Author Topic: Electroforming/electrotyping  (Read 3699 times)

Offline sorveltaja

  • Full Member
  • ****
  • Posts: 72
  • Finland
Re: Electroforming/electrotyping
« Reply #30 on: March 02, 2019, 10:09:17 PM »
Crueby, yes, preferably so. I've been looking for commercially made small pumps, but the specs about their construction materials like valves etc., are always quite sparse. 

Offline steam guy willy

  • Full Member
  • ****
  • Posts: 2090
Re: Electroforming/electrotyping
« Reply #31 on: March 03, 2019, 02:47:15 PM »
Hi All when i used to do stuff with electronics and bought IC's through the post, they always attached them to conducting soft rubbery type of flat stuff that would prevent stray electrical pulses frying them. I had thought of using this materiel for making formers for electro forming applications but never did !! just an idea and one of many that floats around in my brain ??!!!

Willy

Offline sorveltaja

  • Full Member
  • ****
  • Posts: 72
  • Finland
Re: Electroforming/electrotyping
« Reply #32 on: March 03, 2019, 08:49:45 PM »
Willy, any ideas, what the conductive material embedded in the rubber might be? Quick look at the wikipedia proposes carbon: https://en.wikipedia.org/wiki/Conductive_elastomer

It just popped to my mind, that the silicone, which is used to make a mold, could be made conductive, by mixing graphite powder to it. But not necessarily to whole batch of silicone, only small portion of it,
which could then be brushed or otherwise applied as a first, thin layer to provide conductivity. After that, plain silicone is applied to fill the rest of the mold.

Not sure though, how the graphite(and conductivity) of the first layer lasts, if the mold is used more than once. 

Offline steam guy willy

  • Full Member
  • ****
  • Posts: 2090
Re: Electroforming/electrotyping
« Reply #33 on: March 03, 2019, 11:21:31 PM »
lots of room for some
R&D here....

Willy

Offline sorveltaja

  • Full Member
  • ****
  • Posts: 72
  • Finland
Re: Electroforming/electrotyping
« Reply #34 on: March 08, 2019, 07:46:22 PM »
Very much of an off-topic, but the 3d-printer, that I ordered, has finally arrived. First test object, that is on the print, is a part of the primitive diaphragm pump for agitation, that I had to design throw together, because there doesn't seem to be any drawings available on the net.

The ones, that I've found, from Grabcad and Thingiverse, are basically empty outer shells.

To put that aside, the sound of the printer reminds me of the Cylon of the Battlestar Galactica

Offline sorveltaja

  • Full Member
  • ****
  • Posts: 72
  • Finland
Re: Electroforming/electrotyping
« Reply #35 on: March 13, 2019, 08:37:31 PM »
An update: today I tested diaphragm pump, but it needs more tweaking, and maybe some new parts to get it to work. It uses flap valves, which I think are the problem.
It sounds like it has a 'hiccup', when running it, making the flow through it quite lacking:
   

I'm eagerly waiting to get back to electroforming, but some kind of enhanced agitation of electrolyte is a must to get any further.
Be it in a form of air bubbles, or using 'random flow generator' -eductors, can't tell yet.

At the moment I'm about to try out a centrifugal pump, that I found from Thingiverse. With it, there are no valves to worry about, but instead, keeping it watertight may cause problems.
Also, it might need some metal parts, which are exposed to electrolyte. Stainless steel is hopefully inert enough for that purpose.

 

Offline sorveltaja

  • Full Member
  • ****
  • Posts: 72
  • Finland
Re: Electroforming/electrotyping
« Reply #36 on: March 20, 2019, 08:34:57 PM »
Another update: I left the centrifugal pump aside, when I found a 3d-model of a dual diaphragm pump: https://grabcad.com/library/long-life-water-pump-1
Must be one of the very few 3d-models online, that actually includes inner parts too.

I've done some changes to the model, like replacing the magnetic drive with a scotch yoke. The electric motor, that I happen to have, has a suitable bracket to fit to the pump body:


Valves are still bit of a question mark. Might have to test different ones. Haven't been able to source small glass balls for that, so I'm going to use 0,5mm thick rubber sheet instead.

And that requires making 'one of a kind' -punches for the job. And that requires lathe and some more tools... So I had to dig out the lathe and some more tools, also for machining 3d-printed surfaces
to fit better together. Lathe and mill sits happily on the floor, where they have enough room:


So that's why the original subject, electroforming, has grown enormous amount of branches.


 

Offline Ian S C

  • Full Member
  • ****
  • Posts: 1032
  • Stirling Engine Maker Darfield Canterbury N Z
Re: Electroforming/electrotyping
« Reply #37 on: March 21, 2019, 01:14:39 AM »
Small glass ball, some aerosol spray paint cans use glass ball as mixer thingies, can't remember the size.
Ian S C

Online modeng2000

  • Full Member
  • ****
  • Posts: 46
Re: Electroforming/electrotyping
« Reply #38 on: March 21, 2019, 06:41:39 AM »
Hand wash pump bottles have a small glass/plascic ball in the pump.

Offline sorveltaja

  • Full Member
  • ****
  • Posts: 72
  • Finland
Re: Electroforming/electrotyping
« Reply #39 on: March 21, 2019, 10:30:21 PM »
Thanks for the tips, guys.

What comes to electroplating, there is an alternative recipe, besides traditional 'copper sulfate and sulfuric acid' one. Here is Richard Lacey's patent: https://patents.google.com/patent/US7235165B2/en

Recipe consist of 32g oxalic acid, 10g trisodium phosphate, 4g ammonium sulfate, and 950ml (distilled) water. From what I understand, after reading the patent, that solution isn't "metal specific", as it doesn't
contain any metal salts.

So I had to get the required ingredients. But not so much of a surprise, that in my country, they don't sell any of that stuff to consumers. I ended up ordering them from UK.

So far, I have done only very basic tests with that recipe on copper some time ago, before I got the adjustable bench power supply.

Once I get that pump/agitation -thing sorted out, there should be whole new territories to explore.

Offline Ian S C

  • Full Member
  • ****
  • Posts: 1032
  • Stirling Engine Maker Darfield Canterbury N Z
Re: Electroforming/electrotyping
« Reply #40 on: March 22, 2019, 02:10:26 AM »
Small fish tank air pumps are quite good for agitating fluid baths such as citric asid for copper, or alum fue getting broken taps out of brass. There is enough movement of water set up to keep hings going with even the smallest pump.
Ian S C

Offline sorveltaja

  • Full Member
  • ****
  • Posts: 72
  • Finland
Re: Electroforming/electrotyping
« Reply #41 on: March 23, 2019, 09:27:41 PM »
Ian, thanks, that's actually my plan B, if all else fails. But I just have to try out the ''diy options" first. Cant't help it. 

I managed to construct the dual diaphragm pump, but oh boy that thing is one noisy bugger. Sounds like an air compressor.

So I got back to centrifugal pump. Today I tested magnetic coupling, with some 10mm diam. neodymium button magnets, but not enough drive force. Putting a hard drive magnet to the motor side
increased the traction as was expected. Next step is to test it with water. It has two stainless steel parts in the pump chamber, that are to be exposed to the liquid.

If all goes well, I should be able to put it to use in couple of days, to feed eductor(s), or some other 'random flow generator'.

Offline sorveltaja

  • Full Member
  • ****
  • Posts: 72
  • Finland
Re: Electroforming/electrotyping
« Reply #42 on: March 25, 2019, 11:41:02 PM »
Again an update: centrifugal pump is on the test run. There was a numerous fixes I had to make it to work though, because I didn't consider the design carefully enough.

This is the current, and also the first version, running at 10V/~1600rpm:


I'll let it run overnight to make sure there are no leaking or other issues. After that, finally back to electroforming.

 

Offline Ian S C

  • Full Member
  • ****
  • Posts: 1032
  • Stirling Engine Maker Darfield Canterbury N Z
Re: Electroforming/electrotyping
« Reply #43 on: March 26, 2019, 01:11:24 AM »
I made a bath for etching small circuit boards in, and under it I made a rocking device poweredby a little geared motor, can't remember the speed, probably about 20rpm. the tray the bath sat on moved about 1/4".
Ian S C

Offline sorveltaja

  • Full Member
  • ****
  • Posts: 72
  • Finland
Re: Electroforming/electrotyping
« Reply #44 on: March 28, 2019, 12:26:29 AM »
Ian, yes, that is one possible way to provide agitation. When etching, it might also help, if enough straight flow is provided to the surface, to make the copper removal even faster.

Not sure about how the agitation fits for etching, as it is an inverse process to electroforming. Maybe worth testing?