Flux and standard mig wire instead of flux cored ?

[blockhead]

Is it possible to use a gas-less MIG welder without using flux cored mig wire ?
This stuff is really expensive compared to standard mig wire.
If I were to apply a welding / brazing flux to the material before starting a weld with standard 0.8mm mig wire, should this work Ok ?
Isn't it just the action of the flux melting that creates the gas to shield the weld ?
I am a newbie to MIG welding, but I have some Thessco E flux powder and thought this might save on using flux-cored wire. Are there any special
properties about flux cored mig wire that I'm missing ?

Thanks to anyone who might be able to advise.

 

[malcolm]

The reason for keeping oxygen away from the weld is the molten metal is above 1000 degrees C and would oxidise very quickly when exposed to oxygen.

In oxy acetylene welding the oxygen is displaced by the flame so the flux doesn't have to work very hard. In MIG there is no flame so the welds are exposed to atmosphere - you really will need the shielding gas coverage (or the slag cover in gasless MIG).

 

[wyn]

I think what you are trying to do is submerged arc welding, which tends to be a bit more of an industrial process.

It would probably work but the flux might need to be an inch or so deep along where you were going to weld and so tricky to see where you were welding unless the torch was fixed to some sort of guide.

 

[blockhead]

Or maybe this stuff could be used ?

http://uk.rs-online.com/web/search/...)&Ntx=mode+matchallpartial&N=4294954536&Nty=1

 

[blockhead]

Thanks for the responses, I'm going to have to try this out to see.
I agree about the visibility issue, but this problem applies with flux-cored wire too.
Saying that, the flux core volume may be more important than I know.
My thinking is to apply a similar thickness of flux as would be in the wire, directly to the area to be welded.

Flux cored wire appears to have a few patents
http://www.freepatentsonline.com/5403377.html?query=flux-cored+wire&stemming=on
I'm thinking that the ratio of flux in the wire will be less controllable with this approach, I guess this will make the job harder than it already is with gasless mig welding, and me being a newbie to MIG welding and all that.
Then again, you never know until it's been tried.
If it's a disaster, at least I'll know , if it works Ok, I'll save a few quid

 

[Paul.]

Or maybe this stuff could be used ?

http://uk.rs-online.com/web/search/...)&Ntx=mode+matchallpartial&N=4294954536&Nty=1

No good at all, thats a brazing or bronze welding flux, based on boric acid,
Fluxes for arc welding processes are complicated mixtures, which have several functions, they ionise the arc and enable a stable arc to be maintained, provide a gaseous shield such as carbon dioxide and hydrogen which shields the molten pool from nitrogen and oxygen in the atmosphere, they carry alloying elements which can be transferred to the weld, and provide a slag which protects the molten metal, controls cooling and also provides physical support for the molten pool.
Best to buy the correct wire for the job, and save yourself a load of hassle.

 

[blockhead]

Thanks for that. Have to agree, you're right about that particular flux.
I found one suitable for fusion welding , but it's for cast iron use, ie:
http://www.wwsgroup.co.uk/weldability/pages/view_product.asp?product_string=FO090050
It's got me thinking there must be a flux on the market that is of more or less the same composition to that employed in flux cored wire
I'll buy the flux cored for now, unless someone knows of such a flux, it sounds like more research than it's worth trying to find out.

 

[Paul.]

Thanks for that. Have to agree, you're right about that particular flux.
I found one suitable for fusion welding , but it's for cast iron use, ie:
http://www.wwsgroup.co.uk/weldability/pages/view_product.asp?product_string=FO090050
It's got me thinking there must be a flux on the market that is of more or less the same composition to that employed in flux cored wire
I'll buy the flux cored for now, unless someone knows of such a flux, it sounds like more research than it's worth trying to find out.

Thats similar composition to the sifbronze brazing flux, used with the oxy acetylene process, Wyn mentioned submerged arc, definitely not a home or small workshop method though, sometimes used in shipbuilding and similar heavy fabrication, just out of interest have a look here, you'll see that the flux is deposited by a feeder mounted on the welding head,

 

[TechnicAl]

The Oxy Acet fluxes are too volatile for MIG welding. They will simply boil away. With the gas you are contributing to a chemical reaction.

However, MIG welding with a flux and no gas is Submerged Arc Welding, except SAW is usually mechanised. The problem being that once a flux burden has been laid it is difficult to know where the weld is (its submerged) so you would have all sorts of shapes.

In America they have a little motorised magnetic toirch holder called a "SQUIRTMOBILE" which is the first step towards mechanised welding.

 

[blockhead]

That video suggests it could be a viable concept. As we know, gasless is conceptually arc welding , but with an automatic wire feed . Maybe the approach is feasible for the occasional situation, maybe where a seem or channel needs to be welded, and for greater thicknesses
The datasheets for all those fluxes show that borax is the compound used in most fluxes. A little bit of googling on borax :
eg:
http://en.wikipedia.org/wiki/Borax

"A mixture of borax and ammonium chloride is used as a flux when welding iron and steel. It lowers the melting point of the unwanted iron oxide (scale), allowing it to run off"

However, looking at one of the patents for flux-cored steel welding wire, the flux consists of
CaF2, Fe--Si, SiO2, CaCO3, Cr and Mn
ie: Calcium Fluoride, Iron-Silicon, Silicon Dioxide, Calcium Carbonate, Chromium and Manganese.
So no borax there.
However, the patent is for a wire for stainless steel welding but the background of the description makes interesting reading ( if you're into that sort of thing )
http://www.freepatentsonline.com/4086463.html?query=flux-cored+wire&stemming=on
When I read this patent, and others like it, it indicated to me that the flux
compositions and flux quantities can be so different between wire type, application and even inventor / manufacturer.
I can also envisage that an ideal flux composition for welding steel may not be so ideal when it is manufactured into a workable wire product, eg the extrusion process might require other compounds to be used. That submerged welding video showed impressive enough results. The weld flows nicely, I assume the flux is a key element in aiding flow, not just to prevent oxides forming, so I wonder if gasless flux-cored welding results are not so impressive due to the inherent limitation of the flux/weld ratio. Isn't it the case that flux can boil away using flux-cored gasless MIG wire, just as it can if flux is applied separately ?
As long as the flux composition is correct, and sufficient flux is used, I'm wondering if there could be a net benefit to this approach compared to using flux-cored wire and gasless MIG welding.
Actually, I did not know this until after reading that patent, it appears that some wire used for gas MIG welding may contain flux ( but with lower flux content than found in no-gas MIG )

 

[Bullyterrier]

Surely all the hassle and messing around doesn't justify saving a few quid? And if your new to mig welding surely it would be easier to get used to welding the easiest way possible and being able to see what you are doing.

 

[blockhead]

Yes, I'm going to get flux cored to get started. I've done loads of arc welding before, so it's more a case of getting used to MIG controls, feed rate etc ..
That few quid saving each time could turn into something more substantial over a few years, if there is a way of doing it. Hassle isn't something I mind if I find out something meaningful from it. I can get anhydrous borax from a colleague who uses it in fibreglass production and ammonium chloride is readily available. It's not so much hassle, just wondered if anyone had tried it with any success.

I once spent 5/6 hours trying to find out if I could use normal "4 stroke" oil in 2 stroke engines. Doing so has saved me a fortune over the last 10 years, and not once has any of my 2 stroke engines failed.
As long as the oil has a low ash and low detergent content, there is no reason why you cannot. Most people out there told me I should not do it. "Is it worth the risk, the hassle ? etc ..

 

[chunkolini]

Aha, Blockhead is a tightwad with a bent for meddling and improving 'TheThing'.A fine profession, without people like this we would stil be living in caves and wearing bunny skins.

Let us know how it goes. These ideas get under the skin and wont go away, I know the feeling.

Chunko'.

 

[TechnicAl]

Just a comment.
There is a popular misconception that Gasless Flux Cored MIG welding wire produces its own shielding gas, enough to protect it from the atmosphere.

Actually the steel is designed to accomodate the ingress of atmosphere (mostly nitrogen) and remain ductile. You will notice that they commonly contain high Aluminium contents.

The self shielding part is usually Calcium or Barium Carbonate which dissociates at high temperatures forming CO and CO2 and the Oxide which forms the slag. The other flux ingredients are there to alloy and control slag which holds the molten steel in place.

I would be very wary of using Ammonium Chloride (isnt that Bleach) the fumes could be toxic.

Borax is used but only in small quantities in steel fluxes but higher %ages in Aluminium flux. It will not on its own prevent atmospheric ingress, which is the major purpose of flux or shielding gases.

If you use the chemicals you mention you will get a weld that is porous and brittle.

Welding has been on going for quite some time and most of these things have been tried before. I used to develop fluxes for electrodes and I personally have tried a lot of wacky ideas to see what happens.

 

[LastNewt]

Another great thread.

I work in a steel stockholders and we deal with smart arsed artists and welders all day.
Since finding this site I'm finding my theoretical welding knowledge surprises 20 yr old pros.
Your a great bunch of people and very knowledgable with it.

Thank you

Newton

 

[Ratcatcher]

Blockhead,

You are asking for a welding procedure which works and has been tested countless millions of times then you ask how can i save a few quid over your lifespan?.
By all means go and get hold of these various chemicals and try for yourself,"i've yet to check on the restrictions of storage,usage and mixing of the required chemicals"which you mentioned,that is for the near future..
Sorry but there are laws these days governing all chemicals,some are quite legal to have and others require specialist training and storage licences....
Others when mixed require an awful lot more paperwork,testing and praying.....
Also as with everything else these days you are going to follow COSHH regulations whilst carrying out this mixture and testing,if so what knowledge and training do you have?.
Another thing:you say that laying a run of flux down prior to welding via solid mig would work?.How do you actually intend to weld vertical and overhead with your method?.

Sorry for saying this but please wake up before you either do serious harm to yourself or an innocent!!!!!!!.
I've got a lot of time where people who actually want to learn are concerned but have very little time for idiots!!!!!!!.
As in the word of the Dragon's:i'm out!!!!!!!!!!!!!!!!!.

Rat.

 

[GeorgeB]

Blockhead - I hope you succeed but isn't any liquid flux likely to cost more than the premium paid for gasless wire over standard MIG wire and gas? Gasless wire may seem expensive but that's before one takes into account the cost and storage inconvenience of gas bottles.

 

[Drains]

Superb stuff. Blockhead, see the wheel in front of you? Give it a roll along the floor before you decide you should re-design it, there's a good chap.

 

[Alfaman]

I once spent 5/6 hours trying to find out if I could use normal "4 stroke" oil in 2 stroke engines. Doing so has saved me a fortune over the last 10 years, and not once has any of my 2 stroke engines failed.

Saved a fortune? You must do a LOT of running 2-strokes? Last time I bought a couple of litres of Putoline it was about a quid more than normal "4 stroke" oil.

Superb stuff. Blockhead, see the wheel in front of you? Give it a roll along the floor before you decide you should re-design it, there's a good chap.

Love it drains!

 

[TechnicAl]

I once had a boss who wanted me to design an electrode that contained cannabis so we could get the welder hooked on our brand. I think he was joking but he did go to Walkers crips and get packs of cheese and onion flavouring and the others. I told him it wouldnt work as they would simply burn but he wouldnt have it so I had to prove it. They smelled worse than normal.

Incidentally I tried Lemon juice and that worked. The fumes smelled of Lemon. I never got as far as testing shelf life as I explained to my boss that really the last thing we want is welders "sniffing" the fumes. Whilst they might enjoy it, the industrial illness claims would outweigh the benefits. It was dropped but it took a bit of pushing.