Beginning to think I was born under the wrong Star...

[Noods]

The Ups and downs of Tigging at NöØDLe Towers...

Seriously beginning to think I was born under the wrong star*

Mild steel welding has been going great so thought this morning I'd do a little fab work with SS.. So went through my pile of off cuts found a few suitables, Checked them with a magnet to make sure not steel with a chrome covering, no all fine.. Cut and bent all the pieces to form my piece buffed them up ready to tack.. Clamped it and away we go! No we don't .. 2mm stock but as I tried to tack it it was spitting and bubbling away, checked everything, it was all fine, tried again but no.. One piece of the two I was joining was melting away in a fashion I'd never seen before...

Eventually I discovered some of my stock I'd used seemed heavier than other pieces, strange I thought? I then remembered when I was cutting and cleaning the pieces up, one of the sheets had like a green backing to it.. ?

I got two pieces of stock that felt the same weight and tried welding them together.. Absolutely fine, no probs at all..

Now I thought, anything shiney that's not attracted to a magnet was SS.. Obv I was wrong.. Could this piece I purchased as a lot of offcuts have been Aluminium ? Eg have been mixed in where it should not have been..

Whatever, I've just wasted a complete morning.. But, will battle onwards..

X NöØDs

 

[Maker]

Stainless isn't always shiny and isn't always non-magnetic. Sounds like you were trying to weld alu to stainless.

 

[langy]

Surely you can tell the obvious difference between aluminium and stainless ? Weight

 

[Robotstar5]

Thought you were going to burst into the Lee Marvin song....

 

[Noods]

Surely you can tell the obvious difference between aluminium and stainless ? Weight

Obv not in my case, call it inexperience or stupidity.. What I can't understand though is the rogue piece was the heavier of the two pieces.. ? So surely it's not Ali X

 

[Noods]

Thought you were going to burst into the Lee Marvin song....

Ha.. Great.. Luv it x

 

[WorkshopChris]

As a quick test ali should react to something like bleach or vinegar. Does it spark on a grinding disk.

 

[Richard.]

An even easier test is to simply try and bend it. 2mm Alu will bend with enough force by hand. 2mm stainless you got no chance.
Or a light tap with a centre dot or chisel. Pretty much any mechanical test will easily determine the difference given how much softer it is.
I don't think it's needed mind as weight alone usually gives it away.

 

[pedrobedro]

An even easier test is to simply try and bend it. 2mm Alu will bend with enough force by hand. 2mm stainless you got no chance.
Or a light tap with a centre dot or chisel. Pretty much any mechanical test will easily determine the difference given how much softer it is.
I don't think it's needed mind as weight alone usually gives it away.

Depends on grade, I have some aluminium in the shed that will not bend and stay bent, it straightens itself out like spring steel and it's hard to mark it. I think it's some tempered 7xxx series stuff. The weight should give it away though it's only 1/3 the weight of steel.

 

[ronan]

Titanium the same, very strong and hard to mark.

 

[Noods]

As a quick test ali should react to something like bleach or vinegar. Does it spark on a grinding disk.

No.. Just like the SS piece that was ok to weld very little sparks when cutting it.. Thinking about it I'm sure it's a piece I purchased on line a while back, as I say I can't believe it's Ali because I couldn't Bend it by hand (1.2mm ) and size for size it weighed heavier than the piece I could weld.. I even tried using the rod that can weld different materials together but no.. I think I shall have to buy a large piece of sheet SS and keep all the offcuts together so I can be sure of what's what.. X

 

[Noods]

An even easier test is to simply try and bend it. 2mm Alu will bend with enough force by hand. 2mm stainless you got no chance.
Or a light tap with a centre dot or chisel. Pretty much any mechanical test will easily determine the difference given how much softer it is.
I don't think it's needed mind as weight alone usually gives it away.

See below post.. Basically I did as you kindly suggested... X

 

[Maker]

If the heavier piece was the piece that didn't weld nicely then I have no idea, that's really strange.

Could you take a picture of the attempted weld?

 

[Noods]

If the heavier piece was the piece that didn't weld nicely then I have no idea, that's really strange.

Could you take a picture of the attempted weld?

Yep will do in morning and then post.. ( on nights at mo) At first I thought oh no I've gas problems back again.. I did a leak test as Richard showed me and all was fine... The rogue piece when trying to lap weld it to what was a piece of good SS just after the post gas flow you could poke it with the filler rod and it moved about like solder would shiny and bright silver colour.. It melted away without direct heat at it too.. No holes just sort of depressed blisters .. The tig colours were black basically but when I cut and tried to join the lighter ( in weight) piece which obv is SS it joined fine, neat tidy no popping spitting and boiling, just a nice join... I'm thinking someone's sold me a wrong en.. ICF card for them when I find em.. X

 

[hotrodder]

Vinegar won't noticably react with aluminium or it's alloys at room temp, it is a useful way to confirm that the part/chunk of metal which feels too light to be ally is magnesium though as the acetic acid in vinegar reacts vigorously with mag fizzing/bubbling away producing hydrogen

Most of the time colour is usually enough to differentate between ally, stainless and titanium...



My cheap camera and/or lack of photography skill don't help but in real life the differences are waaaaaaaay more noticable as they all have a slightly different colour tint... aluminium is a kinda neutral/whitish silver, stainless has a slight grey-blue tint depending on finish (it's 304L with a 2B* finish in the pic, when polished it has a 'colder' slightly bluish tint compared to polished ally). Ti on the other hand has more of a grey-champagne tint- greyer when the oxide layer has thickened/weathered a bit and a 'warmer' look when polished

* http://www.aalco.co.uk/datasheets/Stainless-Steel-Surface-Finishes_135.ashx

 

[Noods]

Vinegar won't noticably react with aluminium or it's alloys at room temp, it is a useful way to confirm that the part/chunk of metal which feels too light to be ally is magnesium though as the acetic acid in vinegar reacts vigorously with mag fizzing/bubbling away producing hydrogen

Most of the time colour is usually enough to differentate between ally, stainless and titanium...

View attachment 84239

My cheap camera and/or lack of photography skill don't help but in real life the differences are waaaaaaaay more noticable as they all have a slightly different colour tint... aluminium is a kinda neutral/whitish silver, stainless has a slight grey-blue tint depending on finish (it's 304L with a 2B* finish in the pic, when polished it has a 'colder' slightly bluish tint compared to polished ally). Ti on the other hand has more of a grey-champagne tint- greyer when the oxide layer has thickened/weathered a bit and a 'warmer' look when polished

So another Q really.. If you've got brushed or perhaps satin SS can you polish it to a mirror type finish? Or is it a totally different product?

 

[hotrodder]

Yeah it can be polished. The various different brushed, grained, satin finishes are basically sanding scratches (albeit very evenly applied in one direction). Polishing basically = sanding out scratches with progressively finer abrasives so the scratches become finer and finer until they're no longer visible. That's what gets it shiney, to get a mirror finish is a bit trickier as the surface needs to be totally uniform at the same time to produce accurate reflections like this



which is 1050 aluminium and started out like the piece of metal at the right of the 1st pic

If you want to make somethng from stainless that's gonna be polished you're better off starting by buying some bright annealed or mirror finished sheet to begin with though as it'll save a bunch of time. Most grades and finishes of sheet ally and stainless are available with 'laser guard' aka plastic protection which offers a little scratch protection while fabricating

 

[Noods]

P

Yeah it can be polished. The various different brushed, grained, satin finishes are basically sanding scratches (albeit very evenly applied in one direction). Polishing basically = sanding out scratches with progressively finer abrasives so the scratches become finer and finer until they're no longer visible. That's what gets it shiney, to get a mirror finish is a bit trickier as the surface needs to be totally uniform at the same time to produce accurate reflections like this

View attachment 84250

which is 1050 aluminium and started out like the piece of metal at the right of the 1st pic

If you want to make somethng from stainless that's gonna be polished you're better off starting by buying some bright annealed or mirror finished sheet to begin with though as it'll save a bunch of time. Most grades and finishes of sheet ally and stainless are available with 'laser guard' aka plastic protection which offers a little scratch protection while fabricating

Blimey is that a tank you've fabricated... Amazing X

 

[hotrodder]

Yeah, cheers. That one was for a '66 Beetle, more pics of it here along with a post '68 Beetle tank and other stuff http://www.mig-welding.co.uk/forum/members/hotrodder.4093/

 

[Noods]

So how do you achieve the curves is it via an English wheel..? Stunning work mTe.. X