You need Nitric Acid and Methanol.
Or stainless pickling paste. The nasty ones.
30+ years ago the shop I worked in had a guy tigging aluminum all the time... Used to use hydrofloric acid on everything and in those days they sprayed it around like window cleaner. The only warning on the gallon jugs it came in was it "may" cause burns if left on skin! Looked it up recently and there was a whole booklet about it online warning about amputation usually being the safest treatment for inadvertent exposure, and how getting 6 square inches of wetted skin was usually fatal!!! The things you do when you're young and foolish. (And some employers could get away with considering "the help" expendable. )
I've no had time to look in to alternatives...but what % Nitric Acid do you need?
Would this do? https://apcpure.com/product/nitric_...wdKg3RH7TXni0FIBt1lnqp-S099LSeJRoC9-UQAvD_BwE
I've got 69%/70% as per your link. Mine came from Camlab. You will need to purchase via a Limited Company and state good reason for requiring it.
Nitric acid is not to be played around with. Apart from its obviously highly oxidising nature and use in things that go bang, its highly corrosive in contact with organic matter, the fumes it often generates are very nasty and it can form many volatile or unstable compounds with many different chemicals and metals.
If you just want to test some of your own samples, get some stainless pickling paste.
Cheers Brad....yeah sounds like a risk I should avoid. It’s just for testing my own work...prob a bit OTT but now I’ve read it I’m interested in doing it...
Possible daft question but will stainless pickling paste work with mild steel,macro etch test?
I just assumed pickling paste was something you made with the Nitric Acid when I read your first post but see now ithats not the case
Yeah the stainless pickling past will etch Mild Steel. Obviously it cleans up the carbide precipitation on stainless steel, but etches mild steel.
Any particular grade? or brand?
After a quick google Antox71E appears most often
As long as it contains hydrofluoric and nitric acid it will work.
Wear a full face shield, heavy rubber gloves and make sure all exposed skin is covered. It’s nasty nasty stuff.
Once the desired etch has been achieved rinse thoroughly with water, then dab dry with absorbant paper towel then spray clear lacquer on to stop rusting.
Great info Brad..I like knowing the details!
Had a little play with a bit of v up mig, 4mm plate. I' say my technique is loops rather than Xmas tree. Little jerky here and there kept burning my hand!
Very neat. Got that dialed in i would say
Cheers, think in past I spent far to long fiddling with settings, with bit more time under the hood with mig, I seem to be able to get in ball park without thinking. Paying more attention to what happens in the weld pool than what's on the display.
Get a nice setting in the flat of 100-120A. Then do your vertical.
got a new helmet at xmas...much better than old one! never realised you could see 'the pool' so well....old helmet was so blurry/dark in comparison
been trying vertical up again...getting the hang of the xmas tree technique now but I'm struggling to keep the size of the weld down
If I try putting the power down I need to move so slow between the 3 points to keep in the pool/stop it spattering, if I try more power it just builds up faster regardless
on the 3mm steel I was using the throat ends up about 7mm in these welds... it's 1mm wire I'm using, does that have much effect?
is the throat size of vertical welds always bigger than usual? (according to what I've read if it's any bigger than the thinnest bit of metal you're joining then it's a waste...)
Dwell less on the sides progress upwards quicker
That's tidy! But that level of consistency/neatness is prob out of the question for me just now!
Tried moving up faster but still always ends up more convex than I'd like. On.the flat/going down I'd let it burn in more at the start to stop it being too convex
Here's today's effort... Going to get that pickling paste.... Will be interesting to see the results
You need to use the triangle method to put a smaller first pass in. Then if the leg length is required put a weave over the top.
Does it need to be such a wide weld? A fillet joint in the vertical is still a fillet joint and regarding the joint size the rules don’t change. Your leg length dose not need to be any bigger that the thickest side of your joint and if your welding two different thicknesses I’d be inclined to go under that measurement personally so you don’t wreck the mechanicals in the thinner plate.
@Arclikeharrypotter has put up a lovely example of a correctly sized fillet for sensibly sized plate. Your thread title starts at thicker plate to 4mm. How thick are we talking here cos that 4mm doesn’t want a 1 inch fillet slapped across it.
Yes...good point...getting a bit carried away with the Xmas tree technique!
Think the most important thing has been turning the power down....just had a go doing loops and an upside down V type thing....
Was just a mess before when I had the power set higher
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