[Jstruzik]

Hi guys, I have a question or lets say issue. We were in the shop today welding up some 304 stainless turbo exhaust tubing. As he was welding I was following him inside blowing argon on his weld as the purge. No matter what we tried we still go sugaring really bad. We cant figure out what we are doing wrong to save our lives. Any help would be greatly appreciated.

3/32 tungsten
3/32 filler 308
Lincoln precision 275 welder with foot control.

Thanks

[Otto Nobedder]

Welcome!

That's an easy one. You can't just "hose down" the back side with argon; Air will be entrained and actually make it worse for the mixing.

Tape the ends shut. Make a hole in one end to feed a LITTLE bit of argon (5-10 cfh) and tape the supply hose tightly to it, and poke small holes in the other end to let it out. Give it a minute to let the argon push out the air. BTW, argon is slightly heavier than air, so put your source low and exit high, when possible.

Steve S

[Jstruzik]

Otto thanks for the reply, the last set of tubing we put together we did tape it off just like you said. We still got sugaring inside. So that's why we tried the argon blowing directly on it. I have done the blowing on the back side of the weld before on a job and that worked. That's why we ended up trying that because taping off the ends was not working.

[Otto Nobedder]

Otto thanks for the reply, the last set of tubing we put together we did tape it off just like you said. We still got sugaring inside. So that's why we tried the argon blowing directly on it. I have done the blowing on the back side of the weld before on a job and that worked. That's why we ended up trying that because taping off the ends was not working.

You may very well have bad gas in the purge bottle. (It's rare, but it happens.) To prove it, swap bottles. Use your current weld bottle for purge, and vice-versa. If your weld goes to sh!t, you have your answer.

Steve S

[Oscar]

could also be a leak in the argon hose. Where are you getting the extra argon supply? Different argon tank? Same argon tank with a common-manifold dual outlet flowmeter? Single flowmeter and splitting it off at the exit? If it is the latter, there is no guarantee that you are getting sufficient flow through the purge device.

[LtBadd]

Hi guys, I have a question or lets say issue. We were in the shop today welding up some 304 stainless turbo exhaust tubing. As he was welding I was following him inside blowing argon on his weld as the purge. No matter what we tried we still go sugaring really bad. We cant figure out what we are doing wrong to save our lives. Any help would be greatly appreciated.
3/32 tungsten
3/32 filler 308
Lincoln precision 275 welder with foot control.

Thanks

Jstruzik, welcome to the forums.
Otto's method is a good one and it does work. You have to be sure that you have positive pressure in the tube (or whatever you're purging). You can check this by wetting your finger and checking the exhaust hole(s). You should feel the gas (argon) escaping, if not then you may not have the tube properly taped/plugged off, or enough flow into the tube.

Also the purge line should have some sort of diffuser on it, this allows the argon purge to enter the tube, be dispersed in a way that causes the least disturbance of gas flow. The diffuser can be something as simple as a copper tube as shown in my attachment.

Image1.jpg (20.2 KiB) Viewed 2309 times

[Jstruzik]

Thanks for all the input guys! I'm so glad I signed up here!! But to answer a few of the questions. We had both ends taped with hose feeding. We have a single flow meter with a Y off the exit of the meter. Also we did change bottles and tried that.

So even though argon is heavier than air itself why wouldn't me holding the argon hose about 1/4" away from the weld inside prevent sugar? It's not like we are outside or anything near wind. We are in a weld booth in our shop.

Would having the heat to high cause a problem? I wouldn't think so. I welded a lot of stainless and never had this issue before. But sugaring is cause by poor gas coverage correct? So it has to be sucking air somewhere or something. Because even the finished weld doesn't have the nice shiny gold/purple look. Looks like a hot carbon tig pass

[Oscar]

You said it yourself---crappy argon coverage. It's one or the other. The Y-off a single outlet flowmeter is a bad idea IMO.

[Otto Nobedder]

J,

I'm going to call you J, since you won't give us a better name to call you,

If you were spraying syrup on the back of your weld, fine. Syrup won't mix with air. Syrup is much thicker.
Argon IS air, and we get Argon from air. Argon is just as thick (thin?) as air, so they mix when you try that.

Steve S

[LtBadd]

So even though argon is heavier than air itself why wouldn't me holding the argon hose about 1/4" away from the weld inside prevent sugar? It's not like we are outside or anything near wind. We are in a weld booth in our shop.

Would having the heat to high cause a problem? I wouldn't think so. I welded a lot of stainless and never had this issue before. But sugaring is cause by poor gas coverage correct? So it has to be sucking air somewhere or something. Because even the finished weld doesn't have the nice shiny gold/purple look. Looks like a hot carbon tig pass

If you're working off one flow meter then when you start welding the flow to the torch and the purge line is governed by the Y valve, you have to be sure when the gas is flowing to the torch you still have enough flowing to the purge line.

Still holding a hose to the back of a weld is a pot luck at best. Did you have some sort of trailing gas diffuser on the hose? You can't expect a 1/4" hose by itself pointing at the back of a weld to work. We need more information. Pictures would be better.

[noddybrian]

OK - a few random thoughts on this one - nothing wrong with a Y from a single regulator so long as you put a floating ball flow gauge on each leg so you know the flow to each side & the regulator can keep a consistent flow for both - ( like 15 > 20 CFH torch & 5 > 10 CFH purge once pipe is filled ) obviously check all pipework for leaks - the direct argon flow to purge can be done on large diameter or long runs of pipe where the time & argon used would not be economic - but it would involve making a close fitting diffuser assembly that can be placed exactly over the weld - don't see it's worthwhile or necessary on a turbo pipe unless of very large size - even when properly purged some tube butt joints if badly fitted can drag atmosphere from bad torch angle & give problems - also too much heat or too slow a travel speed can do it however good the gas cover is - as always with stainless you need to travel fast & avoid heat build up or use heat sink material to help - most turbo pipe on smaller vehicle applications will only be around 16 gauge - could be slightly more so why are you using 3/32"? a good fitting joint will only need very minimal filler added & the heat needed to melt this adds to overall heat input - surely 1/16" is better or even less ? also while you can needle point 3/32" tungsten 1/16" is plenty big enough to handle the amps your likely using - now when it comes to gas try welding on a flat piece of something that's easy to do & see if the problem is still present - if so then swap gas or investigate any possible leaks - if the gas seems OK then how about the material itself ? if it is bent was it coated in any sort of lubricant for the formers/ dies - have you removed it all ? some can be water soluble some oil based - what you clean it with may not work for both - the tube supplier may have changed this or had it bent somewhere different & last thought - I once had some tube supplied by the client that I could not get a good weld on & had me scratching my head what I was doing different - it was some sort of cheap import material - complete junk - so how about trying some tube from another batch ?

[hamed98ir]

I wanna TIG weld by robot in super duplex stainless steel V-groove , 60 degree and 1 mm root face
what is your suggestions in order to achieve penetration in root?

[LtBadd]

I wanna TIG weld by robot in super duplex stainless steel V-groove , 60 degree and 1 mm root face
what is your suggestions in order to achieve penetration in root?

Hello hamed98ir and welcome to the forums, you should start a new thread with your question as it doesn't follow with the topic of this one, also more people will see it and possibly be able to provide help

[Oscar]

speaking of which, I wonder what the OP found out about his sugaring problem.

[Cricket]

+1 to Oscar.
Y-connection for the gas is a bad idea. I have two separate regulators and flow meters on the same gas tank. Works like a charm. I can set any SEPARATE gas flow for SEPARATE outlets. None affect another.

[Oscar]

+1 to Oscar.
Y-connection for the gas is a bad idea. I have two separate regulators and flow meters on the same gas tank. Works like a charm. I can set any SEPARATE gas flow for SEPARATE outlets. None affect another.

Thanks for the back-up!

[Otto Nobedder]

+1 to Oscar.
Y-connection for the gas is a bad idea. I have two separate regulators and flow meters on the same gas tank. Works like a charm. I can set any SEPARATE gas flow for SEPARATE outlets. None affect another.

I use a single regulator, but tee to two flow meters. Built one for each TIG machine at work, on the cheap. We replace flow meters on these trailers so often, we have a box of spares, so it's as cheap as one brass FNPT tee and one close nipple.

GEDC0359.JPG (199.05 KiB) Viewed 2217 times

Steve S

[Cricket]

I use a single regulator, but tee to two flow meters.

Interesting. My flow meters have regulators in their base, I bet yours do too. They supposedly drop the input pressure to 50psi and you control the air flow from there with the manual valve. So you might have two regulators...

[Otto Nobedder]

I use a single regulator, but tee to two flow meters.

Interesting. My flow meters have regulators in their base, I bet yours do too. They supposedly drop the input pressure to 50psi and you control the air flow from there with the manual valve. So you might have two regulators...

I have some of those flow-meters with the built-in regulator. They do not work for this application. These were built from two-stage types, with the regulator separate from the flow-meter. Each leg off the tee (in the picture) uses the original pipe nipple from the regulator/flow-meter set, because it has a built-in restricting orifice to set a maximum flow (which is above the top reading of the ball, by the way).

Steve S