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oxy acetylene torch beginner

taiwanluthiers

Cast Iron
Joined
Dec 6, 2016
Location
Xinjhuan District, New Taipei City
I just got myself an oxy acetylene torch setup.

I have been trying to weld but for some reason I can't get a weld puddle started. As in by the time I get to the point where there is a puddle the steel burns through instead.

Is this a problem with torch setting? Too much oxygen? I should have a slightly reducing flame for this right?

Just tried again, I was able to get a puddle started, I think maybe it's because I was not seeing the puddle and that of course ends up burning it when I leave the torch in place too long... that flame is hot for sure.
 
Sounds like you're using too large a tip If it's too big you'll experience burn through like you're doing. Get it too
small and you can't get the material hot enough to weld properly. Your tip is the right size when a nice neutral flame
will give you just enough heat to maintain a nice uniform bead. Keep practicing, you'll get it...
 
Torch tip size here is not the same as the US.

In Taiwan torch tip size is 50, 75, 100, 150, 175, 200, etc., not 000, 00, 0, 1, 2, 3, etc.

I do not know how that translates but I was given 150 torch tip, says it's medium. I do like to keep gas consumption to a minimum though... as the O2 tank is only 5 liters.
 
Are you using pure acetylene for gas? Nothing else will burn as hot, which is only a problem when using other fuel gasses for welding. Heating or cutting is fine with other fuels.
 
I'm sure it's pure acetylene. It says so on the bottle. But then gas welding seems to have fallen out of fashion because people prefer TIG these days.

Plus I was able to make some good welds, it's just that I was burning holes and the welds don't look that good... maybe I should get a smaller tip.
 
Cool, Did you try turning the gas down? Less pressure on regulator and less flow from the valves on the torch. You wont be able to go to low on a large tip, it just wont work.
 
as to burn through, how thick is the metal? the tip should be sized to melt the metal and establish a puddle in from 5 to 10 seconds, less and its too hot and you will burn through easily, more and you won't be able to run a good bead.(of corse on heavy plate you never have enough heat with oxyfuel!) for steel, best tip I have is "keep moving" the molten puddle will absorb gases from the flame, mostly CO2, and "boil" so once you have a puddle, get going!

P.S. yes an experienced oxy-fuel welder can use a hot flame and a thicker filler rod on thin stuff, but that is a bit of an advanced technique.
 
Need more info. What material thickness, did you remove mill scale, what size filler, are you wearing proper shade glasses #3-5? I ask because you stated you had a hard time seeing the puddle.
Try just establishing a puddle with the torch and just walking it along the metal with no filler to get a feel for speed and heat control.


Sent from my iPhone using Tapatalk
 
IMG_1025.jpgIMG_1024.jpg

So on the torch pic the one on top is a welding torch, and the one in the bottom is a cutting torch, both made in Japan I believe.

The cutting torch does not have a lever to release oxygen, but rather you heat the material up and then turn the oxygen up manually...

The welding torch on top, with a close up pic has a small nozzle that has a female thread on it, that threads onto the welding torch. Says "150" on it and I am told this is a medium welding tip. I'm just practicing on some cheap hardware...
 
With that torch can you adjust the oxy and acet individually at the torch? It looks like I see only one valve on it.

Can you measure the size of the hole in the tip you are using, that will give a real number to compare to a victor or something common that will have more info on set up etc..
 
I changed the tip. I also found a cheap auto darkening welding goggle but when it darkens it was too dark for me to see anything (at the light setting, 3, it was actually good enough to kill the brightness enough so I don't see spots afterwards, torch welding doesn't seem to be as bright as arc welding). Maybe if I could find a goggle with a shade of 6 or something...

But anyways, I changed the tip to 25 and it was too small to weld anything but the thinnest material, but tip number 50 was the ticket and made a nice little weld puddle for me to work off of. I wanted to weld some bandsaw blades, and those are only .65mm thick so I will probably use the 25 tip for that.
 
Yea I tried to weld bandsaw blades... I kept burning holes through the band (it was practice on a dull blade). So I tried brazing and it worked beautifully, though the flux took higher heat than I expected before it worked, and when it worked it worked instantly.

No wonder I was having such difficulty using propane torches brazing carbide.... it couldn't get it hot enough.
 
One more thing, is there a chart on orifice diameter for torch tips, and what psi should I set the gases to?

In the whole process of learning I am burning through oxygen like crazy. I am using a 5 liter cylinder but I was going from 70 bars to 20 bars just welding for a few minutes at a time. I watched some youtube videos and they say to set the acetylene to 5 psi and oxygen to 60 psi, and if I do that the oxygen runs down FAST, like using up probably about 10 bars for about 10 minutes of welding. But on the other hand if I set oxygen to 20 psi the consumption is a lot less but doesn't seem to affect torch operation. So which is it?
 
Welding Tip Size Comparison Chart

Identifying the right cutting and welding tips

Welding Tip Chart

Welding tip guide

http://s3.amazonaws.com/scschoolfiles/480/victor_tip_charts.pdf

The first few are sizes of tips and cross references of brands and orifice sizes, last two are gas pressures per tip size :cheers: Be sure to look at welding tips, not cutting or MFA (rosebud)

For welding/brazing the oxy and fuel (acetylene) are aprox equal in pressure. Say 3 psi each or so. Cutting will be where you need the high pressure oxy.
 








 
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