Instructables
Picture of Easy electroplating (Galvanizado f�cil)
CUIDADO: este proyecto no debe ser afrontado por niños, porque implica el manejo de sustancias peligrosas y vapores tóxicos.

Repito: Este proyecto implica el manejo de sustancias peligrosas y vapores tóxicos. Por lo tanto, no debe ser afrontado por niños ni personas inexpertas o atolondradas.

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WARNING: this project should not be faced by children, because it involves the handling of hazardous substances and toxic fumes.

I repeat: This project involves the handling of hazardous and toxic fumes. Therefore, should not be faced by children or inexperienced or reckless.
 
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Step 1: Para qu� galvanizar (to what galvanize)

El galvanizado es un procedimiento que sirve para proteger del óxido, y eventualmente embellecer superficialmente, una pieza de hierro. Es muy utilizado industrialmente, siendo prácticamente excluyente en cuanto al tratamiento de chapas corrugadas para techos. No es la panacea universal, pero es sumamente útil.

El presente instructable tratará exclusivamente, en base a mi propia experiencia y siguiendo las indicaciones dadas por un amigo, de cómo recubrir con zinc una pieza de hierro o acero.

Pido que quienes sepan más que yo del tema no duden en corregirme.

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Galvanizing is a process that serves to protect from rust, and eventually beautify the surface, a piece of iron. It is widely used industrially, being almost exclusive in the treatment of corrugated roofing sheets. It is not the universal panacea, but it is extremely useful.

This instructable will exclusively treat, based on my experience and following the instructions given by a friend, how zinc coating a piece of iron or steel.

I ask those who know the subject more than I feel free to correct me.

Step 2: Materiales y herramientas (materials and tools)

Básicamente se necesita lo siguiente:
  • Ácido muriático (clorhídrico).
  • Trozos de zinc.
  • Un cargador de baterías de auto, u otra fuente de corriente continua medianamente potente. También puede usarse una batería de auto, si el trabajo es chico.
  • Un pincel de cerdas plásticas.
  • Un lugar abierto donde poder hacer el trabajo.
  • Elementos de seguridad (guantes, gafas, delantal, etc).
  • Algo para galvanizar.

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Basically you need the following:
  • Muriatic acid (hydrochloric acid).
  • Pieces of zinc.
  • A car battery charger or other DC source fairly powerful. You can also use a car battery, if the job is small.
  • A plastic bristle brush.
  • An open area where you can do the job.
  • Security elements (gloves, goggles, apron, etc).
  • Something to galvanize.

Step 3: Fabricar el cloruro de zinc (manufacturing zinc chloride)

Seguramente se debe poder comprar hecho, pero yo no tengo la menor idea de cómo ni donde ni a qué precio. Por lo tanto, lo hago como aprendí a hacerlo en mi infancia. Es la parte más peligrosa y delicada del trabajo.

El poco cinc puro que pude conseguir lo obtuve en parte de pilas viejas, y en parte de unas pilas que desarmé hace unos años para utilizar los carbones. Tengo entendido que en USA hay monedas chicas hechas de cinc y cubiertas con cobre o bronce. Hay que limarles la cubierta exterior, o arreglarse de alguna manera para separar el cinc del resto.

Luego hay que conseguir un recipiente adecuado para producir la reacción química, y lo suficientemente resistente como para conservar el cloruro de zinc luego, porque es una sustancia relativamente peligrosa. En mi caso usé un frasco plástico con tapa hermética a rosca.

Vertí una pequeña cantidad de ácido clorhídrico dentro del recipiente, aproximadamente 50 cc. Creo que hubiera sido mejor 25 cc.

Corté en pequeños trozos y en tiras delgadas el cinc, para aumentar su superficie. La reacción química tiene lugar en la superficie del cinc, por eso es conveniente no utilizar trozos macizos. Pero como se produce efervescencia, un poco de calor y efusión de hidrógeno, no es conveniente usar limaduras o polvo de cinc. En caso de tener que usarlo de esa manera, sugiero ir agregándolo cuidadosamente en dosis muy pequeñas, de algunos miligramos por vez, para evitar recibir salpicaduras.

Al empezar a arrojar los trocitos de cinc dentro del ácido, se produce una efervescencia bastante fuerte que puede salpicar ácido muriático alrededor del recipiente, por lo cual es conveniente hacer esto tomando todas las precauciones del caso. OJO, el "vapor" que se produce es una mezcla de hidrógeno (muy combustible) y aerosol de ácido clorhídrico, por lo que hay que evitar aspirarlo. Por eso sugiero trabajar en exteriores o en lugar muy ventilado.

A medida que el ácido del recipiente va atacando el cinc, este último se va disolviendo, y al mismo tiempo la fuerza de la reacción va disminuyendo. Es necesario seguir agregando cinc hasta que no se observe ninguna reacción, e incluso a partir de ese momento asegurarse de que quede al menos un trozo de cinc sin diluir, y dejar pasar algunas horas. Esto es porque el hecho de que no se vea ninguna reacción no significa que esta no ocurra lentamente. Insisto: si desaparece todo el cinc, hay que volver a agregar hasta que quede un residuo en forma permanente.

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Probably it can be purchased made, but I have no idea how or where or at what price. So I do it as learned in my childhood. It is the most dangerous and delicate work.

The pure zinc bit I got was part of old batteries, and part of three batteries disassembled years ago to use the kernels. I have heard that in USA there are coins made of zinc and covered with copper or bronze. You must file the outer, or cope in some way to separate the zinc from the rest.

Then you need to get a suitable container to produce the chemical reaction, and strong enough to keep the zinc chloride because it is a relatively dangerous substance. In my case I used a plastic bottle with screw-tight lid.

Shed a small amount of hydrochloric acid within the vessel, approximately 50 cc. I think it would have been better 25 cc.

Cut
zinc into small pieces or thin strips, to increase its surface. The chemical reaction takes place at the zinc's surface, so it is desirable not to use big pieces. But as effervescence occurs, a little warmth and effusion of hydrogen, it is not convenient to use filings or zinc dust. If you have to use it that way, I suggest adding it carefully in very small doses of a few milligrams at a time, to avoid getting spray.

When you start throwing the pieces of zinc in acid, there is a fairly strong effervescence; muriatic acid can splash around the vessel, making it convenient to do this by taking all precautions. WARN, the "vapor" that occurs is a mixture of hydrogen (very
combustible) and hydrochloric acid aerosol, so breathing must be avoided.  I suggest working outdoors or in a very well ventilated place.

As the acid goes attacking the zinc, this is dissolved, while the strength of the reaction decreases. It is necessary to continue adding zinc until no reaction is observed, and even from that time make sure it is at least one piece of raw zinc, and leave pass a few hours. This is because the fact you can not see any reaction does not mean that this does not happen slowly.   I repeat: if all the zinc disappears, it must be re-added until a permanent piece remains.



Step 4: Preparar el pincel (preparing the paintbrush)

Picture of Preparar el pincel (preparing the paintbrush)
IMG_7936.JPG
Antes de meter el pincel dentro del cloruro de cinc, hay que asegurarse de que este no lo va a disolver. Para eso, es fácil cortar unas pocas cerdas, pegarlas con cinta adhesiva a la punta de un alambre y sumergirlas rápidamente en la solución. Sacarlas y observar durante unos segundos si se mantienen enteras. En caso contrario, descartar el uso de ese pincel y conseguir otro. La mayoría de los plásticos servirán.

Sea que el pincel tenga o no mango metálico, hay que tomar alguna precaución para que la corriente que vamos a utilizar llegue lo más cerca posible del extremo de las cerdas. Yo utilicé un trozo de alambre negro, enrollado en el mango metálico y que llegó hasta más o menos media pulgada del extremo.

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Before putting the brush into the zinc chloride, make sure that this is not going to dissolve it. For that, it's easy to cut a few bristles, tape them to the tip of a wire and quickly immerse them in the solution. Take them out and watch for a few seconds if they are kept whole. Otherwise, discard the use of the brush and get another. Most plastics will.

Whether the brush be with or without metal
handle, take any precautions for the current that you will use comes as close as possible to the end of the bristles. I used a piece of black wire, wrapped around the metal handle and reached about half an inch from the end.

Step 5: Preparar la fuente de alimentaci�n el�ctrica (preparing the DC source)

Yo usé como mesa de trabajo un trozo de chapa de hierro, al cual fijé la pinza negativa del cargador de baterías. También se puede fijar la pinza directamente a la pieza a galvanizar.

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I used as a work table a piece of iron sheet, which attached the negative clip from the battery charger. It can also be attached directly to clamp the piece to be galvanized.

Step 6: Preparar la pieza (preparing the piece)

Hay que remover el óxido de la pieza, de otra manera el cinc quedará por encima y no será efectivo. Yo puse la pieza en el tornillo de banco y le apliqué el cepillo rotativo de acero colocado en la amoladora. Como la pieza estaba muy pero muy oxidada, hubo puntos en los cuales quedó óxido por más que me esmeré.

Ignoro si es posible o conveniente proceder a fosfatizar la pieza antes de galvanizarla. Yo podría hacer la prueba, pero tal vez haya que esperar meses antes de poder apreciar alguna reacción negativa. Por tal motivo, me limité a hacer una remoción mecánica del óxido.

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Must remove the oxide of the piece, otherwise the zinc will go above and not be effective. I put the piece in the vise and applied the rotating steel brush placed in the grinder. As the piece was very, very rusty, there were points at which oxide was more than I did my best.

I don't know if it is possible or convenient to phosphate the piece before
galvanize it. I could do the test, but may be have to wait months before you see any negative reaction. For this reason, I just make a mechanical removal of the oxide.

Step 7: Galvanizando (galvanizing)

Picture of Galvanizando (galvanizing)
Conectar la pinza positiva (generalmente señalada con rojo) al mango del pincel, cuidando de que haga contacto también con el alambre que llega cerca de la punta de las cerdas. Mojar el pincel en la solución de cloruro de cinc, encender el cargador de baterías y pincelar lentamente la pieza. Cuidar de que el alambre agregado en el paso 4 no toque la pieza, porque eso haría un cortocircuito con su correspondiente chispa. No es peligroso, pero puede producir un recalentamiento del alambre y/o del cargador.

Si la fuente de alimentación es un cargador con amperímetro, asegurarse de que al pincelar la pieza se mueva la aguja, lo cual indica que hay circulación de corriente. De otro modo, es que el circuito se interrumpe en algún lado. Esto puede ser porque la solución no llega a mojar el alambre, o bien porque alguna de las pinzas no hace buen contacto.

Inmediatamente se podrá apreciar que el cloruro de cinc va depositando una capa de cinc en la pieza, como si se tratara de una pintura. Al mismo tiempo se observará una ligera efervescencia en la punta del pincel. Si la temperatura se eleva demasiado, es que estamos aplicando demasiada corriente. Eso no molesta, mientras la temperatura no sea tan alta que resulte difícil manejarla.

No confiarse en esa primera capa de cinc, porque aunque se vea de un perfecto color gris, es sumamente delgada y no resistirá la humedad ambiente más que unos pocos días. Es necesario pasar el pincel muchas veces por cada lugar, para que la capa adquiera un grosor confiable. Esto queda a criterio de cada uno, depende de la importancia de la pieza a proteger. En mi caso, tratándose de una demostración, no me esmeré demasiado. De todas maneras, estuve unos 10 minutos insistiendo, por lo que estimo que esa vieja llave oxidada que alguna vez desenterré del suelo va a durar unos cuantos años más.

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Connect the positive clamp (usually marked with red) to the brush handle, making sure it contacts also the wire that comes near the tip of the bristles. Dip the brush in the zinc chloride solution, turn on the battery charger and brush slowly the piece. Ensure that the wire added in step 4 does not touch the piece, because that would short-circuit producing the corresponding spark. It is not dangerous but may cause overheating of the wire and/or charger.

If the power supply is a charger with ammeter, make sure that when you brush the piece the ammeter hand moves, which indicates the current flows. Otherwise, is that the circuit is interrupted at one side. This may be because the solution does not soak the wire, or maybe some of the clamps does not make good contact.

Immediately you can see that the zinc chloride deposites a layer of zinc in the piece, as if it were a painting. At the same time a slight effervescence will be observed at the tip of the brush. If the temperature gets too high, is that you are applying too much power. That does not bother, while the temperature is not so high that it is difficult to handle.

Do not rely on that first layer of zinc, because even if you see it a perfect gray, it is extremely thin and will not stand the humidity more than a few days. It is necessary to move the brush many times over each place, so that the layer thickness acquire reliable. This is at your discretion, depending on the importance of the part to be protected. In my case, being a demonstration, I did my best too. Anyway, I was about 10 minutes insisting, so I think that that old rusty wrench once dug up from the soil will last a few more years.

Step 8: Finishing (terminando)

Picture of Finishing (terminando)
Una vez terminado el trabajo, es necesario guardar cuidadosamente lo que queda de la solución, si es posible indicando su peligrosidad para prevenir accidentes, y lavar tanto la pieza como el lugar donde se realizó el trabajo.

La solución de cloruro de cinc puede ser ventajosamente usada para soldar con estaño, aplicada previamente en el lugar donde se va a soldar. Esto es útil sobre todo para soldar piezas relativamente grandes, como chapas por ejemplo. Para electrónica no tiene mucho sentido usarla, porque el alambre de estaño ya trae en su interior resinas que cumplen la misma finalidad.

Quiero terminar repitiendo lo que dije al principio: NO HAGA ESTO SI USTED NO ESTÁ FAMILIARIZADO CON EL MANEJO DE ÁCIDOS o materiales peligrosos.

En caso de salpicadura, lave con abundante agua. Puede aplicar también una solución de bicarbonato de sodio para neutralizar el ácido.

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Once the work ends, is necessary to keep carefully the remainder of the solution, if possible indicating danger to prevent accidents, and clean both the part and the place where the work was done.

The zinc chloride solution can be advantageously used for soldering tin, previously applied in the place of soldering. This is particularly useful to braze relatively large pieces such as plates for example. For electronics it makes little sense to use it, because the tin wire brings inside itself resins that serve the same purpose.

Let me conclude by repeating what I said earlier: DO NOT ATTEMPT THIS IF YOU ARE NOT FAMILIAR WITH THE OPERATION OF ACIDS or hazardous materials.

In case of splashing, wash with
generous water. You can also apply a solution of baking soda to neutralize the acid.
databoy2 years ago
Why anyone would make a dangerous back yard electroplating contraption bamboozles me.

The electroplating process demonstrated in the Instructable is not a viable, durable, long term, corrosion resistant solution.

There is a big difference between galvanising and zinc plating. Zinc plating exposed to the weather will corrode very fast. It is a better solution to spray paint the steel with a weatherproof epoxy paint.

Commercial zinc plating involves the electrolytic application of zinc by immersing clean steel parts in a zinc salt solution and applying an electric current. This process applies a layer of pure zinc that ranges from a few microns on cheap hardware components to 15 microns or more on good quality fasteners. Technical and cost issues prevent the economical plating of components with heavier coatings.

Most industrial steel posts are hot dipped galvanised. In an industrial situation where hot dipped galvanising is welded, the weld is painted with a cold galvanising paint. The cold galvanising paint is just as if not more durable that the hot dipped galvanising.

Weather exposed galvanised posts should be painted at the ground level because the atmospheric moisture and the soil will corrode the galvanising at the soil contact point.

The majority of good quality roofing sheets worldwide are plated with a patented process called zincalume. Zincalume is a far superior product to zinc plating and galvanising. The lifetime of zincalume is up to four times that of ordinary galvanised steel. If the zincalume steel is lightly scratched the zincalume coating reacts with the atmospheric moisture and self heals. That is why you can cut a zincalume sheet and the ends will not rust.

Colorbonding zincalume adds another protection layer to the zincalume layer.
jexter databoy1 year ago

"Why anyone would make a dangerous back yard electroplating contraption bamboozles me."

It's not bad enough to flag as a violation of the "Be Nice" comment policy, but it's still not a nice way to start a comment. I suppose you mean well, databoy, but if this one bothers you, you're probably "bamboozled" by many of the projects on Instructables, because a large percentage of them involve "dangerous backyard contraptions" that yield less-than-industrial-quality results. The fun is in the doing, the jury-rigging, the brainstorming, the re-purposing, the problem solving, the tinkering...that's what this Instructables website is about. You passed along a lot of information about industrial coatings, but almost none of it useful to the do-it-yourselfer. (I do want to learn more about "cold galvanizing paint", though. Where do you buy it?)

Like rimar2000, I'm also retired. I grew up in a time when we threw-out things a lot less and fixed and repaired things a lot more. After a long career I now have the time to do that again, and I really enjoy it. Please don't make comments here or elsewhere that belittle, and don't lecture; it tends to take the fun out of it.

Cheers.

P.S. If you want to be taken seriously, you shouldn't suggest that wrenches should be painted.  :)
rimar2000 (author)  jexter12 months ago
Thanks jexter. I agree fully with you, but I am not annoyed for the comment of databoy. Really I don't know all these technical matters, I do only the things I can, sometimes with good results and others –mostly– failed. But as you said, doing them is the fun.

In this case, a russian friend told me that in his country they use this method often, in cars and other things. I apllied it two or three times, and the result was temporary, maybe databoy is right, a coat of paint would been better.
rimar2000 (author)  databoy12 months ago
Pardon, databoy, just now I see your comment. Thanks for your data, I didn't know that.
rimar2000 (author)  databoy2 years ago
OK, thanks for your comment. I named it "electroplating" because it was an option from Google (sorry, I don't speak English).

If you read carefully my post, you will realize that I am not suggesting this method as industrial procedure or so. It is good enough for little domestic repairs. I know there are other methods, surely some of them better, but I am only speaking about THIS, in order to some persons can know it exists.

Personally, I prefer to use liquid phosphating. It is easier and safer, but I don't know which of both is better.
Hi Rimar, i have recently discovered a process that works really well for me, using household chemicals, the electrolyte is made from White Vinegar, sugar, and epsom salts, or magnesium sulphate, which was commonly used in the old days as a laxative.

Here i have placed the link, it is in english but i am sure google will do it justice.
http://home.comcast.net/%7Ert66tbird/website/index.html
The nice thing about it, is that it does not involve any serious chemicals, although, once mixed up, it does constitute a mild acid.
I live at the coast in South Africa and have made some tee's used as concrete anchors, which have been exposed to the elements for some months now, no sign of rust or degradation.
I used an old industrial computer supply which delivers 12 amps at 5 volts, works really well. Any old pc supply should be able to give you that anyway.
I really enjoy your instructables!!
rimar2000 (author)  andersonhdj1 year ago
OK, finally I found the link here: http://home.comcast.net/~rt66tbird/website/zincplating.html

You can use that method to galvanize little parts, surely it is better. But for big parts that have a little rust stain, you can't use it.
rimar2000 (author)  andersonhdj1 year ago
Thanks for your comment and praise, andersohndj, I could not find the formula in your link, may be you were wrong when pasting it. Where the zinc is in the recipe? Or is it another coating?

I think 5 V 12 A is good for a medium lapse electroplating, but not for this fast method.
Hi Rimar, the link does work, i have just checked, the info is under "Restoration tips" on the right of the screen.
I have found that useful plating takes around 10 mins with this method, obviously also dependant on the item size as well and also the proximity to the zinc anode.
What i like about this method is that it can almost be described as harmless. Here i have added extracts from the link for the recipe.


Here is the recipe. I filled the bucket with 3 liters of white vinegar. I then added 300 grams of Epsom salts and 100 grams of sugar to the solution. The solution was then stirred with a paint stick until it was all well dissolved.
4leggedman1 year ago
¿se puede usar una soldadora como fuente de energía? La pinza a la chapa, el portaelectrodos pellizcando el pincel...
Any chance one could use a common welding machine as source of energy, connecting one clamp to the metal base and the other to the brush?
rimar2000 (author)  4leggedman1 year ago
Yo creo que no sería conveniente, porque la soldadora suministra demasiada potencia. Además, hay muchas de corriente alterna, como la que uso yo, y se necesita corriente continua.
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I think it would be inappropriate, because the welding supplies too power. In addition, there are many AC, like that I use, and you need DC.
juanjomf2 years ago
Gracias,..juanjo ,desde castillos/rocha/ uruguay
rimar2000 (author)  juanjomf2 years ago
Me alegro de serte útil, hermano oriental.
farmboy792 years ago
Zinc chloride powder/crystals are available on eBay if you don't want to mess with dissolving zinc in muriatic/hydrochloric acid. Keep in mind it is still very corrosive and requires the same precautions when you mix it with water, you just eliminate one step.
rimar2000 (author)  farmboy792 years ago
Thanks for the info. I live in Argentina, maybe some drugstores here sells it.
Febigenus2 years ago
Genial. Una explicación completa. Gracias.
rimar2000 (author)  Febigenus2 years ago
Gracias a vos por el comentario positivo.
carlitos2 years ago
I learned in chemistry a rule: AAA (Always add acid [to a base]) So would adding a little acid at a time to zinc instead help in controlling the release of heat and avoid violent splashing?
rimar2000 (author)  carlitos2 years ago
Oh, I did not know that. Maybe it can prevents the splashing. Thanks for your advice.
Mr.Sanchez2 years ago
Lo vi alguna vez en Mecanica Popular una revista muy Interesante.Gracias por compartir.
rimar2000 (author)  Mr.Sanchez2 years ago
Gracias por tu comentario, Mr.Sanchez. Yo recibo el boletín semanal de Mi Mecánica Popular, pondré cuidado en revisarlo con más detenimiento. De ahí he sacado varias ideas interesantes.
Una muy buena fuente de datos...hay proyectos increibles y muy detallados.
daliad1002 years ago
That is genius.
rimar2000 (author)  daliad1002 years ago
Thanks for the compliment, but I didn't invented it!
mmiller522 years ago
The by product is Hydrogen gas....be careful.
rimar2000 (author)  mmiller522 years ago
Yes, I know, thanks for the advice.
Dr Qui2 years ago
That is a very interesting method for electroplating, I never though of brushing the zinc on.  This would be great fro re-galvanizing welds on previously galvanized items.

Is there a limit to the size of object that can be plated?

Excellent works as always :)
rimar2000 (author)  Dr Qui2 years ago
Good idea that of re-galvanizing after welding. I think there are no limits of size.

Thanks for yout comment.
Phil B2 years ago
Thank you. This is very interesting. It appears your wrench turned out well.
rimar2000 (author)  Phil B2 years ago
Thanks, Phil. I will see the result in a few months.
That spanner looks like one I once used on the metal lathe I was operator of many years ago. the one i had was completely rusted, I had it sandblasted and it came up like new, the constant coating of coolant oil never allowed it to rust from that point on and it went that nice chocolate colour that real good quality steel goes. Those old tools had real good metal in them, that one don't look to bad for having bee buried for a number of years.
rimar2000 (author)  Dr Qui2 years ago
Maybe it is your spanner!! ;)
heathbar642 years ago
As ALWAYS, very useful and informative. Thanks for sharing it.
rimar2000 (author)  heathbar642 years ago
Thanks for your kind comment.
spike35792 years ago
I always thought you had to do it in a bath over long periods of time. This seems simpler and more immediate once you have the zinc chloride.
rimar2000 (author)  spike35792 years ago
I think the bath method is far more effective, but it requires much more previous work and installation.

Thanks for your comment.
pfred22 years ago
How strong is the muratic acid? This might work well after doing electrolytic rust removal. There are instructions on this site how to do that. I've used the "right" chemical to do it but I prefer plain old baking soda.
rimar2000 (author)  pfred22 years ago
The bottle says 30/33 %. It smells strong.

Yes, it would be preferable an electrolytic rust removal, but I wanted only to show this method here.