Sciencemadness Discussion Board - Electroforming Copper Liners

Electroforming Copper Liners

gnitseretni - 2-7-2010 at 06:56

I managed to electroform two copper liners. I did a quick writeup on it (with lots of pics) that shows how I made them. Thought I'd share it in case others would like to try it

Attachment: Electroforming Copper Liners.pdf (281kB)
This file has been downloaded 3297 times

quicksilver - 2-7-2010 at 13:25

It's a unique and impressive idea. And from the amount of times it's been downloaded, people are taking a look. The major issue in a SC is the liner. With a utilitarian format like this the concept could broaden.

bbartlog - 2-7-2010 at 17:13

Nice pictures and idea. Consider trying to apply a conductive coating of some sort so as to make separation trivial (graphite?), but it might well just provide one more way to goof things up.
The blisters may be controllable by adjusting the current level, but given your power supply this might not be practical.

gnitseretni - 2-7-2010 at 18:22

Nah, it came off with hardly any effort at all, so no graphite coating needed.

Btw, I found out that those "blisters" are called "nodules", for which the cause could be many things from what I've read.

One cause could be that I didn't have my anode inside a "bag", like commercial platers have, to keep particles out of the solution. Another cause could be that I didn't agitate the solution, which again commercial platers do. I also didn't cover my container to keep dust and what not from getting in my solution

I also didn't use a suppressor, which according to a patent I found "tends to give a more uniform current distribution over the surface of the substrate and allows the metal deposition to proceed with a global leveling."

I also didn't use brighteners, levelers, wetting agents and whatever else they use in there. But I'm not in the business of making liners, so I don't mind having to clean up the few I do make

EDIT: That patent mentioned several examples of suppressors, and one was polyethylene glycol, which is sold as Miralax at Walgreens. $7 for 4oz. Thing is you only need to use 200ppm

[Edited on 3-7-2010 by gnitseretni]

[Edited on 3-7-2010 by gnitseretni]

gnitseretni - 3-7-2010 at 09:50

I just took a better look at my aluminum cone and it got attacked by the plating solution, right above where the copper was forming(at the surface of the solution). It etched a groove all around, about as deep as it is wide.

Next time (with a new alu cone) I'll submerge the alu cone a little more than what I want plated and plate for like just a minute or so. Then I'll slightly raise the cone out of the solution a little bit and continue plating. That should prevent it from happening again.

12AX7 - 3-7-2010 at 21:52

Have you tried thiourea (contained in Tarn-X)?

Good to know copper releases easily from aluminum.

Tim

gnitseretni - 4-7-2010 at 07:41

Haven't tried thiourea yet.

First I'd like to try to get some agitation going and place my anode inside a "bag" and see if that changes anything. I'm thinking/hoping it will, because every time I lift my anode out of the solution, this copper sludge runs off and some of these particles may cling to the cone; and because I don't use additives, it just plates over these particles forming nodules; the use of additives slows down the plating on high spots, so the rest can catch up. Well, that's if I understood right.

Mr. Wizard - 4-7-2010 at 09:08

I read somewhere that Tarn-x was supposed to improve copper plating too. I was copper plating some 250 grain lead castings using a rotating plastic drum in a copper sulfate solution. The rotation was to eliminate the dendrites or fingers that formed when the plating was stationary. I had good results, but the copper had a flat reddish color to it. In an effort to improve the finish and smoothness I added some Tarn-x to the solution and got a yellow cloud of crap in the tank, and eventually a dark precipitate in the bottom that ruined the plating and required a thorough cleaning. I'm guessing the yellow was sulfur and the dark precipitate was CuS.

What results have you had with Tarn-x 12AT7? How did you use it? I happen to have some of the polyethylene glycol powder too.

Obviously copper deposits where the current flows. The current will flow the most where it is closest to the copper anode. That's why dendrites or little fingers of copper would form on my castings, then continue to grow preferentially , as they formed the shortest path.

[Edited on 4-7-2010 by Mr. Wizard]

Aqua_Fortis_100% - 4-7-2010 at 09:13

Very nice write up indeed..
Simple, cheap and giving good results..
Now, good SCs are much more affordable to home experimenter!

gnitseretni, I cant find these aluminium "bullet caps" on hardware stores.. There are similair products to this?
At leats I can try to make a massive Al cone similair of this with green sand box, if I could not find anything similair on market...

Anyway, thanks for that info!

gnitseretni - 4-7-2010 at 09:45

Quote: Originally posted by Aqua_Fortis_100%

There are similair products to this?

Not that I know off. They were cast aluminum, maybe you can cast your own?

quicksilver - 4-7-2010 at 10:54

The idea is a damn good one because it's easy to build on. For "forms" aluminum or otherwise, you can look to chain-link fence "caps", decorative cups or things of that nature. You only really need one "good" one with enough volume to allow trimming, etc. Ideally, you'd collect several in various angles or you may choose to experiment with the geometry as a whole.

Contrabasso - 4-7-2010 at 12:25

Copper plates very nicely from a pyrophosphate solution. Stainless steel doesn't adhere plating very well, so some stainless articles may make good formers and separate easily. Alternatively drill a fine hole at the point and temp bridge it with wax, then use an air line to blow the copper off.

Also a conductive release agent could be made from graphite and a grease or oil.

http://www.pfonline.com/articles/pfd0014.html

[Edited on 4-7-2010 by Contrabasso]

gnitseretni - 4-7-2010 at 14:00

Thanks for that link.

"low chloride will also cause treeing and nodulation of the deposit."

Uh, could someone pass the salt please

Contrabasso - 5-7-2010 at 03:02

Yes copper plates easily, with a little research an adequate plating coat can be applied without proprietory brighteners. I's prefer to plate using a supply capable of a few amp though. Put the same amount of metal on in much less time. The method of getting the forming OFF is good too.

Added
A good coat of lacquer on the cathode, exposing only where you want metal to deposit may help the surface level etching. Or the former will start to grip subsequent products.

[Edited on 5-7-2010 by Contrabasso]

12AX7 - 6-7-2010 at 20:58

I only ever saw a white or blue precipitate when adding Tarn-X, which I presume arises from the soap. (Ingredients listed in MSDS are thiourea 5-7%, sulfamic acid 3-5%, disodium cocoamphodipropionate <1%, methanol <0.05%, balance water.) There is no sulfur compound; perhaps you had some Cu(I) in solution which precipitated?

A little chloride is usually also prescribed. This tends to form a white scum of CuCl on the anode, which probably causes it to dissolve evenly.

I've gotten reasonable results with Tarn-X. Instead of a knobby, crystalline deposit with poor bond, I got a strong, fairly flat, sparkling pink deposit. Though still visible, the crystals were smaller and more dense.

Tim

gnitseretni - 7-7-2010 at 05:30

My anode is black. Which, according to that article Contrabasso linked to, is supposed to happen. So maybe that white scum is from using Tarn-X. I suppose I'll find out, I got me some Tarn-X as well. If my math is right, 2 drops is all it takes.

quicksilver - 12-7-2010 at 10:17

@ gnitseretni :

THANK YOU.
I received the liner you made and it's damn nice! I wish I had a decent camera that could show the idiosyncrasies of the design. It's slightly heavier as it ascends to the cone tip and quite even (I didn't measure it finer than 1/100 via a caliper). It is really impressive and I believe it will function better than most.
I appreciate you sending me the sample; but what's more, now that I've seen them I am quite impressed with the overall concept.

Edit:
I can say with confidence that this is a more than workable concept. It's a damn good one: a real quality & unique addition. I am not sure (until I try making several of them) if they require an element of "technique" to get them looking as good as the sample, but the concept is worth learning.
There are quite a few people that say that a good cone liner is the majority of a SC. I don't know if I'd go that far but it IS extremely significant and can really make a difference. TTBoMK an energetic materiel needs to exceed a VoD of 4K to make it a viable candidate for use in a SC. I know that quite a few materials will punch a promising hole if attention is paid to detail of SC construction.
A fascinating thing would be to learn what is the SLOWEST materiel that could be made to pop a clean hole in a witness plate.

[Edited on 12-7-2010 by quicksilver]

gnitseretni - 12-7-2010 at 11:21

You're welcome, Quicksilver

I finished electroforming another cone last night. Looks quite a bit better, still not without imperfections but far better than my previous cones.

http://img251.imageshack.us/img251/8513/41868127.jpg
http://img291.imageshack.us/img291/9675/31811618.jpg
http://img199.imageshack.us/img199/4364/79664855.jpg
http://img5.imageshack.us/img5/4412/85027335.jpg

Here's a picture while I was electroforming:
http://img3.imageshack.us/img3/7489/picture004je.jpg
(The alu cone is covered in copper due to the spattering of the first agitator.)

I changed the bath composition (included some additives) plus I added agitation. I made a mechanical agitator myself, but it wasn't working when I checked on it the next morning. So I stopped electroforming and went to Petco and got me an aquarium air pump and continued electroforming.

I'll electroform another cone sometime, because that morning when I checked on it to find that my homemade agitator had quit on me, some "treeing" had formed. I don't know if that was due to the agitator quitting on me or not. It could have stopped working anywhere in between 9 the night before and 7 that morning. So I'd like to try again and see what the result will be when using an agitator that doesn't quit on me

But even if it doesn't improve, I can live with that.

Mr. Wizard - 13-7-2010 at 05:26

I saw an example of electroforming using Cerrosafe or Wood's Metal alloy which will melt in hot water. In this example the original shape was cast into plaster or some other easily used material. The Cerrosafe metal was cast into the mold to form a base for the Copper to be deposited upon, with a connecting wire added. After the thickness was correct the whole item was placed in hot water and the Cerrosafe metal recovered as it flowed out of the electroformed shell.

A quick search reveals it is $20 US for 1/2 pound to $25 a pound.

quicksilver - 13-7-2010 at 05:39

You can get woods metal in many re-loading supplier places (on-line) but I think that IS just about the best price if I remember correctly.
You should see these liners: They are impressive. If the same technique were used with a variety of metals I am fairly comfortable they would turn out OK. I'm sure you could add tin, etc. I also know that government surplus often has metal powders (tin, nickle, antimony, moly, Al, copper). There was a place in town that sold same (in pound units) from a very large container.

gnitseretni - 13-7-2010 at 06:16

I tried plating onto one of those low melting point alloys, but it didn't work for me. The copper wouldn't stick at all, it would sink to the bottom of the container. Lead is the problem. But I found some silver solder, lead free, that might just work.

quicksilver - 13-7-2010 at 06:45

I was thinking that one of the most difficult hurdles to overcome is the possible need for a variety of "cone forms".
It may be that using other elemental materials in forms may yield results (but raising the cost & complexity). The need for a dielectric form that would release the plated materiel has an element of complexity that can be challenging.

gnitseretni - 13-7-2010 at 06:52

Here's a bath composition for plating onto solder in case someone wants to try it.

http://www.larrylawson.net/plating.htm

Hennig Brand - 11-9-2011 at 08:26

I originally posted this in the unconventional shaped charge thread. It was suggested to me that this was a more suitable place to post it, so here it is.

The first picture shows some of the aluminum cone forms that were made on a lathe. The big one is 2", the next biggest is 1.25" then three are 3/4" and one tiny 3/8" form. Sixty degrees was chosen for the cones angles. I am plating one 3/4" form right now in the very crude set up shown in the last picture.

I plated a couple of 3/8" cones already because 3/8" was the only aluminum round stock I had in my junk pile. I noticed it was difficult to get the cone off of the aluminum form without damaging the cone, the form, or both (at least for small cones). In the first picture is shown what I think will be a good solution. The end of the aluminum form is drilled and tapped (the one in the plating bath is tapped for standard 1/4" coarse thread, which is what the threads are on standard hardware store 1/4" threaded rod). The short piece of heavy gauge 3/4" copper plumbing pipe in the first picture fits almost perfectly over the 3/4" aluminum form. The fender washer (large washer with small hole), goes over the other end of the short piece of pipe and the steel nut is turned with a wrench to force the copper cone off the form with very even pressure and hopefully without damaging the form or the liner. It is what is called a puller. It is possible to apply some serious pressure without damaging anything if done right.

Now I just need some short pieces of pipe that fit well over the other aluminum forms.

I am a big fan of this electroforming method to form copper cones. I just became aware of it about 2 weeks ago, but I already have a 2kg bag of copper sulfate and some aluminum forms to play with.

Almost forgot, the picture in the middle shows a variac which I use to adjust the voltage to the plating electrodes. There is a small linear DC power supply (not shown) between it and the electrodes.

[Edited on 11-9-2011 by Hennig Brand]

gnitseretni - 11-9-2011 at 09:58

Nice forms. I like the method you described of getting the cones off the forms. Let us know how it works out.

Hennig Brand - 11-9-2011 at 14:57

I just tried today to remove the cone actually, and the copper was thin at the base of the cone (close to where the plating solution meets the aluminum form). The short piece of copper pipe was also a bit too loose which caused a problem with removal. By the time I got the cone off I had damaged it quite badly. The aluminum form was also oxidized/eroded quite badly where the form met the surface of the plating solution. Oh well, it had only been plating for two days, no big loss.

I think I may have a solution to the problem though. If just the cone part of the form were exposed and well submerged below the surface of the plating solution, and the submerged sides of the form covered with an insulating material, I believe this would solve both problems. I am trying electrical tape right now. It was carefully wrapped around the forum, leaving just the cone exposed, then well submerged in the plating solution. If the electrical tape does not work, I am sure something else will.

gnitseretni - 11-9-2011 at 18:27

Quote: Originally posted by Hennig Brand

I just tried today to remove the cone actually, and the copper was thin at the base of the cone (close to where the plating solution meets the aluminum form).

That's due to evaporation. The level keeps dropping as water evaporates. The cone will be paper thin at the very top and gradually increase in thickness to wherever the level is at when you stop plating.

Add water to make up for evaporation and keep it at the exact same level it was at when you started plating and you should get a thicker edge that the piece of plumbing pipe will butt up against so you can push the cone off.

Quote: Originally posted by Hennig Brand

The aluminum form was also oxidized/eroded quite badly where the form met the surface of the plating solution.

Yup, same problems I've been having. That's usually also the only place where the cone is stuck to the form. I use a sharp thin knife and carefully pry it between the cone and the form and go round and round until it pops off. But I like your idea of using a "puller" better.

Quote: Originally posted by Hennig Brand

I think I may have a solution to the problem though. If just the cone part of the form were exposed and well submerged below the surface of the plating solution, and the submerged sides of the form covered with an insulating material, I believe this would solve both problems. I am trying electrical tape right now. It was carefully wrapped around the forum, leaving just the cone exposed, then well submerged in the plating solution. If the electrical tape does not work, I am sure something else will.

Let us know how it works out. I've tried Sharpie myself.. didn't work. (Worth a try

) I thought about using tape but thought the plating solution would probably find a way to get in between the tape and the form. If the tape doesn't work, maybe a layer of paint or varnish or something.

Mr. Wizard - 12-9-2011 at 09:02

Regarding the corrosion on the aluminum forms, be aware they might be using an alloy of zinc and aluminum for these. There is a spectrum of purity in 'white metal' alloys which are heavily recycled. Even aluminum beverage cans have a mixture of products. As the purity goes down, this admix of copper, lead, tin, zinc, magnesium, and everything that will melt gets used to form this non demanding product.

Hennig Brand - 12-9-2011 at 13:31

With all the aluminum products out there, I guess one would need to be careful that they were getting the right thing. I think that most round stock from a machine shop would have a very definite composition though. Admittedly, I forgot to ask what the composition of the aluminum round stock I purchased was.

Here is a basic description of my method for turning aluminum cones.

It is not very difficult to make a cone on a lathe. Just make sure the round stock is chucked as straight as possible, after that you can't really go wrong. As long as it is well centered in the chuck and is going around in a perfect circle, you are almost guaranteed a perfect cone shape. At the very end just take small cuts so as not to leave excessive roughness. Finally use emery cloth, progressively using finer and finer emery cloth until the form is as smooth as glass.

For making smaller forms on the lathe you can easily just use a metal file instead of a cutter, and then emery cloth. I guess you could use a file for the big cones too, but it would take much longer.

[Edited on 13-9-2011 by Hennig Brand]

watson.fawkes - 14-9-2011 at 09:06

Quote: Originally posted by Hennig Brand

With all the aluminum products out there, I guess one would need to be careful that they were getting the right thing. I think that most round stock from a machine shop would have a very definite composition though. Admittedly, I forgot to ask what the composition of the aluminum round stock I purchased was.

Most aluminum alloys in machine shops are alloyed with something: silicon, magnesium, zinc, etc. There are lots of them. The 1xxx series of aluminum alloys are all minimum 99% Al content. Alloy 1199 is 99.99% pure aluminum.

Hennig Brand - 14-9-2011 at 15:51

Thanks for the information. I remember seeing some lettering along the length of the round stock but I didn' t have a lot of choice at the time anyway (I took what they had). It sounds like what I have is probably fine.

I left the 3/4" aluminum form to plate for 3 days. This time the cone popped off very easily with a little pressure from the puller. I had to get a sleeve for the puller that fit the aluminum form better. With some help a piece of an old lamp stand was cut out to a perfect fit. Using the tape as a stop-off to shield the part of the form where plating wasn't desired and to prevent form corrosion was a big success. This is great because it is so easy to wrap a little electrical tape on before plating and remove it after plating is complete.

I have found that it is best to plate with very low current. Slower plating with low current produces smoother and more even plating. My plating bath was run for 3 days at about 50mA. My cone is only 3/4" diameter. If the cone is larger, or the surface area to be plated is larger, the plating bath will require a proportionately larger current to provide the same current density.

Anyway, here are some pictures. I am starting to get some decent results. The bottom of the cone was left a little rough for now. I may do a little more sanding later. Note that the oxidation seen on the aluminum form, in the second picture, was from the previous run without the tape.

[Edited on 15-9-2011 by Hennig Brand]

gnitseretni - 14-9-2011 at 16:31

Nice cone! Can't wait to see how it performed

Good to know the tape was a success.

Hennig Brand - 15-9-2011 at 07:41

Thanks, this is a good pastime. Once everything is setup, it is about as difficult to look after as a goldfish.

This is sort of interesting. It is a lab manual designed to help teachers run a lab on copper plating, or do a lab demontration on copper plating. It is a good introduction to the subject I would say.

Attachment: THE CHEMISTRY OF COPPER PLATING.pdf (192kB)
This file has been downloaded 3244 times

[Edited on 15-9-2011 by Hennig Brand]

Hennig Brand - 20-9-2011 at 12:48

The copy/paste below is from the following link. The whole web page is worth a read. Actually the entire web site looks quite interesting.

http://www.dalmar.net/electroforming.htm

"Trouble shooting electroforming

Two of the biggest mistakes made in Electroforming are

(1) not getting a good connection from the lead wire to the work piece. If you are making a piece of jewelry, you should glue a finding on the piece before you start. When applying the conductive coating, make sure that you cover the glue and part of the finding to make sure that you have a good connection. If you have a work piece that is not jewelry, you should take a piece of copper wire
and bend about 1/4 inch of the wire at the end to a 45 degree angle. Glue
this end of the wire to the work piece in an inconspicuous place like the back
of the piece. Again make sure when applying the conductive coating that you
cover the end of the wire and glue to get a good connection. After you have
finished the copper stage you can clip off the wire and file it smooth. For
your next finish over the copper you can just wrap the wire around the
piece. Don't wrap the wire around the piece when you are electroforming in
copper. If you do this, more than likely you will get a bad connection and the
wire will become part of the work piece due to the thickness that you are
growing. A sure sign of a bad connection between the wire and the
work piece is the crystallizing of the copper on the copper wire with
no growth on the work piece.

(2) The biggest mistake made in electroforming is not setting the machine
to the proper amperage for the area that you are electroforming in the tank
or using a rectifier that is too powerful and won't adjust to the proper
setting. 90% of the technical calls to our company about electroforming are
due to this mistake. You must set the rectifier to 1/10 of an amp per square
inch of metal surface that you are electroforming in your tank with the
copper solution. If your setting is too low the copper will build-up with
a shrimp color on it. If the setting is right it will come out like a new
penny. If the setting is too high you will get a dark color and a
bumpy finish that looks like fried chicken. Also make sure that the size
of your anodes is equal or greater then the total of surface that you are
electroforming in the tank."

I included a picture with basic formulae for cones. The surface area formula would be useful when trying to determine the proper electrical current to use when electroforming.

Copper Electroforming & Troubleshooting

Hennig Brand - 3-6-2012 at 16:01

This is the best write-up I have seen so far. The whole thing is worth a read, but it also has quick reference tables with lots of good information. About half way through there is an acid copper troubleshooting guide which is particularly useful.

Attachment: Copper_Plating.pdf (187kB)
This file has been downloaded 1849 times

[Edited on 4-6-2012 by Hennig Brand]

SjeefOne - 4-6-2012 at 00:07

Thnx for the doc, looks like a valuable read!

I've been starting some electroforming experimenting as well recently and thought I'd share some of it.

The pdf from gnitseretni is what I kind of used as a guide as of how to set my cell up.

For my anode I've used copper brake line bent into a coil shape, my former is turned from aluminum, this particular one is 24mm with a cone angle of 60 degrees.
The electrolyte is a solution of about 150g of CuSO4 and 25ml of H2SO4.

I found that it is indeed important to keep the voltage low, at high(er) voltage the copper will form way to quick and becomes a brittle layer which is easily wiped off.

At low voltage (below cone was formed at around 2V and .5Amps) the layer builds quite nice and dense. However i'm now facing problems getting the cone of the former. I'm therefore am having some new formers made and a puller as well, which I hope will help get the cones off

My first cone.

hissingnoise - 4-6-2012 at 06:49

You could check the coefficients of expansion of both metals.
If copper has the higher rate, heating the cone with a heatgun might shift it ─ if aluminium has the higher rate, cooling it in a freezing mixture might work . . .

SjeefOne - 4-6-2012 at 07:24

Looks like Al has a higher coeficient then Cu..
I'll put my former in the freezer see if anything gives.

Hennig Brand - 6-6-2012 at 16:53

I just recently got back into electroforming and things have not gone perfectly smoothly. I realized after about a week of messing around that I had gotten soldering flux into my plating bath which caused a lot of problems with the plating process. Copper was "burning" easily, even with low current and would not plate in a smooth layer. I started over with fresh electrolyte, but a little flux must have been on the anodes still. The resultant cone is the one in the pictures. It electroformed much better, but not perfectly smoothly and needed to be filed and sanded down on the lathe.
I thought I was doing a good thing by soldering the connections on my electrodes, but I actually ended up poisoning my plating bath. The flux should have been carefully cleaned off after soldering, or soldering should not have been done at all.

I have also had problems with the older lathe that I have been using. It is not very precise anymore and has been making aluminum cone forms that are not entirely symmetrical.

At the same time the electrolyte was changed, the sulfuric acid was changed from drain cleaner to battery electrolyte. There are a lot of impurities in drain cleaner, and it is not always the same impurities from brand to brand and from lot to lot. I figured that battery electrolyte would need to be fairly pure to function properly in a battery.

An aquarium air pump and bubbler were used for agitation. This was a bit messy, but manageable. Electrical tape was used as a stop-off to prevent the aluminum form from being oxidized which worked very well. Careful application of the tape also controlled exactly where the form was plated, and allowed the area on the form being plated to be submerged well below the surface of the plating bath.

I have found that a current density between 0.06A and 0.08A per square inch is optimal for my setup, any more results in burned copper. Without brighteners and other additives the goal should be to achieve a smooth, even coat of salmon colored copper. Without brighteners salmon colored copper is normal right out of the bath. The copper can later be polished to a new penny look after plating.

The power supply in the picture is a switching supply which was taken out of a large photocopier about 10 years ago. The box with the dial on it has a large bank of huge 200-300 watt power resistors in it. It goes from 0 to 33 ohms in increments as the dial is turned. In order to get resistance values between increments an external resistor must be used. The white ceramic inline resistor in the picture is rated for 5 W & 2 ohms. Measuring the voltage drop across this resistor is a quick way of determining the current flow through the plating bath without interfering with its operation (I = V/R).

A much overbuilt puller was made which removed the cone with ease after sanding and polishing was completed on the lathe.

BTW, the cone in the pictures is 1.5 inches in diameter.

[Edited on 7-6-2012 by Hennig Brand]

froot - 6-6-2012 at 23:00

A chap I met recently used to make these for the millitiary. His formers were parabolic shaped 'trumpet' like cones made from stainless steel and pretty much the same size as the ones you guys are making here. The copper liners he electroformed were about 0.5 mm thick and uniform all over.
I would imagine that stainless steel does not passivate like aluminium does ensuring good initial plating performance is less chance of it contaminating the bath. A good source of stainless would be in the form of stainless steel bolts from the local hardware which you could turn into cone formers.

Hennig Brand - 8-6-2012 at 15:05

I have wanted to try stainless steel for a while. I actually purchased some 1 inch SS round stock about a week ago, but then I stuck with the aluminum forms for the time being. The nice thing about aluminum is that it is so much easier to work. I am going to have to try stainless though, it may be worth the extra effort.

NeonPulse - 6-2-2014 at 20:20

Quote: Originally posted by gnitseretni

I managed to electroform two copper liners. I did a quick writeup on it (with lots of pics) that shows how I made them. Thought I'd share it in case others would like to try it

what a great idea! i have one in the plating bath right now. i got the form from ebay a nice Al fence cap that was slightly flat at the tip but there was excess n the tip so i could file it to a point. i followed gnitseretni's PDF with an alteration to the anode and slightly stronger power supply. and it is working a treat. great idea! your process has certainly won me over! cant wait to test its performance though. i expect it it to work very well.

froot - 6-2-2014 at 22:26

I know this is a little late but to ensure uniform density and thickness of the liner you should rotate the cathode slowly in the solution. Additives called 'brighteners' are used to give a smooth shiny plate which indicates a good high density high strength form. I would expect any porosity to negatively affect the performance of the liner.

packetforger - 21-2-2014 at 05:48

Has anyone checked if the purity of copper metal used affects the finished product? I would imagine having the copper (anode?) made of pure copper foil, and "around" the anode (as in, cylindrical anode, with the cathode in the center of it) would help with giving excellent results.

As would using high quality coppersalt and acid without nasty gunk contaminants (boiling drain-cleaner grade sulphuric wiith activated charcoal, followed by filtration through glass wool works good to decolourize it of organic? contaminants).

I will have to aquire some barstock and try this out, am very curious about the mechanical properties of the formed copper piece. Could be interesting for making small conductiveparts for RF stuff!

Vlad1111 - 12-10-2014 at 05:56

Hi

I`ve read really much about copper plating but even after several tries, the results aren`t that good

At the moment i try to copperplate a plastic cone* (3 layers of L100 conducting silver) this a 4.8V-400mA chellphone charger.
Standoff between the anode and cathode is around 1cm (~1/3 inch) at around 16°Celsius (60.8°F)

*radius ~3cm (~1inch) hight is around 5.8cm (~2,2inch)

The process is working for one day now and ive seen that the surface of the plated cone is extremely rough.
most of the cone is a extremely thin layer. the surface is exactly like sandpaper

i tried to plate under the exact conditions an smaler cone* (stainless steel [without L100] and the surface was so smooth you could barely see it was plated in the plating solution)

*radius ~1.5cm (~1/2inch) hight is around 4cm (~1 1/3inch)

Plating solution: 500ml water - 100g CuSO4.6H2O - 25ml H2SO4 - no NaCl

so, can anyone tell me what am i doing wrong?
im getting desperate :mad:

Oscilllator - 20-10-2014 at 16:27

Quote: Originally posted by Vlad1111

Hi
I`ve read really much about copper plating but even after several tries, the results aren`t that good

At the moment i try to copperplate a plastic cone* (3 layers of L100 conducting silver) this a 4.8V-400mA chellphone charger.

Quote: Originally posted by SjeefOne

Please take 30 seconds to read the thread before posting. It isn't that hard.

dangerous amateur - 25-2-2015 at 08:28

Do you guys think it is necessary to agitate the solution?

And how about the target being placed slightly asymmetric to the anode, will this cause the plating to become uneven?

It seems to me that the electrolyte is so conductive that it does not matter, but I would like some other opinion on that.

Fulmen - 25-2-2015 at 09:03

Current density will affect deposit rates.

Camroc37 - 25-4-2016 at 18:55

Quote: Originally posted by Hennig Brand

I originally posted this in the unconventional shaped charge thread. It was suggested to me that this was a more suitable place to post it, so here it is(...)

Could you explain a bit more about this setup? Is the Cathode running from the top right in the picture and the anode under the cone? Thanks.

[Edited on 11-9-2011 by Hennig Brand]

XeonTheMGPony - 29-4-2016 at 07:46

I have don tones of copper plating, I once copper plated cardboard! Why? Because I thought it would be funny! (It was!)

Trick, gently circulate your tank solution, makes for a very even coat, current control is every thing So is voltage, if you can't control both you can end up with a head ache! Use an all copper tank, do what you have too but the better the tank is clad the better the plate.

I used a bubble to keep the solution moving during plating.

Graphite is a great starter! for the paper plating I started off very slow to get a thin even copper coat then I drove the voltages up slowly to get the proper current flow Vs surface area.

To coat the paper I made a graphite paste and worked it in to the surface and a bit of glue to help hold the paper together in the bath.

I would wager one can modify my method by making a pulp slurry with graphite mixed in, mold the cone, then smooth the out side and spray lacquer on the inside to insulate it, this should make a readily dissoluble mold.

XeonTheMGPony - 29-4-2016 at 08:03

Quote: Originally posted by Fulmen

Current density will affect deposit rates.

Exactly, and the distance from the Anode will determine the current density.

You want as even of a distance around the work piece as possible.

for high precision plates I used the rotational method and the bubbling method (I use that with every bath mind you)

Rotational method is the work piece is slowly rotated in the bath, this spreads the errors out over a wider area making it easier to work them out post plate.

The Bubbling keeps the ion concentrations even through out the bath and helps to bring fresh material around the work piece.

The fully clad tank ensures there is an even field of potential around the work piece. It does not have to be sheets either, just a good wire frame will do fine. A length of 14awg ground wire will work great for this, we just need a good even field of potential voltage and an ion donor!

So ideally you want a bowl shaped tanks since you're doing cones!

DO THE MATH!!!!!!!!!!!!!!! with out proper voltage and current your trying to piss into the wind of a tornado! but first you need to do the above as well.