iceT
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| posted on 5/8/03 at 04:26 AM |
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Welder & Gas
Hi All!
How have you all been? Have not logged onto the forum for awhile, got tied up with work.
Just want to share some experience... over the weekend, I had the welder supplier dropped off a Kemppi Super Migger. Tried it and it is sweet &
smooth & less splatter! Also basically I was using Argoshield.
Now, I have a Miller MIGMatic 210 and the Kemppi. Gotta decide which to keep. Looking at the quality of the weld, I would go for the Kemppi, as the
weld result is so much smoother and nicer, makes me look like an experience welder. And Kemppi support team is the friendliest. Unlike Miller, they
are not helpful at all! But the thing that bugs me is, the gun/torch on Kemppi is not removable, anyone care to comment any disadvantage for that?
Also, anyone using/used Kemppi? Any complains?
Argoshield is the way togo! Try it if you have not, you will never look back at CO2!
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David Jenkins
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| posted on 5/8/03 at 07:18 AM |
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quote:
Originally posted by iceT
Argoshield is the way togo! Try it if you have not, you will never look back at CO2!
(Smug grin from all those here who've been saying this for months/years!  )
David
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Mark Allanson
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| posted on 5/8/03 at 12:41 PM |
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The Kemppi torch is removable, it's just not a euro connector. All the parts are available, although the only bits you are going to need are new
tips and probably a liner after several thousand hours of use.
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iceT
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| posted on 7/8/03 at 08:30 AM |
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Thanks Mark! Yeah, Kemppi's torch is removable, just that it requires tools, not so convenient. But again, I dun see why would one wanna remove
it. Parts are available, as Kemppi reseller showed me their store. Friendly bunch of ppl. I think I know the winner now!
(Smug grin from all those here who've been saying this for months/years! )
I guess some will have to learn it the hard way...
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Peteff
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| posted on 7/8/03 at 10:31 AM |
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A big part of getting the weld right is the feed. If the feed roller and block work well it's half of the battle won. If it feeds in fits and
starts you will never get a good run. Get some good instruction on how to set it up and most welders will perform.
yours, Pete.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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craig1410
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| posted on 7/8/03 at 12:07 PM |
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quote:
Originally posted by David Jenkins
(Smug grin from all those here who've been saying this for months/years! )
I would love to be able to agree but I get much better welds from CO2 than I can with Argoshield. The bit which really scares me is that when I use
argoshield it looks like a beautiful smooth weld on the surface but is basically hollow inside and I do mean completely hollow! With CO2 I can get
better penetration and except for the spatter I get a clean weld.
To be fair I think it has a lot to do with the fact that the Argoshield that I am using is Halfords little bottles (as is the CO2) so maybe proper
Argoshield would be better. Anyway I'm going to stick with CO2 for now.
Cheers,
Craig.
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James
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| posted on 7/8/03 at 01:10 PM |
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quote:
Originally posted by craig1410
quote:
Originally posted by David Jenkins
(Smug grin from all those here who've been saying this for months/years! )
I would love to be able to agree but I get much better welds from CO2 than I can with Argoshield. The bit which really scares me is that when I use
argoshield it looks like a beautiful smooth weld on the surface but is basically hollow inside and I do mean completely hollow! With CO2 I can get
better penetration and except for the spatter I get a clean weld.
To be fair I think it has a lot to do with the fact that the Argoshield that I am using is Halfords little bottles (as is the CO2) so maybe proper
Argoshield would be better. Anyway I'm going to stick with CO2 for now.
Cheers,
Craig.
It's not that you've got the gas pressure up too high is it? Mark Allanson or Viper could say much better than me but I believe you can
get that effect as the gas 'blows' through the weld pool.
In non-draughty conditions you want the pressure dial on about 7/8 I believe.
HTH,
James
P.S. In the weld shop the other day I saw for sale a two part spray on liquid that will go a certain colour if the welds no good. I've not used
it myself tho.
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splitrivet
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| posted on 8/8/03 at 03:35 PM |
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Sounds to me that the gas pressures too high just gone on to argoshield myself so Im still getting used to it but did find you only need a whisper of
gas or higher current.But the finished weld is beautifully smooth.
Bob
I used to be a Werewolf but I'm alright nowwoooooooooooooo
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Afro
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| posted on 10/8/03 at 10:40 AM |
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After using the CO2 that came with the welder I borrowed from a mate and not being totally happy, I set it up with pure argon, the welds seemed much
better.
Argon comes out colder than CO2 due to being at a higher pressure in the bottle so depressurising more, and this can result in less penetration. A
thing to try is placing a coil of copper tube in the gas line and placing this in a bucket of luke warm water. In my experience of doing this the
welds looked cleaner, gave less spatter and penetrated well.
However, I still managed to burn the odd hole going too slow and thought the process a bit brutal so after speaking nicely to a guy at work and
getting a few pointers Ive succesfully learned to TIG. This has proved to be time well spent and I would definately recommend it if you can be
bothered trying..
You get complete control of the weld, no mess and it is a quiet relaxing welding process. If you do manage to lay a weld that doesnt look as nice as
you'd like then it can be gone over with the torch and neatened up easily
Plus.. when it comes to your wishbones you can do them in stainless and polish them up... mmmm lovely
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Stu16v
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| posted on 10/8/03 at 08:37 PM |
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quote:
Argoshield is the way togo!
Thats why you aint getting so much spatter, Little or nowt to do with the welding equipment....
quote:
when I use argoshield it looks like a beautiful smooth weld on the surface but is basically hollow inside and I do mean completely hollow
As James/Splitrivit says, sounds like gas pressure is too high. In a garage with no draughts, gas pressure should be set so you can *just* hear it
when the trigger is pressed. That should be more than adequate. Turn it up a little higher in draughty conditions, but try not to work in this
scenario if possible.
Dont just build it.....make it!
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Peteff
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| posted on 11/8/03 at 08:22 AM |
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I set it up with pure argon
Not recommended for carbon steel, only stainless or aluminium. It isn't the temperature of the gas it's the shielding it gives. Different
percentages are used for different steel thicknesses in process work. Pure argon is also more expensive.
yours, Pete.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Afro
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| posted on 11/8/03 at 07:09 PM |
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Hi pete...
I realise that its the shielding thats important, what I meant was that as the gas is colder when exiting the bottle, apparently it is possible to be
generating insufficient heat at the weld thus not getting enough penetration.
Im no expert, but at the place I work, any carbon steel pipework has a 'root' put in with the Tig using Argon as the shielding gas, with
the thicker stuff usually being capped off with arc. This is the usual spec given by our clients in petro-chem industries.
As far as I'm aware Argon is fine for carbon (mild) steel, its cost being the only factor for not recommending it when cheaper alternatives can
be used with no adverse affects, as in the case of Mig welding mild steel.
It also helps that they have 5ft tall bottles of the stuff around the workshop which they let me use for gratis
If it aint broke... it will be soon
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Viper
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| posted on 11/8/03 at 07:39 PM |
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It has come to the point where i have to say something.......
Afro. there is a saying that a little knowledge is a dangerous thing and in this case your little knowledge is a dangerous thing.
when next your gas man delivers to your company ask him for some tech info on the gases that are used in welding and you will find there is a specific
reason you don't mig with pure Argon, they mix co2 with argon to give penetration, co2 alone gives a deep penetrating weld but with the drawback
of spatter and a hardness to the weld, the higher % of argon the shallower the penetration but a lot less spatter, so when welding thin guage mild
steel it is easier to use a argon co2 mix, you only use pure argon (as has been said) on stainless and alloy the reason is a matter of purity in the
weldpool.
So i would suggest before you go and give advice to someone you realy should do your homework a little better.
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Spyderman
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| posted on 11/8/03 at 09:29 PM |
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Viper,
Why should one gas affect the weld pool more than another?
Not trying to be controversial, I just like to know why!
I understand the principles ,but it has been a few years since doing the coarse and need reminding!
Old age makes me forgetful! now wot were we talking about.
Terry
Spyderman
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Viper
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| posted on 11/8/03 at 09:48 PM |
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God now your asking......
i don't know why different gasses affect the weld pool the way they do (its been 20 years since i did my appretiship) i just know what affect
they have through day to day experiance. i do know that it has nothing to do with the prssure in the cylinder.
as a footnote you can use Helium as a shielding gas and that gives a much hotter weld pool great for heavy alli, the yanks use helium more than
argon..
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Afro
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| posted on 11/8/03 at 09:50 PM |
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Fair enough Viper..if a little venomous
As I said Im no expert, most of my info comes from people in the workshop and my own albeit limited experience..
I did notice the welds sitting more on top of the metal than penetrating into it which, as you say, would be dangerous. After adjusting the settings
on the MIG set and adding in the copper tube to the line (how much effect this alone had Im not exactly sure) I get good penetration in the weld. It
is definately worthwhile welding offcuts and cutting them up to have a butchers before setting about welding the chassis... the large hammer test
comes in handy too
If I could ask you a question before I get too far into my chassis (at the 'four uprights' stage now) do you think there is any mileage in
re-doing the welds already done with the MIG and argon? I am confident that the penetration was good from looking at those done on offcuts but its no
major drama to re-do them with the TIG which has become almost a pleasure to use
By the way, if you want danger, I've seen a site somewhere of a guy building one of these locosts who got very frustrated with various welding
processes and has now resorted to BRAZING it.... anyone coming for a spin??
[Edited on 11/8/03 by Afro]
If it aint broke... it will be soon
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Afro
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| posted on 11/8/03 at 09:57 PM |
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Just a foot note about cylinder pressure... the pressure at the torch is the same regardless of the pressure in the cylinder... the gas is
effectively venting to atmosphere. The higher the pressure is to start with, the colder it will be when it has depressurised, not got the figures on
me now but the Argon in the bottle is at a far higher pressure than a CO2 bottle therefore is colder after depressurising.
If it aint broke... it will be soon
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Stu16v
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| posted on 11/8/03 at 10:27 PM |
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quote:
and has now resorted to BRAZING it.... anyone coming for a spin??
....as are Cateringvan chassis....
Brazing is probably THE best way to build chassis if you have the time, and patience to do it.
Dont just build it.....make it!
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Viper
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| posted on 11/8/03 at 10:52 PM |
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Welding gas cyls, co2, argon, argon/co2, heliarc (helium) are all filled to 300bar.
Duno about the mickey mouse stuff halfords sell. but all BOC, Air Products, Linde etc etc are 300 bar and have been for about7 years now.
As far as your welding goes , that is a decision you will have to take,
Brazing a Chassis..
Take a look at tubular racing car chassis a lot of them will be brazed, especialy older formula ford etc. nothing wrong with brazing if you know what
you are doing, in fact a brazed joint (being more flexible) can be very beneficial, my old kart chassis was brazed and i never had any problems with
that and that often exceeded 170mph...
Correction there not 300 bar but 3000psi
[Edited on 12/8/2003 by Viper]
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Stu16v
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| posted on 11/8/03 at 11:29 PM |
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and brazing doesnt form stress raisers like welding does.......
Dont just build it.....make it!
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David Jenkins
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| posted on 12/8/03 at 08:02 AM |
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Two comments on brazing:
First of all, it's not copper/zinc brazing (i.e. general purpose), the stuff car chassis makers use is bronze (copper/tin). This is much
stronger and less prone to corrosion. Also much more expensive!
Second, brazing requires a higher standard of metalworking. The tubes have to be cut and files to a good fit, with a constant gap of a few thou all
round to provide capillary action to get the braze right into the joint.
Personally, if I was starting again (i.e. before even buying a MIG) I would now seriously consider brazing, especially as I have had some experience
before.
cheers,
David
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stephen_gusterson
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| posted on 12/8/03 at 08:47 AM |
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One thing I have learnt on these lists is that welding is a subject thats hard to give advice on, cos as an amateur you just dont have the experience
that someone doing it every day has.
There are those on here that can shoot you down in flames with their better knowledge.
My father until he retired last year was a toolmaker / machinist / welder, and gave me advice, as did a guy I work with who is a qualified welder. I
also spent an hour or two at a welding supplies company ( our cleaners son worked there) getting advice on a previous project before I started
welding.
My end result is still no where near that of a time served professional, but its strong. If its not, in most cases I have used extra gusseting and
tubes cos im a natural pessimist.
I have seen Vipers welding (his company makes parts for the place I work at) and the standard is high.
As far as gases are concerned, I have used pure argon, co2 mix an co2.
I have agon cos I thought i may weld alu one day, but have given that up as way above my capabilities - and the little bit I did need to do can be
done with a product called technoweld. Its a bit like aluminium solder and is applied with a blow torch. Worked ok to tidy up joints on the rear of my
car on folded over corners.
When I ran out of gas once I used a bit of argon on mild in non structural metalwork. There isnt much penetration, the weld sounds completly
different, and it looks a bit porous.
Most of my work has been in co2 cos I have only a 100a welder and I need to maximise penetration - and the bottles of co2 at machine mart have a
greater fill level! CO2 isnt nice to use - lots of spatter and not so tidy welds.
I have recently tried and taken to mix. Its much much much better and is more forgiving for an amateur, as an amatuer I would say its the best
compromise.
atb
steve
[Edited on 12/8/03 by stephen_gusterson]
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JoelP
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| posted on 12/8/03 at 10:30 AM |
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Thanx ste, just yesterday i was in machine mart wondering if i should be bold and get argon, i got the CO2 cos there is indeed more in the bottle. I
may well try a mix next time, cos there is a lot of splatter with CO2, especially as its usually windy when i do it. Nearly all my welds need touching
up when its finished.
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David Jenkins
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| posted on 12/8/03 at 10:54 AM |
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An afterthought on brazing...
I was reading a book about the 750 Motor Club the other week. One of the authors described a crash that the other author suffered...
Driving along in a brazed space-frame single-seater open-wheel racing car, he got nudged by a beginner into the end of the pit-lane wall - 100mph to
zero in 3 feet! He suffered several heart attacks due to the impact of his chest against his harness, but fortunately a nearby mashall was a doctor
who kept him alive until he got to hospital. He had almost no physical damage apart from that.
The point they were trying to make was - if a brazed chassis is designed and made properly, it is very strong.
DJ
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Afro
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| posted on 12/8/03 at 03:55 PM |
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230 bar in the argon (Linde) but the CO2 full was less than 150... the bottle is of unknown origin... possibly a pub, we dont generally carry CO2 in
the workshop.
Brazing seemed always to be the preferred method on the road bike frames I used to ride about 12 yrs ago but most were built using lugs too. The
Italian ones being almost pretty enough to hang on your wall rather than take out in the rain.
I just had a vision of a very frustrated man in a workshop who had given up on trying mig and gas and thought 'next I'll try
brazing'... I wondered how long it would be before he'd given up on that and was off down to the nearest school for a bottle of
evo-stik... Excellent deposition rates, adjustable feed, minimum effort to ensure a flush finish where required etc etc...
If it aint broke... it will be soon
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