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