Spatter on stainless

[chunkolini]

Hi Guys
I am just starting another stainless Mig welded sculpture.
I have made several in this style.

Basically made of bars butt welded together with large fillets to make the structure flow.
Structurally they are sound, but I get a lot of spatter and it sticks like hell.
On Mild steel I hardly get any, and it just knocks off easily.

is it just a matter of using anti spatter spray on the bars, or is there something else I can do? I am using Lincoln 0.8mm wire (cheers Technic Al) so I know it is not consumables. I am using argon/CO2/O2 mix surely I dont need another gas .......

I am expecting this thread to become a debate.

Chunko'.

 

[TechnicAl]

Im afraid it probably is the gas. The best is Ar+2.5% CO2.

enter Backpurge

 

[penfold]

What he said.

 

[dannyweld]

you could try turning up to max amps you can get away with a low wire speed will also help reduce warping

 

[mike os]

dunno about the issue but the sculpture is sweet

 

[chunkolini]

Big Al and Penfold,
I bow down to your experience and knowledge, will look into a bottle of dat stuff.
Interestingly I had guessed it might be the oxygen acting as a surfactant, lowering/breaking the surface tension and leading to the spatter forming, was I anywhere near right? Goes back years, right Al?

Chunko'.

 

[Paul.]

Most likely down to gas as said, I spent a while working on stainless storage vessels, we used Stainshield light, which is a 85% Helium, 13.5%argon, 1.5% co2 mix, I used a SAF synergic set too, but the difference over argoshield is quite marked,

 

[TechnicAl]

Im not sure of the mechanism but there appears to be an optimum mixture for different properties. You will probably get better pen with your mix but the downside is the spatter.
I was once told 1% Oxygen = 3% CO2 in its effect so if your mix has 2 Oxy its a lot different to the current favourite (2.5%CO2).
I always used to recommend 1 or 2%Oxy in Argon but Backpurge put me onto the CO2 and it does work very well........probably better.

TIG Paul..........that mix sounds very very expensive and probably OTT for this. The Helium gives best penetration on thick section

 

[Paul.]

Im not sure of the mechanism but there appears to be an optimum mixture for different properties. You will probably get better pen with your mix but the downside is the spatter.
I was once told 1% Oxygen = 3% CO2 in its effect so if your mix has 2 Oxy its a lot different to the current favourite (2.5%CO2).
I always used to recommend 1 or 2%Oxy in Argon but Backpurge put me onto the CO2 and it does work very well........probably better.

TIG Paul..........that mix sounds very very expensive and probably OTT for this. The Helium gives best penetration on thick section

Yes I agree for a sculpture its overkill, helium mixes are about 50% dearer than normal mig gases, they do work well though even on thinner sections, we were welding 2 to 4mm butts with ceramic backing tiles, the welds were almost as clean as tig, Chunko did say he was expecting a debate.

 

[chunkolini]

This is why I like this site so much, so much expensive knowledge shared so freely.

Al, re surfactants, years back on another site I raised a similar problem re gas mix, I think I was having problems with a possible batch of gas, anyway you described the function of O2 in welding gases in plain english, something to do with lowering the surface tension allowing the weld pool to flow better, or something like that. and it made sense even to little old me.

Cheers all, will speak to my gas suppliers on Monday, can they let me have a test drive.

I dont mind having a bottle sitting around hardly used as long as it works. Will report back.
Chunko'.

 

[JayRS4]

I had exactly the same problems today on a stainless piece. Using settings akin to mild produced a lot of spatter, but a normal bead. I ending up backing off the wire speed and hitting a sort of globular transfer (power too low to really hit it). Ended up producing a bead looking more like pulsed tig, and with no spatter

 

[TechnicAl]

I had exactly the same problems today on a stainless piece. Using settings akin to mild produced a lot of spatter, but a normal bead. I ending up backing off the wire speed and hitting a sort of globular transfer (power too low to really hit it). Ended up producing a bead looking more like pulsed tig, and with no spatter

what gas did you use?

did you get adequate penetration? (thats not a personal question )

Chunko........yes thats what happens the active part of the gas (O2 or CO2) act like fairy liquid in the washing up and allow the molten steel to wash into the sides of the joint (removes the maniscus). But you can have too much of a good thing...........as I am finding out this morning

 

[chunkolini]

I spoke to my gas supplier today, regards Argon/2.5%CO2.
their 'man in the know' has offered to decant me a small bottle to try out, if I dont get on with it he says no problems. He has even offerd to send a some pure Argon to try as well.That is quality service.

I will report back in a few days.
I tried less wire speed, the welds are fine but the blob tends to drop and spatter all over the place.

Chunko'.

 

[TechnicAl]

You dont want pure Ar for MIG....keep it for TIG
If you uae it MIG you will get awful peaky blobs

 

[chunkolini]

Yep,told him that.
When I had it for Tig welding I figured give it a go.
Ha Ha, this is why we have active gas.
I think he was puzzled by how a bloke in a shed can sound like he knows what he is doing.
Where did I acquire this knowledge base?
wink wink.

Chunko'.

 

[TechnicAl]

Have you tried the new gas yet?

Come on tell us we were wrong and it makes no difference..............

 

[chunkolini]

Wel they sent me the wrong mix, Argon 2%co2 + 2%O2, there was some improvement but not much.
Should be getting the next bottle todayish?
I forgot to ask if antispatter spray will be any help.
Chunko'.

 

[chunkolini]

New gas turned up today. On approval which is pretty good compared to some gas suppliers.
I did three test pieces, one with argonsteel 15 15%CO2 plus 2%O2 (middle)
Then with Argonsteel2, 2%O2 +2% CO2 (left)
Then with Argon +2%CO2. (right)
The last mix gives a lt less spatter but the welds are not as tidy, hwhen using it there is a weird harsh spitting noise and the welds are raised compared to the other two tests.


So almost no spatter but no so happy with the welds. I will have a go at it tomorrow and see what improvements I can make by changing power and wire speed.

Looks promising.

More to follow.

Chunko'.

 

[chunkolini]

Did some more of it today, just the same, I need more power but the welds are still very raised, there is some spatter, but not happy with the welds.
Might I be better off with either argon2 or the usual argonCO2/O2 mix and using anti spatter spray? I am hoping to get some of this tomorrow.
Interssting stuff but it is starting to get to me.

Chunko'.

 

[TechnicAl]

There is noticeably less spatter with the 2%CO2 mix.. I was once told that 1% O2 = 3% CO2 in terms of wetting action. Therefore if we assume this to be true (and its always worked for me) you will get peakier beads that with the other mixes. Increasing the voltage may flatten out the beads.
As with most things there is a compromise if you want the wetting action you may have to put up with the spatter and use a higher oxygen content gas.
The welding set can have a big influence on the amount of spatter which is why the £hard and fast" rules dont always apply.
Unfortunately welding has too many variables to be absolute and one of the biggest variables is the hand on the torch.
If the size of tube you show in the pics is the usual it might be worth taking a serious look at a TIG set. Even though you might need to make the prep a bit more sophisticated.