Welding helmet..

[eggsarascal]

8 hours ago, john87 said:

Can i tell you why?? Because nobody ever showed you what you were trying to achieve. It would be like trying to play darts with the numbers missing off the board..

 

I am sure that if someone spent half an hour with you and then left you to it for a few hours, that you would AMAZE yourself with your new found skills..

 

john..

You certainly can tell me, more than happy to learn from people who know a job better than me. I’ve only very limited experience trying to weld and it didn’t turn out well, I’m the same with spray painting, just can’t get the knack of it, yet I can plaster which in my mind is a similar process… steady and equal, if that makes sense?

[john87]

1 hour ago, eggsarascal said:

You certainly can tell me, more than happy to learn from people who know a job better than me. I’ve only very limited experience trying to weld and it didn’t turn out well, I’m the same with spray painting, just can’t get the knack of it, yet I can plaster which in my mind is a similar process… steady and equal, if that makes sense?

Wish i could plaster!!

 

The best welding process to learn with [by a mile] is oxy/acetylene. This teaches you lots of things, heat input, the distribution of heat [think welding a thin sheet to a thicker one], forming and maintaining a weld pool, controlling penetration etc.

 

MMA [stick welding] would come next, then MIG/MAG.

 

Reason being, unless you are skilled at "manual" welding processes, a "semi automatic" process [like MIG/MAG] will just lead you to turning out crap faster!!

 

People with tell you that MIG/MAG is the "easiest process to learn" It is not, it is the easiest process [by a mile] with which to turn out welds that LOOK good, but which are in fact total crap..

 

Take stick welding... Get the rod angle more or less correct, but note that this is just a starting point, you may well have to vary a LOT from the "text book" angles to control the weld pool.

 

Then, [and this is where most people get it wrong] you, do not just strike the arc and "set off" as it were. You have to deliberately form a "weld pool" to your satisfaction, THEN start your travel.

 

Go along smoothly, not too slowly though, as if you do, the weld metal you are depositing and the slag will "catch you up"

 

You do not want this, as, if the slag catches you up you will end up with slag inclusions, and, if the metal catches you up, you will not be able to play the arc on the material you would seek to weld [thus melting and fusing it] but you will end up lengthening the arc [as you are now busy trying to stop the rod getting overtaken] and letting the deposited metal get under you as it were, you will them not be able to fuse the plates then.. The arc MUST stay at the leading edge of the pool you see..

 

Travel too fast and you will have the same problems as you would if you travelled too fast using a silicone gun..

 

It is EXACTLY like using silicone. With silicone you form the shape of the bead when you start, you keep the nozzle VERY close to the work, you vary the angles to place the silicone where you want it, you travel at an appropriate speed, not too slow [as the silicone will catch you up] not too fast [as your bead will be too small and not formed correctly], and, at the end, you do a little twirl to finish off the end of the bead nicely [just as you do with welding!!]

 

You need to keep a short arc too. [this is VERY important] Once again, think if you were using silicone, what would happen if you pulled the nozzle away from the joint about 5 or 10 mm?? EXACTLY!!!!

 

Now, i have to say, that the quality of the welding set plays a good part too. My first welder was an SIP 160 that i got from my mums mail order catalogue. I did AMAZING things with that..

 

Moving on many years [and much better welding sets, Miller, Lincoln, Hobart and the like] and i saw an SIP 160 [like mine] for sale on Ebay. I had to buy it!!

 

When i tried it though, OMG, i could barely weld with it!! Keeping a short arc was just about impossible. Not nice at all!!

 

Form a weld pool [a sort of circular movement to establish the arc correctly and make a little pool where you want it] and after that, short arc and think silicone!! Weld humped up?? More current. Weld too wide and undercut and lots of spatter? Current too high.

 

Oh, yes, butt welds, unless it is thin plate [when you could just leave a gap] grind out a "Vee" to place the weld metal in..

 

Use 6013 rods. You willl see on youtube that crazy americans are obsessed with 7018's but two problems there; 1, unless you are welding 1" thick plate or higher carbon steels it is not needed. 2, none of your "diy" type sets have a high enough open circuit voltage to run them properly..

 

On the usual AC output sets..

 

4mm use 160 to 180A [For fillets use 180]

 

3.2 use 120 to 140A [For fillets use 140]

 

2.5 use 90A

 

If you have a DC set you could often drop these currents down a bit, ESPECIALLY for butt welds.

 

john..

[skc101fc]

Have you ever considered writing a novel, or poetry perhaps?  I've done a fair amount of oxy acet welding and stick welding to a reasonable standard. But hell, you've made it sound sexy !

Yep most important technique is preparation before even switching on the welder, and  control and monitoring the weld pool.

[john87]

11 minutes ago, skc101fc said:

Have you ever considered writing a novel, or poetry perhaps?  I've done a fair amount of oxy acet welding and stick welding to a reasonable standard. But hell, you've made it sound sexy !

Yep most important technique is preparation before even switching on the welder, and  control and monitoring the weld pool.

ha ha!! I have often been asked to write a book, but not on welding!!

 

Yes, as you say, preparation is EVERYTHING.

 

When i was out and about welding many years ago, i would have people say stuff like "How slow are you, my mate could have done that in 10 minutes" I always used to say that, "yes, but it would fall off ten minutes later too.."

 

As you know, leaving aside the type of joint [so the preparation as regards plate edge prep] there is the matter of cleanliness.

 

All mill scale and anything else MUST be removed..

 

You see, apart from the fact that we do not want random shit floating about in our weld pool [and the fact that thick mill scale can make life difficult as regards fusion at the edges of the weld] mill scale is iron oxide, when you heat it up, it will liberate oxygen, not a great idea.. Same goes for rust, that will liberate oxygen, and water too..

 

Why do we not want water or rust?? For the same reason that we do not want oil or paint or anything else.

 

You see, water [and much else] contains hydrogen. Hydrogen is possessed of the smallest of atoms. It/they, are in fact, the smallest atoms of all..

 

The hydrogen will dissolve in the weld metal, this then cools and solidifies, leaving the tiny hydrogen atoms trapped in the interstitial spaces between the atoms of our base metal.

 

Especially, in higher strength steels, over the next few hours or days, this hydrogen will attempt to "escape" generating HUGE pressures as it does so.

 

These pressures will literally tear the steel apart, creating what is known as "cold cracking". The joint appears to be perfect at first, and then, some hours or days later, BANG, and a crack appears, parallel to the weld and in the heat affected zone, although it can be in the weld metal itself. This obviously is not good!!

 

Out of interest, one of the tests to demonstrate this sort of thing, involved cutting out a portion of a welded joint, and immersing it in paraffin. The bubbles of hydrogen can clearly be seen rising...

 

Ok, how much hydrogen we talking about then?? Well, it can reach 40ml of hydrogen per 100 grams of weld metal, so 8 teaspoons of hydrogen for a piece of metal that weighs only a few ounces.. Anything above 15ml per 100g is considered high though, with the attendant risk of cracking..

 

What can we do about this then?? Well, there are two sources of hydrogen to consider; The first, is contamination, but we have covered that, the next is the hydrogen that emanates, or presents itself, as a consequence of the welding process we use.

 

Gas shielded processes are better in general, so long as the gas is dry.

 

The biggest process related factor is moisture in MMA consumables [welding rods] There are three basic types, these are, cellulosic [i will not talk about these, as unless you are doing pipe roots, you will not come across them] rutile, and basic [basic refers to the chemistry of the things..]

 

As i said earlier 15ml of hydrogen per 100 grams of weld metal is considered high. 10ml being "medium" and less than 5ml considered low..

 

A rutile coated rod contains quite a lot of hydrogen, above 15ml, but not much you can do about it..

 

Obviously you need to protect them from moisture and you can dry them out to some extent by "baking" them. Do not go above 100c though, as you will damage the coating of the rod..

 

The "basic" coated rods, your "low hydrogen" ones, these, unless you get them direct from one of them "vac pack" things you can get now, are ALWAYS redried [according to the makers directions on heat and duration]

 

For example, the makers might state, that for a dissolved hydrogen content of less than 5ml/100g redry at 250c for 1 hour.

 

Having done this and removed them from the oven, they then all had to be used within about half an hour, or you had to redry them all over again.. This is why the makers came up with "vac packs" You would open them, use what you needed and chuck the rest in the bin..

 

Unless you are welding high carbon steel or very thick sections, forget all about hydrogen in the consumables though, just make sure there is no moisture, paint, oil, mill scale or rust [or anything else] contaminating the weld area..

 

As you can see then, the gas shielded processes have a bit of a built in advantage so far as hydrogen is concerned, so why use MMA?? [stick welding]

 

Ok, leaving aside the convenience, there are a lot of other advantages.. Say we want to weld an alloyed steel?? We obviously want our weld metal composition to match that of the parent plate.. Problem is, it might be impossible to manufacture MIG wire of this composition, it might be insufficiently ductile to draw into wire for example.

 

This problem can be got around by means of the "metal cored" MIG wires you can get now. They are formed from a strip that is folded up and contains metal powder alloying elements inside..

 

With MMA [stick welding] we can VERY easily get around this though, by adding our alloying agents to the flux coating instead.

 

This is a HUGE advantage of MMA, the flux acts as a "vehicle" for the transport of alloying agents..

 

What else does the flux do then?? Well, FIVE things all in all;

 

These are;

1, Creates a gaseous shield to protect the weld metal DURING welding to prevent atmospheric contamination.

2, The slag forms a shield to protect from atmospheric contamination AFTER welding and during cooling..

3, The slag slows the cooling rate of the weld thus reducing "quench severity" and helping to reduce undesirable hardening and/or cracking.

4, The slag acts as a convenient "mould" for the weld metal that is found to be helpful during vertical welding etc.

5, Finally, the slag acts as a vehicle for out alloying elements as i discussed earlier..

 

As you can see, there is a tendency to "write off" MMA welding as "old fashioned" but it has its advantages..

 

I have not written so much about welding in decades!!!

 

john

[doobin]

Love my migs. Spray and pray and it all holds together fine 😂

[skc101fc]

48 minutes ago, john87 said:

ha ha!! I have often been asked to write a book, but not on welding!!

 

Yes, as you say, preparation is EVERYTHING.

 

When i was out and about welding many years ago, i would have people say stuff like "How slow are you, my mate could have done that in 10 minutes" I always used to say that, "yes, but it would fall off ten minutes later too.."

 

As you know, leaving aside the type of joint [so the preparation as regards plate edge prep] there is the matter of cleanliness.

 

All mill scale and anything else MUST be removed..

 

You see, apart from the fact that we do not want random shit floating about in our weld pool [and the fact that thick mill scale can make life difficult as regards fusion at the edges of the weld] mill scale is iron oxide, when you heat it up, it will liberate oxygen, not a great idea.. Same goes for rust, that will liberate oxygen, and water too..

 

Why do we not want water or rust?? For the same reason that we do not want oil or paint or anything else.

 

You see, water [and much else] contains hydrogen. Hydrogen is possessed of the smallest of atoms. It/they, are in fact, the smallest atoms of all..

 

The hydrogen will dissolve in the weld metal, this then cools and solidifies, leaving the tiny hydrogen atoms trapped in the interstitial spaces between the atoms of our base metal.

 

Especially, in higher strength steels, over the next few hours or days, this hydrogen will attempt to "escape" generating HUGE pressures as it does so.

 

These pressures will literally tear the steel apart, creating what is known as "cold cracking". The joint appears to be perfect at first, and then, some hours or days later, BANG, and a crack appears, parallel to the weld and in the heat affected zone, although it can be in the weld metal itself. This obviously is not good!!

 

Out of interest, one of the tests to demonstrate this sort of thing, involved cutting out a portion of a welded joint, and immersing it in paraffin. The bubbles of hydrogen can clearly be seen rising...

 

Ok, how much hydrogen we talking about then?? Well, it can reach 40ml of hydrogen per 100 grams of weld metal, so 8 teaspoons of hydrogen for a piece of metal that weighs only a few ounces.. Anything above 15ml per 100g is considered high though, with the attendant risk of cracking..

 

What can we do about this then?? Well, there are two sources of hydrogen to consider; The first, is contamination, but we have covered that, the next is the hydrogen that emanates, or presents itself, as a consequence of the welding process we use.

 

Gas shielded processes are better in general, so long as the gas is dry.

 

The biggest process related factor is moisture in MMA consumables [welding rods] There are three basic types, these are, cellulosic [i will not talk about these, as unless you are doing pipe roots, you will not come across them] rutile, and basic [basic refers to the chemistry of the things..]

 

As i said earlier 15ml of hydrogen per 100 grams of weld metal is considered high. 10ml being "medium" and less than 5ml considered low..

 

A rutile coated rod contains quite a lot of hydrogen, above 15ml, but not much you can do about it..

 

Obviously you need to protect them from moisture and you can dry them out to some extent by "baking" them. Do not go above 100c though, as you will damage the coating of the rod..

 

The "basic" coated rods, your "low hydrogen" ones, these, unless you get them direct from one of them "vac pack" things you can get now, are ALWAYS redried [according to the makers directions on heat and duration]

 

For example, the makers might state, that for a dissolved hydrogen content of less than 5ml/100g redry at 250c for 1 hour.

 

Having done this and removed them from the oven, they then all had to be used within about half an hour, or you had to redry them all over again.. This is why the makers came up with "vac packs" You would open them, use what you needed and chuck the rest in the bin..

 

Unless you are welding high carbon steel or very thick sections, forget all about hydrogen in the consumables though, just make sure there is no moisture, paint, oil, mill scale or rust [or anything else] contaminating the weld area..

 

As you can see then, the gas shielded processes have a bit of a built in advantage so far as hydrogen is concerned, so why use MMA?? [stick welding]

 

Ok, leaving aside the convenience, there are a lot of other advantages.. Say we want to weld an alloyed steel?? We obviously want our weld metal composition to match that of the parent plate.. Problem is, it might be impossible to manufacture MIG wire of this composition, it might be insufficiently ductile to draw into wire for example.

 

This problem can be got around by means of the "metal cored" MIG wires you can get now. They are formed from a strip that is folded up and contains metal powder alloying elements inside..

 

With MMA [stick welding] we can VERY easily get around this though, by adding our alloying agents to the flux coating instead.

 

This is a HUGE advantage of MMA, the flux acts as a "vehicle" for the transport of alloying agents..

 

What else does the flux do then?? Well, FIVE things all in all;

 

These are;

1, Creates a gaseous shield to protect the weld metal DURING welding to prevent atmospheric contamination.

2, The slag forms a shield to protect from atmospheric contamination AFTER welding and during cooling..

3, The slag slows the cooling rate of the weld thus reducing "quench severity" and helping to reduce undesirable hardening and/or cracking.

4, The slag acts as a convenient "mould" for the weld metal that is found to be helpful during vertical welding etc.

5, Finally, the slag acts as a vehicle for out alloying elements as i discussed earlier..

 

As you can see, there is a tendency to "write off" MMA welding as "old fashioned" but it has its advantages..

 

I have not written so much about welding in decades!!!

 

john

Wow , that's an entire years engineering education course neatly wrapped up there.

I don't have the luxury of a proper heated rod oven/store, but all rods remain in my airing cupboard. New boxes go straight in there sealed, opened boxes never leave it. I only ever take out as many loose rods as I estimate I'll need to do the job. I  used to waste so much time fighting to strike and maintain the arc with ones left on top the welder for months, and then was taught by an old boy, to treat the rods with more respect than the work I was doing. 

[john87]

15 minutes ago, skc101fc said:

Wow , that's an entire years engineering education course neatly wrapped up there.

I don't have the luxury of a proper heated rod oven/store, but all rods remain in my airing cupboard. New boxes go straight in there sealed, opened boxes never leave it. I only ever take out as many loose rods as I estimate I'll need to do the job. I  used to waste so much time fighting to strike and maintain the arc with ones left on top the welder for months, and then was taught by an old boy, to treat the rods with more respect than the work I was doing. 

 

Thats the way to do it!! Besides, as you will have noticed, dry rods are very much nicer to use than damp ones!!

 

There is a lot of variation in rods mind, even of the same type. Different makes vary a lot, with some being horrible and others great Even rods of the same make and sort, but different sizes of the same rod. Vodex for example, i thought the 4mm ones were ok, but the 3.25's horrible!! Murex seem nice in general, Oerlikon Fincord "M" are nice but the bigger ones are slaggy [and hugely expensive], the last lot of Esab ones i tried [OK 46.30] were terrible..

 

john..

[roboted]

@john87

Just a question, and being nosy 😊

Did you ever work for Nacap in Algeria?

[john87]

No... Are they not all french in Algeria??

 

Was not me anyway!!

 

john..