• Thanks for visiting The Penturners Forum today.

    There are many features and resources that currently you are unable to see or access, either because you're not yet registered, or if you're already registered, because you're not logged in.

    To gain full access to the forum, please log in or register now. Registration is completely free, it only takes a few seconds, and you can join our well established community of like-minded pen makers.

A work in progress: Electropolishing

BradG

Full Member
Joined
Aug 4, 2015
Posts
131
Location
Blackpool
First Name
Brad
Very much a test of a new process to me, and rather pleased with the first run.

This is Electropolishing of Aluminium. The first picture shows a rather rough piece of machined aluminium. As you can see, machining marks can still be seen on it.

The second picture shows after a 7 minute process. the reflection is as good as chrome, albeit mottled due to the machining marks. Id imagine if pushed for longer, and tweaking the process this would smooth out quite nicely, though most probably more practical to give it a light sanding while still on the lathe so it's at least smooth to begin with, and of course improve the process with better agitation and even cathodes rather than being one sided.

Quite a learning curve with regards to temperature, agitation, current density, and time frame, but looking good!

My next tests will be on an etched piece to see how well it cleans the base layer of the etch
 

Attachments

  • 20160706_180028_1467826330854_resized.jpg
    20160706_180028_1467826330854_resized.jpg
    52.1 KB · Views: 106
  • 20160706_182726_1467826327815_resized.jpg
    20160706_182726_1467826327815_resized.jpg
    55.4 KB · Views: 104
  • 20160704_174021_1467826334399_resized.jpg
    20160704_174021_1467826334399_resized.jpg
    66.8 KB · Views: 105
  • 20160706_174730_1467826337845_resized.jpg
    20160706_174730_1467826337845_resized.jpg
    48 KB · Views: 104

BradG

Full Member
Joined
Aug 4, 2015
Posts
131
Location
Blackpool
First Name
Brad
it strips most things lol. 85% Phosphoric acid heated to 75'C. I've dissolved a heating element and two airstones so far ruling out what won't work
 

Penpal

Grand Master
Joined
May 26, 2013
Posts
25,340
Location
Canberra AUSTRALIA
First Name
Peter
Cauldron boil and bubble. Brad another first appreciate your sharing. I have been going through a rough pineapple week or so of experimenting, learning myself.

Peter.
 

BradG

Full Member
Joined
Aug 4, 2015
Posts
131
Location
Blackpool
First Name
Brad
Tonight's test:

The left side has been electropolished, right side mechanically. Note the brightness of the cut lines on the left side. That's exactly what im after.. polishing the hard to reach parts normally the sandpaper skips over.

This still wasn't a perfect run as I only electropolished it for 3 minutes instead of 7. Mainly due to putting my thumb on the 240 degree hotplate! soaked my thumb in a jug of cold water for the three minutes before deciding to stop the process and go get a bag of frozen veg to take the pain away :funny:

Made a note not to touch the hot plate again. Stupid man.

I need to build a jig to suspend the piece accurately in the middle, that's tomorrows joy. On a plus side, I made a bubble diffuser out of a section of LDPE pipe which the acid won;t dissolve so im getting much better agitation. Better than dissolving fish tank airstones anyway!

I will persevere
 

Attachments

  • Capture.jpg
    Capture.jpg
    16.1 KB · Views: 13

edlea

Lobbygobbler
Registered
Joined
Aug 1, 2013
Posts
4,693
Location
Blackpool
First Name
Ed
There's a big difference ,Brad even I can see it....... looks like you know what your doing .:thumbs:
 

Penpal

Grand Master
Joined
May 26, 2013
Posts
25,340
Location
Canberra AUSTRALIA
First Name
Peter
Using timber it shows in the under cut surfaces when you finish so good news on metal mate the effect is magical.

Peter.
 
Warning! This thread has not had any replies for over a year. You are welcome to post a reply here, but it might be better to start a new thread (and maybe include a link to this one if you need to).
Top