im purging all welds and i have to get my rods from the states this is quite a costly exercise, one i really enjoy but i would like to make the money spend count and i thought i would ask for advise.
should i move up to 0.063 filler rod ( or another size )?
is not moving the rod a described above normal practice or is there a better way of doing things ?
please, any other input would also be highly appreciated .
photos will follow shortly,
thanks, mick

[Amaro Bikes]

Hi Mick

I'm afraid there're no magic formulas or standard set-ups, you could ask 10 different titanium builders and none of them would share same machine set-ups, some would use pulse, others won't, others would pulse with the foot pedal, etc. We're all different people with different experiences, different techniques, different confort zones, not to mention we do usually have different welding machines, so you put all that cocktail together and it will never taste same twice

The only thing that I can say is there're not shortcuts, just keep practicing and find your own way. High specific things as titanium don't come easy...

About your sticky rod issue my best advice would be to get higher amps, and anyway titanium and steel do behave quite differently, steel "spreads" titanium "sticks". No matter if you dip the rod or use it as puddle, you'll certainly need to feed the puddle as titanium "eats" heat, so get some high amps and feed the beast. If you find it hard in the beginning because speed, try to make a wider different from peak and bed amps, so you can "rest" during down time. But the least time you take to weld, the better, higher amps less time is usually better than a smaller amps for longer time. Think of rain

As a side note, I read you say "nice" straw colours. Try to work a bit on either the cleaning or purge (or both), sure straw is acceptable but once you get into doing things right, try to get best possible results. Shiny silver is what you really want to get.

Cheers and good luck

[VertigoCycles]

Hey Mick,

First, crank your machine amperage up to something between 100-150. You're going to need the headroom. The reason being that you want to be able to make a puddle quickly so you can move fast rather than be forced to dwell on a spot for a long time just to make a puddle. That forced dwell time heats up the area for too long and will increase your chances of contamination when you move on.

As Aimar said, you'll find your own eventually. I just checked my machine... 170A, 2 PPS, 25% peak, 8 BG amps. I don't set it up to pre-flow, but I pop my pedal to do it manually. Aside from this just being what I've always done, I pre-flow things differently. If I'm doing a simple main frame joint, I give it a couple of seconds and then weld. If I'm welding a joint that needs better coverage like a seat stay bridge, or a "braze-on" I usually have a foil dam that I fill with argon before I weld by pre-flowing 5-10 seconds. My post flow is set at 10 and I don't ever change it though I will pop the pedal again before the post flow stops if I need to (bottle bosses and cable guides sometimes). FWIW, this is just my way, it's not everyone's way and certainly not the only way. I do not post-weld finish my frames and aim to keep them clean and shiny with no color at all. I'm not always 100% successful but this method get's me very close most of the time.

For your filler pass, you can use 045 rod as long as you can push enough of it into the acute joints. You can't do that welding at a low amperage while never taking your rod out of the puddle. In order to push enough rod into an acute joint, you need more heat...no way around that. Ti is sticky, the fix is more heat. If you don't change your settings and move to 062 rod, it'll feel stickier because the thicker rod will cool the puddle even faster.

Most of the time, I leave the rod in the filler and let the current consume it. I do push a lot of material into the acute joints but I also do three passes in those areas. Fusion, 062 filler pass and then 045 when the whole frame gets welded out. The areas that get three passes are under the DT/HT, top and bottom of the TT/HT and TT/ST (on MTB's where the miter angle is close to 90°), the outsides of the chainstays, and underneath the seat stays. I do not fuse the underside of seat stay bridges because the extra heat contributes to suck-in.

There are a lot of ways to do this right. Keep at it and you'll find yours.

[michäel2]

thanks both for your responces,
ill be back in the shed shortly and crank up the amps (-:

sean, pps as in pulses per second ?
thanks, mick

[VertigoCycles]

thanks both for your responces,
ill be back in the shed shortly and crank up the amps (-:

sean, pps as in pulses per second ?
thanks, mick

Yes, Pulses Per Second

[michäel2]

image.jpg

[michäel2]

just scraped the last bits of argon out of the bottle and squeezed another test run out of it.i did get a bitt sloppy with preping the tube, i cleaned with acetone and then hit it with scotch bright and left it at that.
i changed my setttings to 35 amps at.15 of sec peak for fusion run and 60 amps at .15 of sec for the filler run.
im only using the 0.9mm filler rod and im happy with the feed ability. I'm a litlle worried about the deformation of the tube but i need to point out that both the tubes have 0.9 mm walls.

i think what im picking up here is that titanium has perhaps a smaller (amperage) window than any given columbus/truetemper/reynolds steel tubing. im not satisfied yet an after i pick up a refill im going to trial a bitt more amps in the sharp corner when doing the filler run, say 65 amps. but for the open area's ill try both lower peak amp and peak time and lower the background amps to avoid the slight tube distortion. pretty much see how low i can go but still have solid fusion.

one other thing that i have on my mind is the seqence.
for the filler run i have been doing the following sequence
12 till 10
7 to 5
2 till12
10 till 8
5 till 3
8 till 7
3 till 2
im not sure if this makes any chance but im all ears to all input.
thanks again, mick

[Amaro Bikes]

Hi Mick

Seeign the pictures it definetly seems you need to get more attention to tube prep. With titanium there's no choice but do it 100% spot-on in every step, being prep work almost as important (or more) than welding itself. It's good practice to do it absolutely without shortcuts every single time, every practice, even the smaller one, never get lazy or sloppy as this little contaminations would not help much in tightening the focus window for you to reach the pure clean target you're looking for, as they might distract you or put some unnecesary "noise" when you try to understand the whole process and results. That way, once you start doing the actual "real" work on frames, you'll have the procedure completely tuned and inside you as a natural process you almost do it without a thought.

The obvious tube prep questions aside, I would say the tube deformation should not be such of a trouble, and please remember lower amps does not necessarily mean less heat, as it might take you longer to weld the join by a slower feed, so have a try with higher amps and faster feed speed, which might end up with a less amount of overall heat in the weld. Also, heatsinks are almost a must with titanium, both for inner purge and heat control, not sure if you're actually welding with any heatsinks, if not, have a look on this and try to make yourself a kit for the main areas (ht-bb-st) and not bad idea to also get some for dropouts.

About sequences, that's quite a personal thing and each builder has their own, not to mention it also depends on how the frame comes out of the jig, as sometimes when checking the frame alignment after tacking you might decide one particular sequence or another so to keep the frame where you really want it to go. But as an overal thought on your sequence, I would probably say you should try to make it with less steps, something like quarters (12 to 3, 6 to 9, etc), rather than "10 minutes" passes. Also, you can try swaping sequences from one end of tube to the other, both to compensate forces and let the weld to cold a bit till next pass, but as I said sequences are quite a personal world and each people do it differently. Just find the one that works for you for both heat and alignment

[michäel2]

Hi Aimar,
thanks for your feedback, your right its to early to get sloppy all ready.
part of building is prep and bad prep lead to failing welds )-: i suppose i got a little over excited to try new settings.
i was planning on heat sinks for the dropouts so they can purge as well.
i do have limited funds and as such i was planning to work with out heatsinks in other locations but i might have to review that choice.i might save a bitt more and move the time line along.
im trying to find documentation online in regards to ti welding but its thin spread, i was particularly looking for arguments for double or single pass welding, i imagine that double pas gives perhaps more penetration, but iam wondering, when welding material with 0.9mm walls i would think it would be hard not to get very close to 100% penetration, or is that a misconception ?
IMG_20170416_202054.jpg
thanks,mick

[michäel2]

IMG_20170416_202042.jpgIMG_20170416_202025.jpg

[VertigoCycles]

Hi Aimar,
thanks for your feedback, your right its to early to get sloppy all ready.
part of building is prep and bad prep lead to failing welds )-: i suppose i got a little over excited to try new settings.
i was planning on heat sinks for the dropouts so they can purge as well.
i do have limited funds and as such i was planning to work with out heatsinks in other locations but i might have to review that choice.i might save a bitt more and move the time line along.
im trying to find documentation online in regards to ti welding but its thin spread, i was particularly looking for arguments for double or single pass welding, i imagine that double pas gives perhaps more penetration, but iam wondering, when welding material with 0.9mm walls i would think it would be hard not to get very close to 100% penetration, or is that a misconception ?
IMG_20170416_202054.jpg
thanks,mick

I would urge you towards doing a root pass before a filler pass. Not everyone does this but most do. The reason, as I see it, is that it'll hold you to a high standard when it comes to miter tolerance. You're not going to be able to fuse any part of the joint that has more than a few thou gap. More importantly, it helps ensure good penetration, especially in the acute areas. For those who are still getting familiar with titanium, the tendency is to weld a bit cold. If you want to see what the effect is on a single pass weld, cut up your joints so you're cutting down the centerline of the angled tube and look for a void under the filler. Often, people will make a bridge between tubes, leaving a void, which will lead to a broken frame. The root pass not only joins the tubes together, it provides a nice wide bed for you to add filler and when they're joined, there's going to be a lot more thermal stability in your weld path which reduces the likelihood of opening up a keyhole.