Copper plating of lead bullets, cheap & simple

Battery acid

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A. My bullets turn out beautiful because I use a "leveler". I found a college paper which discussed using polyethylene glycol as a leveler. It sounded technical but turns out it was available at Walmart under the name Miralax. Yes it is a laxative! So...

battery acid ⇦this on eBay or Amazon [affil links] (Sulfuric acid from a battery)
Zep Root Kill ⇦[this on Amazon affil links] for copper sulphate
Miralax [adv: Miralax on eBay or Amazon [affil links] for the leveler.

Dissolve Zep in the acid until it won't take anymore.

Add two tbsp of Miralax.

Now you have a perfect bullet plating solution

A. Just a wild guess to get things started, but have you checked to make sure you are not dragging hexavalent chromium up and down the line in cracked rack coatings, or improperly rinsed barrels, or routing chrome rinsewater into the preplate rinses?

I am assuming that your supplier set you up with the preplate cycle, it looks OK except for:

Are you using a copper strike? A hot, full strength copper cyanide may not give you perfect adhesion without a strike.

How are you testing adhesion? (Do you have to work very hard to see the adhesion problem)

A. It seems to me you are going from an acid almost directly into a cyanide solution. This will cause problems. We immersion clean, rinse, rinse, weak fluoboric acid rinse, rinse, rinse, weak sodium cyanide rinse, rinse then into the copper. We don't passivate. We don't strike in our barrel operation and I assume you are barrel plating.

Great help, David. Thanks!

Regards,

A. Contact a brightener vendor who does baths for rotogravure. They include a hardening agent. McGean-Rohco has a bath called 320 or 321 that uses a hardening agent. I'm sure there must be other vendors, too.

A. Hi David. I found a reference to ASTM B319, "Recommended Practice for Preparation of Lead and Lead Alloys for Electroplating".

A. A number of years ago, I was involved with a project for the copper plating of lead bullets. I don't remember all the details, but the use of a fluoboric acid dip (followed by appropriate rinsing) was very important in obtaining good adhesion of the copper. Copper was a cyanide based process.

Trust this helps Ken Lemke

A. Hi David ,

Ken Lemke is right, the use of 5% fluoboric acid as an acid dip prior to a Cyanide Copper plate is most important to achieve good adhesion on lead based products; you cannot use either Sulfuric or Hydrochloric acids because the lead salts of both are insoluble.

Best regards

A. I have worked with lead and plated without cyanide copper plating and directly plated to bright acid copper, it works successfully, but should carefully and quick dip with current connected to hanger always, and acid dip with HNO₃.

A. Match Grade 308's? I prefer 300 Mags on a windy day, and 25-06 on a hot calm day. I've shot those rounds and the Copper still comes off in the rifling. In order for the rifling to function it must gall the bullet surface, and in so doing some of the copper is transferred to the rifling lanes. You can analyze the cleaning patches for copper and find it there. Anyway I recommend barrel plating in a finer media such as BBs. If you are really concerned you can use a rotating kiln design. This would virtually eliminate any distortion of the surface, then screen separate them. Fluoborate process. I used to barrel plate Cadmium with a Chromate conversion coating onto 20mm rounds for the navy without media and they still shot as true as 20mm can shoot.

A. John,

Many years ago I worked at an ammunition company. They manufactured ammo of most common cals. They used a tumbler barrel plating process in very hot potassium cyanide plating solution. I remember the two main hassles they had were with the antimony content of the lead, causing passivity during chemical cleaning. So be sure of that and work back. and the absolutely critical level of free cyanide in the copper strike bath. That's how they did it.

A. Hi I am not a engineer but I have been experimenting with a small drum plating setup for my personal use on 45 acp and 45 70 with mixed results not having access to cyanide I have focused on an acid type plating bath (copper sulphate ⇦this on eBay or Amazon [affil links] / sulfuric acid). My plater handles around 400 rounds at a time and while not the best bullets I have seen it does turn out usable plated bullets. The drum plater itself works great but I am not happy with the rest of the process but I am still learning. Bonding to the lead is not what it should be, and the plating is somewhat brittle. May try annealing after plating. Also I am casting from wheel weights, and other elements in the lead may be affecting the copper-lead bond. Also need to work on the pre-plating preparation. My first batch I washed in sodium hydroxide solution and got very poor bonding; plain hot water worked much better -- may try phosphoric acid wash next. I will email you pics of the plater if you wish; it would be easy to scale up to a larger size if needed. Don't be afraid to experiment!

A. Most job shops do not know how to properly prepare lead for plating, therefore the plated deposit has poor adhesion and "peels" off easy.

The process should be: Alkaline clean off the "organic soil", rinse, dip in 10% Fluoboric Acid. rinse, strike in a Copper Fluoborate Plating Solution, Rinse, Copper Plate in a copper sulphate solution to thickness desired.

Proprietary Hardeners are available from companies listed on finishing.com that will work in the copper sulphate solution.

One of the problems you may be having with your current copper sulphate solution is that fact that lead removes the 50 ppm of Chloride that is necessary for the copper sulphate Solution to work. By first striking in a lead soluble solution you will cover the lead and then the sulphate solution only "sees" pure copper.

A. I think that acid copper plating on lead is not possible.You can use pyrophosphate copper bath (or cyanide but for home use first is better and not so toxic) or you can colour your works,for example:

Brown colour for lead:
20 gm copper sulphate
5 gm potassium permanganate ⇦this on eBay or Amazon [affil links]
1 lit water

Hot immersion(70-80 °C)!1-5 min.

A. Hi, Wayne. Some people believe that some lead objects of the correct shape can be successfully copper plated via a heavy plating that sort of shrinkwraps around them for adhesion. I believe it can work in some limited cases because the ironwork of the William Penn city hall building in Philly was copper plated that way more than a century ago.

But the general case is that you need to pretreat lead in hydrofluoric acid (the single chemical which probably most frightens trained professional platers) then plate with cyanide-based copper solution (a terribly powerful instantaneous-acting poison). Don't even think about using either of these in a hobbyist environment.

But please don't post in the abstract because you might possibly slide by plating some things in some cases with that shrinkwrap approach, but in other cases you'd be doing nothing but wasting your time: What exactly do you wish to copper plate and why? Thanks.

A. There is a mechanical process for plating copper on lead projectiles. This involves no cyanide and no electroplating. It is a variation of mechanical plating and uses a special technique to get a uniform, bright, adherent copper deposit.

Thanks Arnold.

Mechanical plating sounds like it could sometimes be the way to go.

Regards,

A. I don't think you're going to be able to accomplish what you want. I used to plate lead bullets for an industrial munitions company. We used a fluoborate based acid followed by a heavy coating of cyanide copper. This is not a venture for the hobbyist.

Walnut Shell blasting media

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A. Craig,

The only way I have been able to get near polished bullets is:

1, as soon as I remove them from the plating, I hand dry them.
2, then using Cracked walnut dump them in my tumbler ~1hr.
3, then using corn cob and Dillon bullet polish, tumble ~1hr.

The bullets may not be as high a shine as factory but they do look good.

You could use rice for the first tumble if you do not wish to buy the walnut. It is cheaper but will need a bit longer in the tumbler.

Good Luck
david

A. Someone asked how to buff his plated bullets. I wonder if a swage die would help you. I have found links that led me to eBay where you can buy a die that will fit on a Rock Chucker that will swage the entire bullet.

A. I've been researching this thing for a while, and decided that while it seems cool to do, it's a lot easier to use a copper gas-check and a good bullet lube. A lot of leading comes from hot loads burning against the base of the bullet. keep velocities around 1700 FPS or less, and use a good lube, like glycerol monostearate (I found this by accident. It's used as an antistatic treatment for fabrics. It is stable at very high temps, and acts like a hard wax. Melts at 140 °F.)

I digress. Your solution should be made with copper sulphate. It's called "blue-stone". It's used to kill off algae in small ponds, or it used to be. Saturate the copper sulphate into distilled water (mix until the bluestone won't dissolve any further).

In a jar I took clean plumbing pipe scrap and covered it with concentrated sulfuric acid, and allowed that to saturate also.

I made a little tray of 10 Ga. copper wire for 25 bullets in a square 5" on a side suspended like a trapeze. I used a small plastic tub about a one quart size for the solution.

I used 20 Oz. copper sheet as the donor electrode. According to my reading, you need at least one square inch of anode for each square inch of surface to plate, so I just went with 25 square inches formed in a square ring around the perimeter of the tub. The solution is made by taking the saturated copper sulphate and adding the sulfuric acid solution in with a dropper 'til the pH reads (you need litmus paper for this) 2.0 or there about. Mix it in the tub.

Prep the bullets: I used straight muriatic acid ⇦this on eBay or Amazon [affil links] to clean the bullets. I put them on a plastic tray made like the plating tray and let them sit for 10 min. and then dunked them up and down, and let them sit some more, for about an hour, till they're all dulled out. Then dump the acid and fill with distilled water. Rinse the bullets and then let them sit in the distilled water until you're ready to plate.

Power supply: The big boys use expensive power supplies that can supply high current at low voltage. I started with one bullet and one alkaline battery. Not good. I finally made a rack to parallel 25 1.2 V NIMH rechargeable batteries. That's 50 amps at 1.2 volts, but the current drops off quickly. 1.2 V adds material and as the voltage nears 0.4 V the plating gets finer.

Place your prepared, dunked bullets on the plating rack, dunk into the solution and hook 'em up! Raise the rack up and down in the solution every 10 minutes or so and go watch TV. As the volt meter shows the batteries to be about flat (I used a cheapie DVM), pull a bullet and measure it. You should get 2-3 mils of plating. Remove, wash and buff. Had enough work yet?

Problems: I found that the bullets don't plate where they touch the rack. I may try a new rack with nibs sticking up so that I could drill a hole in the point and mount them upside down. I also found that the plating depth was greater where the bullets were closest to the anode, and I'm not sure if that was strictly because of proximity, or if I did not agitate the solution enough. The bullets are murder to squeeze through a sizing die. I wound up lubing them to get them through the die. Pure soft lead helps, but you throw away a lot of bad bullets because pure lead does not fill out the mold well. I saw no big improvement in accuracy at the end of the day. If I was going hunting I would use commercial jacketed bullets and work up the most accurate load, giving power a back seat within reason. That's all I got.

Some great responses and very helpful I have been plating a few bullets and have had acceptable results with acid copper solution in all areas except adhesion which is poor; plating looks great but isn't bonded well. I use a homemade barrel plater made from 8" PVC and it will do about 500 at a time and eliminates the problem of unplated areas on the bullets, plus requires no action once started
Will try the muriatic acid prep described in a previous post.

A. Rich Thompson

I use a simple setup as Richard P, above. I use Root Stop copper sulphate and distilled water. Same saturated solution with root stop and leave some of the undissolved crystal at the bottom to insure a saturated solution.

I take about 1/4 oz from my auto battery to get a pH of about 2, acidic enough to make the solution a good conductor. Just be very careful as the sulfuric acid will do damage and burn you.

Casting the bullets, I do a water drop from the mold and transfer them from the water into a coffee can with Colman fuel. This will prevent oxidation of the lead and can be stored for long periods without danger of acid.

Plating, I use TSP (Tri Sodium Phosphate) and warm water [saturated solution] in a can to clean the bullets of any oils. This is safer than using acid. We used this in the subs to clean most anything. But it is a bit harsh on your hands, so wear gloves.

Plating Bath: I keep the bath at ~110 °F and move the solution around using a miniature pump. I used a desktop fountain waterfall.

Using a simple 110VAC to 24VDC center tapped transformer [110V in 24V center tapped 2A out} and a full wave diode bridge, I control the current using a 50 Ohm wire wound ceramic resistor with a wiper terminal. If you set it at ~20 Ohms you will have ~1A with 24 VDC. I found the resistor at a locale electronics reclaim shop for ~$5. you might find the transformer and diode pact there as well.

I use a sheet of copper on the bottom and copper wires across the top of a cheep glass cooking dish that is about 2" high edge and plastic tube to move the solution around through the pump.

To hold the bullets, I use enameled copper wire [again from the reclaim store] The enamel on the wire is impervious to most any solvent I can find at the hardware store, including some acids. So by cutting the wire at an angle, I have a sharp point of bare copper wire to make electrical contact.

The wire looks like a "C" but at sharp angles. The angular cut section is point up and bends 90 degrees. the bottom runs the diameter of the largest bullet you intend to plate. Then bend it up 90 degrees to a height of about 2x that of the tallest bullet. Now bend it down at ~45 degrees until it lined up with the sharp edge, now bend it up inline with the sharp tip.

The top of the hanger, I scraped off the coating and form it into a loop as a hanger. This loop makes electrical contact with the copper wire.

You may want to add a little strength to the copper wire. Simple, just place one end in a vice and on a long run, using vice grips pull the wire until you feel it stretch a little. This will add more spring strength and give the formed "C" some spring action.

Now place the bullet with the bottom against the pointed section and the head at the sharp bend at the top. If the bullet does not hold fast, just pull the top at 90 degrees to the bullet a little and it should hold.

Drop it onto the copper wires, turn on the pump and power to the DC supply and it takes about 20-30 min to plate 0.002" - 0.003" at 1 A current.

If you want more info, let me know and I will answer your questions and even send you a photo to help explain the above.

By the way, I am an electrical engineer and shooter.

david

A. Hi, Mike; hi, Richard. We have an online article here on Barrel Plating which will show you the basics. Most commercial plating barrels use "danglers" -- heavy insulated cables that come down the hanger arms of the barrel, and through a center hole in the barrel, then have heavy stainless steel knobs attached to their ends, so they and the parts remain at the bottom of the barrel as it rotates.
And, yes, the cathode is the "plate-ee", so those cables are attached to the negative pole, the cathode :-)

Good luck!

Regards,

A. Hi, Stan. Cyanide is not banned in the USA, although it may be banned in South Africa. But the fact that this very powerful poison is available to trained workers in industry doesn't necessarily mean that a hobbyist can easily get it ... let alone use it.
Lead is very hard and dangerous to plate really properly: it requires hydrofluoric acid to activate, which is about the nastiest chemical the plating industry deals with. As hobbyists have reported here, the processes they use offer no adhesion and they are relying on sort of a "shrink wrap" effect to hold the plating on.

We don't presume to censor people and we print all suggestions ... but the internet is a giant one-room schoolhouse, and it certainly doesn't mean we advocate hobbyists using chemicals designed for use by people in an industrial setting, trained in hazmat, wearing proper PPE, and with trained help available.

Regards,

A. Hi Martin. Proper power supplies have become really cheap these days. It just doesn't make sense to use a wrong power source.
Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Hi Daniel
First the simple answer. Nothing happens to the sulfur. You can look on the sulfuric acid as a carrier for the copper ions. copper sulphate baths can operate for years with very little attention and the copper is replenished from the copper anode.

However there are a couple of things to consider.
Lead always has an oxide film on the surface that must be removed to ensure adhesion. For this we usually use fluoboric acid that is not easily obtained by an amateur.
Secondly, lead sulphate is highly insoluble so plating from a sulfuric acid solution is not practical. Fluoborate copper processes are made but unlikely to be available to you and standard copper cyanide processes are not for home use.
Have you considered the problem of barrel plating heavy but relatively soft bullets. Even if you cast a hard alloy the sharp edges of the base are liable to damage and that will seriously affect accuracy.

A. Hi cousin Nico. We appended your inquiry to an existing thread on the subject to offer you some perspectives, cautions, and food for thought. As for how much current you will need, please see our Introduction to Faraday's Law to help you understand that the amount of plating that will occur is directly proportional to the current you apply and the length of time you apply it: essentially you must move 2 electrons through your rectifier and wiring for each atom of copper you want to move from the anode onto your cathode.

But you are not free to use really high amperages and short times because the copper ions can't move through the solution that fast. Probably somewhere around 20 amps per square foot of plating surface area is your limit. Voltage is just whatever is necessary to drive the desired amps -- probably somewhere between 4 and 10 volts depending on the geometry.

Luck & Regards,

A. Lead sulphate is insoluble. Therefore if you try to plate lead bullets in a copper sulphate bath you will achieve only unacceptable adhesion.

A. Hi Tom. Thanks for your response which is certainly correct from a conventional standpoint.

But some bullet platers seem to be claiming that they successfully plate on bullets from copper sulphate, and I tend to believe the claims because I was involved in the replating of the ironwork on Philadelphia city hall's William Penn Tower, and the very heavy copper plating (generally about half the thickness of a penny) had zero adhesion but had lasted a century (although not without damage).

Much but not all of the underlying iron and steel was badly corroded because once the plating was perforated, galvanic corrosion occurred, but it apparently lasted many decades before trouble set in. The copper on the tower ironwork stayed in place, even after some of the iron was badly deteriorated, by sort of a shrink-wrap effect rather than by adhesion to the substrate :-)

Luck & Regards,