Restoring transformers

[jelle]

I am restoring a set of fender 400ps transformers. I removed rust. What type of black paint/varnish can I use on these? Thanks, Jelle

[selloutrr]

It's usually best to not remove the rust do to the particals potentially causing shorts in the LAMs.

Rust inhibitor / rustoleum paint.

A simple google search should give you step by step how to

[jelle]

Thanks, yes, I fully realize the effects of rust particles. I closed the inside off to prevent this. I also did not strip the laminations to the bare iron, to preserve its original functionality.

Several people have suggested epoxy based rust-oleum. THANKS!

[jelle]

Thanks, yes, I fully realize the effects of rust particles. I closed the inside off to prevent this. I also did not strip the laminations to the bare iron, to preserve its original functionality.

Several people have suggested epoxy based rust-oleum. THANKS!

[TUBEDUDE]

I've pondered this on many occasions. I thought phosphoric acid (ospho) would work as it removes the oxygen molecule from the iron, effectively restoring the steel. But I think it's likely not that simple, as the iron may short across the laminations and be worse than leaving the rust alone. The fact that the rust is there in the first place would indicate the lacquer or sealer has lost it's integrity and the isolation of the laminations is at risk. If you have a tranny thats humming,, gets hot, or in some other way indicates a laminar short, it's worth a try I guess.

[Prairie Dawg]

Back a decade or so when this subject came up at the urging of a certain Texican amp doctor, I quizzed my old man about it.

He graduated from MIT with a degree in Metallurgical Engineering-properties of metals.

So I put it to him along with all the hoodoo and mojo and things you ain't supposed to do and he, who had not worked in the field for 25 years but still knew his stuff pretty well said this: "Hmmmmmm....high silicon iron laminations. I'd be surprised if it didn't rust. If the appearance bothers you, get yourself a suede brush, a brass one, and clean the laminations, going with them and not across them. Then, apply a good acrylic coating. Now. What else troubles you, O my son?"

Since then I have happily cleaned rusty transformers and sprayed them with Krylon, and not a one has ever failed or overheated. They look fine, and usually I am the only one who knows I have done this. You can also use a black magic marker or sharpie if you like.

[Cliff Schecht]

Prairie, your dad sounds like mine. When I get into the nitty gritty detailed stuff, I give my dad a call to talk out the problem.

As for rusty transformers, heck I like 'em rusty! Even extremely rusty transformers will usually work without any issues as long as the guts of the transformer itself are in good working order (no cracks/damage to enamel coated wire or actual transformer leads).

[VacuumVoodoo]

One thing to remember when disassembling a transformer. Mark every lamination and orientation of the bobbin. Otherwise you won't be able to reassemble it into exactly same state. When all lams are back in place use a rubber mallet to get all of them to realign.

[martin manning]

I have been using Boeshield T-9 for cleaning and protecting transformer lams: http://boeshield.com It will dissolve most of the surface rust, darken the color of the stack nicely, and it dries to a non-oily coating that prevents further corrosion. You can paint over it if you like.

I originally started buying it as bicycle chain lube, but found many other uses for it. It works particularly well for cleaning and protecting steel bridge and trem components on vintage guitars, as well as coating cast iron machine tables. I've also used it as cutting fluid when drilling aluminum with great success.

[jelle]

And that is why I like this place much better than a Google search. Thanks guys!!!

[Structo]

It seems for years we were told that rusty transformers were evil!

Eddy currents and all that.

Now since Mercury came out with the rust is good video, the general consensus is that Rust Rules!

[VacuumVoodoo]

It seems for years we were told that rusty transformers were evil!

Eddy currents and all that.

Now since Mercury came out with the rust is good video, the general consensus is that Rust Rules!

MM probably had someone to translate relevant chapter from a book in russian,
a venerable definitive encyclopedia on transformer design A.D. 1957.
Unfortunately no translation to any western language exists AFAIK.
BTW rust is non-conductive, as matter of fact it's a pretty good isolator.
I think all that talk about eddy currents caused by rust must have come from someone slightly misinformed.
May I exit besserwisser mode now

[Phil_S]

One thing to remember when disassembling a transformer. Mark every lamination and orientation of the bobbin. Otherwise you won't be able to reassemble it into exactly same state. When all lams are back in place use a rubber mallet to get all of them to realign.

When I have done this, I used a Sharpie to draw a couple of lines across the lams at an angle like this \ /. When re-assembling, there was only way to recreate the lines in that pattern. If you are really compulsive about it, you can nick the lams with the corner of a file to etch a line into them.

[LeftyStrat]

I have been using Boeshield T-9 for cleaning and protecting transformer lams: http://boeshield.com It will dissolve most of the surface rust, darken the color of the stack nicely, and it dries to a non-oily coating that prevents further corrosion. You can paint over it if you like.

I originally started buying it as bicycle chain lube, but found many other uses for it. It works particularly well for cleaning and protecting steel bridge and trem components on vintage guitars, as well as coating cast iron machine tables. I've also used it as cutting fluid when drilling aluminum with great success.

The Boeshield T-9 is pretty amazing stuff. I restored an ancient table saw using that stuff. It got rid of the rust and the rust has never come back, even though the table saw is in a very damp Seattle garage.

[rp]

I have been using Boeshield T-9 for cleaning and protecting transformer lams: http://boeshield.com It will dissolve most of the surface rust, darken the color of the stack nicely, and it dries to a non-oily coating that prevents further corrosion. You can paint over it if you like.

My fave ever chain lube, nothing like changing a flat and having fairly clean hands afterwards. Whatever made you think to try it on tranies?! Might try it one day, but right now I'm saving it for my bikes. I took several small bottles w/ me overseas any idea where to get the big bottles from?