Etching weld samples

[Welderpaul]

I want to do some weld tests for a couple of the young lads..weld up some fillets, cut them up, polish and have a look at the penetration.

It think the acid is Nit-al? Nitric acid and alcohol? Not readily available it would seem. Does pickling paste work?

 

[zardoz]

Wikki says: Add no more than 2 ml concentrated nitric acid slowly to 98 ml ethanol (industrial methylated spirit). Label the solution highly flammable but do not store longer than a week.
.
Thanks for asking the question. I have been meaning to find out myself for a while what it consisted of.

 

[BrokenBiker]

the stuff we have in work is 0.9% nitric acid 99.1% ethanol.

it is mixed by the welders as and when it is needed and always disposed of straight away.

 

[Paul.]

For simple workshop testing 20% nitric in water will do, that's all we used to use for progress testing in the college workshop I worked in,
I have used pickling paste in my own shop, its quite aggressive though and usually water it down a bit, just wash it off before it goes in the scrap you never know who might pick it up.

 

[Robotstar5]

Wikki says: Add no more than 2 ml concentrated nitric acid slowly to 98 ml ethanol (industrial methylated spirit). Label the solution highly flammable but do not store longer than a week.

It's best to get the mixture right, the macro lab at work didn't and for want of a better description it "boiled over" filling the lab with fumes, we ended up getting the fire service in to remove it.

The fire service decided to turn it into a training exercise, we ended up with 2 appliances, a hazmat van and 2 paramedic cars in the carpark! we weren't too impressed as it was cold standing outside for over an hour