Hobbyweld - any good?

[pauldee]

I'm thinking of using Hobbyweld 5 as there is a stockist near me and it sounds good for my purposes. I am after an argon/co2 mix. However, I was surprised to see it has 2% oxygen (apparently to make the arc more stable). I though Oxygen was exactly the thing shielding gasses were tying to eliminate?

Has anyone used this stuff? Is it any good? does the oxygen help/hinder?

 

[Wozzaaah]

A small amount of oxygen is added to most mixed welding gases so yes, it's normal.

 

[pauldee]

Cheers for that, every day's a school day!

 

[grim_d]

As a side note, if you find yourself using more than 2 Hobbyweld cylinders in a year it will very likely be cheaper to go onto a 20l rental bottle.

 

[chunkolini]

I was baffled by this one a while back oxygen in shielding gas?
So I did a whole bunch of research, here and all over the web.
It is included to break the surface tension on the molten metal allowing it to flow better, giving a less raised weld and helping with penetration. Without it you end up with an ugly high ridge of weld.
It acts as a surfactant, (new word of the day) as used in washing up liquids.
Your mission pauldee is to use this word in conversation once a day for the next week.

 

[penfold]

It does exactly the same job as the CO2; it facilitates the small amount of oxidation necessary to do what Chunko has outlined.

 

[KemppiFrog]

Every day is a school day. Esp. on this subject. I was also curious about O2 in the gas. So thanks.
My prob is how to introduce this into conversations with anybody I know around here. I could, but they would probably wander off (quickly) and I would see them talking about me to others. With odd looks.
Is there a cure???

KF

Of course, most of them think I am an investment banker, so I don't want to confuse them. Or do I?

 

[chunkolini]

The cure?
Stand in a corner with a bucket on your head talking to yourself, then nobody will want to speak t you.
Oh! you do this already.

 

[KemppiFrog]

Are you spying on me??

About talking to oneself, everybody does it, just some of YOU do it aloud.

 

[backpurge]

It does exactly the same job as the CO2; it facilitates the small amount of oxidation necessary to do what Chunko has outlined.

More or less echoing what Chunko has said and not wishing to be knoby but it doesn't do quite the same as CO2 otherwise we wouldn't bother adding it to gases, we would just put more CO2 in instead.

CO2 tends to increase heat in the actual "body" of the weld which aids penetration, fusion etc whereas O2 increases the heat on the surface of the weldpool which reduces surface tension aiding surface profile, wetting (to a degree) and reducing spatter generation due to less surface tension

If you look at macros of welds produced with Ar/CO2 and Ar/O2 the penetrion profiles are quite different