Old rusty transformers

[Randall]

"Well, I guess you can't tell everything from a picture. I'm curious about those bonus pots added to the front panel where there should be jacks. Have you discovered what they are, how they're wired or what the mod was? And, for my own curiosity, do you plan to leave them or are you going back to stock? Not that it matters- I'm just curious."

No, I didn't bother trying to figure out the many poorly done mods. I'm not a fan of knobs where jacks used to be. I plan on leaving the Normal channel mostly stock and making the bass channel a tweed tone stack maybe. See my post about it in Build Your Amp,

[Randall]

I opened the covers on the PT and OT, and the don't look bad, so I am going to take advise and not worry about it. PT looks good testing with no load. I'm going to clean and paint the bell covers and go forward.

[cjenrick]

Rupert Neve used to specify laminations with a light coat of rust, do not know why,

shorting edges of laminations is no big deal, it's not like having a solid block or iron for a core, as would be the case if the insulation coating were to break down, there is always a burr from the stamping process that tends to short the edges, to prove this get out your ohm meter.
i would get the main rust off with some steel wool and spray over that with some good paint, or varnish dip the darn thing and bake at 220 for 2 hrs

a newer transformer will draw more current for a little while until the domains loosen up, to see this build a transformer, apply 20 Hz and measure excitation current, it will creep down, you can "break in" a new transformer by subjecting it to 60 Hz at whatever voltage it saturates at, get the core nice and hot, and remeasure excitation.

this is why mr mercury might have been measuring lower power draw from the older transformer, not because of the rust,

[Randall]

Well, here is what I did. Pulled the bell covers and stripped them with a wire wheel drill. Brushed the insides gently with a stiff brush and wiped with alcohol. Rattle canned the covers with a DAP anti rust paint. Lacquer sprayed the insides and laminates. Results were very good. Testing looks good, and I consider this a success.

[J M Fahey]

FWIW our Pickup Forum friends have written quite a few posts on "relicīing" pickup covers , screws and hardware, including dangerous rust enhancing procedures such as using ferric perchloride or muriatic acid vapors, so I am not surprised.

All in the name of allmighty Mojo of course

Yeah, you want the fumes to do the work. I age some hardware that way, suspended in a jar with some vinegar at the bottom. For chrome I use acid.

There's a thread not too far back where there was some good discussion on tarnishing the metal in a fairly controlled manner. I think it was David Schwab who had a missing screw and got a pretty good match using acid fumes iirc.

Need to rust/oxidize the screws and slugs a little. Ferric chloride will do the trick. Staining and abusing the bobbins is only half the battle.

I was going to go more on the rusted side of things on the screws & slugs but he wanted it something like his neck that wasn't so rusted just slightly aged on the scews. I just used a little muratic acid to dull them out and some Marlboro ash.

and so on.

[Chuck H]

The whole "relic'd" thing has rubbed me wrong since the trend started. My personal guitar is definitely a relic. It got that way because it's old, I played it at a lot of shows and it wasn't always afforded the respect it deserved. We want our vintage instruments in like new condition and our new ones to look old.?.

To be fair, if you already have a cool old road dog Strat and it needs a pickup you may not want a bright white pickup in the neck position when the other two are yellowed and nicked up a little with age. I actually don't mind that sort of thing, but I can understand otherwise.

In my observation it started in the home furnishings industry when the "distressed" look came into fashion. Then, hot on the heels of that, Keith Richards wouldn't play his new Fender endorsement guitars because they looked too new. He told them to "Bash them up a bit" and he'd play them. But that's a stage image thing (I guess?). Why someone would want the new guitar they play at home to have been subjected to acid fumes, cigarette ash rubs and being smacked at with a wire brush remains a mystery to me.

There are threads on other guitar oriented forums where players discuss relic-ing their Floyd Rose bridge. It's starting to get stupid.

No one wants a relic'd car!?!

I guess I just "don't get it". But that's not unusual.

[Mick Bailey]

.....shorting edges of laminations is no big deal, it's not like having a solid block or iron for a core,.....

I'm immediately thinking of Peavey PTs that are welded to a baseplate. Welded right the way along the laminations on the bottom corners.

[bob p]

Keith Richards: "A Telecaster's a Damn Good Club"

In my observation it started in the home furnishings industry when the "distressed" look came into fashion. Then, hot on the heels of that, Keith Richards wouldn't play his new Fender endorsement guitars because they looked too new. He told them to "Bash them up a bit" and he'd play them. But that's a stage image thing (I guess?).

Keith Richards had a unique way of breaking-in his Fender guitars. Here's a video where he's playing "Satisfaction", and when a fan runs on-stage, Keef re-grasps his tele like a baseball bat and bashes him in the face.

The guy is damned lucky that Keef didn't pull the 4-inch knife out of his belt, slash him across the forehead and kick him in the balls. That's one of his practiced self-defense techniques.

Keith Richards says he carried gun to score heroin

[bob p]

He's done it more than once!

[Chuck H]

"He still owes me $200."

I was eating a sandwich. I was lucky to keep my food in my mouth when he finished with that line.

[The Dude]

Well, here is what I did. Pulled the bell covers and stripped them with a wire wheel drill. Brushed the insides gently with a stiff brush and wiped with alcohol. Rattle canned the covers with a DAP anti rust paint. Lacquer sprayed the insides and laminates. Results were very good. Testing looks good, and I consider this a success.

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I consider it a success, too. Looking good!

[cjenrick]

you mean like this Artisan xfmr ? we used to drill holes in the side of transformer cores for drive pins that keep the core brackets from sliding, only about 3/8" deep but there were 12 of them, these were for big three phase pwr transformers,

[Timpanogos Slim]

Look out for my new transformer line. I call it "RusticTone". The magic is in the special Fe2O3 coating.

I find that Fe3O4 has better tone. It's harder to make, because it only forms in an oxygen-poor environment.

A few comments about rust and transformers.

That evap-o-rust stuff works, and it turns out to be nothing but a household cleaning fluid that contains 2-butoxyethanol that has been spiked with tannic acid. Instead of buying it for $20/gal you can go to the dollar store and buy a gallon of Totally Awesome Cleaner and then go to your home-brew or vintner supply and get a bottle of tannin. The evap-o-rust is only a little yellow, so i don't think there's much tannin in it.

This converts the Fe2O3 to ferric tannate which is stable and soluble in water and alcohol.

The resulting iron or steel surface will be highly reactive and will flash rust rather quickly after you clean it. Just, word to the wise.

A few weeks ago i asked my retired EET friend about vacuum potting transformers that have been vibrating and he advised me that if it operates under 50c i should use a mixture of beeswax and paraffin, and if it runs above 50c i should use shellac. Immerse transformer in liquid, pull vacuum for a while, release vacuum, remove transformer from immersion and allow to cool / cure.

I specifically asked about using resin or lacquer and he advised against it, saying there is a potential to damage the coating on the windings. Which totally makes sense. shellac is dissolved in alcohol, and that shouldn't be a problem.

An old pressure cooker (lid on top kind rather than lid inside kind) makes a fine vacuum chamber. A hand pump for bleeding brakes from the auto parts store or harbor freight tools is probably good enough - I recently invested in a metal bellows motorized vac pump that goes to 14InHg that i intend to use for vacuum potting in the future.

[Mick Bailey]

The correct lacquer shouldn't damage insulation. I use something called 'transformer varnish' specifically formulated for this job and it's fine even on vintage transformers. I like the idea of using a pressure cooker. I'd be tempted to install a window in 8m or 10mm perspex to see when the bubbling stops. I often see pressure cookers for next to nothing and maybe that could be my next mini-project.

[J M Fahey]

I commercially wind transformers,and if course impregnate them.

Proper transformer varnish comes in two flavours: old style needs oven drying, oherwise it will be sticky forever, modern air drying has a gelling additive, you see it "as liquid as paint" for, say, 39minutes, then it starts gelling, fully dries overnight but if you are in a hurry, you can mount it just after gelling which guarantees your amp wonīt ooze varnish for hours and become a mess.

If no transformer varnish is available and itīs for a hobby project, you can soak it in common household "oil/synthetic" type varnish or paint (pigment does not hurt), only problem is that it will drip overnight and stink for couple days, and a lot the firstbtime it warms up.

Paints which are dissolved in turpentine or similar oil distilled "oily" solvents in general donīt hurt wire enamel; what you must NOT use is thinner solvent car type paint, because it contains very aggressive acetone, ethyl ether, ethyl acetate, xylene, etc. , all of which besides damaging brain cells attack plastics and specially wire enamel.

I try to use "motor winding" rated wire, covered in tough Epoxy enamel which is chemically strong, and try to avoid now very popular "self soldering enamel" , the kind *designed* to evaporate leaving no residue behind at solder temperatures: thin and flimsy, that type stands *nothing*