# Improving TIG welding



## hillm (Jan 6, 2019)

Hi guys, 
so i'm getting near ish starting my first frame after doing a course a bit ago. The jig is pretty much sorted and the tubes are here, the only thing left to do is be good at TIG welding.

I've been having trouble with heat control. I attached some photos of my best joint so far, i don't feel like i'm getting the same colours as some of the really good guys on Instagram etc. For this joint i was running 50 amps on the machine, pulsing at the pedal, 35 thou er70s-2 rod, no heatsink or purge yet. Tubing is 0.9mm/just under 40 thou.

Has anyone got any tips for improving? I've been Youtube teaching myself so far and i'm not really sure if i'm making any major mistakes or anything. As i'm writing this i thought maybe upping the post flow might improve the colouration a bit?
































anyway thanks in advance
max


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## life behind bars (May 24, 2014)

To me it looks like you could run a little hotter, move faster and use more filler, it looks like it could be a bit undercut in spots. Add a dab of filler at the end of each weld segment to prevent cratering. Try welding a segment and letting it cool before starting the next. Better yet, do segments and add a heat sink. Tbh, it looks pretty damned good and if you address the undercut you'll be well on your way.


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## Walt (Jan 23, 2004)

Color is fine, you'll get better at putting in less heat with experience. As long as you're not welding .6mm Spirit tubes or something, you should be fine. 

-Walt


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## customfab (Jun 8, 2008)

My 6g aircraft test coupons were solid grey and damn near burnt. They passed with flying colors, notch, bend (face and root) tensile and yield tests. Structurally speaking, color doesn't mean squat when we're talking steel or stainless. You could put your dips closer together and try to get a little more filler into the puddle.


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## Erichimedes (Jul 30, 2010)

Like has been mentioned, the only issue I see is the possibility of undercut. It's hard to tell without seeing it in person, but just a little more filler and you should be good.

I think it looks a little hot, but really that's fine. Cooler passes will come with experience.


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## hillm (Jan 6, 2019)

great, thanks for the info guys, ill get on with it then


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## Sepp (Oct 13, 2007)

since I spotted some pinholes on your welds too, I'm going to ask the following:

I do get those tiny holes in the center of each dime when pulsing (top weld), but not when running straight amps and dabbing the rod (bottom weld).

I did this example quick without my readers, on non cleaned tubing, but you should understand what my problem is.

I tried to change the flow rate, but that didn't affect it as hoped.
Any ideas?

Thanks,

Joe


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## hillm (Jan 6, 2019)

I haven't really figured it out yet, so take my guess with a pinch of salt. But i think its when the amperage changes really suddenly, i found if i came of the pedal a bit slower at each puddle it stopped forming them as much. 
So i think they form when the centre of the puddle cools too quickly? 

hopefully someone more informed can shine some light on it


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## customfab (Jun 8, 2008)

Sepp said:


> since I spotted some pinholes on your welds too, I'm going to ask the following:
> 
> I do get those tiny holes in the center of each dime when pulsing (top weld), but not when running straight amps and dabbing the rod (bottom weld).
> 
> ...


What you have is essentially a series of tack welds, which is awful from a structural standpoint. Hot, cold, hot cold. What you need is hot all the time. Since you're pulsing, increase your background amperage and that should solve the problem. It very well could expose a weakness in your shielding setup but that's easy enough to fix. The other thing I would recommend is putting your pulses closer together, like twice as close. Ideally you would do that by increasing your pulse rate but you could also decrease your travel speed, or a combination of both. This will help the weld flow more consistently and will look and be a lot better.


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## Sepp (Oct 13, 2007)

customfab said:


> What you have is essentially a series of tack welds, which is awful from a structural standpoint. Hot, cold, hot cold. What you need is hot all the time. Since you're pulsing, increase your background amperage and that should solve the problem. It very well could expose a weakness in your shielding setup but that's easy enough to fix. The other thing I would recommend is putting your pulses closer together, like twice as close. Ideally you would do that by increasing your pulse rate but you could also decrease your travel speed, or a combination of both. This will help the weld flow more consistently and will look and be a lot better.


I had the stacks closer together at first, but from judging pics from experienced welders and the distance of their pulses I thought, I'd have to move faster, to avoid overheating the tubes. I do like the tighter stacks better look wise for sure...

I think I am running 5% as per recommendation from BungedUp and others...Too low?

Thanks for the recommendation - good read!


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## Sepp (Oct 13, 2007)

Hey guys,

I am asking this question here, as I didn't want to open a new topic on this...I couldn't find a relevant topic for it.

Got myself a cheapo propane/butane torch for silver brazing my bottle cage mounts.
Now I was wondering if I also could silver braze the cinch bolt on the seat tube.

Would that be too weak? I can tig weld it, but prefer the cleaner appearance of brazing.


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## Walt (Jan 23, 2004)

I'd use brass instead of silver, but silver is *probably* strong enough.

-Walt


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## Sepp (Oct 13, 2007)

Walt said:


> I'd use brass instead of silver, but silver is *probably* strong enough.
> 
> -Walt


Cool - thanks
Is propane hot enough for brass? Do you know?


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## Walt (Jan 23, 2004)

Oxy-propane yes albeit grudgingly, I think. Normal propane torch, no chance. But I'm not the right person to ask, I just use acetylene. 

-Walt


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## Sepp (Oct 13, 2007)

It's oxy-propane actually - I will order some brass then and give it a try.


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## Eric Malcolm (Dec 18, 2011)

Sepp said:


> View attachment 1256285
> Hey guys,
> 
> I am asking this question here, as I didn't want to open a new topic on this...I couldn't find a relevant topic for it.
> ...


You can silver this no problem.

I do this same application on Handle Bar Stems. Never had a breakage.

Eric


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## m-gineering (Feb 5, 2012)

Don't use silver, the peel strenght is pretty mediocre. You will devellop a crack where the boss ends and the tube starts to deform and it will grow. Brass is much more resilient. If you're stuck with silver get a collar with a full wrap


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## kampgnar (Apr 13, 2007)

Sepp said:


> Cool - thanks
> Is propane hot enough for brass? Do you know?


Oxy-propane is hot enough to braze with brass. As stated above, not the best, but it works for me.


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## duandr (Jan 7, 2016)

Many use Oxy-propane setups for fillet brazing with brass. I use it for lugs with silver and brass. Shouldn't be a problem at all. 

The tips you use will be important. Doug Fattic has posted in other forums a ton of great info on using Oxy-propane for frame building.


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## Sepp (Oct 13, 2007)

I will get myself one of these little kits, as I will be doing small parts only. Other tasks I aspire will be TIG. Thanks guys.


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## Sepp (Oct 13, 2007)

After my first frame attempt got crooked like a banana, I went back to practice...On this picture you see what I believe is called undercut (when the edges of the weld dip under the original tube surface).

What do you recommend trying to solve this?

At a 1.6 pulse rate it's obvious that my speed is slow. Too slow maybe, and does that cause the undercut as well?

Or/And should I push in more filler? What you see on the picture is pretty much laid down wire.


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## life behind bars (May 24, 2014)

Sepp said:


> After my first frame attempt got crooked like a banana, I went back to practice...On this picture you see what I believe is called undercut (when the edges of the weld dip under the original tube surface).
> 
> What do you recommend trying to solve this?
> 
> ...


More filler, move faster, reduce amperage or a combination of all of the above. Point your tungsten at the point that the tubes meet. What size filler wire? What diameter tungsten? What amperage?


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## Sepp (Oct 13, 2007)

life behind bars said:


> More filler, move faster, reduce amperage or a combination of all of the above. Point your tungsten at the point that the tubes meet. What size filler wire? What diameter tungsten? What amperage?


1.2mm wire
1.6mm Tungsten
110 amps 1.6pps don't know the % settings right now, but I set it to a recommendation of a pro in this forum

I am too slow I guess, yeah...still having that fear of hitting the pedal hard at the start.


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## life behind bars (May 24, 2014)

Sepp said:


> I am too slow I guess, yeah...still having that fear of hitting the pedal hard at the start.


Getting the puddle liquid quickly is what allows you to limit the heat introduced in every joint, get it going and start moving, tapering the amperage to suit conditions. Practice on some tubing drops, find out for yourself exactly what it takes to blow holes in it. You'll be surprised just how quickly you can get a puddle going without blowing holes but you have to know just how much it'll take and then walk it back a bit.


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## Sepp (Oct 13, 2007)

life behind bars said:


> Getting the puddle liquid quickly is what allows you to limit the heat introduced in every joint, get it going and start moving, tapering the amperage to suit conditions. Practice on some tubing drops, find out for yourself exactly what it takes to blow holes in it. You'll be surprised just how quickly you can get a puddle going without blowing holes but you have to know just how much it'll take and then walk it back a bit.


THat sounds good - I will try that.

Do you have tips on how to tackle acute angles like found on DT/TT junction on frames with shorter head tubes?

Do you start the weld from the center tack and work your way out to the sides, or the other way around?
Or do you start on the side and weld past the center to the other side?


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## Meriwether (Jul 26, 2007)

It only looks undercut at the more acute angle of the joint, which to me means you’re moving too slowly likely because you’re stalling a little to make sure the puddle bridges the tubes before moving on. This means you’re not adding enough heat. I always turn it up quite a bit in the acute angles especially the DT/HT joint where the tubing is usually thicker too. So if you’re using 110 max amps I’d try 130 or 140 even, and up the background amps too. For steel MTB tubes I’ll do something like 134/22/34%/1.6pps.
Just like another said get the puddle going fast and move along, lay wire is fine but you’re still feeding/pushing the wire into the puddle so it takes as much as it needs. What you see in the photo is looking good, just needs more filler, more heat, and move faster. 
You can either back off the pedal for the sides if you can do long passes or stop at the 4/8 o’clock positions and go back to your lower pulse settings for the sides and obtuse angles. 

It’s easier to start and stop at tacks, but that also means you’re adding a lot of heat to those tack locations so it’s best to weld over them IMO but that means you’re not starting and stopping at your tacks and that is a bit more challenging.



Sent from my iPhone using Tapatalk


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## Sepp (Oct 13, 2007)

Meriwether said:


> It only looks undercut at the more acute angle of the joint, which to me means you're moving too slowly likely because you're stalling a little to make sure the puddle bridges the tubes before moving on. This means you're not adding enough heat. I always turn it up quite a bit in the acute angles especially the DT/HT joint where the tubing is usually thicker too. So if you're using 110 max amps I'd try 130 or 140 even, and up the background amps too. For steel MTB tubes I'll do something like 134/22/34%/1.6pps.
> Just like another said get the puddle going fast and move along, lay wire is fine but you're still feeding/pushing the wire into the puddle so it takes as much as it needs. What you see in the photo is looking good, just needs more filler, more heat, and move faster.
> You can either back off the pedal for the sides if you can do long passes or stop at the 4/8 o'clock positions and go back to your lower pulse settings for the sides and obtuse angles.
> 
> ...


Good read - I now realize that I weld too cold mostly, so I will readjust, hammer the pedal, and see what happens - do I understand right?: 34% background? I think I have it set at 5% right now.

When I start a weld between tacks: is it ok to lay the wire down, and start the arc on the tip of the wire? That's what I did so far, and I feel it helps me to not blow through.


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## Meriwether (Jul 26, 2007)

It's hard to describe things that i now take for granted and do without thinking but yes, hammer the pedal *once you get the puddle started*. So when there's no tack i don't hammer it, i will ramp up and dab filler to get the puddle started and then get it going with almost or full pedal and try to get a full 1/4 tube pass (4-8). That tends to be hard under the downtube so for awhile i'd stop at the tack and continue on when i re-positioned a little (after the post-flow of course). This is not ideal but...it is what it is and i feel it still holds the frame in alignment better than doing 3-6, 9-12, 12-3, 6-9, or something like that. But this is just my opinion and literally everybody does it their own way.

For amps, my ThermalArc has different pulse settings than a Miller and for some reason i have trouble converting between the two. It's not 34% background amps but the % of time at max. So if my low/background amperage is set at 18, that would be about 15% background? I tend to change my max more than the background to get better penetration on thicker tubes, and also the % on max amps varies from 22-40% going from fusion passes on 0.9mm tubes to tapered steerer forks where you need a ton of heat.


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## DSaul (Dec 13, 2012)

You should try welding without pulse, so you can learn the mechanics of how to start a puddle, add filler and move the puddle forward while maintaining arc length and torch angle. It really helps to see what is happening and make sure the puddle flows into the root of the joint, while trying to maintain a consistent bead width. 

I found that it was easier to learn how to weld without the stress of trying to push filler with each pulse and waiting for the next one, if it didn't go right on the previous pulse. Not to mention the all of the times the pulse would burn back the filler rod and it would stick to the tube, because I had too much torch angle or too long of an arc length. 

Once I got comfortable with welding thin tubes without pulse, I never felt the need to use it again. I can do nice practice welds with pulse, but I still feel more comfortable welding frames without it.


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