Etching welds.

[Shield Arc]

I love this phosphoric acid! It give results very fast.
This is really dis hearting:shocked:. This is the 3/8-inch thick V-butt test plate I ran with the Everlast 120-volt Mig welder. Wire speed maxed out, and the voltage turned down just a bit. This is the last 1/2-inch of the plate. So it should have been about as hot as it was going to get. And I preheated this test plate before I started welding.

 

[MinnesotaDaveChalmers]

Looks like that stuff works great! Very clear results.

 

[Shield Arc]

Oh it does Dave! Only takes a couple minutes to see the results too! :cool2:

 

[bumperm]

Very interesting. What phosphoric acid concentration are you using for the tests?

 

[Shield Arc]

Very interesting. What phosphoric acid concentration are you using for the tests?

This is what I bought.
Phosphoric Acid 85 1000ml Trace Metal Grade | eBay

 

[MinnesotaDaveChalmers]

Oh it does Dave! Only takes a couple minutes to see the results too! :cool2:

Ah, made with my level of patience in mind

 

[orezok]

Back in the mid 60's when I was working on my degree in metallurgy, I spent a couple of summers working for Kaiser Steel in the metallurgy lab. The acid we used for etching was hydroflouric acid. It will actually disolve metal and leaves a very clear image of the grain structure. It has to be stored in a special plastic bottle as it eats glass.

It looks like this.

 

[BukitCase]

Glass isn't the ONLY thing Hydroflouric acid eats - at 49% (one of the standard dilutions it's delivered in) a handprint size exposure on your skin will, according to the TONS of safety info we were required to read, will STOP YOUR HEART.

This is because HF has an affinity for Calcium, and serum calcium is what regulates your heart rhythm (at least that's what we were told) - in smaller doses, if it's not discovered right away it will dissolve your bones (calcium again)

Another downside - you most likely won't even KNOW you've been exposed in time to do anything about it, because in "chemicalese" it's called a MILD acid - other acids, like HydroChloric and Sulphuric, burn the skin more (= more pain) and don't seek out calcium.

I spent the last 30 years having as LITTLE to do with HF as possible - I still have 206 bones in my body and would just as soon keep it that way... Steve

 

[orezok]

Glass isn't the ONLY thing Hydroflouric acid eats - at 49% (one of the standard dilutions it's delivered in) a handprint size exposure on your skin will, according to the TONS of safety info we were required to read, will STOP YOUR HEART.

This is because HF has an affinity for Calcium, and serum calcium is what regulates your heart rhythm (at least that's what we were told) - in smaller doses, if it's not discovered right away it will dissolve your bones (calcium again)



Another downside - you most likely won't even KNOW you've been exposed in time to do anything about it, because in "chemicalese" it's called a MILD acid - other acids, like HydroChloric and Sulphuric, burn the skin more (= more pain) and don't seek out calcium.

I spent the last 30 years having as LITTLE to do with HF as possible - I still have 206 bones in my body and would just as soon keep it that way... Steve

Yeah, I know that when we used it we had to fully suit up, elbow length rubber gloves, full face/head protection and a fume hood. They told us that if it gets on your skin, it will keep burning until nothing is left. Water will not stop it and in fact makes it worse.

 

[BukitCase]

Yup, my company made anyone who EVER expected to get close to anywhere HF was used, get TWO tubes of Calcium Gel from the stock room - one to keep at work, the other to take home. The instructions were that if you even THOUGHT you might have been exposed (pinhole in glove, whatever) to smear some of that stuff on the affected spot and get to the ER.

Just to make sure we got the point, on orientation (and every few years) we were shown pictures of two fingers of a millwright that had a glove leak - he went home, just thought he had an itch, came back the next day - by the end of his ordeal, his finger looked like he'd drilled a hole in the end, stuck a firecracker in the hole and lit it

He ended up losing half of one finger and about a third of the other one. Got MY attention... Steve

 

[Reverser]

Third picture is the weld made with the Lincoln V350-Pro,

Shield Arc, that V350-Pro must be an awesome machine. That etch is picture perfect.
I've never seen an etch weld pic showing that much penetration down into the corner before. :thumbsup:

 

[Shield Arc]

Oh yeah she is a sweet machine. These inverters just amaze me with the control they have over the puddle. That weld was run with 0.0 on the pinch / arc force. Need to run a fillet weld with it, and set the pinch / arc force up more and see if that gives any more penetration.

 

[Shield Arc]

I was just in the shop cleaning up around the saw. I found this 3/4" thick V-butt weld I did last summer with .068" NR-211. I thought, well lets see how it did.:laughing:

 

[Reverser]

Looking good. :thumbsup:
Now that you've got your etching skills perfected, you'll probably be etching anything and everything you've done in the past, that you can find.
You might even need to order a couple more bottles of that etching elixir. :cool2:

 

[dragoneggs]

Hey SA, I doubt you have the weld you did with my 211 on 3/4" Tee fully cranked but if you do, I wonder what kind of penetration you got?

 

[Shield Arc]

Oh boy, I'll have to look. It might have gone to Navy City Metals. I took a load there not to long ago.

 

[Shield Arc]

Welp, I couldn't find it, it must have went to the scrap yard. Would have been interesting to see how much penetration it got.

 

[Gary Fowler]

Very Interesting. Better than a bend test.

Etching shows the weld profile but not the strength of the weld metal. There is no substitute for a proper bend test for determining quality of weld metal, not even an X-ray will prove the welders and welding rod ability like a bend test will. That is why even after all macro-graphs, etchings, xray testing etc have been done on a welding PROCEDURE qualification, a bend test is the acceptance standard.

I have seen beautiful welds that failed the ASME IX bend test procedure.

 

[Sodo]

Here's a natural etch, using water.

I welded the ball onto this simple pin hitch. It's for a neighbor's ATV, used mostly to move his firewood splitter around. He wouldn't go on the highway with it, this is an ATV unit.

I welded the ball on, then realized that the ball was too close to the hitch so had to move the hitch pin hole. I cut 3/4" off the end, cut in the middle and welded it back in with 1/8" gaps to get a full inch.