JoelP
|
| posted on 24/9/03 at 05:19 PM |
|
|
Argon Trouble
They'd ran out of CO2 at MM today, so i bought argon. Couldn't make it work so i came home and reread that thread recently on argon, and
realised i'd forgotten everything i'd read about how a mix was better.
Basically had to up the wire feed and turn down the gas, and the weld was essentially cr4p. Came out looking like a blow torch, all the gas glowing
green (thru the visor) and the wire seemed to disappear, barely any hit the joint or settled into a weld pool.
is this normal for argon on mild steel? Gonna get a bottle of mix anyway, are there any good alternative uses for nearly full minatures of argon?
gutted when i reread that old thread... my memory is terrible, i'd even posted myself saying id use a mix next! misspent youth i guess...
anyone out there making argon work for them?
|
|
|
|
|
blueshift
|
| posted on 24/9/03 at 05:59 PM |
|
|
use pure argon for mig welding aluminium.. and some other exotic things (tig welding magnesium anyone?)
|
|
|
Viper
|
| posted on 24/9/03 at 09:57 PM |
|
|
Tig ing mag no worries plenty of gas flow and back purge....
JoelP,
pure argon shouldn't cause the effects you describe, not trying to be funny but it sounds like you have the wire feed far to low....
|
|
|
JoelP
|
| posted on 24/9/03 at 10:54 PM |
|
|
usually i have the feed on around 5 out of 9, turned it up somewhat and eventually got it to form, but there was no penentration.
one problem is that my welder has two switches, one sayinf min and max, the other saying one and two. since i dont know what these do i usually have
them on 1 and max.
2morow im gonna try having both on full, lots of wire and minimal gas (gas i usually have on full, never seems too much?), and see where i get.
i'll post tommorow and say how it went.
thanks for the posts both of you, any comment is helpful cos i have no training and very limited experience.
it was just very odd, i couldn't even see thru the glow of it all. And the noise was a lot less crackly, all that could be heard was the hum of
the electricity and gas flow. sounds odd when ur use to fireworks!
normally with CO2 there is only glow from the molten pool, but with the argon it was like the gas itself was glowing?
so i reckon full power and lots of wire, gas to suit.
should the gas be at the minimum amount to prevent pitting?
thanks again, Joel.
|
|
|
suparuss
|
| posted on 25/9/03 at 05:36 AM |
|
|
argon makes the arc really really hot so as you say the wire will just melt before its get to your material, try unscrewing the tip out a little or
shorten the shroud to make the gap smaller, but then you risk melting the tip (and/or shroud). tis not meant for mild, just stainless and ally that
need higher welding temps and a more pure weld.
Cheers,
Russ.
|
|
|
craig1410
|
| posted on 25/9/03 at 11:58 AM |
|
|
Hi,
I asked about this exact same problem a while back. I was using the 80/20 mix from Halfords and was getting this "plasma effect" with a
wierd sound. I eventually gave up and went back to CO2 as I got much better results. I wondered if it had something to do with polarity of the welder
but could never get to the bottom of it. I'd be very interested in the solution to the problem if you find it.
Cheers,
Craig.
|
|
|
suparuss
|
| posted on 25/9/03 at 03:01 PM |
|
|
i think the plasma effect you are talking about is just the fact that the wire is melting before it gets to the metal you are welding and thus no
impurities are entering the the metal when its in a molten state. when you get impurities you get splatter, so wii let get the fireworks and the
noises as well, that humming sound that it makes is how it should sound when you are making a perfect weld with a really clean metal like ally or
really good stainless. the crackling noise you get is from the impurities in the mild steel, which are unavoidable, but id the wire is melting before
it gets that far, then the impurities will not get into the pool and will get the nice humming noise.
|
|
|
Tigers
|
| posted on 26/9/03 at 09:26 AM |
|
|
So, after all...
I just about getting gas shield for my MIG, and now I'm quite confused.
I'm still learning to weld (temporary training without shielding gas). As i have read before, 80% argon mix is supposed to be better than pure
CO2. And I was almost sure to get it.
But now I'd don't understand - should I get CO2 or 80% argon?
What is better and easier to weld with?
T.
|
|
|
David Jenkins
|
| posted on 26/9/03 at 09:39 AM |
|
|
If you're buying big bottles, there are several Argon/CO2 mixes, depending on what you want to weld. The one I use came from BOC, and was
called Argoshield Light.
I think that the disposable bottles only come with one mix - so you have to manage with that one!
The Argon/CO2 mix does make welding a lot easier. Pure CO2 also works very well, but maybe needs a bit more skill as it's hotter, and it can
also produce more spatter (which means more clean-up work).
FWIW, I noticed a book that might prove useful to some people:
http://www.welduk.com/
It's the book in the top-right corner (I couldn't get its link to work this morning!). Anyway, it's the cheapest place I've
seen it, at £5. It's written in the UK, and all about starting to weld with a MIG.
Disclaimer: no connection, etc.
David
|
|
|
JoelP
|
| posted on 26/9/03 at 10:16 AM |
|
|
I personally will avoid pure argon in future. Gonna get a mix in today, so i'll let u know how it goes. Probably 2morow now, lazy bones here
cant be arsed cos its cold!
If welding a joint that is in a good position, i find CO2 very good, but when its fiddly, and either upside down or if you cant get to it properly, i
get a lot of splatter and a lower quality weld. Maybe the mix will help this situation, maybe i just need to get better first. Time will tell.
anyone know the ratio in argoshield?
|
|
|
David Jenkins
|
| posted on 26/9/03 at 10:21 AM |
|
|
Argoshield Light is 5% CO2, 2% Oxygen, 93% Argon.
Recommended for mild steel up to 3mm, but OK for thicker stuff.
There are 2 other Argoshields, with up to 20% CO2, depending on the thickness of steel. The 'Universal' grade is around 10% CO2.
DJ
[Edited on 26/9/03 by David Jenkins]
|
|
|
stephen_gusterson
|
| posted on 26/9/03 at 10:42 AM |
|
|
I use 20% argon / co2 and it is WAY WAY BETTER.
I also have a cyl of argon I thought i might use when I was nuts enuf to think I might weld alu.
If you attempt to use it on steel it doesnt seem to penetrate ans sits on top of the metal.
getting it right with mig is always hit and miss at first. With a mix its a big head start.
atb
steve
|
|
|
Tigers
|
| posted on 26/9/03 at 11:06 AM |
|
|
Ok, thanx for answers!
Then it will be argonmix for me 
|
|
|
JoelP
|
| posted on 26/9/03 at 11:08 AM |
|
|
and me. again, thanx all.
|
|
|
JoelP
|
| posted on 26/9/03 at 05:19 PM |
|
|
Got a can of the mixed stuff from machine mart today. I was quite disappointed how high i had to turn the wire feed up, as i said previously i liked
it nice and slow, however the result is very nice, so im chuffed over all, sod doing it slow when you can get nice results fast!
really is a nice finish, it sinks in well and is smooth as you like. Suspect thats due to the heat and fast wire, less time to go bumpy? Plus the weld
is a nicer colour, a smooth dull silver.
Do have to be careful about melting holes though, but i guess thats just down to practice.
anyway argon mix is definitely my future.
and whilst im here, i got a pillar drill off ebay, off a chap who sells loads so they're always available, delivered for £46ish, 9 speeds so
jobs a good un. if you want one do a search, its bob in wales. Blinder. 'scuse the shameless plugging. ofsky.
|
|
|
Mark Allanson
|
| posted on 26/9/03 at 07:15 PM |
|
|
superuss,
The crackle noise you get from MIG welding has nothing to do with impurities
There are two types of MIG welding, spray and dip. We all use dip welding because we are all using less than 300A. Dip welding - if you could see the
wire in slow motion, the end of the wire heats, melts and is transfered to the workpiece by polarity and the inertia effect. It does this 50 times a
second or 60 times a second in the USA, hence the crackle sound - heat splat heat splat at 50 Hz. Spray welding is where the arc is so strong that
the wire is heated and forms a constant stream onto the workpiece because the wire is in a constant state of melt - using this method, you can blow
1" holes in 1/4 plate in no time if you are not careful!
Another technique is to turn down the wire feed at normal amperages until the arc hums. The wire forms a ball of moulten metal about 2mm from the tip
and deposits a steady stream of metal to the workpiece, similar to spray, but is very prone to gagging the tip unless you keep the nozzle very close
the the workpiece. You can produce supersmooth welds doing this, but will get increased distortion because of the heat. It is ideal for welding
heavier plate when you need strong VERY accurate welds.
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
|
|
|
suparuss
|
| posted on 26/9/03 at 07:37 PM |
|
|
so is that why with argon it humms? because it is so hot that the wire never gets a chance to cool down enough for the next pulse to make a noise?
Cheers,
Russ.
[Edited on 26/9/03 by suparuss]
|
|
|
Mark Allanson
|
| posted on 26/9/03 at 08:03 PM |
|
|
With argon mix, the co2 is there to give additional cooling, and to give the weld bite, it allows a small amount of metallic burn to give penetration,
very small amount of o2 vasty increase penetration as well. Steel is actually flamable but only in extreem circumstances.
Using pure argon, the shield is perfect as the argon is a noble gas and is completely inert and cannot react with anything. However, it reduces the
penetration into the workpiece at the expence of the heat in the filler wire (the amps have to go somewhere). I have never welded steel with pure
argon so have never seen the results, but I assume the effect would be similar to welding with the wire feed too slow, but without the associated
increased penetration. I cannot workout joel's plasma effect, and I am buggered if i'm going to get a bottle of argon just to find out!!
Sorry joel!
Pure argon is only used for TIG, the penetration is dependant on the amps used and the dwell of the welder (person, not machine). You pause the weld
to increase the size of the weld and dip the filler wire to swell the pool to prevent undercut, you can weld without filler wire on things such as
flange joints where you are basically just fuzing the parent metals together.
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
|
|
|
JoelP
|
| posted on 26/9/03 at 08:35 PM |
|
|
No worries mark, im not gonna bother with argon again, so sod its silly effects! It looked like the wire was melting before contacting the work piece,
hence all sticking to the nozzle or all over the place.
I dont really understand which gasses would cause high temperature or need more wire etc so i cant think of a reason for the 'plasma'
stuff, i had concluded the gas must be a lot hotter, theoretically if it ionized it would conduct more and glow but argon is indeed nobility, so who
knows? summut to do with electrons and orbitals. Long time since my formal education ended... thank goodness!
but im sure with time and the mix i'll get better. as it stands in 3inch of welds i got it looking nice and smooth. A good portion of that is
due to the feed rate i guess, having it slow made it end up like a mountain range!
does anyone out there weld under things or do y'all turn the work round where possible? thats one thing i cant stand is splatter falling all
over me.
|
|
|
Mark Allanson
|
| posted on 26/9/03 at 09:00 PM |
|
|
Q. How do you avoid falling hair
A. Jump out of the way!
If the spatter is falling on you, move!
Seriously - hold the torch at 90 degrees to the weld, get it really close and you will reduce the spatter, and wear good gloves, and keep your head
away from the fall zone. You can get fire proof baseball caps from BOC and others which when worn backwards (in true wide wheeled Nova style) protect
you from the spatter. (obviously under you mask!)
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
|
|
|
suparuss
|
| posted on 26/9/03 at 09:48 PM |
|
|
i was welding a leaking hole up under a large concrete mixer at work last week, was an awkward position and had to get right underneath to see what i
was doing, plus there was the bonus that i had to do it while the mixer was running so we didnt stop production, then i ran out of gas half way
through so was getting constantly showered with splatter and burned concrete. ohh the joy of working for a cheapskate!!
i have a bottle of argon in the shed so might give a go on some mild steel on the morrow to see what happens.
Russ.
|
|
|
Mark Allanson
|
| posted on 26/9/03 at 10:01 PM |
|
|
I suppose thats a new variation on stitch welding, get a quick run in every revolution!
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
|
|
|
stephen_gusterson
|
| posted on 26/9/03 at 10:44 PM |
|
|
Joel
as an amateur thats tried argon on steel and gave up, I didnt see what you saw. The weld looked quite neat, but didnt have much penetration, the sound
was different, but there was no 'balling' at the tip.
reading your other posts, it looks like you wanted a slow wire feed. I dont think you have that flexibility. For a given current you need a matched
feed speed - if you dont you either get the wire hitting the work (fast) or burning back or spattering (too slow). You have to weld at a speed that
suits your feed and current settings. Slow weld speed will need a low current and low feed which will give low penetration.
thats my experience - a real welder may telll different!
atb
steve
|
|
|
JoelP
|
| posted on 26/9/03 at 11:57 PM |
|
|
i'd agree with u there ste. cant argue with that. it was only idleness that made me prefer slow wire rate (though i may try thicker wire next to
get some of it back!), dont really mind the fast wire feed, just you gotta do it fast to match the speed that it comes out at. pays your money and
takes your choice...
i'll live with that happily though, weld finish is much nice. Might try the pure argon again one day with a higher wire feed, cos i saw a
similar thing with the mix when it was too slow. thats one of the joys of life i guess, even if it goes wrong you learn from it!
|
|
|
Hugh Paterson
|
| posted on 27/9/03 at 11:59 AM |
|
|
Welding gas
We used to use an Argon co2 commercial gas on our 150 amp mig that left a lot to be desired of, and changed it recently to a "mix" called
Cogar, I dont know what the make up of it is but will find out on Tuesday, this stuff is the mutts nutts to use, but dont ask me on the availability
of it in your part of the world!.
Shug.
|
|
|
