Rusted SVT transformers

[WholeToneMusic]

I am servicing an Ampeg SVT that has heavy rust on 2 of the transformers, Output and Power, It is so bad that the rust is crystallized on the chassis. On moderately rusted transformers I have been succesfull with lightly sanding the rust in a circular motion with non conductive sand paper and spraying rustoleum flat black spray paint on the laminates. These transformers are way to rusted to even attempt that method. They need relaminating. Does anyone know of a good source for relaminating transformers or is there an in shop method that can be used to relaminate them?

[Gtr_tech]

Jeebus.....was that thing stored out on the back porch year-round??!!

[WholeToneMusic]

Rusted X-fmers

Not sure, We get alot of moisture in the northbay california.
My digital camera went out or I would send a pic. Man it looks like it was in a Florida swamp for 10 years!!

[Gtr_tech]

It just may have been. I always tell my customers not to store any gear (guitars, amps,et al) where you wouldn't want to sleep.

[Amp Kat]

If you can't find a relaminator which btw I haven't seen anything even close too much less a rewinder at a somewhat decent price, you may try a product called rust converter by Benjamin Moore and Klean Strip makes one also. It will turn it back to it's original metal and then you can recoat it. There is a special finish they use that I read has no thinners in it. I think it maybe a special kind but can't remember where I read it at. I would think if you did find a relaminator it would cost you as much as a new tranny to have it done.

[Bruce / Mission Amps]

I am servicing an Ampeg SVT that has heavy rust on 2 of the transformers, Output and Power, It is so bad that the rust is crystallized on the chassis. On moderately rusted transformers I have been succesfull with lightly sanding the rust in a circular motion with non conductive sand paper and spraying rustoleum flat black spray paint on the laminates. These transformers are way to rusted to even attempt that method. They need relaminating. Does anyone know of a good source for relaminating transformers or is there an in shop method that can be used to relaminate them?

I've had very good luck with using regular old Naval Jelly and just keep applying it and wiping it off with a damp rag.
Then lightly buffing with a course 3M pad.
When cleaner and dry, I use stuff like this instead of paint.

http://store.interstateproducts.com/...&category=7605

By the way, it is a old wife's tale that rusty transformer laminations or sanding them will short out or wreck the tranny.
Many PTs have their laminations welded at the outside edge!!
After repairs like this they can run a little warmer, with eddy currents or maybe hysteresis losses but I don't think I've ever run into one that I couldn't fix up and make usable again.


*********** Added **********

http://www.mojomusicalsupply.com/ite...008&id=7020100
http://www.mojomusicalsupply.com/ite...008&id=7021100

[Albert Kreuzer]

Does it look like this?
Don't worry, it will work just fine

Cheers,
Albert

[Steve Conner]

I agree, if the rust bothers you just scrape off the worst of it and put Naval Jelly on it. I don't think it affects the performance at all, though. Rust is an insulator after all.

Relaminating a transformer is hard since most good transformers are impregnated into a solid lump with varnish. Which also makes them moisture-proof, so you don't need to worry about the rust.

[pila]

Re-finishing the laminations seem to be more for appearances than how it will work, unless it looks like the one Albert posted!

[Steve Conner]

I know the story behind this transformer, it's from an African arc welder I saw a bigger photo where someone was using it to weld what looked worryingly like the frame of a microlight.

I heard the wire is fence wire with hand-wrapped paper insulation, and the core is made of flattened beer cans, though that's hard to believe because fence wire is steel with lousy conductivity, and beer cans are often aluminium.

Nevertheless, I bet there's some audiophile out there who would pay $1k for it and swear it sounded like heaven.

[Suburbanite]

I did, and it does

[WholeToneMusic]

They do not look that bad!! They are still bolted onto the chassis Albert!!! haha
I spoke with the owner and found out that after gigs he was putting the amp into it's roadcase before it cooled down, which was causing condensation in the case. Thanks for the tips all.