First Stainless welds

[alogaparaloga]

I thought to start a thread with some photos of my welds so as I can get some constructive comments and improve my skills.

I don't have any scrap material to play with so I started welding anged tube slices which I cut some time ago for my custom exhaust system.
The pipe is quite forgiving as it is 2.0mm thick.

I started with problems due to a leak on the regulator as the arrow shows on the pic

I have to call weld equip if they can get this replaced as I have it for a few months but I just got it out of the box. For that the only fix was to buy a replacement one from Halfords and I managed to start.

The following pictures show my welds. BTW I use 86/14% argon/CO2. and the welder is set to the power recommended for my clarke 151en, with the feed rate set at 7 instead of 6 as per manual's recomendations as the wire melts back in the shroud.

I also found my torch angle not to be the best so I started welding smaller sections and tha sorted thing a bit.

 

[TechnicAl]

not exactly pretty are they?
you are using the wrong gas, you need Argon with 2.5%CO2
what wire is it?

 

[alogaparaloga]

The wire is 0.8mm 308LSi.
regarding the gas I thought to use two bottles together. 1 pure argon and the one I used today but with one regulator leaking that's not an option.
Tomorrow I ll switch to pure argon for the rest of the bends and I ll see how it goes.

The other thing is that I have to get used in overlapping the weld sections, as I did massive welds for just to weld tiny spots that I left inbetween sections.

and I dont want to spend another half day for grinding.

One more thing.
What gap should I leave between slices for 2.0mm wall thickness?

 

[TechnicAl]

No not pure Argon

Argon + 2.5% CO2 or Argon + 1to2% Oxygen

Pure Argon will give you peaky welds

The wire sounds good

 

[SwissTony]

The leakage you had on the valve can often be solved by chopping 5mm off the end of the pipe with a sharp knife, so that the end is not at an angle, clean, and has no chewed up plastic to prevent it from making a bad seal.

 

[Wozzaaah]

Another tip is to use flap discs for dressing the welds. It looks like you're using normal abrasive discs and they're far too aggressive.

 

[alogaparaloga]

The leakage you had on the valve can often be solved by chopping 5mm off the end of the pipe with a sharp knife, so that the end is not at an angle, clean, and has no chewed up plastic to prevent it from making a bad seal.

The hose end is clean and square. The leakage comes though from the space between the metal bit that holds the hose and the hex bit. I am familiar with that type of connectors for air supply at work and I believe that there should be some sort of clip or seal for the two parts that make form the connector.

 

[alogaparaloga]

No not pure Argon

Argon + 2.5% CO2 or Argon + 1to2% Oxygen

Pure Argon will give you peaky welds

The wire sounds good

Thanks for the correct ratios.
I was reading threads about stainless welding and I have seen these figures and the tables of various gas mixtures, but I don't have another option as I am using disposable gas cylinders.
That's why I was thinking about using two cylinders and adjusting the flow output so as I could get a good ratio of Argon to CO2.

Will the two cylinders mix well or my trials will fail???

 

[alogaparaloga]

Another tip is to use flap discs for dressing the welds. It looks like you're using normal abrasive discs and they're far too aggressive.

Yes I use stadard grinding discs, but the photos show unfinished parts.
When I took the welds down I finished with a 60 Grit flap wheel on my drill.
And I also clean the inside of the bend with the same wheel.

 

[shenion]

You cant really mix the two as they are both either argon or CO2.

You need a few % of oxygen to add heat. The ideal mix is helium, argon and a bit of CO2. You can get away with the light tri-mix for steel (Ar/CO2/O2.)

The 14% will turn the surface black and may make the welds a bit brittle as the stainless will absorb carbon from the gas.

I use about 5% CO2 and it seems to work well. The welds do have a black surface though but they are strong enough.

Pure argon will produce clean welds but they will be tall. you will have to up the power/speed to get good fusion. Then you will have more to grind off.

Given those only two choices, I'd go with pure argon. I used a large tank on my Clarke (supplier gae me the wrong one.) It worked fine but the welds were as tall as they were wide.

 

[alogaparaloga]

This is what I thought to do.

If I do 50/50 flow ratio per bottle from their regulators, it will be near 6.5% CO2, but by letting more argon out of the pure argon cylinder I thought I would correct the ratio at the torch and get some good results

 

[backpurge]

As Al has already said, if you want to make a decent job of MAG welding stainless you don't want anymore than 2.5% CO2 in the mix

If you want the weld to be as clean as possible don't go near it with any gas mixes with oxygen in it, results are crap. Best mixes are argon/helium/Co2 but these are costly for DIY type work

 

[alogaparaloga]

Time for an update

It took me some time to get around and do some welding,
and I can say that I have improved my welds a bit, by using pure argon and 6.5 feed rate on my clarke 151en.

I also pay some more attention to my torch speed and angle the welds look better.

The following images show two of the old welded bends after grinding, that I used for my twin loop exhaust silencer in semi-finished form.

And this is as it is welded on the silencer..
I could have done some better finish by using a finer flap disc but I am OK with this as it's going to be hidden.

I hope that by the time I finish this exhaust I will be good enough for building my stainless manifold.

 

[backpurge]

As has been repeatedly said pure argon is crap for MAG welding stainless (or any type of steel for that matter), you will produce very peaky welds that have virtually no penetration.
You will spend lots of time and money having to grind off the crappy looking welds and when you have you are left with a joint with no mechanical strength