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Discussion Starter · #1 ·
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? FINALRENDER_1 (2 of 7).jpg FINALRENDER_1 (1 of 7).jpg FINALRENDER_1 (3 of 7).jpg FINALRENDER_1 (4 of 7).jpg FINALRENDER_1 (5 of 7).jpg

anyway thanks in advance
max
 

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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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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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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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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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Discussion Starter · #8 ·
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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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
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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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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IMG_3137.jpg 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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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.

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.
You can silver this no problem.

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

Eric
 

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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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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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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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