Rust Converter For Transformer's Laminations

[sarakisof]

Hello, some of my transformers in old equipment appear the common rusty surface on laminations. So after having asked and searched all this time i decided to first go with a Rust Converter first and then apply clear varnish like Rustoleum and so.  I was suggested the Fertan rust converter or smthng similar based on Tannic Acid, not Phosphoric Acid. As i cannot find it in my country i searched and found other brands. I found a product called Ambro-Sol Rust Converter. Found the pdf datasheet but neither phosphoric nor tannic mentioned anywhere. Have just contacted the local dealer and waiting for response.
Do you think it is safe to use?

https://www.ambro-sol.com/wp-content/uploads//I260_EN_rev.0.pdf

I guess every rust "converter" is based on tannic and "remover" on phosphoric but i may be wrong huh.

[PRR]

The contents are usually listed in what I call the "MDS", which must be available to US workers.
"BEFORE USE, CONSULT THE SAFETY DATA SHEET OF THE PRODUCT"
Where is it??

I found a French sheet which appears to list ingredients and dangers. If I read it right, it is acrylic paint with a 2-Butoxyethanol solvent. Not what I would call a "remover". However another site showed a valve-spring where the 'after' sure looked like Phosphate conversion.

The rust does NO harm. It's just ugly. Do NOT "scrape"! Wire-brush gently with the grain. Apply an oil-based wood-stain, as dark-black as you can find, maybe without fully stirring the can just taking glop off the bottom. When it fully dries, it will look a lot like factory paint, for many years.

RUBRIQUE 3. Composition/informations sur les composants
3.1. Substances
Informations non pertinentes
3.2. Mélanges
Contenu:
Identification x = Conc. % Classification 1272/2008 (CLP) vinyl acrylic emulsion polymer CAS 23 ≤ x < 27 Eye Irrit. 2 H319, Skin Irrit. 2 H315 CE INDEX - 2-BUTOXYETHANOL CAS 111-76-2 3 ≤ x < 5 Acute Tox. 4 H302, Acute Tox. 4 H312, Acute Tox. 4 H332, Eye Irrit. 2 H319, Skin Irrit. 2 H315 CE 203-905-0 INDEX 603-014-00-0
Le texte complet des indictions de danger (H) figure à la section 16 de la fiche.

[GibsonGM]

Paul, I was wondering if you'd ever tried amber shellac for this purpose? Fast-drying, alcohol based (no water, no slow dry time).   Applied to a coil or laminations, it would be dry in < 45 minutes.   

[samhay]

https://www.ambro-sol.com/wp-content/uploads//I260_EN_rev.0.pdf

Data sheet says it's at pH = 3, so there's some form of acid in it.
MSDS only has to list hazardous contents (e.g. toxins) and hazardous properties, so I'm guessing phosphoric acid doesn't need to be specifically listed in it.

[GibsonGM]

Phosphoric acid is poisonous, so it SHOULD be listed, shouldn't it?

https://beta-static.fishersci.com/content/dam/fishersci/en_US/documents/programs/education/regulatory-documents/sds/chemicals/chemicals-o/S25470B.pdf

[samhay]

That's 85% phosphoric acid.
If you look on page 2 it says conc < 10%, not classified for physical or health hazards under GHS (globally harmonised system).

phosphoric acid is not intrinsically poisonous (in fact, it quit a common biological acid), but concentrated solutions, like those of any acid, will cause burns.

As the pH of the solution is significantly higher than the relevant pKa of phosphoric acid (2.15), and as it's a weak acid and thus probably acting as a buffer in this context, the concentration of phosphoric acid will almost certainly be less than 10% (probably closer to ~ 1%).

[sarakisof]

Thank you all guys for the great inputs.
Discussion could be continued here:

https://www.diystompboxes.com/smfforum/index.php?topic=123844.msg1172914#msg1172914

[PRR]

> tried amber shellac

I shouldn't argue with a pro. Here goes...

This is not a get-in-and-out for-profit job; or a 13-hand-rub-coats beauty-job; he's got hundreds of hours of electronic fixing so dry-time is moot.

It is hard for non-pros to get GOOD shellac.

_I_ think oil stains hold-up to damp better than shellac.

Transformers are typically painted black. You never get all the rust off (without damaging the lams), so the "scar" is a little brown, a little shiny, not black. A very dark oil-stain soaks INTO the rust pores and resists damp for years.

I pulled some heavy steel stamped handrail brackets from a muddy pile, didn't try to de-rust, just brushed them with Golden Oak oil stain, and got a nice gold/brown tone which is nice to the hand and has held-up in a damp garage for 7 years. I have black-stained some screwdrivers and prybars which have stayed rust-free.

[sarakisof]

PRR i will glue them with oil based wood varnish. I found a simple one and another which contains a little wax too. Do you think the one with wax would be better? I will do it after having applied Fertan rust converter(tannic acid).
https://www.diystompboxes.com/smfforum/index.php?topic=123844.msg1172914#msg1172914

So rust converter, then wood oil and then rustoleum spray black.

[sarakisof]

The materials i have in hand here now is a simple water based wood varnish and an acrylic varnish spray can for metals. So i guess i should wait for the Fertan and other materials to come.

[sarakisof]

Resume of the story

https://www.diystompboxes.com/smfforum/index.php?topic=123844.0