Pickling Stainless Steel

What do you use in the home workshop for pickling/cleaning stainless steel after welding. I would prefer to use something a little safer than sulphuric acid.

Paul.

Edited By Paul Lousick on 19/12/2017 06:10:38

Where I worked the welders used a proprietary white paste which had a weak ( 2-3%? ) solution of Hydrofluoric acid plus Nitric acid in it, it worked well and being a paste wouldn't splash but I think that would be also too nasty to use at home due to the HF..

John

would prefer to use something a little safer

Wouldn't we all! But do remember that even dihydrogen monoxide can be lethal in the wrong circumstances. If used properly and utilising all the ppe recommended, sulphuric acid is safe to use. I would not say perfectly safe because there is always the human element, of the operation, that may not be reliable. It is concentrated sulphuric acid one should really worry about - a great deal more than pickling concentrations.

I used hot concentrated acids and alkalis at work and it never bothered me - because we took the necessary precautions for handling such corrosive (or poisonous) compounds.

Presumably you never arc weld? Never use oxy acetylene (or oxypropane or even propane/air) to heat things really hot? Would never contemplate using anything as dangerous as a lathe or milling machine?

Do your risk assessment, take all reasonable precautions - and it will be safe enough.

Sounds a bit like this stuff **LINK** sold for use in a domestic environment

Rod

Sounds a bit like this stuff **LINK** sold for use in a domestic environment........and clearly has a label which says 'danger' on it!

Edited By not done it yet on 19/12/2017 10:20:03

Funny i was watching people using this on you tube last week, most had no gloves on or anything at all.

Its a mixture of Barium sulphate,Sulphuric acid and Fluoride salts ,obviously produces a weak HF solution due to the sulphuric acid and fluoride.

According to the MSDS for Armour etch, 160cm2 of skin coverage can lead to hypercalcaemia (which is only around 4"- 5" square area)

Can't believe that a product as dangerous as glass etching cream is available mail order with no controls over who accesses it. HF acid no matter how it's generated is a very dangerous substance, then as you can buy various strengths of hydrochloric and sulphuric acid also by mail order I am not surprised.

Dave W

It's amazing the dangerous things you can buy if you know where to look. I went into a shop the other day and they had lathes and milling machines for sale - so irresponsible of the vendor to make items available that could seriously injure the user.

Rod

They dont even wear gloves on the official videos. A bit silly really even if it is relatively tame compared to HF, id advise wearing gloves with any sort of chemicals.

**LINK**

Edited By mark smith 20 on 19/12/2017 11:04:48

Also a rather amusing thread on this forum. Hence why gloves should be worn.

http://www.wetcanvas.com/forums/archive/index.php/t-216350.html

Edited By mark smith 20 on 19/12/2017 11:10:37

Posted by Roderick Jenkins on 19/12/2017 10:53:16:

It's amazing the dangerous things you can buy if you know where to look. I went into a shop the other day and they had lathes and milling machines for sale - so irresponsible of the vendor to make items available that could seriously injure the user.

Rob

-------------------------------------------------------------------------

I went to get a piece of glass the other day and there were broken pieces laying all over the floor in the glass shop

and there people working around it. Why would they make such dangerous stuff.

I cannot imagine what use it would be. :- 0

regards

Edited By Oldiron on 19/12/2017 14:17:20

Also says, "MAY BE FATAL"

Russell

Also says, "MAY BE FATAL"

More than dihydrogen monoxide in the wrong concentration?

Edited By not done it yet on 19/12/2017 15:45:15

They even deliver dihydrogen monoxide to My house and have the nerve to want Me to pay for it. Crafty scheme!

This is why some chemicals are different? They can sneak up on you.
**LINK**

A couple of drops and straight through the gloves it went. many months later she was gone and a terrible journey it was too.. Note she was a professional chemist. Bitten by a nasty that can be absorbed through the skin.
Imagine if the chemicals spilled in the post, or were in the hands of a criminal.

Weak hydrofluoric acid, another sneak
**LINK**

Materials like these need to have a restricted supply chain. Not banned but restricted. Available to all who can prove they know the risks and have the means to handle and dispose of them properly.

Rather different to a machinery injury where the danger is more obvious. you can see what happens if you stick any part of your body in danger.

Regards
John

You could always ask to be disconnected if you're that worried about it.

You could always ask to be disconnected if you're that worried about it.

Most of it is sent back - the supplly companies charge to dispose of 90% of the original delivery to residential customers! Further, they charge more for disposal and then supply it to other customers.

There is no end to the supply chain then! You can't be last?

Being a chemist I do pay respect to hydrofluoric acid and there are rather few compounds which are causing my concerns.

So for example sulfuric acid diluted or concentrated is nothing of particular concerns comparing to HF.

Hydrochloric acid in comparison would be good handwash and cyanides only moderately poisonous.

Burns from HF have delayed onset (8-24hrs) so at the time of contamination nothing is felt, they are chewing tissue down to the bone and meet falls off the wound and tissue around simply rot. Healing takes many months. Wounds of older or sensitive peoples may never heal. Sometimes aputations are necessary.

Rubber gloves of industrial standard, rubber apron and face protection are mandatory and special paste made of calcium gluconate must be at hand to work into skin accidently treated with HF. Cacium gluconate paste applied promptly may (and often does) prevent development of said burns. Should be applied after initial washing with plenty of water BEFORE one seeks medical attention as time counts and waiting an hour or two or three will make it useless and doctors will have much more difficult case.

Saying all that I must note that HF is used in hobbies, say by glass staining/etching artists. It is branch of litography.

Martin

That'll not stop the airborne deliveries.