Rusted Magnets - Cure?

[Goahead]

Hi everyone,

After 3 years of my 10ft axial flux spinning and making some nice amps, the rotor as serious rust in all 24 magnets.

I disassembled the generator, and would like to ear from you all, how to remove rust and protect the magnets for the next years to come.

I should probably exchange magnets, but i don't want/have money to spend on this.
Best way to remove rust? (magnets are bound welded to plate)
How can i protect them? what type of paint should i use?

Kind regards
Goahead

[Flux]

Rust is  problem with neos. You give no indication whether your magnets are potted in something or just left with the nickel plating.

The best I can suggest is that you clean off the worst of the rust and paint with POR15, possibly with an additional coat of epoxy paint.

Potting in Polyester seems worse than useless, potting in epoxy may be better but may be no use once rust has started.

Phosphate rust converters and a good heavy coating of paint does slow things a lot, too early to really comment but my attempt with POR 15 looks to be the most promising.

Flux

[Goahead]

Hi Flux.

I see that you still help people in forum    What a wonderful human being you are....and with a lot of knowledge and free time 

Magnets are not potted. Nickel was left clean, open air. I just used Nural 21 to fix magnets to plate.
Nickel "exploded" from magnets due to rust being formed bellow the cote.

I tried to clean them, removing renaming nickel platting, and removing rust from neos...a monster job...since rust attracts to magnets
They are fairly clean, so now i need o good cote to contain the left overs (rust and more rust).

Dont know if i can get POR15 here in Portugal. Have to look at local stores. So its like rubber after paint?

keep up the good work
Kind regards
Goahead

[Goahead]

I found this one:

http://www.u-pol.co.uk/product-cat/81/gravitex-plus%C2%AE-hs-stone-chip-protector.htm



Gravitex seems ok for the job?

Kind regards
G.

[Flux]

POR 15 is American, but is available in the UK from Frost Auto Restoration Products. I would think it likely that Frost would ship to European companies.

I have no experience of the U pol gravitex product, it may be fine, but from here I find their web site unstable and unhelpful. If you can't get the POR 15 then it seems as though it would be worth a try.

The nickel plating on neos seems to be a bit of a joke, it seems to offer little real protection, the epoxy coated magnets seem to survive better.

Flux

[DanG]

Here is one example of being in the UK - but supposedly the British Post declines to handle it...

http://www.frost.co.uk/por15-rust-prevention-paint-473ml.html

No - it is not undercoating or rubberized paint. I've used a couple of gallons of this on various projects.

This is a very thin bodied Naptha based paint that captures water molecules to catalyze the urethane base paint, either from the ambient air or from the metals/oxides matrix you're applying it to.

For best results it'd be lightly brush/sand off external damaged compositions and get the magnets 99.5% free of moisture - like drying fireworks or something, bake in sunshine a couple of days inside glass jars with lid loose, tighten lids to seal them up in glass overnight or when it's cloudy - then dip each magnet for a minute or two and allow to drip-drain safely where they WILL NOT get anywhere near another magnet or iron, that would be ugly for sure.

When the Naptha carrier evaporates away the resin reactions start cooking - when the coating has dried to the touch but is still a bit soft do another coat, 2nd/3rd coats do not need to be dipped, you're filling in any pits left by air bubbles and adding armor to the corners/edges.

If you were applying this to 'new' magnets you've got to get the silicone lubricant oils off the factory applies to reduce wear and tear on their equipment, the POR-15 keys into nooks and crannies and will peel off like cellophane if there is any oils present.

Hope that helped.

[dnix71]

POR15 is really foul stuff until it cures. It also degrades under UV so you need to coat it with a UV blocker. Hot dip galvanize is the best rust proofing. Unfortunately neos can't take the heat. I own a utility trailer that was hot dipped like fence wire is. It has been outside for years with no sign of corrosion.

I used Loctite Extend more than 20 years ago. It's still available and not toxic. Surface rust has to be present for Extend to work. It won't affect clean bare metal.

http://www.zrcworldwide.com/products/zrc-cold-galvanizing-compound   ZRC is one of a kind cold galvanizing. The dries coat is 95% zinc. ZRC is expensive.

[Goahead]

Thanks everyone for the kind answers.

dnix71;
Zinc (Cold Galvanizing) is also a nice approach, and i think i can ignore its conductivity. (if any)

Zinc is way cheaper then POR15, U-POL Raptor or GRAVITEX and its also sold in self spray cans.
A spray can of ZRC (98%) costs 7€ and POR15 costs 29€. And i will only need one can.
There must be something missing in the spray can to cost only a fraction of the ZRC gallon container???

I used some of that cold Zinc in my house front gate, where i had some rust spots, and it does contain the rust after 5 years.

I never used Loctite Extend...maybe it can "kill" rust...just like some people say that vinegar do.
Something i must look at.

DanG;
Thank you for the uk online shop...i see no restriction to my country...but then, thats an expensive product 


Kind regards
G.

[Flux]

Yes Por15 is nasty but if you brush it in a well ventilated area it is not a big deal. Don't attempt to spray it under any circumstance without  full paint shop facilities and fresh air breathing masks, it is almost certainly one of the isocyanates as used in 2 part paint systems.

It is expensive but one small tin will be enough for several alternators, would make more sense if you have friends with a similar problem to share the cost.

Whether some of the other things will work effectively depends on your climate, cold zinc spray is I suspect likely to be the least successful, Phosphate converters ( Jenolite and similar) and a good coat of Hammerite primer and top paint coat will keep things at bay for a year or two but the POR 15 I used has been holding things at bay for about 4 years. In that respect it is not so bad in comparison with new magnet costs.

If you have got this far with no protection at all then some of the other alternatives may keep you going for a reasonable length of time. If you are on the coast then it becomes difficult.

Flux

[oztules]

For drying you can heat them up to 50C or a bit more, and hold them under a vacuum overnight you should get most of the water boiled out of them ... as good as you possibly can do i expect.... then coat ans Dang says.

..............oztules

[bart]

   I used some Por15 on the inside and outside on a old boiler tank. On the outside after the por15 was cured, painted over with some latex for UV protection. been out in the weather for over 5 years and no peeling or flaking.

[dnix71]

Extend chemically converts the rust to a black latex compound. It isn't impact resistant, and needs to be coated/painted over.

[Frank S]

If you will Use some KBS rust blast as per instructions it will take all of the rust off and leave a zinc phosphate coating then paint with KBS black top they will probably never rust again
http://kbs.justoldtrucks.com/

[Goahead]

Thank you all again for the nice info.

By the way...can someone explain to me what Molasses is?
I could try to find this in a local store..but i cant find any translation for this

Seems that Molasses and water does remove rust...eco friendly

Regards
Goahead

[Mary B]

Molasses is a sweetener, probably find it in the same location as sugar or breakfast syrups in your store. It is the unrefined stage of sugar basically.

[DanG]

Would y'all kindy stop & think for a second? 

NO WATER OR WATER BASED PRODUCTS ON CORRODED (OPEN-PORE) RARE EARTH MAGNET COMPOSITION.

£29 is $44 USD, the price of a proven encapsulation method (POR-15).

That is the price of one or two large Neo Magnets.  How many are on the rotor? 24?  18?

[frackers]

I used a generic phosphoric acid rust eating liquid (2-3 goes with a good drying and brushing between) on mine and then sprayed with 90% zinc galv paint.

Seems to be holding up a lot better than the original car enamel spray paint.

[equiluxe]

Molasses is sold in the UK as black treacle, you will also find it in animal feed stuffs stores, Horses love it.

[tecker]

Nckel has to come off .Baking soda in a gal  water about a table spoon use a piece of clean steel to sacrifice .use a battery charger connect the magnet to the negative side and the clean steel to the positive .  Use ospho ot similar and paint really well.

[electrondady1]

Extend works.
it turns iron oxide into iron sulfide
coated some cut up hardrive mags 9 years ago
paint the rotors too
then a good finish enamel

[hiker]

Molasses-great on flapjacks.............not sure about mags.......... :}

[scoraigwind]

I just soak the affected area in oil these days.  spray on some WD40, soak in linseed oil, coat with waxoil.  Seems to offer the best protection.  I imagine that waste oil from a car engine would probably work pretty well for a shorter while.  Cheap and low tech.  I never was much good at fancy resin mixtures and stuff.

[richhagen]

If you can't get it from a local vender, which would likely be cheaper, you may be able to get someone to ship you Por 15 via EBay.  They have a starter kit apparently which comes in a 4 Oz. can.  I am not sure if you can see this link in Portugal, but here is an example:

http://www.ebay.com/itm/POR-15-Super-Starter-Kit-Gloss-Black-Rust-Paint-POR15-/371321087717?hash=item56747626e5&item=371321087717&vxp=mtr

[niall2]

you can get rust inhibitor stuff in a can from the local auto factors ......its a chemical thing that reacts with the rust to give a .....bluish sticky tinge

it does bubble and fizz  (a bit disconcerting) to watch ...but then wipe it off ...and chance your arm ...kind off 

the stuff i got was a kind of clear gell.....