I'm going to be refurbing these amps I got, and not quite sure what to do with the edges of the laminates on the trannys that have rust on them.

I've heard you don't want to sand them down until they are bare? How about knocking off the buildup and using a rust converter on them then painting?

What do you all do?

I sand them as flat as I can, then prime and paint with some sort of textured paint.

I don't sand 'em - just wire brush the loose rust off and use a rust converter primer (but needs some REAL paint to keep 'em from rusting again...)

So in other words, you really don't want bare metal of one touching the bare metal of another from all I've read?

I use a stripping pad and/or phosphoric acid to get the rust off, then clean it with isopropal alcohol to remove all grease, dust etc, then prime and so on...

So in other words, you really don't want bare metal of one touching the bare metal of another from all I've read?

I think they touch when they stack'em don't they?:scratch2: Can you point me to the article?:scratch2: Now I'm worried about all the ones I've sanded over the years.:D

I can't remember where the hell I've seen it. I know I've seen a thread or two around here, and a couple on the net though... Supposedly once the metal of each laminate has the insulator covering taken off and they start to touch, it does something to the magnet field within the winding...

I know little enough about that, to stop and ask before I proceed..

What do you all do?

Sandblast 'em with pecan shells.:D

Eddy currents maybe??:scratch2:

Eddy currents maybe??:scratch2:

Duane.:yes:

Duane.:yes:

Go to bed, right now mister.:smoke:

You hit me on a great idea Ken... Baking soda.. Seriously, it's a well knowin media.. I've been wanting to buy a small blasting cab for a long time, maybe this might give me an excuse....

But on that same realm, I just got the bill for the lease on my tanks for the MIG welder and the oxy-act tanks last week, and my wife asked me once again... WHY?

I hate justifying that once a year. Do I really need to get into justifying a compressor, the electric, the media, and the used up space in the garage her car still won't fit in?

I restored a pretty fugly altec 1569 that had a lot of tranny rust. I just used a wire brush wheel on my shop grinder to clean up the endbells and sprayed with satin black, and wire brushed the core and sprayed with hairspray. After 5 years, no returning rust, the hairspray works great, and looks original.

Just this week, I finished working on my Scott 299B. Mostly in good cosmetic condition. However, the laminates of the transformers were rusty on the top.

Depending on when a Scott amplifier was made, the transformers could have been made by various manufacturers. This amp had flat black bells and enameled laminates. I sanded the laminates and just used polyurethane on them to try to look original. If I had some gun blue, I might have used that to get back some of the original look. But, alas, I don't have any right now.

They came out looking very good and since the original bells were flat black, I use Rustoleum flat black. The bells came out very nice.

On an LK-72 with rusty transformers, I sanded them as well, wet sanded the bells and used gloss black since that was what was used originally. Those transformers had the laminates painted as well as the bells. As I said, different models used different transformer manufacturers.

I am not worried about eddy currents or sanding the laminates. I think that while there may be some credit to that thinking, it is not a big thing. Never had any problems what so ever. Just my 2¢ though. "Your results will vary".

And I am guilty of not taking progressive pictures. I gotta start doing that, sorry...

From what i get out of this page(scroll down to "Energy Losses"), it looks like defeating the laminate insulation on output trannys might be more of an issue that on the power tranny as the effect of eddy currents seems to be a frequency dependent thing.

http://www.allaboutcircuits.com/vol_2/chpt_9/8.html

Duane.:yes:

And that's his Chesterfield then, is it?

Fine grade wire wheel in a drill, about 10 minutes worth of work. Rust converting primer and rustoleum black. Been 2 years ish and still looks great!

Evan

I wire brush or use a light sandpaper, then paint with lacquer. I have come to love lacquer as it smells decent compared to most paint, and dries fast, very fast. You can recoat in 10 minutes.

For that matter, if you use other paint such as Rustoleum, 150°F is not all that hot. You can even bake the transformer in the oven to dry the paint. Done it many times...

Here I sit looking at my amp and wondering if there are eddy currents dancing on the OPTS.:no:

Maybe this is why Morgan Jones is so dead set against paying big money for vintage iron. He claims it "degrades" over time, and he's a lot smarter n me.:yes:

.....endbells and sprayed with satin black, and wire brushed the core and sprayed with hairspray......

Hairspray? Is that code for something, or do you really mean hairspray?

Go to the auto store and get a spray can of chassis black. It'd matte black, perfect for trannys. I would do a minimal job of rust removal, no solvents, no media blasting, no steel wool. Use a scotch brite pad and paint. I'll get off my soap box now.

Scanning the posted article I see that the laminations are insulated from each other..... I wasn't sure if that was the case or not, beforehand. I can't see how stripping the rust/paint off of the transformer would hurt anything unless you connected the lamentations together electrically. If you're just taking paint and rust off, you aren't shorting anything, you're just un-insulating the edges..... re-insulate and call it good. I suppose it's possible that the paint could be a conductor..... a poor one, Though. You could always buy some of that motor winding varnish, and then paint it.

I think there is more concern about this than is necessary. Just sand them down, get inexpensive Rustoleum and spray away. Guaranteed to work just fine!

What about re-alignment of said laminations?Not only are they rusty on my Stancor P-6165 power transformer,but they also look like they have slid apart.looks like stair steps.

Here are a couple of good threads with some good advice.

http://db.audioasylum.com/cgi/m.mpl?forum=magnequest&n=7396&highlight=rust

http://db.audioasylum.com/cgi/m.mpl?forum=magnequest&n=8017&highlight=rust&r=

John

What about re-alignment of said laminations?Not only are they rusty on my Stancor P-6165 power transformer,but they also look like they have slid apart.looks like stair steps.

I have an Altec 1590A power amp with a uneven transformer. I can't imagine how that would happen other than at the time of manufacture. On the other hand I wouldn't think that Peerless would let a transformer through in that kind of shape.

I have an Altec 1590A power amp with a uneven transformer. I can't imagine how that would happen other than at the time of manufacture. On the other hand I wouldn't think that Peerless would let a transformer through in that kind of shape.

I've found lots of JBL inductors like that. :thumbsdn:

I have an Altec 1590A power amp with a uneven transformer. I can't imagine how that would happen other than at the time of manufacture. On the other hand I wouldn't think that Peerless would let a transformer through in that kind of shape.

Can this cause a problem with output transformers? I have an old stromberg carlson that's "bent" - the laminations have slid one way on one side and it stands crooked on the chassis....

You hit me on a great idea Ken... Baking soda.. Seriously, it's a well knowin media.. I've been wanting to buy a small blasting cab for a long time, maybe this might give me an excuse....

But on that same realm, I just got the bill for the lease on my tanks for the MIG welder and the oxy-act tanks last week, and my wife asked me once again... WHY?

I hate justifying that once a year. Do I really need to get into justifying a compressor, the electric, the media, and the used up space in the garage her car still won't fit in?

Simple solution for that - you can buy smaller MIG tanks. I own both of mine. The purchase expense really isn't that bad.

Can this cause a problem with output transformers? I have an old stromberg carlson that's "bent" - the laminations have slid one way on one side and it stands crooked on the chassis....


It probably depends on what you consider a problem......... safety or sound quality?

Regarding safety.......I'm not %100 sure, but unless one of the lamentations rubs/cuts through the insulation of the magnet wire and shorts, I believe it's just cosmetics. I've never taken a transformer apart, but I believe they have a paper/cardboard piece in between the lamentation core and the windings, so shorting shouldn't be very likely.

If you're talking about sound..... I'm guessing that the cores aren't going to shift enough to make a significant difference, but my understanding of transformers is very basic.

i didn't read the whole thread, but am i the only one who got a mental picture of pile o'guys in womens' clothing who all really needed a shower?

i didn't read the whole thread, but am i the only one who got a mental picture of pile o'guys in womens' clothing who all really needed a shower?

LOL what the crap... :lmao:

GWhifi: I've taken apart quite a few transformers and put back together less, but the ones I put back together worked just fine when I was done. I didn't know however, if the magnetic field would be disrupted enough to cause a loss of inductance in the OT if the laminations did cause a shift in the core. However, as you stated, you are probably right that the core probably did not shift enough to affect it.

i didn't read the whole thread, but am i the only one who got a mental picture of pile o'guys in womens' clothing who all really needed a shower?

Yes, I think you probably are the only one :D

i was afraid of that....

GWhifi: I've taken apart quite a few transformers and put back together less......

What do you mean you've taken them apart? You unwound all the wire?

I don't need a shower.:no:

:D

hey goodwill_hifi,

yep, good old hairspray works fab on cores, put on probably three coats with a few minutes between each. seals great, and has a good gloss. some of the car guys will use hairspray on their tires to get a little more shine for the car shows too.

Brian

hey goodwill_hifi,

yep, good old hairspray works fab on cores, put on probably three coats with a few minutes between each. seals great, and has a good gloss. some of the car guys will use hairspray on their tires to get a little more shine for the car shows too.

I never would have guessed...... does it last very long?

What do you mean you've taken them apart? You unwound all the wire?

No but I have taken off end bells, taken the E-core laminations apart and the bobbin off, cleaned, put back together. I have wound and unwound lengths of wire from a transformer. Its all about turns ratio. I had a 120v transformer that put out 135v on the other side, and I needed 120 so I unwound it until I read 120v. With a CT transformer, you need to unwind from each outer leg-if its even possible since mostly one lead is buried because it was started first.

No but I have taken off end bells, taken the E-core laminations apart and the bobbin off, cleaned, put back together......

I didn't know it was possible to take them apart that way. I thought they were pressed together.

yes. Once you take out the bolts that hold it together, and pull the endbells off, you then have to carefully pry the first one or two laminations out of the bobbin (they slide out of the middle.) Once those are out the rest is easy to take apart. You may have to do some smacking to loosen any paint/urethane caking the lam's together.